AppleWin/source/CPU.cpp

672 lines
18 KiB
C++

/*
AppleWin : An Apple //e emulator for Windows
Copyright (C) 1994-1996, Michael O'Brien
Copyright (C) 1999-2001, Oliver Schmidt
Copyright (C) 2002-2005, Tom Charlesworth
Copyright (C) 2006-2010, Tom Charlesworth, Michael Pohoreski
AppleWin 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.
AppleWin 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 AppleWin; if not, write to the Free Software
Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
*/
/* Description: 6502/65C02 emulation
*
* Author: Various
*/
// TO DO:
// . All these CPP macros need to be converted to inline funcs
// TeaRex's Note about illegal opcodes:
// ------------------------------------
// . I've followed the names and descriptions given in
// . "Extra Instructions Of The 65XX Series CPU"
// . by Adam Vardy, dated Sept 27, 1996.
// . The exception is, what he calls "SKB" and "SKW" I call "NOP",
// . for consistency's sake. Several other naming conventions exist.
// . Of course, only the 6502 has illegal opcodes, the 65C02 doesn't.
// . Thus they're not emulated in Enhanced //e mode. Games relying on them
// . don't run on a real Enhanced //e either. The old mixture of 65C02
// . emulation and skipping the right number of bytes for illegal 6502
// . opcodes, while working surprisingly well in practice, was IMHO
// . ill-founded in theory and has thus been removed.
// Note about bSlowerOnPagecross:
// -------------------
// . This is used to determine if a cycle needs to be added for a page-crossing.
//
// Modes that are affected:
// . ABS,X; ABS,Y; (IND),Y
//
// The following opcodes (when indexed) add a cycle if page is crossed:
// . ADC, AND, Bxx, CMP, EOR, LDA, LDX, LDY, ORA, SBC
// . NB. Those opcode that DO NOT write to memory.
// . 65C02: JMP (ABS-INDIRECT): 65C02 fixes JMP ($xxFF) bug but needs extra cycle in that case
// . 65C02: JMP (ABS-INDIRECT,X): Probably. Currently unimplemented.
//
// The following opcodes (when indexed) DO NOT add a cycle if page is crossed:
// . ASL, DEC, INC, LSR, ROL, ROR, STA, STX, STY
// . NB. Those opcode that DO write to memory.
//
// What about these:
// . 65C02: STZ?, TRB?, TSB?
// . Answer: TRB & TSB don't have affected addressing modes
// . STZ probably doesn't add a cycle since otherwise it would be slower than STA which doesn't make sense.
//
// NB. 'Zero-page indexed' opcodes wrap back to zero-page.
// . The same goes for all the zero-page indirect modes.
//
// NB2. bSlowerOnPagecross can't be used for r/w detection, as these
// . opcodes don't init this flag:
// . $EC CPX ABS (since there's no addressing mode of CPY which has variable cycle number)
// . $CC CPY ABS (same)
//
// 65C02 info:
// . Read-modify-write instructions abs indexed in same page take 6 cycles (cf. 7 cycles for 6502)
// . ASL, DEC, INC, LSR, ROL, ROR
// . This should work now (but makes bSlowerOnPagecross even less useful for r/w detection)
//
// . Thanks to Scott Hemphill for the verified CMOS ADC and SBC algorithm! You rock.
// . And thanks to the VICE team for the NMOS ADC and SBC algorithms as well as the
// . algorithms for those illops which involve ADC or SBC. You rock too.
