/*
    Title:  Machine dependent code for Power architecture.

    Copyright (c) 2000-7
        Cambridge University Technical Services Limited

    This library is free software; you can redistribute it and/or
    modify it under the terms of the GNU Lesser General Public
    License as published by the Free Software Foundation; either
    version 2.1 of the License, or (at your option) any later version.
    
    This library 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
    Lesser General Public License for more details.
    
    You should have received a copy of the GNU Lesser General Public
    License along with this library; if not, write to the Free Software
    Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA  02110-1301  USA

*/

#ifdef WIN32
#include "winconfig.h"
#else
#include "config.h"
#endif

#ifdef HAVE_STDLIB_H
#include <stdlib.h>
#endif

#ifdef HAVE_SIGNAL_H
#include <signal.h>
#endif

#ifdef HAVE_STRING_H
#include <string.h>
#endif

#ifdef HAVE_STDIO_H
#include <stdio.h>
#endif

#ifdef HAVE_ASSERT_H
#include <assert.h>
#define ASSERT(x) assert(x)
#else
#define ASSERT(x)
#endif

#ifdef HAVE_MCONTEXT_T_REGS
// Linux
#define NIP(scp)    (scp)->uc_mcontext.regs->nip
#define GPR27(scp)  (scp)->uc_mcontext.regs->gpr[PT_R27]

#elif (defined(HAVE_STRUCT_MCONTEXT_SS) || defined(HAVE_STRUCT___DARWIN_MCONTEXT_SS))
/* Mac OS X 10.2, 10.3 and 10.4. */
#define NIP(scp)    scp->uc_mcontext->ss.srr0
#define GPR27(scp)  scp->uc_mcontext->ss.r27

#elif (defined(HAVE_STRUCT___DARWIN_MCONTEXT___SS))
// Mac OS X 10.5
#define NIP(scp)    scp->uc_mcontext->__ss.__srr0
#define GPR27(scp)  scp->uc_mcontext->__ss.__r27

#elif defined(HAVE_MCONTEXT_T_GREGS)
// Linux (new)
#define NIP(scp)    (scp)->uc_mcontext.uc_regs->gregs[PT_NIP]
#define GPR27(scp)  (scp)->uc_mcontext.uc_regs->gregs[PT_R27]

#else

/* Before OS X 10.2 signal handlers were given sigcontext structures. */
// This may need testing
#define NIP(scp)    scp->sc_ir
#define GPR27(scp)  (((int*)(scp)->sc_regs)[27+2])
#endif

// R27 is used as the ML stack pointer
#define GPSP(scp)   GPR27(scp)

#include "globals.h"
#include "gc.h"
#include "run_time.h"
#include "mpoly.h"
#include "arb.h"
#include "int_opcodes.h"
#include "reals.h"
#include "diagnostics.h"
#include "processes.h"
#include "sighandler.h"
#include "machine_dep.h"
#include "profiling.h"
#include "save_vec.h"
#include "scanaddrs.h"
#include "sys.h"
#include "check_objects.h"
#include "memmgr.h"

// Values for the returnReason
enum RETURN_REASON {
    RETURN_IO_CALL = 0,
    RETURN_HEAP_OVERFLOW,
    RETURN_STACK_OVERFLOW,
    RETURN_STACK_OVERFLOWEX,
    RETURN_RAISE_DIV,
    RETURN_ARB_EMULATION
};

// Registers saved in taskData->stack.
#define NUMCHECKED      21  // Number of checked registers.
#define NUMUNCHECKED    3   // Number of unchecked registers

// These registers must contain valid PolyWord values.  Any addresses
// may be updated as the result of a garbage collection.
#define PS_R3   p_reg[0] // First argument and function result - r3
#define PS_R4   p_reg[1] // Second argument - r4
#define PS_R5   p_reg[2] // Third argument - r5
#define PS_R6   p_reg[3] // Fourth argument - r6
#define PS_R7   p_reg[4] // r7
#define PS_R8   p_reg[5] // r8
#define PS_R9   p_reg[6] // r9
#define PS_R10  p_reg[7] // r10
#define PS_R14  p_reg[8] // r14
#define PS_R15  p_reg[9] // r15
#define PS_R16  p_reg[10] // r16
#define PS_R17  p_reg[11] // r17
#define PS_R18  p_reg[12] // r18
#define PS_R19  p_reg[13] // r19
#define PS_R20  p_reg[14] // r20
#define PS_R21  p_reg[15] // r21
#define PS_R22  p_reg[16] // r22
#define PS_R23  p_reg[17] // r23
#define PS_R24  p_reg[18] // r24 - Closure register
#define PS_R25  p_reg[19] // r25 - Return register
#define PS_LR   p_reg[20] // lr - Link register

// These registers can contain values that are not valid PolyWord values.
// They are copied unchanged if the stack is moved so must not contain addresses.
#define PS_R11  p_reg[NUMCHECKED+1] // r11 - untagged register
#define PS_R12  p_reg[NUMCHECKED+2] // r12 - untagged register
#define PS_CR0  p_reg[NUMCHECKED+3] // Condition code register - untagged


#define EXTRA_STACK 0

/* the amount of ML stack space to reserve for registers,
   C exception handling etc. The compiler requires us to
   reserve 2 stack-frames worth (2 * 20 words) plus whatever
   we require for the register save area. We actually reserve
   slightly more than this. SPF 3/3/97
*/
#define OVERFLOW_STACK_SIZE \
  (50 + \
   sizeof(StackObject)/sizeof(PolyWord) + \
   NUMCHECKED + \
   NUMUNCHECKED + \
   EXTRA_STACK)


// This vector is pointed to by r13 
typedef struct MemRegisters {
    int inRTS;
        /* This is set when taskData->stack->p_pc and taskData->stack->p_sp are set */
    int requestCode;
    int returnReason;

    PolyWord    *heapPointer;
    PolyWord    *heapBase;
    StackObject *polyStack;
    PolyWord    *stackLimit;
    byte        *heapOverflow;
    byte        *stackOverflow;
    byte        *stackOverflowEx;
    byte        *raiseException;
    byte        *ioEntry; /* Offset 44 */
    byte        *raiseDiv;
    byte        *arbEmulation;
    PolyWord    *stackTop; // Used in "raisex"
    PolyObject  *threadId;
} MemRegisters;

class PowerPCTaskData: public MDTaskData {
public:
    PowerPCTaskData(): allocWords(0)
    {
    memRegisters.inRTS = 1; // We start off in the RTS.
    }
    POLYUNSIGNED allocWords; // The words to allocate.
    MemRegisters memRegisters;
};

class PowerPCDependent: public MachineDependent {
public:
    PowerPCDependent() {}

    // Create a task data object.
    virtual MDTaskData *CreateTaskData(void) { return new PowerPCTaskData(); }

    virtual void InitStackFrame(TaskData *taskData, Handle stack, Handle proc, Handle arg);
    virtual unsigned InitialStackSize(void) { return 128+OVERFLOW_STACK_SIZE; } // Initial size of a stack 
    virtual int SwitchToPoly(TaskData *taskData);
    virtual void SetForRetry(TaskData *taskData, int ioCall);
    virtual void InitInterfaceVector(void);
    virtual void SetException(TaskData *taskData, poly_exn *exc);
    virtual void ResetSignals(void);
    virtual void ScanConstantsWithinCode(PolyObject *addr, PolyObject *oldAddr, POLYUNSIGNED length, ScanAddress *process);
    virtual void InterruptCode(TaskData *taskData);
    virtual int  GetIOFunctionRegisterMask(int ioCall);
    virtual bool GetPCandSPFromContext(TaskData *taskData, SIGNALCONTEXT *context, PolyWord *&sp, POLYCODEPTR &pc);
    virtual void CallIO0(TaskData *taskData, Handle(*ioFun)(TaskData *));
    virtual void CallIO1(TaskData *taskData, Handle(*ioFun)(TaskData *, Handle));
    virtual void CallIO2(TaskData *taskData, Handle(*ioFun)(TaskData *, Handle, Handle));
    virtual void CallIO3(TaskData *taskData, Handle(*ioFun)(TaskData *, Handle, Handle, Handle));
    virtual void CallIO4(TaskData *taskData, Handle(*ioFun)(TaskData *, Handle, Handle, Handle, Handle));
    virtual void CallIO5(TaskData *taskData, Handle(*ioFun)(TaskData *, Handle, Handle, Handle, Handle, Handle));
    virtual Handle CallBackResult(TaskData *taskData);
    virtual void SetExceptionTrace(TaskData *taskData);
    virtual void CallCodeTupled(TaskData *taskData);
    virtual void SetCodeConstant(TaskData *taskData, Handle data, Handle constant, Handle offseth, Handle base);
    virtual void FlushInstructionCache(void *p, POLYUNSIGNED bytes);
    virtual Architectures MachineArchitecture(void) { return MA_PPC; } 
    // Increment or decrement the first word of the object pointed to by the
    // mutex argument and return the new value.
    virtual Handle AtomicIncrement(TaskData *taskData, Handle mutexp);
    virtual Handle AtomicDecrement(TaskData *taskData, Handle mutexp);

private:

    void StartIOCall(TaskData *taskData);
    void SetMemRegisters(TaskData *taskData);
    void HeapOverflowTrap(TaskData *taskData);
    void ArbitraryPrecisionTrap(TaskData *taskData);

    Handle BuildCodeSegment(TaskData *taskData, const byte *code, unsigned codeWords, char functionName);
    Handle BuildKillSelfCode(TaskData *taskData);

