src/Unix/main_unix.cpp

/*
 *  main_unix.cpp - Emulation core, Unix implementation
 *
 *  SheepShaver (C) 1997-2002 Christian Bauer and Marc Hellwig
 *
 *  This program is free software; you can redistribute it and/or modify
 *  it under the terms of the GNU General Public License as published by
 *  the Free Software Foundation; either version 2 of the License, or
 *  (at your option) any later version.
 *
 *  This program is distributed in the hope that it will be useful,
 *  but WITHOUT ANY WARRANTY; without even the implied warranty of
 *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 *  GNU General Public License for more details.
 *
 *  You should have received a copy of the GNU General Public License
 *  along with this program; if not, write to the Free Software
 *  Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
 */

/*
 *  NOTES:
 *
 *  See main_beos.cpp for a description of the three operating modes.
 *
 *  In addition to that, we have to handle the fact that the MacOS ABI
 *  is slightly different from the SysV ABI used by Linux:
 *    - Stack frames are different (e.g. LR is stored in 8(r1) under
 *      MacOS, but in 4(r1) under Linux)
 *    - There is no TOC under Linux; r2 is free for the user
 *    - r13 is used as a small data pointer under Linux (but appearently
 *      it is not used this way? To be sure, we specify -msdata=none
 *      in the Makefile)
 *    - As there is no TOC, there are also no TVECTs under Linux;
 *      function pointers point directly to the function code
 *  The Execute*() functions have to account for this. Additionally, we
 *  cannot simply call MacOS functions by getting their TVECT and jumping
 *  to it. Such calls are done via the call_macos*() functions in
 *  asm_linux.S that create a MacOS stack frame, load the TOC pointer
 *  and put the arguments into the right registers.
 *
 *  As on the BeOS, we have to specify an alternate signal stack because
 *  interrupts (and, under Linux, Low Memory accesses) may occur when r1
 *  is pointing to the Kernel Data or to Low Memory. There is one
 *  problem, however, due to the alternate signal stack being global to
 *  all signal handlers. Consider the following scenario:
 *    - The main thread is executing some native PPC MacOS code in
 *      MODE_NATIVE, running on the MacOS stack (somewhere in the Mac RAM).
 *    - A SIGUSR2 interrupt occurs. The kernel switches to the signal
 *      stack and starts executing the SIGUSR2 signal handler.
 *    - The signal handler sees the MODE_NATIVE and calls ppc_interrupt()
 *      to handle a native interrupt.
 *    - ppc_interrupt() sets r1 to point to the Kernel Data and jumps to
 *      the nanokernel.
 *    - The nanokernel accesses a Low Memory global (most likely one of
 *      the XLMs), a SIGSEGV occurs.
 *    - The kernel sees that r1 does not point to the signal stack and
 *      switches to the signal stack again, thus overwriting the data that
 *      the SIGUSR2 handler put there.
 *  The same problem arises when calling ExecutePPC() inside the MODE_EMUL_OP
 *  interrupt handler.
 *
 *  The solution is to set the signal stack to a second, "extra" stack
 *  inside the SIGUSR2 handler before entering the Nanokernel or calling
 *  ExecutePPC (or any function that might cause a mode switch). The signal
 *  stack is restored before exiting the SIGUSR2 handler.
 *
 *  TODO:
 *    check if SIGSEGV handler works for all registers (including FP!)
 */

#include <unistd.h>
#include <fcntl.h>
#include <time.h>
#include <errno.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <pthread.h>
#include <sys/mman.h>
#include <sys/ipc.h>
#include <sys/shm.h>
#include <signal.h>

#include "sysdeps.h"
#include "main.h"
#include "version.h"
#include "prefs.h"
#include "prefs_editor.h"
#include "cpu_emulation.h"
#include "emul_op.h"
#include "xlowmem.h"
#include "xpram.h"
#include "timer.h"
#include "adb.h"
#include "sony.h"
#include "disk.h"
#include "cdrom.h"
#include "scsi.h"
#include "video.h"
#include "audio.h"
#include "ether.h"
#include "serial.h"
#include "clip.h"
#include "extfs.h"
#include "sys.h"
#include "macos_util.h"
#include "rom_patches.h"
#include "user_strings.h"
#include "vm_alloc.h"
#include "sigsegv.h"
#include "thunks.h"

#define DEBUG 0
#include "debug.h"


#include <X11/Xlib.h>

#ifdef ENABLE_GTK
#include <gtk/gtk.h>
#endif

#ifdef ENABLE_XF86_DGA
#include <X11/Xlib.h>
#include <X11/Xutil.h>
#include <X11/extensions/xf86dga.h>
#endif

#ifdef ENABLE_MON
#include "mon.h"
#endif


// Enable Execute68k() safety checks?
#define SAFE_EXEC_68K 0

// Interrupts in EMUL_OP mode?
#define INTERRUPTS_IN_EMUL_OP_MODE 1

// Interrupts in native mode?
#define INTERRUPTS_IN_NATIVE_MODE 1


// Constants
const char ROM_FILE_NAME[] = "ROM";
const char ROM_FILE_NAME2[] = "Mac OS ROM";

const uintptr RAM_BASE = 0x20000000;            // Base address of RAM
const uint32 SIG_STACK_SIZE = 0x10000;          // Size of signal stack


#if !EMULATED_PPC
// Structure in which registers are saved in a signal handler;
// sigcontext->regs points to it
// (see arch/ppc/kernel/signal.c)
typedef struct {
        uint32 u[4];
} __attribute((aligned(16))) vector128;
#include <linux/elf.h>

struct sigregs {
        elf_gregset_t   gp_regs;                                // Identical to pt_regs
        double                  fp_regs[ELF_NFPREG];    // f0..f31 and fpsrc
        //more (uninteresting) stuff following here
};
#endif


// Global variables (exported)
#if !EMULATED_PPC
void *TOC;                              // Small data pointer (r13)
#endif
uint32 RAMBase;                 // Base address of Mac RAM
uint32 RAMSize;                 // Size of Mac RAM
uint32 KernelDataAddr;  // Address of Kernel Data
uint32 BootGlobsAddr;   // Address of BootGlobs structure at top of Mac RAM
uint32 PVR;                             // Theoretical PVR
int64 CPUClockSpeed;    // Processor clock speed (Hz)
int64 BusClockSpeed;    // Bus clock speed (Hz)


// Global variables
char *x_display_name = NULL;                            // X11 display name
Display *x_display = NULL;                                      // X11 display handle

static int zero_fd = 0;                                         // FD of /dev/zero
static bool lm_area_mapped = false;                     // Flag: Low Memory area mmap()ped
static int kernel_area = -1;                            // SHM ID of Kernel Data area
static bool rom_area_mapped = false;            // Flag: Mac ROM mmap()ped
static bool ram_area_mapped = false;            // Flag: Mac RAM mmap()ped
static KernelData *kernel_data;                         // Pointer to Kernel Data
static EmulatorData *emulator_data;

static uint8 last_xpram[XPRAM_SIZE];            // Buffer for monitoring XPRAM changes

static bool nvram_thread_active = false;        // Flag: NVRAM watchdog installed
static pthread_t nvram_thread;                          // NVRAM watchdog
static bool tick_thread_active = false;         // Flag: MacOS thread installed
static pthread_t tick_thread;                           // 60Hz thread
static pthread_t emul_thread;                           // MacOS thread

static bool ready_for_signals = false;          // Handler installed, signals can be sent
static int64 num_segv = 0;                                      // Number of handled SEGV signals

static struct sigaction sigusr2_action;         // Interrupt signal (of emulator thread)
#if !EMULATED_PPC
static struct sigaction sigsegv_action;         // Data access exception signal (of emulator thread)
static struct sigaction sigill_action;          // Illegal instruction signal (of emulator thread)
static void *sig_stack = NULL;                          // Stack for signal handlers
static void *extra_stack = NULL;                        // Stack for SIGSEGV inside interrupt handler
static bool emul_thread_fatal = false;          // Flag: MacOS thread crashed, tick thread shall dump debug output
static sigregs sigsegv_regs;                            // Register dump when crashed
#endif

uintptr SheepMem::base = 0x60000000;            // Address of SheepShaver data
uintptr SheepMem::top = 0;                                      // Top of SheepShaver data (stack like storage)


// Prototypes
static void Quit(void);
static void *emul_func(void *arg);
static void *nvram_func(void *arg);
static void *tick_func(void *arg);
#if EMULATED_PPC
static void sigusr2_handler(int sig);
extern void emul_ppc(uint32 start);
extern void init_emul_ppc(void);
extern void exit_emul_ppc(void);
#else
static void sigusr2_handler(int sig, sigcontext_struct *sc);
static void sigsegv_handler(int sig, sigcontext_struct *sc);
static void sigill_handler(int sig, sigcontext_struct *sc);
#endif


