mpw/toolbox/dispatch.cpp

1130 lines
21 KiB
C++

/*
* Copyright (c) 2014, Kelvin W Sherlock
* All rights reserved.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions are met:
*
* 1. Redistributions of source code must retain the above copyright notice, this
* list of conditions and the following disclaimer.
* 2. Redistributions in binary form must reproduce the above copyright notice,
* this list of conditions and the following disclaimer in the documentation
* and/or other materials provided with the distribution.
*
* THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS" AND
* ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED
* WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
* DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR CONTRIBUTORS BE LIABLE FOR
* ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES
* (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
* LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND
* ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
* (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
* SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
*
*/
#include <cstdio>
#include <cstdint>
#include <cassert>
#include <string>
#include <utility>
#include <stdlib.h>
#include <cpu/defs.h>
#include <cpu/CpuModule.h>
#include <cpu/fmem.h>
#include "loader.h"
#include "mm.h"
#include "os.h"
#include "packages.h"
#include "qd.h"
#include "rm.h"
#include "sane.h"
#include "stackframe.h"
#include "toolbox.h"
#include "utility.h"
#include "debug.h"
#include <macos/sysequ.h>
#include <macos/errors.h>
#include <macos/traps.h>
// yuck. TST.W d0
extern "C" void cpuSetFlagsNZ00NewW(UWO res);
namespace {
uint32_t trap_address[1024];
uint32_t os_address[256];
uint32_t ToolGlue;
uint32_t OSGlue;
inline constexpr bool is_tool_trap(uint16_t trap)
{
// %1010 | x . . . | . . . . . . . . |
//
// x = 1 if this is a toolbox call, x = 0 if this is an os call.
return (trap & 0x0800) == 0x0800;
}
inline constexpr bool auto_pop(uint16_t trap)
{
// %1010 | 1 x . . | . . . . . . . . |
//
// if x = 1, an extra rts is pushed,
return (trap & 0x0c00) == 0x0c00;
}
inline constexpr bool save_a0(uint16_t trap)
{
// %1010 | 0 . . x | . . . . . . . . |
//
// if x = 0, a0 is saved and restored.
// if x = 1, a0 is not saved and restored.
return (trap & 0x0900) == 0x0000;
}
inline constexpr unsigned os_flags(uint16_t trap)
{
// %1010 | 0 x x . | . . . . . . . . |
return trap & 0x0600;
}
#if BYTE_ORDER == LITTLE_ENDIAN
inline constexpr uint16_t host_to_big_endian_16(uint16_t x)
{
return __builtin_bswap16(x);
}
#endif
#if BYTE_ORDER == BIG_ENDIAN
inline constexpr uint16_t host_to_big_endian_16(uint16_t x)
{
return x;
}
#endif
}
namespace OS {
using ToolBox::Log;
#pragma mark - Trap Manager
uint16_t GetToolTrapAddress(uint16_t trap)
{
/*
* on entry:
* D0 trap number
*
* on exit:
* A0 Address of patch
*
*/
uint16_t trapNumber = cpuGetDReg(0);
const char *trapName = TrapName(trapNumber | 0xa800);
if (!trapName) trapName = "Unknown";
Log("%04x GetToolTrapAddress($%04x (%s))\n", trap, trapNumber, trapName);
trapNumber &= 0x03ff;
if (trap_address[trapNumber])
{
cpuSetAReg(0, trap_address[trapNumber]);
return 0;
}
cpuSetAReg(0, ToolGlue + trapNumber * 4);
return 0; //MacOS::dsCoreErr;
}
uint16_t SetToolTrapAddress(uint16_t trap)
{
//pascal void SetToolTrapAddress(long trapAddr, short trapNum);
/*
* on entry:
* A0 Address of patch
* D0 trap number
*
* on exit:
*
*/
// this is used by the far model stub, presumably
// to replace LoadSeg.