};


// Entry code sequences - copied to memRegisters before entering ML.
static byte *heapOverflow, *stackOverflow, *stackOverflowEx, *raiseDiv, *arbEmulation;

// Functions in the assembly code segment.
extern "C" {
extern int str_compare();
extern int teststreq();
extern int teststrneq();
extern int teststrgtr();
extern int teststrlss();
extern int teststrgeq();
extern int teststrleq();
extern int locksega();
extern int add_long();
extern int sub_long(); 
extern int mult_long();
extern int div_long();
extern int rem_long();
extern int neg_long();
extern int or_long();
extern int and_long();
extern int xor_long();
extern int equal_long();
extern int shift_right_word();
extern int word_neq();
extern int not_bool();
extern int string_length();
extern int int_eq();
extern int int_neq();
extern int int_geq();
extern int int_leq();
extern int int_gtr();
extern int int_lss();
extern int or_word();
extern int and_word();
extern int xor_word();
extern int shift_left_word();
extern int word_eq();
extern int load_byte();
extern int load_word();
extern int assign_byte();
extern int assign_word();
extern int kill_selfa();
extern int alloc_store();
extern int get_length_a();
extern int int_to_word();
extern int move_bytes();
extern int move_words();
extern int shift_right_arith_word();
extern int raisex();
extern int extrace_normal_return();
extern int offset_address();
extern int is_shorta();
extern int is_big_endian();
extern int bytes_per_word();
extern int mul_word();
extern int plus_word();
extern int minus_word();
extern int div_word();
extern int mod_word();
extern int word_geq();
extern int word_leq();
extern int word_gtr();
extern int word_lss();
extern int set_string_length_a();
extern int get_first_long_word_a();
extern int atomic_incr();
extern int atomic_decr();
extern int thread_self();
extern void PPCAsmSwitchToPoly(struct MemRegisters *);
extern void MD_flush_instruction_cache(void *p, POLYUNSIGNED bytes);
extern void PPCSaveStateAndReturn(void);
};

/******************************************************************************/
/*                                                                            */
/*      Stack Frame                                                           */
/*                                                                            */
/******************************************************************************/

/*

What do we store in the ML stack object?

  p_space
  p_pc
  p_sp (r30)
  p_hr (r31)
  p_nregs = 27
  20 tagged registers (r3-r10, r14-r25)
  the literal 3
  3 untagged registers (r11, r12, CR)
  the real ML stack
  
Register Usage
--------------

r0 scratch register (unsaved?)
r1 - don't touch - dedicated C register (stack - like SPARC %o6) 
r2 - don't touch - dedicated C register (TOC) (Is the relevant now?)
r3      used for the first argument to a function, and for the result.
r4-r6  used for the next 3 args, any others being passed on the stack.
(We may later decide to use r7-r10 for parameters too).
 
r24        is the closure pointer or static link pointer
r25 (rr)   is used as the compiler-visible link register
r26        is an RTS scratch register (unsaved).
r27 (rsp)  is the ML stack pointer,
r28        is no longer used (formerly the stack limit reg)
r29 (rhp)  is the heap pointer,
r30 (rhl)  is the heap limit,
r31 (rhr)  points to the top exception handler.

r7-r10 and r14-r23 (15 registers) are available as general work registers,
as are r3-r6 and r24-r25, when they are not fulfilling their specialised
duties. That's a total of 20 general-purpose registers (as opposed to
17 on the SPARC).

r11, r12 are used as code-generator visible untagged registers.
r26 is used as a compiler-invisible RTS scratch register for
handling traps.

LR is a semi-volatile register used to cache the return address.
Executing a trap can copy rr into LR, even if it wasn't
there before. Furthermore, it can change the tagged status of
LR - it may be tagged after the trap, even if it was untagged
before. What we do guarantee is that if LR cached rr before
the trap, then it caches it afterwards (modulo possible tag bit
discrepancies). Executing any function call (including an RTS
call) invalidates both rr and LR.

CTR is a volatile register - we use it to to return from traps
and normal RTS calls, and it is also used to implement tail-calls.

*/
#define ML_HR 31
#define ML_HL 30
#define ML_HP 29
#define ML_SL 28
#define ML_SP 27

/* The first instruction executed after native code returns
   is the saved return address -2 */ 
#define RETURNOFFSET 2

/* The first instruction executed in a handler
   is the stored address -2 */
#define HANDLEROFFSET 2

#ifndef NOISY
#define NOISY 0
#endif
#define NOTIFYGC 0

// InitStackFrame.  Set up a stack frame for a new thread (process).
void PowerPCDependent::InitStackFrame(TaskData *taskData, Handle stackh, Handle proc, Handle arg)
/* Initialise stack frame. */
{
    StackObject *stack = (StackObject *)DEREFWORDHANDLE(stackh);
    POLYUNSIGNED stack_size = stack->Length();
    stack->p_space = OVERFLOW_STACK_SIZE;
    stack->p_pc = PC_RETRY_SPECIAL; /* As if we had called MD_set_for_retry. */
    stack->p_nreg = NUMCHECKED; /* r3-r8, r13-r25, link */
    stack->p_hr = stack->Offset(stack_size-3);
    stack->p_sp  = stack->Offset(stack_size-3); /* sp */
    /* Reset all registers since this may be an old stack frame */
    for (unsigned i = 0; i < NUMCHECKED; i++)
        stack->p_reg[i] = TAGGED(0);
        
    // Set the default handler and return address to point to this code.
    // We have to offset the addresses by two bytes because the code to enter and a handler
    // or return from a function always subtracts two.
    Handle killCode = BuildKillSelfCode(taskData);
    PolyWord killJump = PolyWord::FromUnsigned(killCode->Word().AsUnsigned() | HANDLEROFFSET);
    stack = (StackObject *)DEREFWORDHANDLE(stackh); // In case it's moved

    stack->PS_R24 = DEREFWORD(proc); /* Set r24 to the closure address. */
    stack->PS_LR = killJump; /* Set link reg to code to kill process. */
    stack->p_reg[NUMCHECKED] = PolyWord::FromUnsigned(NUMUNCHECKED); /* 3 unchecked registers. */
    /* Since they're unchecked, they don't need to be initialised,
       but set them to 0 anyway. */
    stack->PS_R11 = PolyWord::FromUnsigned(0);
    stack->PS_R12 = PolyWord::FromUnsigned(0);
    stack->PS_CR0 = PolyWord::FromUnsigned(0);
    /* If this function takes an argument store it in the argument register. */
    if (arg != 0) stack->PS_R3 = DEREFWORD(arg);
    /* No previous handler so point it at itself. */
    stack->Set(stack_size-1, PolyWord::FromStackAddr(stack->Offset(stack_size-1)));

    /* Default handler. */
    stack->Set(stack_size-2, killJump);
    /* Set up exception handler */
    stack->Set(stack_size-3, TAGGED(0)); /* Default handler. */
}

// These are just for debugging.  They record the last point before
// the memory was checked.
byte *lastPC;
int lastRequest, lastReason;

// SwitchToPoly - start running Poly code.  
int PowerPCDependent::SwitchToPoly(TaskData *taskData)
/* (Re)-enter the Poly code from C. */
{
    PowerPCTaskData *mdTask = (PowerPCTaskData*)taskData->mdTaskData;
    Handle mark = taskData->saveVec.mark();
    while (1)
    {
        taskData->saveVec.reset(mark); // Remove old data e.g. from arbitrary precision.
        CheckMemory(); // Do any memory checking.

        // Remember the position after the last time we checked
        // the memory.
        lastPC = taskData->stack->p_pc;
        lastRequest = mdTask->memRegisters.requestCode;
        lastReason = mdTask->memRegisters.returnReason;
        
        SetMemRegisters(taskData);

        PPCAsmSwitchToPoly(&mdTask->memRegisters); // Load registers.  Returns as a result of an RTS call.
        taskData->allocPointer = mdTask->memRegisters.heapPointer; // Get updated limit pointer.
        mdTask->allocWords = 0;

        switch (mdTask->memRegisters.returnReason)
        {
        case RETURN_IO_CALL:
            // The ML code wants an IO call.
            return mdTask->memRegisters.requestCode;

        case RETURN_HEAP_OVERFLOW:
            try {
                // The heap has overflowed.  Put the return address into the program counter.
                // It may well not be a valid code address anyway.
                taskData->stack->p_pc = (byte*)taskData->stack->PS_LR.AsUnsigned();
                taskData->stack->PS_LR = TAGGED(0); // Clobber this
                HeapOverflowTrap(taskData);
            }
            catch (IOException) {
                // We may get an exception while handling this if we run out of store
            }
            break;

        case RETURN_STACK_OVERFLOW:
            try {
                // The stack check has failed.  This may either be because we really have
                // overflowed the stack or because the stack limit value has been adjusted
                // to result in a call here.
                taskData->stack->p_pc = (byte*)taskData->stack->PS_LR.AsUnsigned();
                // Restore the original value from the link register (with the
                // +2 byte tagging).  This enables the link register caching to work.
                taskData->stack->PS_LR = taskData->stack->PS_R25;
                CheckAndGrowStack(taskData, taskData->stack->p_sp);
            }
            catch (IOException) {
               // We may get an exception while handling this if we run out of store
            }
            return -1; // We're in a safe state to handle any interrupts.