// From asm_linux.S
#if !EMULATED_PPC
extern "C" void *get_toc(void);
extern "C" void *get_sp(void);
extern "C" void flush_icache_range(void *start, void *end);
extern "C" void jump_to_rom(uint32 entry, uint32 context);
extern "C" void quit_emulator(void);
extern "C" void execute_68k(uint32 pc, M68kRegisters *r);
extern "C" void ppc_interrupt(uint32 entry, uint32 kernel_data);
extern "C" int atomic_add(int *var, int v);
extern "C" int atomic_and(int *var, int v);
extern "C" int atomic_or(int *var, int v);
extern void paranoia_check(void);
#endif


#if EMULATED_PPC
/*
 *  Atomic operations
 */

#if HAVE_SPINLOCKS
static spinlock_t atomic_ops_lock = SPIN_LOCK_UNLOCKED;
#else
#define spin_lock(LOCK)
#define spin_unlock(LOCK)
#endif

int atomic_add(int *var, int v)
{
        spin_lock(&atomic_ops_lock);
        int ret = *var;
        *var += v;
        spin_unlock(&atomic_ops_lock);
        return ret;
}

int atomic_and(int *var, int v)
{
        spin_lock(&atomic_ops_lock);
        int ret = *var;
        *var &= v;
        spin_unlock(&atomic_ops_lock);
        return ret;
}

int atomic_or(int *var, int v)
{
        spin_lock(&atomic_ops_lock);
        int ret = *var;
        *var |= v;
        spin_unlock(&atomic_ops_lock);
        return ret;
}
#endif


/*
 *  Main program
 */

static void usage(const char *prg_name)
{
        printf("Usage: %s [OPTION...]\n", prg_name);
        printf("\nUnix options:\n");
        printf("  --display STRING\n    X display to use\n");
        PrefsPrintUsage();
        exit(0);
}

int main(int argc, char **argv)
{
        char str[256];
        uint32 *boot_globs;
        int16 i16;
        int rom_fd;
        FILE *proc_file;
        const char *rom_path;
        uint32 rom_size, actual;
        uint8 *rom_tmp;
        time_t now, expire;

        // Initialize variables
        RAMBase = 0;
        tzset();

        // Print some info
        printf(GetString(STR_ABOUT_TEXT1), VERSION_MAJOR, VERSION_MINOR);
        printf(" %s\n", GetString(STR_ABOUT_TEXT2));

#if !EMULATED_PPC
        // Get TOC pointer
        TOC = get_toc();
#endif

#ifdef ENABLE_GTK
        // Init GTK
        gtk_set_locale();
        gtk_init(&argc, &argv);
#endif

        // Read preferences
        PrefsInit(argc, argv);

        // Parse command line arguments
        for (int i=1; i<argc; i++) {
                if (strcmp(argv[i], "--help") == 0) {
                        usage(argv[0]);
                } else if (strcmp(argv[i], "--display") == 0) {
                        i++;
                        if (i < argc)
                                x_display_name = strdup(argv[i]);
                } else if (argv[i][0] == '-') {
                        fprintf(stderr, "Unrecognized option '%s'\n", argv[i]);
                        usage(argv[0]);
                }
        }

        // Open display
        x_display = XOpenDisplay(x_display_name);
        if (x_display == NULL) {
                char str[256];
                sprintf(str, GetString(STR_NO_XSERVER_ERR), XDisplayName(x_display_name));
                ErrorAlert(str);
                goto quit;
        }

#if defined(ENABLE_XF86_DGA) && !defined(ENABLE_MON)
        // Fork out, so we can return from fullscreen mode when things get ugly
        XF86DGAForkApp(DefaultScreen(x_display));
#endif

#ifdef ENABLE_MON
        // Initialize mon
        mon_init();
#endif

        // Get system info
        PVR = 0x00040000;                       // Default: 604
        CPUClockSpeed = 100000000;      // Default: 100MHz
        BusClockSpeed = 100000000;      // Default: 100MHz
#if !EMULATED_PPC
        proc_file = fopen("/proc/cpuinfo", "r");
        if (proc_file) {
                char line[256];
                while(fgets(line, 255, proc_file)) {
                        // Read line
                        int len = strlen(line);
                        if (len == 0)
                                continue;
                        line[len-1] = 0;

                        // Parse line
                        int i;
                        char value[256];
                        if (sscanf(line, "cpu : %s", value) == 1) {
                                if (strcmp(value, "601") == 0)
                                        PVR = 0x00010000;
                                else if (strcmp(value, "603") == 0)
                                        PVR = 0x00030000;
                                else if (strcmp(value, "604") == 0)
                                        PVR = 0x00040000;
                                else if (strcmp(value, "603e") == 0)
                                        PVR = 0x00060000;
                                else if (strcmp(value, "603ev") == 0)
                                        PVR = 0x00070000;
                                else if (strcmp(value, "604e") == 0)
                                        PVR = 0x00090000;
                                else if (strcmp(value, "604ev5") == 0)
                                        PVR = 0x000a0000;
                                else if (strcmp(value, "750") == 0)
                                        PVR = 0x00080000;
                                else if (strcmp(value, "821") == 0)
                                        PVR = 0x00320000;
                                else if (strcmp(value, "860") == 0)
                                        PVR = 0x00500000;
                                else
                                        printf("WARNING: Unknown CPU type '%s', assuming 604\n", value);
                        }
                        if (sscanf(line, "clock : %dMHz", &i) == 1)
                                CPUClockSpeed = BusClockSpeed = i * 1000000;
                }
                fclose(proc_file);
        } else {
                sprintf(str, GetString(STR_PROC_CPUINFO_WARN), strerror(errno));
                WarningAlert(str);
        }
#endif
        D(bug("PVR: %08x (assumed)\n", PVR));

        // Init system routines
        SysInit();

        // Show preferences editor
        if (!PrefsFindBool("nogui"))
                if (!PrefsEditor())
                        goto quit;

#if !EMULATED_PPC
        // Check some things
        paranoia_check();
#endif

        // Open /dev/zero
        zero_fd = open("/dev/zero", O_RDWR);
        if (zero_fd < 0) {
                sprintf(str, GetString(STR_NO_DEV_ZERO_ERR), strerror(errno));
                ErrorAlert(str);
                goto quit;
        }

        // Create Low Memory area (0x0000..0x3000)
        if (vm_acquire_fixed((char *)0, 0x3000) < 0) {
                sprintf(str, GetString(STR_LOW_MEM_MMAP_ERR), strerror(errno));
                ErrorAlert(str);
                goto quit;
        }
        lm_area_mapped = true;

        // Create areas for Kernel Data
        kernel_area = shmget(IPC_PRIVATE, KERNEL_AREA_SIZE, 0600);
        if (kernel_area == -1) {
                sprintf(str, GetString(STR_KD_SHMGET_ERR), strerror(errno));
                ErrorAlert(str);
                goto quit;
        }
        if (shmat(kernel_area, (void *)KERNEL_DATA_BASE, 0) < 0) {
                sprintf(str, GetString(STR_KD_SHMAT_ERR), strerror(errno));
                ErrorAlert(str);
                goto quit;
        }
        if (shmat(kernel_area, (void *)KERNEL_DATA2_BASE, 0) < 0) {
                sprintf(str, GetString(STR_KD2_SHMAT_ERR), strerror(errno));
                ErrorAlert(str);
                goto quit;
        }
        kernel_data = (KernelData *)KERNEL_DATA_BASE;
        emulator_data = &kernel_data->ed;
        KernelDataAddr = KERNEL_DATA_BASE;
        D(bug("Kernel Data at %p, Emulator Data at %p\n", kernel_data, emulator_data));

        // Create area for SheepShaver data
        if (!SheepMem::Init()) {
                sprintf(str, GetString(STR_SHEEP_MEM_MMAP_ERR), strerror(errno));
                ErrorAlert(str);
                goto quit;
        }

        // Create area for Mac ROM
        if (vm_acquire_fixed((char *)ROM_BASE, ROM_AREA_SIZE) < 0) {
                sprintf(str, GetString(STR_ROM_MMAP_ERR), strerror(errno));
                ErrorAlert(str);
                goto quit;
        }
#if !EMULATED_PPC || defined(__powerpc__)
        if (vm_protect((char *)ROM_BASE, ROM_AREA_SIZE, VM_PAGE_READ | VM_PAGE_WRITE | VM_PAGE_EXECUTE) < 0) {
                sprintf(str, GetString(STR_ROM_MMAP_ERR), strerror(errno));
                ErrorAlert(str);
                goto quit;
        }
#endif
        rom_area_mapped = true;
        D(bug("ROM area at %08x\n", ROM_BASE));