uint16_t trapNumber = cpuGetDReg(0);
uint32_t trapAddress = cpuGetAReg(0);
const char *trapName = TrapName(trapNumber | 0xa800);
if (!trapName) trapName = "Unknown";
Log("%04x SetToolTrapAddress($%08x, $%04x (%s))\n",
trap, trapAddress, trapNumber, trapName);
trapNumber &= 0x03ff;
trap_address[trapNumber] = trapAddress;
return 0;
}
uint16_t GetOSTrapAddress(uint16_t trap)
{
/*
* on entry:
* D0 trap number
*
* on exit:
* A0 Address of patch
*
*/
uint16_t trapNumber = cpuGetDReg(0);
const char *trapName = TrapName(trapNumber | 0xa000);
if (!trapName) trapName = "Unknown";
Log("%04x GetOSTrapAddress($%04x (%s))\n", trap, trapNumber, trapName);
trapNumber &= 0x00ff;
if (os_address[trapNumber])
{
cpuSetAReg(0, os_address[trapNumber]);
return 0;
}
cpuSetAReg(0, OSGlue + trapNumber * 4);
return 0; // MacOS::dsCoreErr;
}
uint16_t SetOSTrapAddress(uint16_t trap)
{
//pascal void SetOSTrapAddress(long trapAddr, short trapNum);
/*
* on entry:
* A0 Address of patch
* D0 trap number
*
* on exit:
*
*/
// Used by 3.2, 3.3 Link to patch
// MaxBlock (bug with CloseResFile).
uint16_t trapNumber = cpuGetDReg(0);
uint32_t trapAddress = cpuGetAReg(0);
const char *trapName = TrapName(trapNumber | 0xa000);
if (!trapName) trapName = "Unknown";
Log("%04x SetToolTrapAddress($%08x, $%04x (%s))\n",
trap, trapAddress, trapNumber, trapName);
trapNumber &= 0x00ff;
os_address[trapNumber] = trapAddress;
return 0;
}
uint16_t GetTrapAddress(uint16_t trap)
{
// FUNCTION GetTrapAddress (trapNum: Integer) :LongInt;
/*
* on entry:
* D0 An A-line trap word
*
* on exit:
* A0 Address of next routine in the daisy chain (a system software routine or a patch)
*/
/*
* The GetTrapAddress function was used when both the Operating
* System trap addresses and Toolbox trap addresses were located
* in the same trap dispatch table. Today, any system software
* routine with the trap number $00 to $4F, $54, or $57 is drawn
* from the Operating System dispatch table; any other software
* routine is taken from the Toolbox dispatch table.
*/
uint16_t trapNumber = cpuGetDReg(0);
const char *trapName = TrapName(trapNumber | 0xa000);
if (!trapName) trapName = "Unknown";
Log("%04x GetTrapAddress($%04x (%s))\n", trap, trapNumber, trapName);
trapNumber &= 0x03ff;
bool os = false;
if (trapNumber >= 0x00 && trapNumber <= 0x4f) os = true;
if (trapNumber >= 0x54 && trapNumber <= 0x57) os = true;
if (os)
{
if (os_address[trapNumber])
{
cpuSetAReg(0, os_address[trapNumber]);
return 0;
}
cpuSetAReg(0, OSGlue + trapNumber * 4);
return 0;
}
else
{
if (trap_address[trapNumber])
{
cpuSetAReg(0, trap_address[trapNumber]);
return 0;
}
cpuSetAReg(0, ToolGlue + trapNumber * 4);
return 0;
}
}
uint16_t OSDispatch(uint16_t trap)
{
uint16_t selector;
StackFrame<2>(selector);
Log("%04x OSDispatch(%04x)\n", trap, selector);
switch(selector)
{
case 0x0015:
return MM::TempMaxMem();
case 0x0018:
return MM::TempFreeMem();
case 0x001d:
return MM::TempNewHandle();
case 0x001e:
return MM::TempHLock();
case 0x001f:
return MM::TempHUnlock();
case 0x0020:
return MM::TempDisposeHandle();
default:
fprintf(stderr, "OSDispatch: selector %04x not implemented\n",
selector);
exit(1);
}
}
}
namespace ToolBox {
bool Init() {
//
std::fill(std::begin(trap_address), std::end(trap_address), 0);
std::fill(std::begin(os_address), std::end(os_address), 0);
// alternate entry code
MM::Native::NewPtr(1024 * 4 + 256 * 4, false, ToolGlue);
OSGlue = ToolGlue + 1024 * 4;
uint16_t *code = (uint16_t *)memoryPointer(ToolGlue);
for (unsigned i = 0; i < 1024; ++i) {
*code++ = host_to_big_endian_16(0xafff);
*code++ = host_to_big_endian_16(0xa800 | i);
}
for (unsigned i = 0; i < 256; ++i) {
*code++ = host_to_big_endian_16(0xafff);
*code++ = host_to_big_endian_16(0xa000 | i);
}
// os return code... pull registers, TST.W d0, etc.