        case RETURN_STACK_OVERFLOWEX:
            try {
                // Stack limit overflow.  If the required stack space is larger than
                // the fixed overflow size the code will calculate the limit in rtemp1
                PolyWord *stackP = taskData->stack->PS_R11.AsStackAddr();
                taskData->stack->p_pc = (byte*)taskData->stack->PS_LR.AsUnsigned();
                taskData->stack->PS_LR = taskData->stack->PS_R25; // Restore LR
                CheckAndGrowStack(taskData, stackP);
            }
            catch (IOException) {
               // We may get an exception while handling this if we run out of store
            }
            return -1; // We're in a safe state to handle any interrupts.

        case RETURN_RAISE_DIV:
            try {
                // Generally arithmetic operations don't raise exceptions.  Overflow
                // is either ignored, for Word operations, or results in a call to
                // the abitrary precision emulation code.  This is the exception
                // (no pun intended).
                taskData->stack->p_pc = (byte*)taskData->stack->PS_LR.AsUnsigned();
                taskData->stack->PS_LR = TAGGED(0);
                // Set all the registers to a safe value here.  We will almost certainly
                // have shifted a value in one of the registers before testing it for zero.
                // This may not actually be needed on the PPC
                for (POLYUNSIGNED i = 0; i < taskData->stack->p_nreg; i++)
                    taskData->stack->p_reg[i] = TAGGED(0);
                raise_exception0(taskData, EXC_divide);
            }
            catch (IOException) {
                // Handle the C++ exception.
            }
            break;

        case RETURN_ARB_EMULATION:
            try {
                taskData->stack->p_pc = (byte*)taskData->stack->PS_LR.AsUnsigned();
                taskData->stack->PS_LR = TAGGED(0);
                ArbitraryPrecisionTrap(taskData);
            }
            catch (IOException) {
                // We may get an exception in the trap handler e.g. if we run out of store.
            }
            break;
        }
    }
}

void PowerPCDependent::SetMemRegisters(TaskData *taskData)
{
    PowerPCTaskData *mdTask = (PowerPCTaskData*)taskData->mdTaskData;
    mdTask->memRegisters.requestCode = 0;
    mdTask->memRegisters.returnReason = RETURN_IO_CALL;

    // If we haven't yet set the allocation area or we don't have enough we need
    // to create one (or a new one).
    if (taskData->allocPointer <= taskData->allocLimit + mdTask->allocWords ||
        (userOptions.debug & DEBUG_FORCEGC))
    {
        if (taskData->allocPointer < taskData->allocLimit)
            Crash ("Bad length in heap overflow trap");

        // Find some space to allocate in.  Updates taskData->allocPointer and
        // returns a pointer to the newly allocated space (if allocWords != 0)
        (void)processes->FindAllocationSpace(taskData, mdTask->allocWords, true);
    }
    else if (mdTask->allocWords != 0) // May just be store profiling.
        taskData->allocPointer -= mdTask->allocWords;

    mdTask->memRegisters.polyStack = taskData->stack;
    mdTask->memRegisters.stackTop = taskData->stack->Offset(taskData->stack->Length());

    // Set the raiseException entry to point to the assembly code.
    mdTask->memRegisters.raiseException = (byte*)raisex;
    // Entry point to save the state for an IO call.  This is the common entry
    // point for all the return and IO-call cases.
    mdTask->memRegisters.ioEntry = (byte*)PPCSaveStateAndReturn;
    
    mdTask->memRegisters.heapOverflow = heapOverflow;
    mdTask->memRegisters.stackOverflow = stackOverflow;
    mdTask->memRegisters.stackOverflowEx = stackOverflowEx;
    mdTask->memRegisters.raiseDiv = raiseDiv;
    mdTask->memRegisters.arbEmulation = arbEmulation;

    // If we have run out of store, either just above or while allocating in the RTS,
    // allocPointer and allocLimit will have been set to zero as part of the GC.  We will
    // now be raising an exception which may free some store but we need to come back here
    // before we allocate anything.  The compiled code uses unsigned arithmetic to check for
    // heap overflow but only after subtracting the space required.  We need to make sure
    // that the values are still non-negative after substracting any object size.
    if (taskData->allocPointer == 0) taskData->allocPointer += MAX_OBJECT_SIZE;
    if (taskData->allocLimit == 0) taskData->allocLimit += MAX_OBJECT_SIZE;

    mdTask->memRegisters.heapPointer = taskData->allocPointer;

    // If we want heap profiling set the size to zero otherwise to the free space.
    // Setting this to zero may result in the heap size register becoming negative.
    // The code to allocate memory generated by the code generator tests for space,
    // traps if it is negative and afterwards subtracts the allocated space from
    // the space available.  If we set it to zero here it will then become negative.
    if (profileMode == kProfileStoreAllocation || (userOptions.debug & DEBUG_REGION_CHECK))
        mdTask->memRegisters.heapBase = taskData->allocPointer;
    else
        mdTask->memRegisters.heapBase = taskData->allocLimit;
    // Whenever the ML code enters a function it checks that the stack pointer is above
    // this value.  The default is to set it to the top of the reserved area
    // but if we've had an interrupt we set it to the end of the stack.
    // InterruptCode may be called either when the thread is in the RTS or in ML code.    
    if (taskData->pendingInterrupt)
        mdTask->memRegisters.stackLimit = taskData->stack->Offset(taskData->stack->Length()-1);
    else mdTask->memRegisters.stackLimit = taskData->stack->Offset(taskData->stack->p_space);
    mdTask->memRegisters.threadId = taskData->threadObject;

    if (taskData->stack->p_pc == PC_RETRY_SPECIAL)
        // We need to retry the call.  The entry point should be the
        // first word of the closure which is in r24.
        taskData->stack->p_pc = taskData->stack->PS_R24.AsObjPtr()->Get(0).AsCodePtr();
}

// Called as part of the call of an IO function.
void PowerPCDependent::StartIOCall(TaskData *taskData)
{
    // Set the return address to be the contents of the link register.
    // This is a real return address which is safe for the p_pc field but
    // not allowed to remain in a register field.  We have to add the
    // return offset there.  Because this may be a retry of the call we may
    // already have put in the offset in which case we have to remove it before we
    // put it into the pc.
    taskData->stack->p_pc = (byte*)(taskData->stack->PS_LR.AsUnsigned() & ~RETURNOFFSET);
    taskData->stack->PS_LR = PolyWord::FromUnsigned(taskData->stack->PS_LR.AsUnsigned() | RETURNOFFSET);
}

// IO Functions called indirectly from assembly code.
void PowerPCDependent::CallIO0(TaskData *taskData, Handle (*ioFun)(TaskData *))
{
    StartIOCall(taskData);
    try {
        Handle result = (*ioFun)(taskData);
        taskData->stack->PS_R3 = result->Word();
    }
    catch (IOException exc) {
        switch (exc.m_reason)
        {
        case EXC_EXCEPTION:
            return;
        case EXC_RETRY:
            return;
        }
    }
}

void PowerPCDependent::CallIO1(TaskData *taskData, Handle (*ioFun)(TaskData *, Handle))
{
    StartIOCall(taskData);
    Handle saved1 = taskData->saveVec.push(taskData->stack->PS_R3);
    try {
        Handle result = (*ioFun)(taskData, saved1);
        taskData->stack->PS_R3 = result->Word();
    }
    catch (IOException exc) {
        switch (exc.m_reason)
        {
        case EXC_EXCEPTION:
            return;
        case EXC_RETRY:
            return;
        }
    }
}

void PowerPCDependent::CallIO2(TaskData *taskData, Handle (*ioFun)(TaskData *, Handle, Handle))
{
    StartIOCall(taskData);
    Handle saved1 = taskData->saveVec.push(taskData->stack->PS_R3);
    Handle saved2 = taskData->saveVec.push(taskData->stack->PS_R4);
    try {
        Handle result = (*ioFun)(taskData, saved2, saved1);
        taskData->stack->PS_R3 = result->Word();
    }
    catch (IOException exc) {
        switch (exc.m_reason)
        {
        case EXC_EXCEPTION:
            return;
        case EXC_RETRY:
            return;
        }
    }
}

void PowerPCDependent::CallIO3(TaskData *taskData, Handle (*ioFun)(TaskData *, Handle, Handle, Handle))
{
    StartIOCall(taskData);
    Handle saved1 = taskData->saveVec.push(taskData->stack->PS_R3);
    Handle saved2 = taskData->saveVec.push(taskData->stack->PS_R4);
    Handle saved3 = taskData->saveVec.push(taskData->stack->PS_R5);
    try {
        Handle result = (*ioFun)(taskData, saved3, saved2, saved1);
        taskData->stack->PS_R3 = result->Word();
    }
    catch (IOException exc) {
        switch (exc.m_reason)
        {
        case EXC_EXCEPTION:
            return;
        case EXC_RETRY:
            return;
        }
    }
}

void PowerPCDependent::CallIO4(TaskData *taskData, Handle (*ioFun)(TaskData *, Handle, Handle, Handle, Handle))
{
    StartIOCall(taskData);
    Handle saved1 = taskData->saveVec.push(taskData->stack->PS_R3);
    Handle saved2 = taskData->saveVec.push(taskData->stack->PS_R4);
    Handle saved3 = taskData->saveVec.push(taskData->stack->PS_R5);
    Handle saved4 = taskData->saveVec.push(taskData->stack->PS_R6);
    try {
        Handle result = (*ioFun)(taskData, saved4, saved3, saved2, saved1);
        taskData->stack->PS_R3 = result->Word();
    }
    catch (IOException exc) {
        switch (exc.m_reason)
        {
        case EXC_EXCEPTION:
            return;
        case EXC_RETRY:
            return;
        }
    }
}