        // Create area for Mac RAM
        RAMSize = PrefsFindInt32("ramsize");
        if (RAMSize < 8*1024*1024) {
                WarningAlert(GetString(STR_SMALL_RAM_WARN));
                RAMSize = 8*1024*1024;
        }

        if (vm_acquire_fixed((char *)RAM_BASE, RAMSize) < 0) {
                sprintf(str, GetString(STR_RAM_MMAP_ERR), strerror(errno));
                ErrorAlert(str);
                goto quit;
        }
#if !EMULATED_PPC
        if (vm_protect((char *)RAM_BASE, RAMSize, VM_PAGE_READ | VM_PAGE_WRITE | VM_PAGE_EXECUTE) < 0) {
                sprintf(str, GetString(STR_RAM_MMAP_ERR), strerror(errno));
                ErrorAlert(str);
                goto quit;
        }
#endif
        RAMBase = RAM_BASE;
        ram_area_mapped = true;
        D(bug("RAM area at %08x\n", RAMBase));

        if (RAMBase > ROM_BASE) {
                ErrorAlert(GetString(STR_RAM_HIGHER_THAN_ROM_ERR));
                goto quit;
        }

        // Load Mac ROM
        rom_path = PrefsFindString("rom");
        rom_fd = open(rom_path ? rom_path : ROM_FILE_NAME, O_RDONLY);
        if (rom_fd < 0) {
                rom_fd = open(rom_path ? rom_path : ROM_FILE_NAME2, O_RDONLY);
                if (rom_fd < 0) {
                        ErrorAlert(GetString(STR_NO_ROM_FILE_ERR));
                        goto quit;
                }
        }
        printf(GetString(STR_READING_ROM_FILE));
        rom_size = lseek(rom_fd, 0, SEEK_END);
        lseek(rom_fd, 0, SEEK_SET);
        rom_tmp = new uint8[ROM_SIZE];
        actual = read(rom_fd, (void *)rom_tmp, ROM_SIZE);
        close(rom_fd);
        
        // Decode Mac ROM
        if (!DecodeROM(rom_tmp, actual)) {
                if (rom_size != 4*1024*1024) {
                        ErrorAlert(GetString(STR_ROM_SIZE_ERR));
                        goto quit;
                } else {
                        ErrorAlert(GetString(STR_ROM_FILE_READ_ERR));
                        goto quit;
                }
        }
        delete[] rom_tmp;

        // Load NVRAM
        XPRAMInit();

        // Set boot volume
        i16 = PrefsFindInt32("bootdrive");
        XPRAM[0x1378] = i16 >> 8;
        XPRAM[0x1379] = i16 & 0xff;
        i16 = PrefsFindInt32("bootdriver");
        XPRAM[0x137a] = i16 >> 8;
        XPRAM[0x137b] = i16 & 0xff;

        // Create BootGlobs at top of Mac memory
        memset((void *)(RAMBase + RAMSize - 4096), 0, 4096);
        BootGlobsAddr = RAMBase + RAMSize - 0x1c;
        boot_globs = (uint32 *)BootGlobsAddr;
        boot_globs[-5] = htonl(RAMBase + RAMSize);      // MemTop
        boot_globs[0] = htonl(RAMBase);                         // First RAM bank
        boot_globs[1] = htonl(RAMSize);
        boot_globs[2] = htonl((uint32)-1);                      // End of bank table

        // Init thunks
        if (!ThunksInit())
                goto quit;

        // Init drivers
        SonyInit();
        DiskInit();
        CDROMInit();
        SCSIInit();

        // Init external file system
        ExtFSInit(); 

        // Init audio
        AudioInit();

        // Init network
        EtherInit();

        // Init serial ports
        SerialInit();

        // Init Time Manager
        TimerInit();

        // Init clipboard
        ClipInit();

        // Init video
        if (!VideoInit())
                goto quit;

        // Install ROM patches
        if (!PatchROM()) {
                ErrorAlert(GetString(STR_UNSUPPORTED_ROM_TYPE_ERR));
                goto quit;
        }

        // Clear caches (as we loaded and patched code) and write protect ROM
#if !EMULATED_PPC
        MakeExecutable(0, (void *)ROM_BASE, ROM_AREA_SIZE);
#endif
        vm_protect((char *)ROM_BASE, ROM_AREA_SIZE, VM_PAGE_READ | VM_PAGE_EXECUTE);

        // Initialize Kernel Data
        memset(kernel_data, 0, sizeof(KernelData));
        if (ROMType == ROMTYPE_NEWWORLD) {
                uintptr of_dev_tree = SheepMem::Reserve(4 * sizeof(uint32));
                memset((void *)of_dev_tree, 0, 4 * sizeof(uint32));
                uintptr vector_lookup_tbl = SheepMem::Reserve(128);
                uintptr vector_mask_tbl = SheepMem::Reserve(64);
                memset((uint8 *)kernel_data + 0xb80, 0x3d, 0x80);
                memset((void *)vector_lookup_tbl, 0, 128);
                memset((void *)vector_mask_tbl, 0, 64);
                kernel_data->v[0xb80 >> 2] = htonl(ROM_BASE);
                kernel_data->v[0xb84 >> 2] = htonl(of_dev_tree);                        // OF device tree base
                kernel_data->v[0xb90 >> 2] = htonl(vector_lookup_tbl);
                kernel_data->v[0xb94 >> 2] = htonl(vector_mask_tbl);
                kernel_data->v[0xb98 >> 2] = htonl(ROM_BASE);                           // OpenPIC base
                kernel_data->v[0xbb0 >> 2] = htonl(0);                                          // ADB base
                kernel_data->v[0xc20 >> 2] = htonl(RAMSize);
                kernel_data->v[0xc24 >> 2] = htonl(RAMSize);
                kernel_data->v[0xc30 >> 2] = htonl(RAMSize);
                kernel_data->v[0xc34 >> 2] = htonl(RAMSize);
                kernel_data->v[0xc38 >> 2] = htonl(0x00010020);
                kernel_data->v[0xc3c >> 2] = htonl(0x00200001);
                kernel_data->v[0xc40 >> 2] = htonl(0x00010000);
                kernel_data->v[0xc50 >> 2] = htonl(RAMBase);
                kernel_data->v[0xc54 >> 2] = htonl(RAMSize);
                kernel_data->v[0xf60 >> 2] = htonl(PVR);
                kernel_data->v[0xf64 >> 2] = htonl(CPUClockSpeed);
                kernel_data->v[0xf68 >> 2] = htonl(BusClockSpeed);
                kernel_data->v[0xf6c >> 2] = htonl(CPUClockSpeed);
        } else {
                kernel_data->v[0xc80 >> 2] = htonl(RAMSize);
                kernel_data->v[0xc84 >> 2] = htonl(RAMSize);
                kernel_data->v[0xc90 >> 2] = htonl(RAMSize);
                kernel_data->v[0xc94 >> 2] = htonl(RAMSize);
                kernel_data->v[0xc98 >> 2] = htonl(0x00010020);
                kernel_data->v[0xc9c >> 2] = htonl(0x00200001);
                kernel_data->v[0xca0 >> 2] = htonl(0x00010000);
                kernel_data->v[0xcb0 >> 2] = htonl(RAMBase);
                kernel_data->v[0xcb4 >> 2] = htonl(RAMSize);
                kernel_data->v[0xf80 >> 2] = htonl(PVR);
                kernel_data->v[0xf84 >> 2] = htonl(CPUClockSpeed);
                kernel_data->v[0xf88 >> 2] = htonl(BusClockSpeed);
                kernel_data->v[0xf8c >> 2] = htonl(CPUClockSpeed);
        }

        // Initialize extra low memory
        D(bug("Initializing Low Memory...\n"));
        memset(NULL, 0, 0x3000);
        WriteMacInt32(XLM_SIGNATURE, FOURCC('B','a','a','h'));                  // Signature to detect SheepShaver
        WriteMacInt32(XLM_KERNEL_DATA, KernelDataAddr);                                 // For trap replacement routines
        WriteMacInt32(XLM_PVR, PVR);                                                                    // Theoretical PVR
        WriteMacInt32(XLM_BUS_CLOCK, BusClockSpeed);                                    // For DriverServicesLib patch
        WriteMacInt16(XLM_EXEC_RETURN_OPCODE, M68K_EXEC_RETURN);                // For Execute68k() (RTS from the executed 68k code will jump here and end 68k mode)
#if EMULATED_PPC
        WriteMacInt32(XLM_ETHER_INIT, NativeFunction(NATIVE_ETHER_INIT));
        WriteMacInt32(XLM_ETHER_TERM, NativeFunction(NATIVE_ETHER_TERM));
        WriteMacInt32(XLM_ETHER_OPEN, NativeFunction(NATIVE_ETHER_OPEN));
        WriteMacInt32(XLM_ETHER_CLOSE, NativeFunction(NATIVE_ETHER_CLOSE));
        WriteMacInt32(XLM_ETHER_WPUT, NativeFunction(NATIVE_ETHER_WPUT));
        WriteMacInt32(XLM_ETHER_RSRV, NativeFunction(NATIVE_ETHER_RSRV));
        WriteMacInt32(XLM_VIDEO_DOIO, NativeFunction(NATIVE_VIDEO_DO_DRIVER_IO));
#else
        WriteMacInt32(XLM_TOC, (uint32)TOC);                                                    // TOC pointer of emulator
        WriteMacInt32(XLM_ETHER_INIT, (uint32)InitStreamModule);                // DLPI ethernet driver functions
        WriteMacInt32(XLM_ETHER_TERM, (uint32)TerminateStreamModule);
        WriteMacInt32(XLM_ETHER_OPEN, (uint32)ether_open);
        WriteMacInt32(XLM_ETHER_CLOSE, (uint32)ether_close);
        WriteMacInt32(XLM_ETHER_WPUT, (uint32)ether_wput);
        WriteMacInt32(XLM_ETHER_RSRV, (uint32)ether_rsrv);
        WriteMacInt32(XLM_VIDEO_DOIO, (uint32)VideoDoDriverIO);
#endif
        D(bug("Low Memory initialized\n"));