return true;
}
void native_dispatch(uint16_t trap);
void dispatch(uint16_t trap)
{
uint32_t returnPC = 0;
bool saveA0 = false;
uint32_t a0 = cpuGetAReg(0);
// hold off on actually _calling_ for now...
#if 0
if (trap == 0xafff)
{
// called from the trap address stub.
// uint16_t 0xafff
// uint16_t trap
// return address, etc, is on stack.
uint32_t pc = cpuGetPC();
trap = memoryReadWord(pc);
if (is_tool_trap(trap))
{
StackFrame<4>(returnPC);
}
#if 0
/*
* os stubs:
* os_return_a0
* pop registers a0, a1, d0, d1, d2
* pop long word
* tst.w d0
* rts
*
* os_return:
* pop registers a0, a1, d0, d1, d2
* pop long word
* tst.w d0
* rts
*
* os_entry_a0:
*
*/
else
{
// os calls push the trap dispatcher pc as well.
uint32_t tmp;
uint32_t a0, a1, d0, d1, d2;
if (save_a0(trap))
{
StackFrame<4*8>(returnPC, tmp, a0, a1, d0, d1, d2, tmp);
}
else
{
StackFrame<4*7>(returnPC, tmp, a1, d0, d1, d2, tmp);
}
trap = d1; // trap w/ flag bits.
}
#endif
native_dispatch(trap);
cpuInitializeFromNewPC(returnPC);
return;
}
#endif
/*
* The auto-pop bit is bit 10 in an A-line instruction for a
* Toolbox routine. Some language systems prefer to generate
* jump-subroutine calls (JSR) to intermediate routines, called
* glue routines, which then call Toolbox routines instead of
* executing the Toolbox routine directly. This glue method
* would normally interfere with Toolbox traps because the
* return address of the glue subroutine is placed on the stack
* between the Toolbox routine's parameters and the address of
* the place where the glue routine was called from (where
* control returns once the Toolbox routine has completed
* execution).
*
* The auto-pop bit forces the trap dispatcher to remove the
* top 4 bytes from the stack before dispatching to the Toolbox
* routine. After the Toolbox routine completes execution,
* control is transferred back to the place where the glue
* routine was called from, not back to the glue routine.
*
* Most development environments, including MPW, do not use
* this feature.
*
* (Trap Manager, 8-20)
*/
if (auto_pop(trap))
{
/*
* | args |
* | returnPC |
* -------------
*/
StackFrame<4>(returnPC);
trap &= ~0x0400;
}
#if 0
if (is_tool_trap(trap))
{
uint16_t tt = trap & 0x03ff;
uint32_t address = trap_address[tt];
if (address)
{
/*
* parameters were pushed on the stack but
* the a-line instruction was intercepted
* before an exception occurred. Therefore,
* we need to push the return address on the
* stack and set the new pc to the trap address.
*
* returnPC may have been previously set from the
* auto pop bit.
*/
Push<4>(returnPC == 0 ? cpuGetPC() : returnPC);
Log("$04x *%s - $%08x", trap, TrapName(trap), address);
cpuInitializeFromNewPC(address);
return;
}
}
else
{
// os calls - check the return/save a0 bit.
// if bit 8 is 0, a0 is saved and restored.
// if bit 8 is 1, a0 is modified.
// Trap Manager 8-12.