#include "StdAfx.h"
#include "AppleWin.h"
#include "CPU.h"
#include "Frame.h"
#include "Memory.h"
#include "Mockingboard.h"
#include "MouseInterface.h"
#ifdef USE_SPEECH_API
#include "Speech.h"
#endif
#include "Video.h"
#include "z80emu.h"
#include "Z80VICE\z80.h"
#include "Z80VICE\z80mem.h"
#include "Debugger\Debug.h"
#define AF_SIGN 0x80
#define AF_OVERFLOW 0x40
#define AF_RESERVED 0x20
#define AF_BREAK 0x10
#define AF_DECIMAL 0x08
#define AF_INTERRUPT 0x04
#define AF_ZERO 0x02
#define AF_CARRY 0x01
#define SHORTOPCODES 22
#define BENCHOPCODES 33
// What is this 6502 code?
static BYTE benchopcode[BENCHOPCODES] = {0x06,0x16,0x24,0x45,0x48,0x65,0x68,0x76,
0x84,0x85,0x86,0x91,0x94,0xA4,0xA5,0xA6,
0xB1,0xB4,0xC0,0xC4,0xC5,0xE6,
0x19,0x6D,0x8D,0x99,0x9D,0xAD,0xB9,0xBD,
0xDD,0xED,0xEE};
regsrec regs;
unsigned __int64 g_nCumulativeCycles = 0;
static ULONG g_nCyclesExecuted; // # of cycles executed up to last IO access
//static signed long g_uInternalExecutedCycles;
// TODO: Use IRQ_CHECK_TIMEOUT=128 when running at full-speed else with IRQ_CHECK_TIMEOUT=1
// - What about when running benchmark?
static const int IRQ_CHECK_TIMEOUT = 128;
static signed int g_nIrqCheckTimeout = IRQ_CHECK_TIMEOUT;
//
// Assume all interrupt sources assert until the device is told to stop:
// - eg by r/w to device's register or a machine reset
static bool g_bCritSectionValid = false; // Deleting CritialSection when not valid causes crash on Win98
static CRITICAL_SECTION g_CriticalSection; // To guard /g_bmIRQ/ & /g_bmNMI/
static volatile UINT32 g_bmIRQ = 0;
static volatile UINT32 g_bmNMI = 0;
static volatile BOOL g_bNmiFlank = FALSE; // Positive going flank on NMI line
#include "cpu/cpu_general.inl"
#include "cpu/cpu_instructions.inl"
void RequestDebugger()
{
// BUG: This causes DebugBegin to constantly be called.
// It's as if the WM_KEYUP are auto-repeating?
// FrameWndProc()
// ProcessButtonClick()
// DebugBegin()
// PostMessage( g_hFrameWindow, WM_KEYDOWN, DEBUG_TOGGLE_KEY, 0 );
// PostMessage( g_hFrameWindow, WM_KEYUP , DEBUG_TOGGLE_KEY, 0 );
// Not a valid solution, since hitting F7 (to exit) debugger gets the debugger out of sync
// due to EnterMessageLoop() calling ContinueExecution() after the mode has changed to DEBUG.
// DebugBegin();
FrameWndProc( g_hFrameWindow, WM_KEYDOWN, DEBUG_TOGGLE_KEY, 0 );
FrameWndProc( g_hFrameWindow, WM_KEYUP , DEBUG_TOGGLE_KEY, 0 );
}
// Break into debugger on invalid opcodes
#define INV IsDebugBreakOnInvalid(AM_1);
/****************************************************************************
*
* OPCODE TABLE
*
***/
#ifdef _DEBUG
static unsigned __int64 g_nCycleIrqStart;
static unsigned __int64 g_nCycleIrqEnd;
static UINT g_nCycleIrqTime;
static UINT g_nIdx = 0;
static const UINT BUFFER_SIZE = 4096; // 80 secs
static UINT g_nBuffer[BUFFER_SIZE];
static UINT g_nMean = 0;
static UINT g_nMin = 0xFFFFFFFF;
static UINT g_nMax = 0;
#endif
static __forceinline void DoIrqProfiling(DWORD uCycles)