        // Start 60Hz thread
        tick_thread_active = (pthread_create(&tick_thread, NULL, tick_func, NULL) == 0);
        D(bug("Tick thread installed (%ld)\n", tick_thread));

        // Start NVRAM watchdog thread
        memcpy(last_xpram, XPRAM, XPRAM_SIZE);
        nvram_thread_active = (pthread_create(&nvram_thread, NULL, nvram_func, NULL) == 0);
        D(bug("NVRAM thread installed (%ld)\n", nvram_thread));

#if !EMULATED_PPC
        // Create and install stacks for signal handlers
        sig_stack = malloc(SIG_STACK_SIZE);
        D(bug("Signal stack at %p\n", sig_stack));
        if (sig_stack == NULL) {
                ErrorAlert(GetString(STR_NOT_ENOUGH_MEMORY_ERR));
                goto quit;
        }
        extra_stack = malloc(SIG_STACK_SIZE);
        D(bug("Extra stack at %p\n", extra_stack));
        if (extra_stack == NULL) {
                ErrorAlert(GetString(STR_NOT_ENOUGH_MEMORY_ERR));
                goto quit;
        }
        struct sigaltstack new_stack;
        new_stack.ss_sp = sig_stack;
        new_stack.ss_flags = 0;
        new_stack.ss_size = SIG_STACK_SIZE;
        if (sigaltstack(&new_stack, NULL) < 0) {
                sprintf(str, GetString(STR_SIGALTSTACK_ERR), strerror(errno));
                ErrorAlert(str);
                goto quit;
        }
#endif

#if !EMULATED_PPC
        // Install SIGSEGV handler
        sigemptyset(&sigsegv_action.sa_mask);   // Block interrupts during SEGV handling
        sigaddset(&sigsegv_action.sa_mask, SIGUSR2);
        sigsegv_action.sa_handler = (__sighandler_t)sigsegv_handler;
        sigsegv_action.sa_flags = SA_ONSTACK;
        sigsegv_action.sa_restorer = NULL;
        if (sigaction(SIGSEGV, &sigsegv_action, NULL) < 0) {
                sprintf(str, GetString(STR_SIGSEGV_INSTALL_ERR), strerror(errno));
                ErrorAlert(str);
                goto quit;
        }

        // Install SIGILL handler
        sigemptyset(&sigill_action.sa_mask);    // Block interrupts during ILL handling
        sigaddset(&sigill_action.sa_mask, SIGUSR2);
        sigill_action.sa_handler = (__sighandler_t)sigill_handler;
        sigill_action.sa_flags = SA_ONSTACK;
        sigill_action.sa_restorer = NULL;
        if (sigaction(SIGILL, &sigill_action, NULL) < 0) {
                sprintf(str, GetString(STR_SIGILL_INSTALL_ERR), strerror(errno));
                ErrorAlert(str);
                goto quit;
        }
#endif

        // Install interrupt signal handler
        sigemptyset(&sigusr2_action.sa_mask);
        sigusr2_action.sa_handler = (__sighandler_t)sigusr2_handler;
        sigusr2_action.sa_flags = 0;
#if !EMULATED_PPC
        sigusr2_action.sa_flags = SA_ONSTACK | SA_RESTART;
#endif
        sigusr2_action.sa_restorer = NULL;
        if (sigaction(SIGUSR2, &sigusr2_action, NULL) < 0) {
                sprintf(str, GetString(STR_SIGUSR2_INSTALL_ERR), strerror(errno));
                ErrorAlert(str);
                goto quit;
        }

        // Get my thread ID and execute MacOS thread function
        emul_thread = pthread_self();
        D(bug("MacOS thread is %ld\n", emul_thread));
        emul_func(NULL);

quit:
        Quit();
        return 0;
}


/*
 *  Cleanup and quit
 */

static void Quit(void)
{
#if EMULATED_PPC
        // Exit PowerPC emulation
        exit_emul_ppc();
#endif

        // Stop 60Hz thread
        if (tick_thread_active) {
                pthread_cancel(tick_thread);
                pthread_join(tick_thread, NULL);
        }

        // Stop NVRAM watchdog thread
        if (nvram_thread_active) {
                pthread_cancel(nvram_thread);
                pthread_join(nvram_thread, NULL);
        }

#if !EMULATED_PPC
        // Uninstall SIGSEGV handler
        sigemptyset(&sigsegv_action.sa_mask);
        sigsegv_action.sa_handler = SIG_DFL;
        sigsegv_action.sa_flags = 0;
        sigaction(SIGSEGV, &sigsegv_action, NULL);

        // Uninstall SIGILL handler
        sigemptyset(&sigill_action.sa_mask);
        sigill_action.sa_handler = SIG_DFL;
        sigill_action.sa_flags = 0;
        sigaction(SIGILL, &sigill_action, NULL);
#endif

        // Save NVRAM
        XPRAMExit();

        // Exit clipboard
        ClipExit();

        // Exit Time Manager
        TimerExit();

        // Exit serial
        SerialExit();

        // Exit network
        EtherExit();

        // Exit audio
        AudioExit();

        // Exit video
        VideoExit();

        // Exit external file system
        ExtFSExit();

        // Exit drivers
        SCSIExit();
        CDROMExit();
        DiskExit();
        SonyExit();

        // Delete SheepShaver globals
        SheepMem::Exit();

        // Delete RAM area
        if (ram_area_mapped)
                vm_release((char *)RAM_BASE, RAMSize);

        // Delete ROM area
        if (rom_area_mapped)
                vm_release((char *)ROM_BASE, ROM_AREA_SIZE);

        // Delete Kernel Data area
        if (kernel_area >= 0) {
                shmdt((void *)KERNEL_DATA_BASE);
                shmdt((void *)KERNEL_DATA2_BASE);
                shmctl(kernel_area, IPC_RMID, NULL);
        }

        // Delete Low Memory area
        if (lm_area_mapped)
                munmap((char *)0x0000, 0x3000);

        // Close /dev/zero
        if (zero_fd > 0)
                close(zero_fd);

        // Exit system routines
        SysExit();

        // Exit preferences
        PrefsExit();

#ifdef ENABLE_MON
        // Exit mon
        mon_exit();
#endif

        // Close X11 server connection
        if (x_display)
                XCloseDisplay(x_display);

        exit(0);
}


/*
 *  Jump into Mac ROM, start 680x0 emulator
 */

#if EMULATED_PPC
void jump_to_rom(uint32 entry)
{
        init_emul_ppc();
        emul_ppc(entry);
}
#endif


/*
 *  Emulator thread function
 */

static void *emul_func(void *arg)
{
        // We're now ready to receive signals
        ready_for_signals = true;

        // Decrease priority, so more time-critical things like audio will work better
        nice(1);

        // Jump to ROM boot routine
        D(bug("Jumping to ROM\n"));
#if EMULATED_PPC
        jump_to_rom(ROM_BASE + 0x310000);
#else
        jump_to_rom(ROM_BASE + 0x310000, (uint32)emulator_data);
#endif
        D(bug("Returned from ROM\n"));

        // We're no longer ready to receive signals
        ready_for_signals = false;
        return NULL;
}


#if !EMULATED_PPC
/*
 *  Execute 68k subroutine (must be ended with RTS)
 *  This must only be called by the emul_thread when in EMUL_OP mode
 *  r->a[7] is unused, the routine runs on the caller's stack
 */

void Execute68k(uint32 pc, M68kRegisters *r)
{
#if SAFE_EXEC_68K
        if (ReadMacInt32(XLM_RUN_MODE) != MODE_EMUL_OP)
                printf("FATAL: Execute68k() not called from EMUL_OP mode\n");
        if (!pthread_equal(pthread_self(), emul_thread))
                printf("FATAL: Execute68k() not called from emul_thread\n");
#endif
        execute_68k(pc, r);
}


/*
 *  Execute 68k A-Trap from EMUL_OP routine
 *  r->a[7] is unused, the routine runs on the caller's stack
 */

void Execute68kTrap(uint16 trap, M68kRegisters *r)
{
        uint16 proc[2] = {trap, M68K_RTS};
        Execute68k((uint32)proc, r);
}