// The only functions with 5 args are move_bytes/word_long
void PowerPCDependent::CallIO5(TaskData *taskData, Handle (*ioFun)(TaskData *, Handle, Handle, Handle, Handle, Handle))
{
    StartIOCall(taskData);
    Handle saved1 = taskData->saveVec.push(taskData->stack->PS_R3);
    Handle saved2 = taskData->saveVec.push(taskData->stack->PS_R4);
    Handle saved3 = taskData->saveVec.push(taskData->stack->PS_R5);
    Handle saved4 = taskData->saveVec.push(taskData->stack->PS_R6);
    Handle saved5 = taskData->saveVec.push(taskData->stack->p_sp[0]);
    try {
        Handle result = (*ioFun)(taskData, saved5, saved4, saved3, saved2, saved1);
        taskData->stack->PS_R3 = result->Word();
        taskData->stack->p_sp++; // Pop the final argument now we're returning.
    }
    catch (IOException exc) {
        switch (exc.m_reason)
        {
        case EXC_EXCEPTION:
            return;
        case EXC_RETRY:
            return;
        }
    }
}

// Return the callback result.  The current ML process (thread) terminates.
Handle PowerPCDependent::CallBackResult(TaskData *taskData)
{
    return taskData->saveVec.push(taskData->stack->PS_R3); // Argument to return is in r3.
}

bool PowerPCDependent::GetPCandSPFromContext(TaskData *taskData, SIGNALCONTEXT *scp, PolyWord *&sp, POLYCODEPTR &pc)
{
    PowerPCTaskData *mdTask = (PowerPCTaskData*)taskData->mdTaskData;
    if (mdTask->memRegisters.inRTS)
    {
        sp = taskData->stack->p_sp;
        pc = taskData->stack->p_pc;
        return true;
    }
    else {
        sp = (PolyWord *)(GPSP(scp));
        pc = (byte *)(NIP(scp));
        return true;
    }
}

void PowerPCDependent::InterruptCode(TaskData *taskData)
{
    PowerPCTaskData *mdTask = (PowerPCTaskData*)taskData->mdTaskData;
    // Set the stack limit pointer to the top of the stack to cause
    // a trap when we next check for stack overflow.
    // SetMemRegisters actually does this anyway if "pendingInterrupt" is set but
    // it's safe to do this repeatedly.
    if (taskData->stack != 0) 
        mdTask->memRegisters.stackLimit = taskData->stack->Offset(taskData->stack->Length()-1); 
    taskData->pendingInterrupt = true;
}

void PowerPCDependent::SetForRetry(TaskData *taskData, int ioCall)
{
    taskData->stack->p_pc = PC_RETRY_SPECIAL; /* This value is treated specially. */
}

static PolyWord *get_reg(TaskData *taskData, int rno)
/* Returns a pointer to the register given by the 5 bit value rno. */
{
    /* Registers r0, r1, r2, r26, ML_SL, ML_HL and ML_HP should not be
       needed by the emulation code. */
    switch (rno)
    {
    case 3: return &taskData->stack->PS_R3;
    case 4: return &taskData->stack->PS_R4;
    case 5: return &taskData->stack->PS_R5;
    case 6: return &taskData->stack->PS_R6;
    case 7: return &taskData->stack->PS_R7;
    case 8: return &taskData->stack->PS_R8;
    case 9: return &taskData->stack->PS_R9;
    case 10: return &taskData->stack->PS_R10;
    case 11: return &taskData->stack->PS_R11;
    case 12: return &taskData->stack->PS_R12;
    case 14: return &taskData->stack->PS_R14;
    case 15: return &taskData->stack->PS_R15;
    case 16: return &taskData->stack->PS_R16;
    case 17: return &taskData->stack->PS_R17;
    case 18: return &taskData->stack->PS_R18;
    case 19: return &taskData->stack->PS_R19;
    case 20: return &taskData->stack->PS_R20;
    case 21: return &taskData->stack->PS_R21;
    case 22: return &taskData->stack->PS_R22;
    case 23: return &taskData->stack->PS_R23;
    case 24: return &taskData->stack->PS_R24;
    case 25: return &taskData->stack->PS_R25;
    case ML_SP: return (PolyWord*)&taskData->stack->p_sp;
    case ML_HR: return (PolyWord*)&taskData->stack->p_hr;
    default:
        Crash("Unknown register %d at 0x%8x\n", rno, (int)(taskData->stack->p_pc));
    }
}

static void set_CR0(TaskData *taskData, int CR0)
{
    /* insert CR0 into condition register */
    taskData->stack->PS_CR0 =
      PolyWord::FromUnsigned(
        (taskData->stack->PS_CR0.AsUnsigned() & 0x0fffffff) | (CR0 << 28));
}

// Get the next instruction in the sequence, skipping over any
// branch-forwarding jumps that the code-generator may have inserted.
static POLYUNSIGNED getNextInstr(TaskData *taskData)
{
    while (1) {
        POLYUNSIGNED instr = *(POLYUNSIGNED*)taskData->stack->p_pc;
        if ((instr & 0xfc000000) == 0x48000000)
        {
            POLYUNSIGNED offset = (instr >> 2) & 0xffffff;
            ASSERT((offset & 0x800000) == 0); // Shouldn't be a jump back.
            taskData->stack->p_pc += offset*sizeof(PolyWord);
        }
        else
        {
            taskData->stack->p_pc += sizeof(PolyWord); // Skip this instr
            return instr;
        }
    }
}

static void emulate_trap(TaskData *taskData, POLYUNSIGNED instr)
/* Emulate an "addo.", "subfco.", "cmpw" or "cmpwi" instruction */
{
    
    unsigned opcode   = (instr >> 26) & 0x3f;  /*  6 bits */
    unsigned RT       = (instr >> 21) & 0x1f;  /*  5 bits */
    unsigned RA       = (instr >> 16) & 0x1f;  /*  5 bits */
    
    /* added 19/12/95 SPF */
    if (profileMode == kProfileEmulation)
    {
        add_count(taskData, taskData->stack->p_pc, taskData->stack->p_sp, 1);
    }
    
#define OPCODE2_addodot   ((1 << 10) | (266 << 1) | 1)   
#define OPCODE2_subfcodot ((1 << 10) | (8   << 1) | 1)   
#define OPCODE2_cmp       ((0 << 10) | (0   << 1) | 0)
#define OPCODE2_srawi                 ((824 << 1) | 0)
    
    /* We emulate comparisons only if they use CR field 0 */
    if (opcode == 11 && RT == 0)
    {
        /* cmpwi  RA,SI */
        int UI = instr & 0xffff; /* 16 bits */
        
        /* signed comparisons sign-extend the immediate. */
        int exp2_15 = 1 << 15;
        int exp2_16 = 1 << 16;
        int SI = (UI < exp2_15) ? UI : UI - exp2_16;
        
        Handle arg1 = taskData->saveVec.push(*get_reg(taskData, RA));
        Handle arg2 = taskData->saveVec.push(PolyWord::FromSigned(SI));
        
        {
            /* arguments to comp_longc are backwards */
            int res = compareLong(taskData, arg2,arg1);
            
            switch (res)
            {
            case 1: /* arg1 > arg2 */
                set_CR0(taskData, 0x4); /* not LT; GT; not EQ; not SO */
                break;
                
            case 0: /* arg1 = arg2 */
                set_CR0(taskData, 0x2); /* not LT; not GT; EQ; not SO */
                break;
                
            case -1: /* arg1 < arg2 */
                set_CR0(taskData, 0x8); /* LT; not GT; not EQ; not SO */
                break;
                
            default:
                Crash("Bad return value 0x%08x from comp_longc\n", res);
                break;
            }
        }
        
    } /* opcode == 11 */
    
    else if (opcode == 31)
    { 
        unsigned RB       = (instr >> 11) & 0x1f;  /*  5 bits */
        unsigned opcode2  = instr & 0x7ff;         /* 11 bits */
        
        if (opcode2 == OPCODE2_addodot)
        {
            PolyWord a1 = *get_reg(taskData, RA);
            PolyWord a2 = *get_reg(taskData, RB);
            /* We may have trapped either because one of the arguments
               was long or because of overflow.  In the latter case
               we may well have modified the destination register already.
               That's fine unless RT == RA. */
            if (RB != 12) Crash("RB != regtemp2");
            a2 = PolyWord::FromUnsigned(a2.AsUnsigned() + 1); /* We've removed the tag from this. */
            /* printf("Emulating addition rt=%d, ra=%d, rb=%d\n", RT, RA, RB); */
            if (IS_INT(a1) && IS_INT(a2))
            {
                /* Must have been overflow.  May have to undo the addition. */
                if (RT == RA) a1 = PolyWord::FromUnsigned(a1.AsUnsigned() - (a2.AsUnsigned()-1));
            }
            Handle arg1 = taskData->saveVec.push(a1);
            Handle arg2 = taskData->saveVec.push(a2);
            Handle res = add_longc(taskData, arg2, arg1);
            
            /* store result in RT */
            *(get_reg(taskData, RT)) = DEREFWORD(res);
            