{
#ifdef _DEBUG
if(regs.ps & AF_INTERRUPT)
return; // Still in Apple's ROM
g_nCycleIrqEnd = g_nCumulativeCycles + uCycles;
g_nCycleIrqTime = (UINT) (g_nCycleIrqEnd - g_nCycleIrqStart);
if(g_nCycleIrqTime > g_nMax) g_nMax = g_nCycleIrqTime;
if(g_nCycleIrqTime < g_nMin) g_nMin = g_nCycleIrqTime;
if(g_nIdx == BUFFER_SIZE)
return;
g_nBuffer[g_nIdx] = g_nCycleIrqTime;
g_nIdx++;
if(g_nIdx == BUFFER_SIZE)
{
UINT nTotal = 0;
for(UINT i=0; i<BUFFER_SIZE; i++)
nTotal += g_nBuffer[i];
g_nMean = nTotal / BUFFER_SIZE;
}
#endif
}
//===========================================================================
BYTE CpuRead(USHORT addr, ULONG uExecutedCycles)
{
return READ;
}
void CpuWrite(USHORT addr, BYTE a, ULONG uExecutedCycles)
{
WRITE(a);
}
//===========================================================================
#ifdef USE_SPEECH_API
const USHORT COUT = 0xFDED;
const UINT OUTPUT_BUFFER_SIZE = 256;
char g_OutputBuffer[OUTPUT_BUFFER_SIZE+1+1]; // +1 for EOL, +1 for NULL
UINT OutputBufferIdx = 0;
bool bEscMode = false;
void CaptureCOUT(void)
{
const char ch = regs.a & 0x7f;
if (ch == 0x07) // Bell
{
// Ignore
}
else if (ch == 0x08) // Backspace
{
if (OutputBufferIdx)
OutputBufferIdx--;
}
else if (ch == 0x0A) // LF
{
// Ignore
}
else if (ch == 0x0D) // CR
{
if (bEscMode)
{
bEscMode = false;
}
else if (OutputBufferIdx)
{
g_OutputBuffer[OutputBufferIdx] = 0;
g_Speech.Speak(g_OutputBuffer);
#ifdef _DEBUG
g_OutputBuffer[OutputBufferIdx] = '\n';
g_OutputBuffer[OutputBufferIdx+1] = 0;
OutputDebugString(g_OutputBuffer);
#endif
OutputBufferIdx = 0;
}
}
else if (ch == 0x1B) // Escape
{
bEscMode = bEscMode ? false : true; // Toggle mode
}
else if (ch >= ' ' && ch <= '~')
{
if (OutputBufferIdx < OUTPUT_BUFFER_SIZE && !bEscMode)
g_OutputBuffer[OutputBufferIdx++] = ch;
}
}
#endif
//===========================================================================
//#define DBG_HDD_ENTRYPOINT
#if defined(_DEBUG) && defined(DBG_HDD_ENTRYPOINT)
// Output a debug msg whenever the HDD f/w is called or jump to.
static void DebugHddEntrypoint(const USHORT PC)
{
static bool bOldPCAtC7xx = false;
static WORD OldPC = 0;
static UINT Count = 0;
if ((PC >> 8) == 0xC7)
{
if (!bOldPCAtC7xx /*&& PC != 0xc70a*/)
{
Count++;
char szDebug[100];
sprintf(szDebug, "HDD Entrypoint: $%04X\n", PC);
OutputDebugString(szDebug);
}
bOldPCAtC7xx = true;
}
else
{
bOldPCAtC7xx = false;
}
OldPC = PC;
}
#endif
static __forceinline int Fetch(BYTE& iOpcode, ULONG uExecutedCycles)
{
const USHORT PC = regs.pc;
#if defined(_DEBUG) && defined(DBG_HDD_ENTRYPOINT)
DebugHddEntrypoint(PC);
#endif
iOpcode = ((PC & 0xF000) == 0xC000)
? IORead[(PC>>4) & 0xFF](PC,PC,0,0,uExecutedCycles) // Fetch opcode from I/O memory, but params are still from mem[]
: *(mem+PC);
if (IsDebugBreakOpcode( iOpcode ))
return 0;
#ifdef USE_SPEECH_API
if (PC == COUT && g_Speech.IsEnabled() && !g_bFullSpeed)
CaptureCOUT();
#endif
regs.pc++;
return 1;
}