/*
 *  Execute PPC code from EMUL_OP routine (real mode switch)
 */

void ExecutePPC(void (*func)())
{
        uint32 tvect[2] = {(uint32)func, 0};    // Fake TVECT
        SheepRoutineDescriptor desc(0, (uint32)tvect);
        M68kRegisters r;
        Execute68k(desc.addr(), &r);
}
#endif


/*
 *  Quit emulator (cause return from jump_to_rom)
 */

void QuitEmulator(void)
{
#if EMULATED_PPC
        Quit();
#else
        quit_emulator();
#endif
}


/*
 *  Pause/resume emulator
 */

void PauseEmulator(void)
{
        pthread_kill(emul_thread, SIGSTOP);
}

void ResumeEmulator(void)
{
        pthread_kill(emul_thread, SIGCONT);
}


/*
 *  Dump 68k registers
 */

void Dump68kRegs(M68kRegisters *r)
{
        // Display 68k registers
        for (int i=0; i<8; i++) {
                printf("d%d: %08x", i, r->d[i]);
                if (i == 3 || i == 7)
                        printf("\n");
                else
                        printf(", ");
        }
        for (int i=0; i<8; i++) {
                printf("a%d: %08x", i, r->a[i]);
                if (i == 3 || i == 7)
                        printf("\n");
                else
                        printf(", ");
        }
}


/*
 *  Make code executable
 */

void MakeExecutable(int dummy, void *start, uint32 length)
{
        if (((uintptr)start >= ROM_BASE) && ((uintptr)start < (ROM_BASE + ROM_SIZE)))
                return;
#if EMULATED_PPC
        FlushCodeCache((uintptr)start, (uintptr)start + length);
#else
        flush_icache_range(start, (void *)((uintptr)start + length));
#endif
}


/*
 *  Patch things after system startup (gets called by disk driver accRun routine)
 */

void PatchAfterStartup(void)
{
#if EMULATED_PPC
        ExecuteNative(NATIVE_VIDEO_INSTALL_ACCEL);
#else
        ExecutePPC(VideoInstallAccel);
#endif
        InstallExtFS();
}


/*
 *  NVRAM watchdog thread (saves NVRAM every minute)
 */

static void *nvram_func(void *arg)
{
        struct timespec req = {60, 0};  // 1 minute

        for (;;) {
                pthread_testcancel();
                nanosleep(&req, NULL);
                pthread_testcancel();
                if (memcmp(last_xpram, XPRAM, XPRAM_SIZE)) {
                        memcpy(last_xpram, XPRAM, XPRAM_SIZE);
                        SaveXPRAM();
                }
        }
        return NULL;
}


/*
 *  60Hz thread (really 60.15Hz)
 */

static void *tick_func(void *arg)
{
        int tick_counter = 0;
        struct timespec req = {0, 16625000};

        for (;;) {

                // Wait
                nanosleep(&req, NULL);

#if !EMULATED_PPC
                // Did we crash?
                if (emul_thread_fatal) {

                        // Yes, dump registers
                        pt_regs *r = (pt_regs *)&sigsegv_regs;
                        char str[256];
                        sprintf(str, "SIGSEGV\n"
                                "   pc %08lx     lr %08lx    ctr %08lx    msr %08lx\n"
                                "  xer %08lx     cr %08lx  \n"
                                "   r0 %08lx     r1 %08lx     r2 %08lx     r3 %08lx\n"
                                "   r4 %08lx     r5 %08lx     r6 %08lx     r7 %08lx\n"
                                "   r8 %08lx     r9 %08lx    r10 %08lx    r11 %08lx\n"
                                "  r12 %08lx    r13 %08lx    r14 %08lx    r15 %08lx\n"
                                "  r16 %08lx    r17 %08lx    r18 %08lx    r19 %08lx\n"
                                "  r20 %08lx    r21 %08lx    r22 %08lx    r23 %08lx\n"
                                "  r24 %08lx    r25 %08lx    r26 %08lx    r27 %08lx\n"
                                "  r28 %08lx    r29 %08lx    r30 %08lx    r31 %08lx\n",
                                r->nip, r->link, r->ctr, r->msr,
                                r->xer, r->ccr,
                                r->gpr[0], r->gpr[1], r->gpr[2], r->gpr[3],
                                r->gpr[4], r->gpr[5], r->gpr[6], r->gpr[7],
                                r->gpr[8], r->gpr[9], r->gpr[10], r->gpr[11],
                                r->gpr[12], r->gpr[13], r->gpr[14], r->gpr[15],
                                r->gpr[16], r->gpr[17], r->gpr[18], r->gpr[19],
                                r->gpr[20], r->gpr[21], r->gpr[22], r->gpr[23],
                                r->gpr[24], r->gpr[25], r->gpr[26], r->gpr[27],
                                r->gpr[28], r->gpr[29], r->gpr[30], r->gpr[31]);
                        printf(str);
                        VideoQuitFullScreen();

#ifdef ENABLE_MON
                        // Start up mon in real-mode
                        printf("Welcome to the sheep factory.\n");
                        char *arg[4] = {"mon", "-m", "-r", NULL};
                        mon(3, arg);
#endif
                        return NULL;
                }
#endif

                // Pseudo Mac 1Hz interrupt, update local time
                if (++tick_counter > 60) {
                        tick_counter = 0;
                        WriteMacInt32(0x20c, TimerDateTime());
                }

                // Trigger 60Hz interrupt
                if (ReadMacInt32(XLM_IRQ_NEST) == 0) {
                        SetInterruptFlag(INTFLAG_VIA);
                        TriggerInterrupt();
                }
        }
        return NULL;
}


/*
 *  Pthread configuration
 */

void Set_pthread_attr(pthread_attr_t *attr, int priority)
{
#ifdef HAVE_PTHREADS
        pthread_attr_init(attr);
#if defined(_POSIX_THREAD_PRIORITY_SCHEDULING)
        // Some of these only work for superuser
        if (geteuid() == 0) {
                pthread_attr_setinheritsched(attr, PTHREAD_EXPLICIT_SCHED);
                pthread_attr_setschedpolicy(attr, SCHED_FIFO);
                struct sched_param fifo_param;
                fifo_param.sched_priority = ((sched_get_priority_min(SCHED_FIFO) + 
                                              sched_get_priority_max(SCHED_FIFO)) / 2 +
                                             priority);
                pthread_attr_setschedparam(attr, &fifo_param);
        }
        if (pthread_attr_setscope(attr, PTHREAD_SCOPE_SYSTEM) != 0) {
#ifdef PTHREAD_SCOPE_BOUND_NP
            // If system scope is not available (eg. we're not running
            // with CAP_SCHED_MGT capability on an SGI box), try bound
            // scope.  It exposes pthread scheduling to the kernel,
            // without setting realtime priority.
            pthread_attr_setscope(attr, PTHREAD_SCOPE_BOUND_NP);
#endif
        }
#endif
#endif
}


/*
 *  Mutexes
 */

#ifdef HAVE_PTHREADS

struct B2_mutex {
        B2_mutex() { 
            pthread_mutexattr_t attr;
            pthread_mutexattr_init(&attr);
            // Initialize the mutex for priority inheritance --
            // required for accurate timing.
#ifdef HAVE_PTHREAD_MUTEXATTR_SETPROTOCOL
            pthread_mutexattr_setprotocol(&attr, PTHREAD_PRIO_INHERIT);
#endif
#if defined(HAVE_PTHREAD_MUTEXATTR_SETTYPE) && defined(PTHREAD_MUTEX_NORMAL)
            pthread_mutexattr_settype(&attr, PTHREAD_MUTEX_NORMAL);
#endif
#ifdef HAVE_PTHREAD_MUTEXATTR_SETPSHARED
            pthread_mutexattr_setpshared(&attr, PTHREAD_PROCESS_PRIVATE);
#endif
            pthread_mutex_init(&m, &attr);
            pthread_mutexattr_destroy(&attr);
        }
        ~B2_mutex() { 
            pthread_mutex_trylock(&m); // Make sure it's locked before
            pthread_mutex_unlock(&m);  // unlocking it.
            pthread_mutex_destroy(&m);
        }
        pthread_mutex_t m;
};

B2_mutex *B2_create_mutex(void)
{
        return new B2_mutex;
}

void B2_lock_mutex(B2_mutex *mutex)
{
        pthread_mutex_lock(&mutex->m);
}

void B2_unlock_mutex(B2_mutex *mutex)
{
        pthread_mutex_unlock(&mutex->m);
}

void B2_delete_mutex(B2_mutex *mutex)
{
        delete mutex;
}

#else

struct B2_mutex {
        int dummy;
};