// not actually an issue yet, will only matter
// if os address is overridden.
if (save_a0(trap)) {
saveA0 = true;
}
uint16_t tt = trap & 0x00ff;
uint32_t address = os_address[tt];
if (address) {
assert("OS trap overrides are not yet supported.");
}
}
#endif
native_dispatch(trap);
if (saveA0) cpuSetAReg(0, a0);
if (returnPC) cpuInitializeFromNewPC(returnPC);
}
void native_dispatch(uint16_t trap)
{
uint32_t d0 = 0;
switch (trap)
{
case 0xa000: // Open
case 0xa200: // HOpen
d0 = OS::Open(trap);
break;
case 0xa00a: // OpenRF
case 0xa20a: // HOpenRF
d0 = OS::OpenRF(trap);
break;
case 0xa001:
d0 = OS::Close(trap);
break;
case 0xa002:
d0 = OS::Read(trap);
break;
case 0xa003:
d0 = OS::Write(trap);
break;
case 0xa207:
d0 = OS::HGetVInfo(trap);
break;
case 0xa008: // Create
case 0xa208: // HCreate
d0 = OS::Create(trap);
break;
case 0xa009: // Delete
case 0xa209: // HDelete
d0 = OS::Delete(trap);
break;
case 0xa00c: // GetFInfo
case 0xa20c: // HGetFInfo
d0 = OS::GetFileInfo(trap);
break;
case 0xa00d: // SetFileInfo
case 0xa20d: // HSetFileInfo
d0 = OS::SetFileInfo(trap);
break;
case 0xa011:
d0 = OS::GetEOF(trap);
break;
case 0xa012:
d0 = OS::SetEOF(trap);
break;
case 0xa013:
d0 = OS::FlushVol(trap);
break;
case 0xa014:
d0 = OS::GetVol(trap);
break;
case 0xa214:
d0 = OS::HGetVol(trap);
break;
case 0xa015: // SetVol
d0 = OS::SetVol(trap);
break;
case 0xa215: // HSetVol
d0 = OS::HSetVol(trap);
break;
case 0xa018:
d0 = OS::GetFPos(trap);
break;
case 0xa044:
d0 = OS::SetFPos(trap);
break;
case 0xa051:
d0 = OS::ReadXPRam(trap);
break;
case 0xa060:
d0 = OS::FSDispatch(trap);
break;
case 0xa260:
d0 = OS::HFSDispatch(trap);
break;
case 0xaa52:
d0 = OS::HighLevelHFSDispatch(trap);
break;
case 0xa146:
d0 = OS::GetTrapAddress(trap);
break;
case 0xA746:
d0 = OS::GetToolTrapAddress(trap);
break;
case 0xa647:
d0 = OS::SetToolTrapAddress(trap);
break;
case 0xA346:
d0 = OS::GetOSTrapAddress(trap);
break;
case 0xa247:
d0 = OS::SetOSTrapAddress(trap);
break;
case 0xA823:
d0 = OS::AliasDispatch(trap);
break;
case 0xA1AD:
d0 = OS::Gestalt(trap);
break;
case 0xa090:
d0 = OS::SysEnvirons(trap);
break;
// SetPtrSize (p: Ptr; newSize: Size);
case 0xa020:
d0 = MM::SetPtrSize(trap);
break;
// GetPtrSize (p: Ptr) : Size
case 0xa021:
d0 = MM::GetPtrSize(trap);
break;
case 0xA023:
d0 = MM::DisposeHandle(trap);
break;
case 0xa024:
d0 = MM::SetHandleSize(trap);
break;
case 0xa025:
d0 = MM::GetHandleSize(trap);
break;
case 0xa029:
d0 = MM::HLock(trap);
break;