//#define ENABLE_NMI_SUPPORT // Not used - so don't enable
static __forceinline void NMI(ULONG& uExecutedCycles, UINT& uExtraCycles, BOOL& flagc, BOOL& flagn, BOOL& flagv, BOOL& flagz)
{
#ifdef ENABLE_NMI_SUPPORT
if(g_bNmiFlank)
{
// NMI signals are only serviced once
g_bNmiFlank = FALSE;
#ifdef _DEBUG
g_nCycleIrqStart = g_nCumulativeCycles + uExecutedCycles;
#endif
PUSH(regs.pc >> 8)
PUSH(regs.pc & 0xFF)
EF_TO_AF
PUSH(regs.ps & ~AF_BREAK)
regs.ps = regs.ps | AF_INTERRUPT & ~AF_DECIMAL;
regs.pc = * (WORD*) (mem+0xFFFA);
CYC(7)
}
#endif
}
static __forceinline void IRQ(ULONG& uExecutedCycles, UINT& uExtraCycles, BOOL& flagc, BOOL& flagn, BOOL& flagv, BOOL& flagz)
{
if(g_bmIRQ && !(regs.ps & AF_INTERRUPT))
{
// IRQ signals are deasserted when a specific r/w operation is done on device
#ifdef _DEBUG
g_nCycleIrqStart = g_nCumulativeCycles + uExecutedCycles;
#endif
PUSH(regs.pc >> 8)
PUSH(regs.pc & 0xFF)
EF_TO_AF
PUSH(regs.ps & ~AF_BREAK)
regs.ps = regs.ps | AF_INTERRUPT & ~AF_DECIMAL;
regs.pc = * (WORD*) (mem+0xFFFE);
CYC(7)
}
}
static __forceinline void CheckInterruptSources(ULONG uExecutedCycles)
{
if (g_nIrqCheckTimeout < 0)
{
MB_UpdateCycles(uExecutedCycles);
sg_Mouse.SetVBlank(VideoGetVbl(uExecutedCycles));
g_nIrqCheckTimeout = IRQ_CHECK_TIMEOUT;
}
}
//===========================================================================
#include "cpu/cpu6502.h" // MOS 6502
#include "cpu/cpu65C02.h" // WDC 65C02
#include "cpu/cpu65d02.h" // Debug CPU Memory Visualizer
//===========================================================================
static DWORD InternalCpuExecute (DWORD uTotalCycles)
{
if (IS_APPLE2 || (g_Apple2Type == A2TYPE_APPLE2E))
return Cpu6502(uTotalCycles); // Apple ][, ][+, //e
else
return Cpu65C02(uTotalCycles); // Enhanced Apple //e
}
//
// ----- ALL GLOBALLY ACCESSIBLE FUNCTIONS ARE BELOW THIS LINE -----
//
//===========================================================================
void CpuDestroy ()
{
if (g_bCritSectionValid)
{
DeleteCriticalSection(&g_CriticalSection);
g_bCritSectionValid = false;
}
}
//===========================================================================
// Description:
// Call this when an IO-reg is accessed & accurate cycle info is needed
// NB. Safe to call multiple times from the same IO function handler (as 'nExecutedCycles - g_nCyclesExecuted' will be zero the 2nd time)
// Pre:
// nExecutedCycles = # of cycles executed by Cpu6502() or Cpu65C02() for this iteration of ContinueExecution()
// Post:
// g_nCyclesExecuted
// g_nCumulativeCycles
//
void CpuCalcCycles(const ULONG nExecutedCycles)
{
// Calc # of cycles executed since this func was last called
const ULONG nCycles = nExecutedCycles - g_nCyclesExecuted;
_ASSERT( (LONG)nCycles >= 0 );
g_nCumulativeCycles += nCycles;
g_nCyclesExecuted = nExecutedCycles;
}
//===========================================================================
// Old method with g_uInternalExecutedCycles runs faster!