B2_mutex *B2_create_mutex(void)
{
        return new B2_mutex;
}

void B2_lock_mutex(B2_mutex *mutex)
{
}

void B2_unlock_mutex(B2_mutex *mutex)
{
}

void B2_delete_mutex(B2_mutex *mutex)
{
        delete mutex;
}

#endif


/*
 *  Trigger signal USR2 from another thread
 */

#if !EMULATED_PPC || ASYNC_IRQ
void TriggerInterrupt(void)
{
        if (ready_for_signals)
                pthread_kill(emul_thread, SIGUSR2);
}
#endif


/*
 *  Interrupt flags (must be handled atomically!)
 */

volatile uint32 InterruptFlags = 0;

void SetInterruptFlag(uint32 flag)
{
        atomic_or((int *)&InterruptFlags, flag);
}

void ClearInterruptFlag(uint32 flag)
{
        atomic_and((int *)&InterruptFlags, ~flag);
}


/*
 *  Disable interrupts
 */

void DisableInterrupt(void)
{
        atomic_add((int *)XLM_IRQ_NEST, 1);
}


/*
 *  Enable interrupts
 */

void EnableInterrupt(void)
{
        atomic_add((int *)XLM_IRQ_NEST, -1);
}


/*
 *  USR2 handler
 */

#if EMULATED_PPC
static void sigusr2_handler(int sig)
{
#if ASYNC_IRQ
        extern void HandleInterrupt(void);
        HandleInterrupt();
#endif
}
#else
static void sigusr2_handler(int sig, sigcontext_struct *sc)
{
        pt_regs *r = sc->regs;

        // Do nothing if interrupts are disabled
        if (*(int32 *)XLM_IRQ_NEST > 0)
                return;

        // Disable MacOS stack sniffer
        WriteMacInt32(0x110, 0);

        // Interrupt action depends on current run mode
        switch (ReadMacInt32(XLM_RUN_MODE)) {
                case MODE_68K:
                        // 68k emulator active, trigger 68k interrupt level 1
                        WriteMacInt16(ntohl(kernel_data->v[0x67c >> 2]), 1);
                        r->ccr |= ntohl(kernel_data->v[0x674 >> 2]);
                        break;

#if INTERRUPTS_IN_NATIVE_MODE
                case MODE_NATIVE:
                        // 68k emulator inactive, in nanokernel?
                        if (r->gpr[1] != KernelDataAddr) {
                                // Prepare for 68k interrupt level 1
                                WriteMacInt16(ntohl(kernel_data->v[0x67c >> 2]), 1);
                                WriteMacInt32(ntohl(kernel_data->v[0x658 >> 2]) + 0xdc, ReadMacInt32(ntohl(kernel_data->v[0x658 >> 2]) + 0xdc) | ntohl(kernel_data->v[0x674 >> 2]));

                                // Execute nanokernel interrupt routine (this will activate the 68k emulator)
                                atomic_add((int32 *)XLM_IRQ_NEST, 1);
                                if (ROMType == ROMTYPE_NEWWORLD)
                                        ppc_interrupt(ROM_BASE + 0x312b1c, KernelDataAddr);
                                else
                                        ppc_interrupt(ROM_BASE + 0x312a3c, KernelDataAddr);
                        }
                        break;
#endif

#if INTERRUPTS_IN_EMUL_OP_MODE
                case MODE_EMUL_OP:
                        // 68k emulator active, within EMUL_OP routine, execute 68k interrupt routine directly when interrupt level is 0
                        if ((ReadMacInt32(XLM_68K_R25) & 7) == 0) {

                                // Set extra stack for SIGSEGV handler
                                struct sigaltstack new_stack;
                                new_stack.ss_sp = extra_stack;
                                new_stack.ss_flags = 0;
                                new_stack.ss_size = SIG_STACK_SIZE;
                                sigaltstack(&new_stack, NULL);
#if 1
                                // Execute full 68k interrupt routine
                                M68kRegisters r;
                                uint32 old_r25 = ReadMacInt32(XLM_68K_R25);     // Save interrupt level
                                WriteMacInt32(XLM_68K_R25, 0x21);                       // Execute with interrupt level 1
                                static const uint16 proc[] = {
                                        0x3f3c, 0x0000,         // move.w       #$0000,-(sp)    (fake format word)
                                        0x487a, 0x000a,         // pea          @1(pc)                  (return address)
                                        0x40e7,                         // move         sr,-(sp)                (saved SR)
                                        0x2078, 0x0064,         // move.l       $64,a0
                                        0x4ed0,                         // jmp          (a0)
                                        M68K_RTS                        // @1
                                };
                                Execute68k((uint32)proc, &r);
                                WriteMacInt32(XLM_68K_R25, old_r25);            // Restore interrupt level
#else
                                // Only update cursor
                                if (HasMacStarted()) {
                                        if (InterruptFlags & INTFLAG_VIA) {
                                                ClearInterruptFlag(INTFLAG_VIA);
                                                ADBInterrupt();
                                                ExecutePPC(VideoVBL);
                                        }
                                }
#endif
                                // Reset normal signal stack
                                new_stack.ss_sp = sig_stack;
                                new_stack.ss_flags = 0;
                                new_stack.ss_size = SIG_STACK_SIZE;
                                sigaltstack(&new_stack, NULL);
                        }
                        break;
#endif
        }
}
#endif


/*
 *  SIGSEGV handler
 */

#if !EMULATED_PPC
static void sigsegv_handler(int sig, sigcontext_struct *sc)
{
        pt_regs *r = sc->regs;

        // Get effective address
        uint32 addr = r->dar;
        
#if ENABLE_VOSF
        // Handle screen fault.
        extern bool Screen_fault_handler(sigsegv_address_t fault_address, sigsegv_address_t fault_instruction);
        if (Screen_fault_handler((sigsegv_address_t)addr, (sigsegv_address_t)r->nip))
                return;
#endif

        num_segv++;

        // Fault in Mac ROM or RAM?
        bool mac_fault = (r->nip >= ROM_BASE) && (r->nip < (ROM_BASE + ROM_AREA_SIZE)) || (r->nip >= RAMBase) && (r->nip < (RAMBase + RAMSize));
        if (mac_fault) {

                // "VM settings" during MacOS 8 installation
                if (r->nip == ROM_BASE + 0x488160 && r->gpr[20] == 0xf8000000) {
                        r->nip += 4;
                        r->gpr[8] = 0;
                        return;
        
                // MacOS 8.5 installation
                } else if (r->nip == ROM_BASE + 0x488140 && r->gpr[16] == 0xf8000000) {
                        r->nip += 4;
                        r->gpr[8] = 0;
                        return;
        
                // MacOS 8 serial drivers on startup
                } else if (r->nip == ROM_BASE + 0x48e080 && (r->gpr[8] == 0xf3012002 || r->gpr[8] == 0xf3012000)) {
                        r->nip += 4;
                        r->gpr[8] = 0;
                        return;
        
                // MacOS 8.1 serial drivers on startup
                } else if (r->nip == ROM_BASE + 0x48c5e0 && (r->gpr[20] == 0xf3012002 || r->gpr[20] == 0xf3012000)) {
                        r->nip += 4;
                        return;
                } else if (r->nip == ROM_BASE + 0x4a10a0 && (r->gpr[20] == 0xf3012002 || r->gpr[20] == 0xf3012000)) {
                        r->nip += 4;
                        return;
                }

                // Get opcode and divide into fields
                uint32 opcode = *((uint32 *)r->nip);
                uint32 primop = opcode >> 26;
                uint32 exop = (opcode >> 1) & 0x3ff;
                uint32 ra = (opcode >> 16) & 0x1f;
                uint32 rb = (opcode >> 11) & 0x1f;
                uint32 rd = (opcode >> 21) & 0x1f;
                int32 imm = (int16)(opcode & 0xffff);