            /* we don't emulate the condition codes properly,
            but we MUST ensure that we reset the SO flag,
            because the compiled code tests this flag.
            If we left it set, the compiled code would loop
            back to re-emulate the instruction, giving us an
            endless succession of traps. SPF 11/8/95
            */
            set_CR0(taskData, 0x0); /* not LT; not GT; not EQ; not SO */
        }
        
        else if (opcode2 == OPCODE2_subfcodot)
        {
            /* We may have trapped either because one of the arguments
               was long or because of overflow.  In the latter case
               we may well have modified the destination register already.
               That's fine unless RT == RA or RT == RB. */
            PolyWord a1 = *get_reg(taskData, RA);
            PolyWord a2 = *get_reg(taskData, RB);
            /* printf("Emulating subtraction rt=%d, ra=%d, rb=%d\n", RT, RA, RB); */
            if (RA == 12) a1 = PolyWord::FromUnsigned(a1.AsUnsigned() + 1);
            else if (RB == 12) a2 = PolyWord::FromUnsigned(a2.AsUnsigned() - 1);
            else Crash("RA != regtemp2 and RB != regtemp2");
            if (IS_INT(a1) && IS_INT(a2))
            {
                /* Must have been overflow.  May have to undo the
                    subtraction. */
                if (RT == RB)
                    a2 = PolyWord::FromUnsigned(a2.AsUnsigned() + (a1.AsUnsigned()-1));
                else if (RT == RB)
                    a1 = PolyWord::FromUnsigned((a2.AsUnsigned()+1) - a1.AsUnsigned());
            }
            
            Handle arg1 = taskData->saveVec.push(a1);
            Handle arg2 = taskData->saveVec.push(a2);
            /* subf is *reversed* subtraction, but sub_longc
            (currently) expects reversed arguments, so the
            following call ought to be correct. */
            Handle res = sub_longc(taskData, arg1, arg2);
            
            /* store result in RT */
            *(get_reg(taskData, RT)) = DEREFWORD(res);
            
            /* we don't emulate the condition codes properly,
            but we MUST ensure that we reset the SO flag.
            */
            set_CR0(taskData, 0x0); /* not LT; not GT; not EQ; not SO */
        }
        
        /* We emulate comparisons only if they use CR field 0 */
        else if (opcode2 == OPCODE2_cmp && RT == 0)
        {
            /* arguments to comp_longc are backwards */
            PolyWord a1 = *get_reg(taskData, RA);
            PolyWord a2 = *get_reg(taskData, RB);
            Handle arg1 = taskData->saveVec.push(a1);
            Handle arg2 = taskData->saveVec.push(a2);
            int res = compareLong(taskData, arg2,arg1);
            
            switch (res)
            {
            case 1: /* arg1 > arg2 */
                set_CR0(taskData, 0x4); /* not LT; GT; not EQ; not SO */
                break;
                
            case 0: /* arg1 = arg2 */
                set_CR0(taskData, 0x2); /* not LT; not GT; EQ; not SO */
                break;
                
            case -1: /* arg1 < arg2 */
                set_CR0(taskData, 0x8); /* LT; not GT; not EQ; not SO */
                break;
                
            default:
                Crash("Bad return value 0x%08x from comp_longc\n", res);
                break;
            }
        }
        else if (opcode2 == OPCODE2_srawi)
        {
            /* Start of multiply sequence.  taskData->stack->p_pc now
                points at the multiply. */
            PolyWord a1 = *get_reg(taskData, RT); /* srawi has regs reversed. */
            PolyWord a2 = *get_reg(taskData, 12); /* The second arg is in regtemp2. */
            POLYUNSIGNED mullwInstr = getNextInstr(taskData);
            assert(RA == 11); /* destination of srawi. */
            /* Should be mullwo. rt,r12,r11 */
            assert((mullwInstr & 0xfc1fffff) == 0x7C0C5DD7);
            RT = (mullwInstr >> 21) & 0x1f;
            Handle arg1 = taskData->saveVec.push(a1);
            Handle arg2 = taskData->saveVec.push(PolyWord::FromUnsigned(a2.AsUnsigned()+1)); /* This has been untagged. */
            Handle res = mult_longc(taskData, arg2, arg1);
            *(get_reg(taskData, RT)) = PolyWord::FromUnsigned(DEREFWORD(res).AsUnsigned() - 1); /* Next instr will tag it. */
            set_CR0(taskData, 0x0); /* Clear overflow bit. */
        }
        
        else
        {
            Crash("Can't emulate instruction: 0x%08x\n",instr);
        }
        
    } /* opcode == 31 */
    
    else /* opcode != 11 && opcode != 31 */
    {
        Crash("Can't emulate instruction: 0x%08x\n",instr);
    } 
    
}

void PowerPCDependent::ArbitraryPrecisionTrap(TaskData *taskData)
{
    emulate_trap(taskData, getNextInstr(taskData));
}

void PowerPCDependent::HeapOverflowTrap(TaskData *taskData)
{
    PowerPCTaskData *mdTask = (PowerPCTaskData*)taskData->mdTaskData;
    // When we come here we have attempted to allocate some memory by
    // decrementing the heap pointer register.  We have compared it against
    // the heap base and found there is insufficient space.  That may be a
    // fake trap for heap profiling or it may be a real trap.
    // R12 should contain the length word.
    POLYUNSIGNED lengthWord = taskData->stack->PS_R12.AsUnsigned();
    // We need one extra word for the length word itself.
    POLYUNSIGNED wordsNeeded = OBJ_OBJECT_LENGTH(lengthWord) + 1;
    
    if (profileMode == kProfileStoreAllocation)
        add_count(taskData, taskData->stack->p_pc, taskData->stack->p_sp, wordsNeeded);
    else if (taskData->allocPointer >= taskData->allocLimit && ! (userOptions.debug & DEBUG_REGION_CHECK)) 
        Crash ("Spurious heap-limit trap");
    
    taskData->allocPointer += wordsNeeded; // Adjust the heap pointer back
    mdTask->allocWords = wordsNeeded; // Actually allocate it in SetMemRegisters.
}

// This is the number of words in the call sequence
#define MAKE_CALL_SEQUENCE_WORDS 5

#ifdef MACOSX
// Mac OS X uses an older assembler syntax.
#define MAKE_IO_CALL_SEQUENCE(ioNum, result) \
{ \
    __asm__ __volatile__ ( "bl 1f \n" \
           "li r0,%1 \n" \
           "stw r0,4(r13) \n" \
           "lwz r0,44(r13) \n" \
           "mtctr r0 \n" \
           "bctr \n" \
           "1: mflr r0 \n" \
           "stw r0,%0" \
           :"=m"(result) \
           :"i"(ioNum) \
           : "lr","r0" \
           ); \
}

#else
// Linux
#define MAKE_IO_CALL_SEQUENCE(ioNum, result) \
{ \
    __asm__ __volatile__ ( "bl 1f;" \
           "li 0,%1;" \
           "stw 0,4(13);" \
           "lwz 0,44(13);" \
           "mtctr 0;" \
           "bctr;" \
           "1: mflr 0;" \
           "stw 0,%0" \
           :"=m"(result) \
           :"i"(ioNum) \
           :"lr","0" \
           ); \
}

#endif

#ifdef MACOSX
// Mac OS X uses an older assembler syntax.
#define MAKE_EXTRA_CALL_SEQUENCE(exNum, result) \
{ \
    __asm__ __volatile__ ( "bl 1f \n" \
           "li r0,%1 \n" \
           "stw r0,8(r13) \n" \
           "lwz r0,44(r13) \n" \
           "mtctr r0 \n" \
           "bctr \n" \
           "1: mflr r0 \n" \
           "stw r0,%0" \
           :"=m"(result) \
           :"i"(exNum) \
           :"lr","r0" \
           ); \
}

#else
// Linux
#define MAKE_EXTRA_CALL_SEQUENCE(exNum, result) \
{ \
    __asm__ __volatile__ ( "bl 1f;" \
           "li 0,%1;" \
           "stw 0,8(13);" \
           "lwz 0,44(13);" \
           "mtctr 0;" \
           "bctr;" \
           "1: mflr 0;" \
           "stw 0,%0" \
           :"=m"(result) \
           :"i"(exNum) \
           :"lr","0" \
           ); \
}

#endif


static void add_function_to_io_area(int x, int (*y)())
{
    add_word_to_io_area(x, PolyWord::FromUnsigned((POLYUNSIGNED)y));
}

void PowerPCDependent::InitInterfaceVector(void)
{     
    unsigned char *codeAddr;
    
    MAKE_IO_CALL_SEQUENCE(POLY_SYS_exit, codeAddr);
    add_word_to_io_area(POLY_SYS_exit, PolyWord::FromCodePtr(codeAddr));
    
    add_function_to_io_area(POLY_SYS_alloc_store, alloc_store);
    
    MAKE_IO_CALL_SEQUENCE(POLY_SYS_chdir, codeAddr);
    add_word_to_io_area(POLY_SYS_chdir, PolyWord::FromCodePtr(codeAddr));
    
    add_function_to_io_area(POLY_SYS_get_length, get_length_a);
    
    MAKE_IO_CALL_SEQUENCE(POLY_SYS_get_flags, codeAddr);    
    add_word_to_io_area(POLY_SYS_get_flags, PolyWord::FromCodePtr(codeAddr));
   
    add_function_to_io_area(POLY_SYS_str_compare, str_compare);
    add_function_to_io_area(POLY_SYS_teststreq, teststreq);
    add_function_to_io_area(POLY_SYS_teststrneq, teststrneq);
    add_function_to_io_area(POLY_SYS_teststrgtr, teststrgtr);
    add_function_to_io_area(POLY_SYS_teststrlss, teststrlss);
    add_function_to_io_area(POLY_SYS_teststrgeq, teststrgeq);
    add_function_to_io_area(POLY_SYS_teststrleq, teststrleq);
     