case 0xa02a:
d0 = MM::HUnlock(trap);
break;
case 0xa02d:
d0 = MM::SetApplLimit(trap);
break;
// BlockMove (sourcePtr,destPtr: Ptr; byteCount: Size);
case 0xa02e: // BlockMove
case 0xa22e: // BlockMoveData
d0 = MM::BlockMove(trap);
break;
case 0xa049:
d0 = MM::HPurge(trap);
break;
case 0xa04a:
d0 = MM::HNoPurge(trap);
break;
case 0xA11D:
d0 = MM::MaxMem(trap);
break;
case 0xA01C:
d0 = MM::FreeMem(trap);
break;
// CompactMem (cbNeeded: Size) : Size;
case 0xa04c:
d0 = MM::CompactMem(trap);
break;
case 0xa040:
d0 = MM::ReserveMem(trap);
break;
case 0xa055:
d0 = MM::StripAddress(trap);
break;
case 0xa061:
d0 = MM::MaxBlock(trap);
break;
case 0xa069:
d0 = MM::HGetState(trap);
break;
case 0xa06a:
d0 = MM::HSetState(trap);
break;
// MoveHHi (h: Handle);
case 0xa064:
d0 = MM::MoveHHi(trap);
break;
case 0xa9e1:
d0 = MM::HandToHand(trap);
break;
case 0xa9e3:
d0 = MM::PtrToHand(trap);
break;
case 0xa9ef:
d0 = MM::PtrAndHand(trap);
break;
case 0xa11a:
d0 = MM::GetZone(trap);
break;
case 0xa01b:
d0 = MM::SetZone(trap);
break;
case 0xa126:
d0 = MM::HandleZone(trap);
break;
case 0xa128:
d0 = MM::RecoverHandle(trap);
break;
// MaxApplZone
case 0xa063:
d0 = MM::MaxApplZone(trap);
break;
case 0xa162:
d0 = MM::PurgeSpace(trap);
break;
// ReadDateTime (VAR sees: LONGINT) : OSErr;
case 0xa039:
d0 = OS::ReadDateTime(trap);
break;
// SecondsToDate (s: LongInt; VAR d: DateTimeRec);
case 0xa9c6:
d0 = OS::SecondsToDate(trap);
break;
// TickCount : LONGINT;
case 0xa975:
d0 = OS::TickCount(trap);
break;
case 0xa193:
d0 = OS::Microseconds(trap);
break;
case 0xa9ed:
d0 = Packages::Pack6(trap);
break;
//_CmpString [MARKS,CASE]
case 0xa03c:
case 0xa23c:
case 0xa43c:
case 0xa63c:
d0 = OS::CmpString(trap);
break;
// NewPtr [Sys, Clear] (logicalSize: Size): Ptr;
case 0xa11e:
case 0xa31e:
case 0xa51e:
case 0xa71e:
// clear = bit 9, sys = bit 10
d0 = MM::NewPtr(trap);
break;
// DisposPtr (p: Ptr);
case 0xa01f:
d0 = MM::DisposePtr(trap);
break;
case 0xa065:
d0 = MM::StackSpace(trap);
break;
// NewHandle (logicalSize: Size) : Handle;
case 0xA122:
case 0xa322:
d0 = MM::NewHandle(trap);
break;
case 0xA027:
d0 = MM::ReallocHandle(trap);
break;
case 0xA02B:
d0 = MM::EmptyHandle(trap);
break;
case 0xa058:
d0 = OS::InsTime(trap);
break;
case 0xa059:
d0 = OS::RmvTime(trap);
break;
case 0xa05a:
d0 = OS::PrimeTime(trap);
break;
case 0xA0BD:
d0 = OS::FlushCodeCache(trap);
break;
case 0xA098:
case 0xA198: // don't save a0
d0 = OS::HWPriv(trap);
break;
// resource manager stuff.