                // Analyze opcode
                enum {
                        TYPE_UNKNOWN,
                        TYPE_LOAD,
                        TYPE_STORE
                } transfer_type = TYPE_UNKNOWN;
                enum {
                        SIZE_UNKNOWN,
                        SIZE_BYTE,
                        SIZE_HALFWORD,
                        SIZE_WORD
                } transfer_size = SIZE_UNKNOWN;
                enum {
                        MODE_UNKNOWN,
                        MODE_NORM,
                        MODE_U,
                        MODE_X,
                        MODE_UX
                } addr_mode = MODE_UNKNOWN;
                switch (primop) {
                        case 31:
                                switch (exop) {
                                        case 23:        // lwzx
                                                transfer_type = TYPE_LOAD; transfer_size = SIZE_WORD; addr_mode = MODE_X; break;
                                        case 55:        // lwzux
                                                transfer_type = TYPE_LOAD; transfer_size = SIZE_WORD; addr_mode = MODE_UX; break;
                                        case 87:        // lbzx
                                                transfer_type = TYPE_LOAD; transfer_size = SIZE_BYTE; addr_mode = MODE_X; break;
                                        case 119:       // lbzux
                                                transfer_type = TYPE_LOAD; transfer_size = SIZE_BYTE; addr_mode = MODE_UX; break;
                                        case 151:       // stwx
                                                transfer_type = TYPE_STORE; transfer_size = SIZE_WORD; addr_mode = MODE_X; break;
                                        case 183:       // stwux
                                                transfer_type = TYPE_STORE; transfer_size = SIZE_WORD; addr_mode = MODE_UX; break;
                                        case 215:       // stbx
                                                transfer_type = TYPE_STORE; transfer_size = SIZE_BYTE; addr_mode = MODE_X; break;
                                        case 247:       // stbux
                                                transfer_type = TYPE_STORE; transfer_size = SIZE_BYTE; addr_mode = MODE_UX; break;
                                        case 279:       // lhzx
                                                transfer_type = TYPE_LOAD; transfer_size = SIZE_HALFWORD; addr_mode = MODE_X; break;
                                        case 311:       // lhzux
                                                transfer_type = TYPE_LOAD; transfer_size = SIZE_HALFWORD; addr_mode = MODE_UX; break;
                                        case 343:       // lhax
                                                transfer_type = TYPE_LOAD; transfer_size = SIZE_HALFWORD; addr_mode = MODE_X; break;
                                        case 375:       // lhaux
                                                transfer_type = TYPE_LOAD; transfer_size = SIZE_HALFWORD; addr_mode = MODE_UX; break;
                                        case 407:       // sthx
                                                transfer_type = TYPE_STORE; transfer_size = SIZE_HALFWORD; addr_mode = MODE_X; break;
                                        case 439:       // sthux
                                                transfer_type = TYPE_STORE; transfer_size = SIZE_HALFWORD; addr_mode = MODE_UX; break;
                                }
                                break;
        
                        case 32:        // lwz
                                transfer_type = TYPE_LOAD; transfer_size = SIZE_WORD; addr_mode = MODE_NORM; break;
                        case 33:        // lwzu
                                transfer_type = TYPE_LOAD; transfer_size = SIZE_WORD; addr_mode = MODE_U; break;
                        case 34:        // lbz
                                transfer_type = TYPE_LOAD; transfer_size = SIZE_BYTE; addr_mode = MODE_NORM; break;
                        case 35:        // lbzu
                                transfer_type = TYPE_LOAD; transfer_size = SIZE_BYTE; addr_mode = MODE_U; break;
                        case 36:        // stw
                                transfer_type = TYPE_STORE; transfer_size = SIZE_WORD; addr_mode = MODE_NORM; break;
                        case 37:        // stwu
                                transfer_type = TYPE_STORE; transfer_size = SIZE_WORD; addr_mode = MODE_U; break;
                        case 38:        // stb
                                transfer_type = TYPE_STORE; transfer_size = SIZE_BYTE; addr_mode = MODE_NORM; break;
                        case 39:        // stbu
                                transfer_type = TYPE_STORE; transfer_size = SIZE_BYTE; addr_mode = MODE_U; break;
                        case 40:        // lhz
                                transfer_type = TYPE_LOAD; transfer_size = SIZE_HALFWORD; addr_mode = MODE_NORM; break;
                        case 41:        // lhzu
                                transfer_type = TYPE_LOAD; transfer_size = SIZE_HALFWORD; addr_mode = MODE_U; break;
                        case 42:        // lha
                                transfer_type = TYPE_LOAD; transfer_size = SIZE_HALFWORD; addr_mode = MODE_NORM; break;
                        case 43:        // lhau
                                transfer_type = TYPE_LOAD; transfer_size = SIZE_HALFWORD; addr_mode = MODE_U; break;
                        case 44:        // sth
                                transfer_type = TYPE_STORE; transfer_size = SIZE_HALFWORD; addr_mode = MODE_NORM; break;
                        case 45:        // sthu
                                transfer_type = TYPE_STORE; transfer_size = SIZE_HALFWORD; addr_mode = MODE_U; break;
                }
        
                // Ignore ROM writes
                if (transfer_type == TYPE_STORE && addr >= ROM_BASE && addr < ROM_BASE + ROM_SIZE) {
//                      D(bug("WARNING: %s write access to ROM at %08lx, pc %08lx\n", transfer_size == SIZE_BYTE ? "Byte" : transfer_size == SIZE_HALFWORD ? "Halfword" : "Word", addr, r->nip));
                        if (addr_mode == MODE_U || addr_mode == MODE_UX)
                                r->gpr[ra] = addr;
                        r->nip += 4;
                        goto rti;
                }

                // Ignore illegal memory accesses?
                if (PrefsFindBool("ignoresegv")) {
                        if (addr_mode == MODE_U || addr_mode == MODE_UX)
                                r->gpr[ra] = addr;
                        if (transfer_type == TYPE_LOAD)
                                r->gpr[rd] = 0;
                        r->nip += 4;
                        goto rti;
                }

                // In GUI mode, show error alert
                if (!PrefsFindBool("nogui")) {
                        char str[256];
                        if (transfer_type == TYPE_LOAD || transfer_type == TYPE_STORE)
                                sprintf(str, GetString(STR_MEM_ACCESS_ERR), transfer_size == SIZE_BYTE ? "byte" : transfer_size == SIZE_HALFWORD ? "halfword" : "word", transfer_type == TYPE_LOAD ? GetString(STR_MEM_ACCESS_READ) : GetString(STR_MEM_ACCESS_WRITE), addr, r->nip, r->gpr[24], r->gpr[1]);
                        else
                                sprintf(str, GetString(STR_UNKNOWN_SEGV_ERR), r->nip, r->gpr[24], r->gpr[1], opcode);
                        ErrorAlert(str);
                        QuitEmulator();
                        return;
                }
        }

        // For all other errors, jump into debugger (sort of...)
        if (!ready_for_signals) {
                printf("SIGSEGV\n");
                printf(" sigcontext %p, pt_regs %p\n", sc, r);
                printf(
                        "   pc %08lx     lr %08lx    ctr %08lx    msr %08lx\n"
                        "  xer %08lx     cr %08lx  \n"
                        "   r0 %08lx     r1 %08lx     r2 %08lx     r3 %08lx\n"
                        "   r4 %08lx     r5 %08lx     r6 %08lx     r7 %08lx\n"
                        "   r8 %08lx     r9 %08lx    r10 %08lx    r11 %08lx\n"
                        "  r12 %08lx    r13 %08lx    r14 %08lx    r15 %08lx\n"
                        "  r16 %08lx    r17 %08lx    r18 %08lx    r19 %08lx\n"
                        "  r20 %08lx    r21 %08lx    r22 %08lx    r23 %08lx\n"
                        "  r24 %08lx    r25 %08lx    r26 %08lx    r27 %08lx\n"
                        "  r28 %08lx    r29 %08lx    r30 %08lx    r31 %08lx\n",
                        r->nip, r->link, r->ctr, r->msr,
                        r->xer, r->ccr,
                        r->gpr[0], r->gpr[1], r->gpr[2], r->gpr[3],
                        r->gpr[4], r->gpr[5], r->gpr[6], r->gpr[7],
                        r->gpr[8], r->gpr[9], r->gpr[10], r->gpr[11],
                        r->gpr[12], r->gpr[13], r->gpr[14], r->gpr[15],
                        r->gpr[16], r->gpr[17], r->gpr[18], r->gpr[19],
                        r->gpr[20], r->gpr[21], r->gpr[22], r->gpr[23],
                        r->gpr[24], r->gpr[25], r->gpr[26], r->gpr[27],
                        r->gpr[28], r->gpr[29], r->gpr[30], r->gpr[31]);
                exit(1);
                QuitEmulator();
                return;
        } else {
                // We crashed. Save registers, tell tick thread and loop forever
                sigsegv_regs = *(sigregs *)r;
                emul_thread_fatal = true;
                for (;;) ;
        }
rti:;
}


/*
 *  SIGILL handler
 */

static void sigill_handler(int sig, sigcontext_struct *sc)
{
        pt_regs *r = sc->regs;
        char str[256];

        // Fault in Mac ROM or RAM?
        bool mac_fault = (r->nip >= ROM_BASE) && (r->nip < (ROM_BASE + ROM_AREA_SIZE)) || (r->nip >= RAMBase) && (r->nip < (RAMBase + RAMSize));
        if (mac_fault) {

                // Get opcode and divide into fields
                uint32 opcode = *((uint32 *)r->nip);
                uint32 primop = opcode >> 26;
                uint32 exop = (opcode >> 1) & 0x3ff;
                uint32 ra = (opcode >> 16) & 0x1f;
                uint32 rb = (opcode >> 11) & 0x1f;
                uint32 rd = (opcode >> 21) & 0x1f;
                int32 imm = (int16)(opcode & 0xffff);

                switch (primop) {
                        case 9:         // POWER instructions
                        case 22:
power_inst:             sprintf(str, GetString(STR_POWER_INSTRUCTION_ERR), r->nip, r->gpr[1], opcode);
                                ErrorAlert(str);
                                QuitEmulator();
                                return;