    MAKE_IO_CALL_SEQUENCE(POLY_SYS_exception_trace, codeAddr);    
    add_word_to_io_area(POLY_SYS_exception_trace, PolyWord::FromCodePtr(codeAddr));

    add_function_to_io_area(POLY_SYS_lockseg, locksega);
    
    MAKE_IO_CALL_SEQUENCE(POLY_SYS_profiler, codeAddr);
    add_word_to_io_area(POLY_SYS_profiler, PolyWord::FromCodePtr(codeAddr));
    
    add_function_to_io_area(POLY_SYS_is_short, is_shorta);
    add_function_to_io_area(POLY_SYS_aplus, add_long);
    add_function_to_io_area(POLY_SYS_aminus, sub_long);
    add_function_to_io_area(POLY_SYS_amul, mult_long);
    add_function_to_io_area(POLY_SYS_adiv, div_long);
    add_function_to_io_area(POLY_SYS_amod, rem_long);
    add_function_to_io_area(POLY_SYS_aneg, neg_long);
    add_function_to_io_area(POLY_SYS_equala, equal_long);
    add_function_to_io_area(POLY_SYS_ora, or_long);
    add_function_to_io_area(POLY_SYS_anda, and_long);
    add_function_to_io_area(POLY_SYS_xora, xor_long);
    
    MAKE_IO_CALL_SEQUENCE(POLY_SYS_Real_str, codeAddr);
    add_word_to_io_area(POLY_SYS_Real_str, PolyWord::FromCodePtr(codeAddr));
    MAKE_IO_CALL_SEQUENCE(POLY_SYS_Real_geq, codeAddr);
    add_word_to_io_area(POLY_SYS_Real_geq, PolyWord::FromCodePtr(codeAddr));
    MAKE_IO_CALL_SEQUENCE(POLY_SYS_Real_leq, codeAddr);
    add_word_to_io_area(POLY_SYS_Real_leq, PolyWord::FromCodePtr(codeAddr));
    MAKE_IO_CALL_SEQUENCE(POLY_SYS_Real_gtr, codeAddr);
    add_word_to_io_area(POLY_SYS_Real_gtr, PolyWord::FromCodePtr(codeAddr));
    MAKE_IO_CALL_SEQUENCE(POLY_SYS_Real_lss, codeAddr);
    add_word_to_io_area(POLY_SYS_Real_lss, PolyWord::FromCodePtr(codeAddr));
    MAKE_IO_CALL_SEQUENCE(POLY_SYS_Real_eq, codeAddr);
    add_word_to_io_area(POLY_SYS_Real_eq, PolyWord::FromCodePtr(codeAddr));
    MAKE_IO_CALL_SEQUENCE(POLY_SYS_Real_neq, codeAddr);
    add_word_to_io_area(POLY_SYS_Real_neq, PolyWord::FromCodePtr(codeAddr));
    MAKE_IO_CALL_SEQUENCE(POLY_SYS_Real_Dispatch, codeAddr);
    add_word_to_io_area(POLY_SYS_Real_Dispatch, PolyWord::FromCodePtr(codeAddr));
    MAKE_IO_CALL_SEQUENCE(POLY_SYS_Add_real, codeAddr);
    add_word_to_io_area(POLY_SYS_Add_real, PolyWord::FromCodePtr(codeAddr));
    MAKE_IO_CALL_SEQUENCE(POLY_SYS_Sub_real, codeAddr);
    add_word_to_io_area(POLY_SYS_Sub_real, PolyWord::FromCodePtr(codeAddr));
    MAKE_IO_CALL_SEQUENCE(POLY_SYS_Mul_real, codeAddr);
    add_word_to_io_area(POLY_SYS_Mul_real, PolyWord::FromCodePtr(codeAddr));
    MAKE_IO_CALL_SEQUENCE(POLY_SYS_Div_real, codeAddr);
    add_word_to_io_area(POLY_SYS_Div_real, PolyWord::FromCodePtr(codeAddr));
    MAKE_IO_CALL_SEQUENCE(POLY_SYS_Neg_real, codeAddr);
    add_word_to_io_area(POLY_SYS_Neg_real, PolyWord::FromCodePtr(codeAddr));
    MAKE_IO_CALL_SEQUENCE(POLY_SYS_Repr_real, codeAddr);
    add_word_to_io_area(POLY_SYS_Repr_real, PolyWord::FromCodePtr(codeAddr));
    MAKE_IO_CALL_SEQUENCE(POLY_SYS_conv_real, codeAddr);
    add_word_to_io_area(POLY_SYS_conv_real, PolyWord::FromCodePtr(codeAddr));
    MAKE_IO_CALL_SEQUENCE(POLY_SYS_real_to_int, codeAddr);
    add_word_to_io_area(POLY_SYS_real_to_int, PolyWord::FromCodePtr(codeAddr));
    MAKE_IO_CALL_SEQUENCE(POLY_SYS_int_to_real, codeAddr);
    add_word_to_io_area(POLY_SYS_int_to_real, PolyWord::FromCodePtr(codeAddr));
    MAKE_IO_CALL_SEQUENCE(POLY_SYS_sqrt_real, codeAddr);
    add_word_to_io_area(POLY_SYS_sqrt_real, PolyWord::FromCodePtr(codeAddr));
    MAKE_IO_CALL_SEQUENCE(POLY_SYS_sin_real, codeAddr);
    add_word_to_io_area(POLY_SYS_sin_real, PolyWord::FromCodePtr(codeAddr));
    MAKE_IO_CALL_SEQUENCE(POLY_SYS_cos_real, codeAddr);
    add_word_to_io_area(POLY_SYS_cos_real, PolyWord::FromCodePtr(codeAddr));
    MAKE_IO_CALL_SEQUENCE(POLY_SYS_arctan_real, codeAddr);
    add_word_to_io_area(POLY_SYS_arctan_real, PolyWord::FromCodePtr(codeAddr));
    MAKE_IO_CALL_SEQUENCE(POLY_SYS_exp_real, codeAddr);
    add_word_to_io_area(POLY_SYS_exp_real, PolyWord::FromCodePtr(codeAddr));
    MAKE_IO_CALL_SEQUENCE(POLY_SYS_ln_real, codeAddr);
    add_word_to_io_area(POLY_SYS_ln_real, PolyWord::FromCodePtr(codeAddr));
    MAKE_IO_CALL_SEQUENCE(POLY_SYS_io_operation, codeAddr);
    add_word_to_io_area(POLY_SYS_io_operation, PolyWord::FromCodePtr(codeAddr));

    add_function_to_io_area(POLY_SYS_atomic_incr, atomic_incr);
    add_function_to_io_area(POLY_SYS_atomic_decr, atomic_decr);
    add_function_to_io_area(POLY_SYS_thread_self, thread_self);
    
    MAKE_IO_CALL_SEQUENCE(POLY_SYS_thread_dispatch, codeAddr);
    add_word_to_io_area(POLY_SYS_thread_dispatch, PolyWord::FromCodePtr(codeAddr));

    add_function_to_io_area(POLY_SYS_offset_address, offset_address);
    add_function_to_io_area(POLY_SYS_shift_right_word, shift_right_word);
    add_function_to_io_area(POLY_SYS_word_neq, word_neq);
    add_function_to_io_area(POLY_SYS_not_bool, not_bool);
    add_function_to_io_area(POLY_SYS_string_length, string_length);
    add_function_to_io_area(POLY_SYS_int_eq, int_eq);
    add_function_to_io_area(POLY_SYS_int_neq, int_neq);
    add_function_to_io_area(POLY_SYS_int_geq, int_geq);
    add_function_to_io_area(POLY_SYS_int_leq, int_leq);
    add_function_to_io_area(POLY_SYS_int_gtr, int_gtr);
    add_function_to_io_area(POLY_SYS_int_lss, int_lss);    
    add_function_to_io_area(POLY_SYS_or_word, or_word);
    add_function_to_io_area(POLY_SYS_and_word, and_word);
    add_function_to_io_area(POLY_SYS_xor_word, xor_word);
    add_function_to_io_area(POLY_SYS_shift_left_word, shift_left_word);
    add_function_to_io_area(POLY_SYS_word_eq, word_eq);
    add_function_to_io_area(POLY_SYS_load_byte, load_byte);
    add_function_to_io_area(POLY_SYS_load_word, load_word);
    add_function_to_io_area(POLY_SYS_is_big_endian, is_big_endian);
    add_function_to_io_area(POLY_SYS_bytes_per_word, bytes_per_word);
    
    add_function_to_io_area(POLY_SYS_assign_byte, assign_byte);
    add_function_to_io_area(POLY_SYS_assign_word, assign_word);

    MAKE_IO_CALL_SEQUENCE(POLY_SYS_objsize, codeAddr);
    add_word_to_io_area(POLY_SYS_objsize, PolyWord::FromCodePtr(codeAddr));
    MAKE_IO_CALL_SEQUENCE(POLY_SYS_showsize, codeAddr);
    add_word_to_io_area(POLY_SYS_showsize, PolyWord::FromCodePtr(codeAddr));
    MAKE_IO_CALL_SEQUENCE(POLY_SYS_timing_dispatch, codeAddr);
    add_word_to_io_area(POLY_SYS_timing_dispatch, PolyWord::FromCodePtr(codeAddr));