// Count1Resources (theType: ResType): Integer;
case 0xa80d:
d0 = RM::Count1Resources(trap);
break;
case 0xa80e:
d0 = RM::Get1IndResource(trap);
break;
case 0xa80f:
d0 = RM::Get1IndType(trap);
break;
case 0xa81a:
d0 = RM::HOpenResFile(trap);
break;
case 0xa81b:
d0 = RM::HCreateResFile(trap);
break;
case 0xa81c:
d0 = RM::Count1Types(trap);
break;
// Get1Resource (theType: ResType; thelD: INTEGER) : Handle;
case 0xa81f:
d0 = RM::Get1Resource(trap);
break;
// Get1NamedResource (theType: ResType; name: Str255) : Handle;
case 0xa820:
d0 = RM::Get1NamedResource(trap);
break;
case 0xa992:
d0 = RM::DetachResource(trap);
break;
case 0xa994:
d0 = RM::CurResFile(trap);
break;
case 0xA997:
d0 = RM::OpenResFile(trap);
break;
case 0xA998:
d0 = RM::UseResFile(trap);
break;
case 0xa999:
d0 = RM::UpdateResFile(trap);
break;
case 0xa99a:
d0 = RM::CloseResFile(trap);
break;
case 0xa99b:
d0 = RM::SetResLoad(trap);
break;
// GetResource (theType: ResType; thelD: INTEGER) : Handle;
case 0xa9a0:
d0 = RM::GetResource(trap);
break;
case 0xa9a1:
d0 = RM::GetNamedResource(trap);
break;
case 0xa9a2:
d0 = RM::LoadResource(trap);
break;
// ReleaseResource (theResource: Handle);
case 0xa9a3:
d0 = RM::ReleaseResource(trap);
break;
case 0xa9a4:
d0 = RM::HomeResFile(trap);
break;
case 0xa9a5:
d0 = RM::GetResourceSizeOnDisk(trap);
break;
case 0xa9a6:
d0 = RM::GetResAttrs(trap);
break;
case 0xa9a7:
d0 = RM::SetResAttrs(trap);
break;
case 0xa9a8:
d0 = RM::GetResInfo(trap);
break;
case 0xa9ab:
d0 = RM::AddResource(trap);
break;
case 0xa9aa:
d0 = RM::ChangedResource(trap);
break;
case 0xa9ad:
d0 = RM::RemoveResource(trap);
break;
// ResError : INTEGER;
case 0xa9af:
d0 = RM::ResError(trap);
break;
case 0xa9b0:
d0 = RM::WriteResource(trap);
break;
// CreateResFile(fileName: Str255);
case 0xa9b1:
d0 = RM::CreateResFile(trap);
break;
// OpenRFPerm (fileName: Str255; vRefNum: Integer;
// permission: SignedByte): Integer;
case 0xa9c4:
d0 = RM::OpenRFPerm(trap);
break;
case 0xa9f6:
d0 = RM::GetResFileAttrs(trap);
break;
case 0xa9f7:
d0 = RM::SetResFileAttrs(trap);
break;
// UnloadSeg (routineAddr: Ptr);
case 0xa9f1:
d0 = Loader::UnloadSeg(trap);
break;
// quickdraw (AsmIIgs ... )
// _ShowCursor();
case 0xA853:
d0 = QD::ShowCursor(trap);
break;
// GetCursor (cursorlD: INTEGER) : CursHandle;
case 0xA9B9:
d0 = QD::GetCursor(trap);
break;
case 0xa834:
d0 = QD::SetFScaleDisable(trap);
break;
//SetCursor (crsr: Cursor)
case 0xA851:
d0 = QD::SetCursor(trap);
break;
case 0xa86e:
d0 = QD::InitGraf(trap);
break;
// GetFNum (fontName: Str255; VAR theNum: INTEGER);
case 0xa900:
d0 = QD::GetFNum(trap);
break;
// sane
case 0xa9Eb:
d0 = SANE::fp68k(trap);
cpuSetDReg(0, d0);
return; // SANE sets the flags.
break;
case 0x0a9ee:
d0 = SANE::decstr68k(trap);
break;
// utility
case 0xa906:
d0 = Utility::NewString(trap);
break;
case 0xa9ba:
d0 = Utility::GetString(trap);
break;
case 0xa85d:
d0 = Utility::BitTst(trap);
break;
case 0xa88f:
d0 = OS::OSDispatch(trap);
break;
case 0xa8b5:
d0 = Packages::ScriptUtil(trap);
break;
case 0xABFF:
d0 = Debug::DebugStr(trap);
break;
default:
fprintf(stderr, "Unsupported tool trap: %04x (%s)\n",
trap, TrapName(trap));
fprintf(stderr, "pc: %08x\n", cpuGetPC());
exit(255);
}
// n.b. - os calls return via d0 and tst.w d0.
// toolcalls return any error info as the return
// value on the stack.
if (d0)
{
int16_t v = (int16_t)d0;
Log(" -> %d\n", v);
}
cpuSetDReg(0, d0);
cpuSetFlagsNZ00NewW(d0);
}
}