                        case 31:
                                switch (exop) {
                                        case 83:        // mfmsr
                                                r->gpr[rd] = 0xf072;
                                                r->nip += 4;
                                                goto rti;

                                        case 210:       // mtsr
                                        case 242:       // mtsrin
                                        case 306:       // tlbie
                                                r->nip += 4;
                                                goto rti;

                                        case 339: {     // mfspr
                                                int spr = ra | (rb << 5);
                                                switch (spr) {
                                                        case 0:         // MQ
                                                        case 22:        // DEC
                                                        case 952:       // MMCR0
                                                        case 953:       // PMC1
                                                        case 954:       // PMC2
                                                        case 955:       // SIA
                                                        case 956:       // MMCR1
                                                        case 957:       // PMC3
                                                        case 958:       // PMC4
                                                        case 959:       // SDA
                                                                r->nip += 4;
                                                                goto rti;
                                                        case 25:        // SDR1
                                                                r->gpr[rd] = 0xdead001f;
                                                                r->nip += 4;
                                                                goto rti;
                                                        case 287:       // PVR
                                                                r->gpr[rd] = PVR;
                                                                r->nip += 4;
                                                                goto rti;
                                                }
                                                break;
                                        }

                                        case 467: {     // mtspr
                                                int spr = ra | (rb << 5);
                                                switch (spr) {
                                                        case 0:         // MQ
                                                        case 22:        // DEC
                                                        case 275:       // SPRG3
                                                        case 528:       // IBAT0U
                                                        case 529:       // IBAT0L
                                                        case 530:       // IBAT1U
                                                        case 531:       // IBAT1L
                                                        case 532:       // IBAT2U
                                                        case 533:       // IBAT2L
                                                        case 534:       // IBAT3U
                                                        case 535:       // IBAT3L
                                                        case 536:       // DBAT0U
                                                        case 537:       // DBAT0L
                                                        case 538:       // DBAT1U
                                                        case 539:       // DBAT1L
                                                        case 540:       // DBAT2U
                                                        case 541:       // DBAT2L
                                                        case 542:       // DBAT3U
                                                        case 543:       // DBAT3L
                                                        case 952:       // MMCR0
                                                        case 953:       // PMC1
                                                        case 954:       // PMC2
                                                        case 955:       // SIA
                                                        case 956:       // MMCR1
                                                        case 957:       // PMC3
                                                        case 958:       // PMC4
                                                        case 959:       // SDA
                                                                r->nip += 4;
                                                                goto rti;
                                                }
                                                break;
                                        }

                                        case 29: case 107: case 152: case 153:  // POWER instructions
                                        case 184: case 216: case 217: case 248:
                                        case 264: case 277: case 331: case 360:
                                        case 363: case 488: case 531: case 537:
                                        case 541: case 664: case 665: case 696:
                                        case 728: case 729: case 760: case 920:
                                        case 921: case 952:
                                                goto power_inst;
                                }
                }

                // In GUI mode, show error alert
                if (!PrefsFindBool("nogui")) {
                        sprintf(str, GetString(STR_UNKNOWN_SEGV_ERR), r->nip, r->gpr[24], r->gpr[1], opcode);
                        ErrorAlert(str);
                        QuitEmulator();
                        return;
                }
        }

        // For all other errors, jump into debugger (sort of...)
        if (!ready_for_signals) {
                printf("SIGILL\n");
                printf(" sigcontext %p, pt_regs %p\n", sc, r);
                printf(
                        "   pc %08lx     lr %08lx    ctr %08lx    msr %08lx\n"
                        "  xer %08lx     cr %08lx  \n"
                        "   r0 %08lx     r1 %08lx     r2 %08lx     r3 %08lx\n"
                        "   r4 %08lx     r5 %08lx     r6 %08lx     r7 %08lx\n"
                        "   r8 %08lx     r9 %08lx    r10 %08lx    r11 %08lx\n"
                        "  r12 %08lx    r13 %08lx    r14 %08lx    r15 %08lx\n"
                        "  r16 %08lx    r17 %08lx    r18 %08lx    r19 %08lx\n"
                        "  r20 %08lx    r21 %08lx    r22 %08lx    r23 %08lx\n"
                        "  r24 %08lx    r25 %08lx    r26 %08lx    r27 %08lx\n"
                        "  r28 %08lx    r29 %08lx    r30 %08lx    r31 %08lx\n",
                        r->nip, r->link, r->ctr, r->msr,
                        r->xer, r->ccr,
                        r->gpr[0], r->gpr[1], r->gpr[2], r->gpr[3],
                        r->gpr[4], r->gpr[5], r->gpr[6], r->gpr[7],
                        r->gpr[8], r->gpr[9], r->gpr[10], r->gpr[11],
                        r->gpr[12], r->gpr[13], r->gpr[14], r->gpr[15],
                        r->gpr[16], r->gpr[17], r->gpr[18], r->gpr[19],
                        r->gpr[20], r->gpr[21], r->gpr[22], r->gpr[23],
                        r->gpr[24], r->gpr[25], r->gpr[26], r->gpr[27],
                        r->gpr[28], r->gpr[29], r->gpr[30], r->gpr[31]);
                exit(1);
                QuitEmulator();
                return;
        } else {
                // We crashed. Save registers, tell tick thread and loop forever
                sigsegv_regs = *(sigregs *)r;
                emul_thread_fatal = true;
                for (;;) ;
        }
rti:;
}
#endif


/*
 *  Helpers to share 32-bit addressable data with MacOS
 */

bool SheepMem::Init(void)
{
        if (vm_acquire_fixed((char *)base, size) < 0)
                return false;
        top = base + size;
        return true;
}

void SheepMem::Exit(void)
{
        if (top)
                vm_release((void *)base, size);
}


/*
 *  Display alert
 */

#ifdef ENABLE_GTK
static void dl_destroyed(void)
{
        gtk_main_quit();
}

static void dl_quit(GtkWidget *dialog)
{
        gtk_widget_destroy(dialog);
}

void display_alert(int title_id, int prefix_id, int button_id, const char *text)
{
        char str[256];
        sprintf(str, GetString(prefix_id), text);

        GtkWidget *dialog = gtk_dialog_new();
        gtk_window_set_title(GTK_WINDOW(dialog), GetString(title_id));
        gtk_container_border_width(GTK_CONTAINER(dialog), 5);
        gtk_widget_set_uposition(GTK_WIDGET(dialog), 100, 150);
        gtk_signal_connect(GTK_OBJECT(dialog), "destroy", GTK_SIGNAL_FUNC(dl_destroyed), NULL);

        GtkWidget *label = gtk_label_new(str);
        gtk_widget_show(label);
        gtk_box_pack_start(GTK_BOX(GTK_DIALOG(dialog)->vbox), label, TRUE, TRUE, 0);

        GtkWidget *button = gtk_button_new_with_label(GetString(button_id));
        gtk_widget_show(button);
        gtk_signal_connect_object(GTK_OBJECT(button), "clicked", GTK_SIGNAL_FUNC(dl_quit), GTK_OBJECT(dialog));
        gtk_box_pack_start(GTK_BOX(GTK_DIALOG(dialog)->action_area), button, FALSE, FALSE, 0);
        GTK_WIDGET_SET_FLAGS(button, GTK_CAN_DEFAULT);
        gtk_widget_grab_default(button);
        gtk_widget_show(dialog);

        gtk_main();
}
#endif


/*
 *  Display error alert
 */

void ErrorAlert(const char *text)
{
#ifdef ENABLE_GTK
        if (PrefsFindBool("nogui") || x_display == NULL) {
                printf(GetString(STR_SHELL_ERROR_PREFIX), text);
                return;
        }
        VideoQuitFullScreen();
        display_alert(STR_ERROR_ALERT_TITLE, STR_GUI_ERROR_PREFIX, STR_QUIT_BUTTON, text);
#else
        printf(GetString(STR_SHELL_ERROR_PREFIX), text);
#endif
}


/*
 *  Display warning alert
 */

void WarningAlert(const char *text)
{
#ifdef ENABLE_GTK
        if (PrefsFindBool("nogui") || x_display == NULL) {
                printf(GetString(STR_SHELL_WARNING_PREFIX), text);
                return;
        }
        display_alert(STR_WARNING_ALERT_TITLE, STR_GUI_WARNING_PREFIX, STR_OK_BUTTON, text);
#else
        printf(GetString(STR_SHELL_WARNING_PREFIX), text);
#endif
}


/*
 *  Display choice alert
 */

bool ChoiceAlert(const char *text, const char *pos, const char *neg)
{
        printf(GetString(STR_SHELL_WARNING_PREFIX), text);
        return false;   //!!
}
Revision:	1.16
Committed:	2003-12-04T22:33:24Z (20 years, 6 months ago) by gbeauche
Branch:	MAIN
Changes since 1.15:	+2 -2 lines
Log Message:	Fix ExecutePPC() merge with new SheepRoutineDescriptor