    MAKE_IO_CALL_SEQUENCE(POLY_SYS_XWindows, codeAddr);
    add_word_to_io_area(POLY_SYS_XWindows, PolyWord::FromCodePtr(codeAddr));
    MAKE_IO_CALL_SEQUENCE(POLY_SYS_full_gc, codeAddr);
    add_word_to_io_area(POLY_SYS_full_gc, PolyWord::FromCodePtr(codeAddr));
    MAKE_IO_CALL_SEQUENCE(POLY_SYS_stack_trace, codeAddr);
    add_word_to_io_area(POLY_SYS_stack_trace, PolyWord::FromCodePtr(codeAddr));
    MAKE_IO_CALL_SEQUENCE(POLY_SYS_foreign_dispatch, codeAddr);
    add_word_to_io_area(POLY_SYS_foreign_dispatch, PolyWord::FromCodePtr(codeAddr));
    MAKE_IO_CALL_SEQUENCE(POLY_SYS_callcode_tupled, codeAddr);
    add_word_to_io_area(POLY_SYS_callcode_tupled, PolyWord::FromCodePtr(codeAddr));
    MAKE_IO_CALL_SEQUENCE(POLY_SYS_process_env, codeAddr);
    add_word_to_io_area(POLY_SYS_process_env, PolyWord::FromCodePtr(codeAddr));
    
    add_function_to_io_area(POLY_SYS_set_string_length, &set_string_length_a); /* DCJM 28/2/01 */
    add_function_to_io_area(POLY_SYS_get_first_long_word, &get_first_long_word_a); /* DCJM 28/2/01 */
    
    MAKE_IO_CALL_SEQUENCE(POLY_SYS_shrink_stack, codeAddr);
    add_word_to_io_area(POLY_SYS_shrink_stack, PolyWord::FromCodePtr(codeAddr));
    MAKE_IO_CALL_SEQUENCE(POLY_SYS_code_flags, codeAddr);
    add_word_to_io_area(POLY_SYS_code_flags, PolyWord::FromCodePtr(codeAddr));
    
    add_function_to_io_area(POLY_SYS_shift_right_arith_word, shift_right_arith_word); /* DCJM 10/10/99 */
    add_function_to_io_area(POLY_SYS_int_to_word,      int_to_word);        /* DCJM 10/10/99 */

    MAKE_IO_CALL_SEQUENCE(POLY_SYS_set_code_constant, codeAddr); /* DCJM 2/1/01 */
    add_word_to_io_area(POLY_SYS_set_code_constant, PolyWord::FromCodePtr(codeAddr));
    MAKE_IO_CALL_SEQUENCE(POLY_SYS_poly_specific, codeAddr); /* DCJM 19/6/06 */
    add_word_to_io_area(POLY_SYS_poly_specific, PolyWord::FromCodePtr(codeAddr));
    
    add_function_to_io_area(POLY_SYS_move_bytes,       move_bytes);        /* DCJM 10/10/99 */
    add_function_to_io_area(POLY_SYS_move_words,       move_words);        /* DCJM 10/10/99 */
    add_function_to_io_area(POLY_SYS_mul_word,         mul_word);        /* DCJM 10/10/99 */
    add_function_to_io_area(POLY_SYS_plus_word,        plus_word);        /* DCJM 10/10/99 */
    add_function_to_io_area(POLY_SYS_minus_word,       minus_word);        /* DCJM 10/10/99 */
    add_function_to_io_area(POLY_SYS_div_word,         div_word);        /* DCJM 10/10/99 */
    add_function_to_io_area(POLY_SYS_mod_word,         mod_word);        /* DCJM 10/10/99 */
    add_function_to_io_area(POLY_SYS_word_geq,         word_geq);
    add_function_to_io_area(POLY_SYS_word_leq,         word_leq);
    add_function_to_io_area(POLY_SYS_word_gtr,         word_gtr);
    add_function_to_io_area(POLY_SYS_word_lss,         word_lss);
    
    // This is now a "closure" like all the other entries.
    add_function_to_io_area(POLY_SYS_raisex,           raisex);

    MAKE_IO_CALL_SEQUENCE(POLY_SYS_io_dispatch, codeAddr);
    add_word_to_io_area(POLY_SYS_io_dispatch, PolyWord::FromCodePtr(codeAddr));
    MAKE_IO_CALL_SEQUENCE(POLY_SYS_network, codeAddr);
    add_word_to_io_area(POLY_SYS_network, PolyWord::FromCodePtr(codeAddr));
    MAKE_IO_CALL_SEQUENCE(POLY_SYS_os_specific, codeAddr);
    add_word_to_io_area(POLY_SYS_os_specific, PolyWord::FromCodePtr(codeAddr));
    MAKE_IO_CALL_SEQUENCE(POLY_SYS_signal_handler, codeAddr);
    add_word_to_io_area(POLY_SYS_signal_handler, PolyWord::FromCodePtr(codeAddr));

    // Entries for special cases.  These are generally, but not always, called from
    // compiled code.
    MAKE_EXTRA_CALL_SEQUENCE(RETURN_HEAP_OVERFLOW, heapOverflow);
    MAKE_EXTRA_CALL_SEQUENCE(RETURN_STACK_OVERFLOW, stackOverflow);
    MAKE_EXTRA_CALL_SEQUENCE(RETURN_STACK_OVERFLOWEX, stackOverflowEx);
    MAKE_EXTRA_CALL_SEQUENCE(RETURN_RAISE_DIV, raiseDiv);
    MAKE_EXTRA_CALL_SEQUENCE(RETURN_ARB_EMULATION, arbEmulation);
}

// Build an ML code segment on the heap to hold a copy of a piece of code
Handle PowerPCDependent::BuildCodeSegment(TaskData *taskData, const byte *code, unsigned codeWords, char functionName)
{
    POLYUNSIGNED words = codeWords + 6;
    Handle codeHandle = alloc_and_save(taskData, words, F_CODE_OBJ);
    byte *cp = codeHandle->Word().AsCodePtr();
    memcpy(cp, code, codeWords*sizeof(PolyWord));
    codeHandle->WordP()->Set(codeWords++, PolyWord::FromUnsigned(0)); // Marker word
    codeHandle->WordP()->Set(codeWords, PolyWord::FromUnsigned(codeWords*sizeof(PolyWord))); // Bytes to the start
    codeWords++;
    codeHandle->WordP()->Set(codeWords++, PolyWord::FromUnsigned(0)); // Profile count
    codeHandle->WordP()->Set(codeWords++, TAGGED(functionName)); // Name of function - single character
    codeHandle->WordP()->Set(codeWords++, TAGGED(0)); // Register set
    codeHandle->WordP()->Set(codeWords++, PolyWord::FromUnsigned(2)); // Number of constants
    FlushInstructionCache(cp, codeWords*sizeof(PolyWord));
    return codeHandle;
}

// We need the kill-self code in a little function.
Handle PowerPCDependent::BuildKillSelfCode(TaskData *taskData)
{
    byte *codeAddr;
    MAKE_IO_CALL_SEQUENCE(POLY_SYS_kill_self, codeAddr);
    return BuildCodeSegment(taskData, codeAddr, MAKE_CALL_SEQUENCE_WORDS, 'K');
}

void PowerPCDependent::SetException(TaskData *taskData, poly_exn *exc)
/* Set up the stack of a process to raise an exception. */
{
    // This IO entry has changed from being the code to being a closure
    // like all the other entries.
    taskData->stack->PS_R24 = (PolyObject*)IoEntry(POLY_SYS_raisex);
    taskData->stack->p_pc   = PC_RETRY_SPECIAL;
    taskData->stack->PS_R3  = (PolyWord)exc; /* r3 to exception data */
}

void PowerPCDependent::ResetSignals(void)
{
  /* restore default signal handling in child process after a "fork". */
  signal(SIGFPE,  SIG_DFL);
#ifdef SIGEMT
  signal(SIGEMT,  SIG_DFL);
#endif
  signal(SIGTRAP, SIG_DFL);
  signal(SIGILL,  SIG_DFL);

  /* "just in case" */
  signal(SIGBUS,  SIG_DFL);
  signal(SIGSEGV, SIG_DFL);
}


// Call a piece of compiled code.  Note: this doesn't come via CallIO1
// so StartIOCall has not been called.
void PowerPCDependent::CallCodeTupled(TaskData *taskData)
{
    // The eventual return address is in the link register - leave it there
    // but call StartIOCall to make sure it's tagged before any possible G.C.
    StartIOCall(taskData);
    PolyObject *argTuple = taskData->stack->PS_R3.AsObjPtr();
    Handle closure = taskData->saveVec.push(argTuple->Get(0));
    Handle argvec = taskData->saveVec.push(argTuple->Get(1));

    if (! IS_INT(DEREFWORD(argvec))) // May be nil if there are no args.
    {
        PolyObject *argv = DEREFHANDLE(argvec);
        POLYUNSIGNED argCount = argv->Length();
        if (argCount > 4)
        {
            // Check we have space for the arguments.  This may result in a GC which
            // in turn may throw a C++ exception.
            try {
                CheckAndGrowStack(taskData, taskData->stack->p_sp - (argCount - 4));
            }
            catch (IOException exc)
            {
                ASSERT(exc.m_reason == EXC_EXCEPTION);  // This should be the only one
                return; // Will have been set up to raise an exception.
            }
        }
        // First argument is in r3
        taskData->stack->PS_R3 = argv->Get(0);
        // Second arg, if there is one, goes into r4 etc.
        if (argCount > 1)
            taskData->stack->PS_R4 = argv->Get(1);
        if (argCount > 2)
            taskData->stack->PS_R5 = argv->Get(2);
        if (argCount > 3)
            taskData->stack->PS_R6 = argv->Get(3);
        // Remaining args go on the stack.
        for (POLYUNSIGNED i = 4; i < argCount; i++)
            *(--taskData->stack->p_sp) = argv->Get(i+2);
    }
    // The closure goes into the closure reg.
    taskData->stack->PS_R24 = DEREFWORD(closure);
    // First word of closure is entry point.
    taskData->stack->p_pc = DEREFHANDLE(closure)->Get(0).AsCodePtr(); // pc points to the start of the code
}

// Set up a special handler that will trace any uncaught exception within a function.
void PowerPCDependent::SetExceptionTrace(TaskData *taskData)
{
    // Save the return address for when we've called the function.
    *(--taskData->stack->p_sp) =
        PolyWord::FromUnsigned(taskData->stack->PS_LR.AsUnsigned() | RETURNOFFSET);
    *(--taskData->stack->p_sp) = PolyWord::FromStackAddr(taskData->stack->p_hr); // Save previous handler.
    *(--taskData->stack->p_sp) = TAGGED(0); // Push special handler address.
    *(--taskData->stack->p_sp) = TAGGED(0); // Push "catch all" exception id.
    taskData->stack->p_hr = taskData->stack->p_sp; // This is the new handler.
    Handle fun = taskData->saveVec.push(taskData->stack->PS_R3); // Argument - function to call and trace
    taskData->stack->PS_R24 = DEREFWORD(fun); // r24 must contain the closure
    taskData->stack->p_pc = DEREFHANDLE(fun)->Get(0).AsCodePtr(); // pc points to the start of the code

    // We have to use a special entry here that can be recognised by the exception
    // unwinding code because we want to know the stack pointer that is in effect
    // at the time the exception is raised.  If we simply put a normal handler in here
    // that handler would be called after the stack was unwound.
    byte *codeAddr;
#ifdef MACOSX
    __asm__ __volatile__ (
     "bl 1f \n"
        "lwz     r0,12(r27)\n"  // Restore old return address
        "lwz     r31,8(r27)\n"  // Restore old handler
        "mtlr    r0\n"
        "addi    r27,r27,16\n"  // Pop stack
        "blr\n"                 // Return to exception_trace's caller
    "1: mflr r0\n"
    "stw r0,%0"
    :"=m"(codeAddr)
    :
    : "lr","r0"
    );
#else
    __asm__ __volatile__ (
     "bl 1f; "
        "lwz     0,12(27); "  // Restore old return address
        "lwz     31,8(27); "  // Restore old handler
        "mtlr    0; "
        "addi    27,27,16; "  // Pop stack
        "blr; "               // Return to exception_trace's caller
    "1: mflr 0; "
    "stw 0,%0"
    :"=m"(codeAddr)
    :
    :"lr","0"
    );
#endif
    Handle retCode = BuildCodeSegment(taskData, codeAddr, 5 /* Code is 5 words */, 'R');

    // Set the link register so that if the traced function returns normally (i.e. without
    // raising an exception) it will enter the "return" code which will remove this handler.
    taskData->stack->PS_LR = PolyWord::FromUnsigned(retCode->Word().AsUnsigned() | RETURNOFFSET);
    taskData->stack->PS_R3 = TAGGED(0); // Give the function we're calling a unit argument.
}

void PowerPCDependent::ScanConstantsWithinCode(PolyObject *addr, PolyObject */*old*/,
                                               POLYUNSIGNED length, ScanAddress *process)
{
    PolyWord *pt = (PolyWord*)addr;
    PolyWord *end;
    POLYUNSIGNED unused;
    /* Find the end of the code (before the constants). */
    addr->GetConstSegmentForCode(length, end, unused);
    /* Find the end of the code (before the constants). */
    end -= 3;
    assert(end->AsUnsigned() == 0); /* This should be the marker word. */

    while (pt != end)
    {
        POLYUNSIGNED instr = (*pt).AsUnsigned();
        pt++;
        if ((instr & 0xfc1f0000) == 0x3c000000) /* addis rd,r0. */
        {
            POLYUNSIGNED reg = (instr >> 21) & 31;
            /* Ignore the unchecked registers. */
            if (reg == 11 || reg == 12) continue;
            /* Next must be an ADD or OR instruction. */
            POLYUNSIGNED instr2 = (*pt).AsUnsigned();
            assert((instr2 & 0xfc000000) == 0x38000000 || (instr2 & 0xfc000000) == 0x60000000);
            bool isSigned = (instr2 & 0xfc000000) == 0x38000000; /* Add instruction. */
            process->ScanConstant((byte*)(pt-1),
                isSigned ? PROCESS_RELOC_PPCDUAL16SIGNED :  PROCESS_RELOC_PPCDUAL16UNSIGNED);
            pt++;
        }
    }
}

/* Store a constant at a specific address in the code.  This is used by
   the code generator.  It needs to be built into the RTS because we
   have to split the value in order to store it into two instructions.
   Separately the two values might well be invalid addresses. */
void PowerPCDependent::SetCodeConstant(TaskData *taskData, Handle/*data*/, Handle constant, Handle offseth, Handle base)
{
    /* The offset is a byte count. */
    POLYUNSIGNED offset = get_C_ulong(taskData, DEREFWORD(offseth));
    PolyWord *pointer = DEREFHANDLE(base)->Offset(offset/sizeof(PolyWord));
    POLYUNSIGNED c = DEREFWORD(constant).AsUnsigned(); // N.B.  This may well really be an address.
    unsigned hi = c >> 16, lo = c & 0xffff;
    POLYUNSIGNED instr1 = pointer[0].AsUnsigned();
    POLYUNSIGNED instr2 = pointer[1].AsUnsigned();
    bool isSigned = (instr2 & 0xfc000000) == 0x38000000; /* Add instruction. */
    if (isSigned && (lo & 0x8000)) hi++; /* Adjust the for sign extension */
    assert((offset & 3) == 0);
    // The first word must be addis rd,r0,0.
    assert((instr1 & 0xfc1fffff) == 0x3c000000);
    // and the next must be addi rd,rd,1 or ori rd,rd,1
    assert((instr2 & 0xfc00ffff) == 0x38000001 || (instr2 & 0xfc00ffff) == 0x60000001);
    pointer[0] = PolyWord::FromUnsigned(pointer[0].AsUnsigned() | hi);
    pointer[1] = PolyWord::FromUnsigned((pointer[1].AsUnsigned() & 0xffff0000) | lo);
}

// We have assembly code versions of atomic increment and decrement and it's
// important that if we use the same method of locking a mutex whether it's
// done in the assembly code or the RTS.
// Increment the value contained in the first word of the mutex.
Handle PowerPCDependent::AtomicIncrement(TaskData *taskData, Handle mutexp)
{
    PolyObject *p = DEREFHANDLE(mutexp);
    POLYUNSIGNED result;
    __asm__ __volatile__ (
     "1: lwarx   %0,0,%1\n"    //  Load value at 0(r3) with reservation.
        "addi    %0,%0,2\n"    // 2 is TAGGED(1)-TAG
        "stwcx.  %0,0,%1\n"    // Store the updated value unless someone else did.
        "bne-    1b\n"         // Repeat if we couldn't do the store
    :"=&r"(result)  // %0 - Output - updated value.  Must not be same as input reg.
    :"r"(p)         // %1 - Input  - address of mutex
    : "cc", "memory" // Modifies cc and memory
    );
    return taskData->saveVec.push(PolyWord::FromUnsigned(result));
}

// Decrement the value contained in the first word of the mutex.
Handle PowerPCDependent::AtomicDecrement(TaskData *taskData, Handle mutexp)
{
    PolyObject *p = DEREFHANDLE(mutexp);
    POLYUNSIGNED result;
    __asm__ __volatile__ (
     "1: lwarx   %0,0,%1\n"    //  Load value at 0(r3) with reservation.
        "subi    %0,%0,2\n"    // 2 is TAGGED(1)-TAG
        "stwcx.  %0,0,%1\n"    // Store the updated value unless someone else did.
        "bne-    1b\n"         // Repeat if we couldn't do the store
    :"=&r"(result)  // %0 - Output - updated value.  Must not be same as input reg.
    :"r"(p)         // %1 - Input  - address of mutex
    : "cc", "memory" // Modifies cc and memory
    );
    return taskData->saveVec.push(PolyWord::FromUnsigned(result));
}

// On the PPC it's important to flush the cache.  The PPC has separate data and instruction
// caches and there is no internal synchronisation.  This actually does two things: it
// flushes the data cache to memory and also clears the instruction prefetch cache.
void PowerPCDependent::FlushInstructionCache(void *p, POLYUNSIGNED bytes)
{
#if (1)
    byte *q = (byte*)p;
    // Apparently some processors have 16 byte cache lines and others 32.
#define CACHE_LINE_SIZE   16
    while (bytes > 0)
    {
        // Flush the data cache
        __asm__ __volatile("dcbf 0,%0" :: "r"(q));
        __asm__ __volatile("sync");
        __asm__ __volatile("icbi 0,%0" :: "r"(q));
        q += CACHE_LINE_SIZE;
        if (bytes <= CACHE_LINE_SIZE)
            break;
        bytes -= CACHE_LINE_SIZE;
    }
    __asm__ __volatile("sync");
    __asm__ __volatile("isync");
#else
    MD_flush_instruction_cache(p, bytes);
#endif
}

extern "C" int registerMaskVector[];

int PowerPCDependent::GetIOFunctionRegisterMask(int ioCall)
{
    return registerMaskVector[ioCall];
}

static PowerPCDependent ppcDependent;

MachineDependent *machineDependent = &ppcDependent;