// Old vs New
// - 68.0,69.0MHz vs 66.7, 67.2MHz (with check for VBL IRQ every opcode)
// - 89.6,88.9MHz vs 87.2, 87.9MHz (without check for VBL IRQ)
// - 75.9, 78.5MHz (with check for VBL IRQ every 128 cycles)
// - 137.9,135.6MHz (with check for VBL IRQ & MB_Update every 128 cycles)
#if 0 // TODO: Measure perf increase by using this new method
ULONG CpuGetCyclesThisVideoFrame(ULONG) // Old func using g_uInternalExecutedCycles
{
CpuCalcCycles(g_uInternalExecutedCycles);
return g_dwCyclesThisFrame + g_nCyclesExecuted;
}
#else
ULONG CpuGetCyclesThisVideoFrame(const ULONG nExecutedCycles)
{
CpuCalcCycles(nExecutedCycles);
return g_dwCyclesThisFrame + g_nCyclesExecuted;
}
#endif
//---------------------------------------------------------------------------
static DWORD g_dwEmulationTime_ms = 0;
static void UpdateEmulationTime(const DWORD dwExecutedCycles)
{
static DWORD dwEmulationTimeFrac_clks = 0;
const DWORD CLKS_PER_MS = (DWORD)g_fCurrentCLK6502 / 1000;
dwEmulationTimeFrac_clks += dwExecutedCycles;
if (dwEmulationTimeFrac_clks > CLKS_PER_MS)
{
g_dwEmulationTime_ms += dwEmulationTimeFrac_clks / CLKS_PER_MS;
dwEmulationTimeFrac_clks %= CLKS_PER_MS;
}
}
DWORD CpuGetEmulationTime_ms(void)
{
return g_dwEmulationTime_ms;
}
//===========================================================================
DWORD CpuExecute(const DWORD uCycles)
{
g_nCyclesExecuted = 0;
MB_StartOfCpuExecute();
// uCycles:
// =0 : Do single step
// >0 : Do multi-opcode emulation
const DWORD uExecutedCycles = InternalCpuExecute(uCycles);
MB_UpdateCycles(uExecutedCycles); // Update 6522s (NB. Do this before updating g_nCumulativeCycles below)
UpdateEmulationTime(uExecutedCycles);
//
const UINT nRemainingCycles = uExecutedCycles - g_nCyclesExecuted;
g_nCumulativeCycles += nRemainingCycles;
return uExecutedCycles;
}
//===========================================================================
void CpuInitialize ()
{
CpuDestroy();
regs.a = regs.x = regs.y = regs.ps = 0xFF;
regs.sp = 0x01FF;
CpuReset(); // Init's ps & pc. Updates sp
InitializeCriticalSection(&g_CriticalSection);
g_bCritSectionValid = true;
CpuIrqReset();
CpuNmiReset();
z80mem_initialize();
z80_reset();
}
//===========================================================================
void CpuSetupBenchmark ()
{
regs.a = 0;
regs.x = 0;
regs.y = 0;
regs.pc = 0x300;
regs.sp = 0x1FF;
// CREATE CODE SEGMENTS CONSISTING OF GROUPS OF COMMONLY-USED OPCODES
{
int addr = 0x300;
int opcode = 0;
do
{
*(mem+addr++) = benchopcode[opcode];
*(mem+addr++) = benchopcode[opcode];
if (opcode >= SHORTOPCODES)
*(mem+addr++) = 0;
if ((++opcode >= BENCHOPCODES) || ((addr & 0x0F) >= 0x0B))
{
*(mem+addr++) = 0x4C;
*(mem+addr++) = (opcode >= BENCHOPCODES) ? 0x00 : ((addr >> 4)+1) << 4;
*(mem+addr++) = 0x03;
while (addr & 0x0F)
++addr;
}
} while (opcode < BENCHOPCODES);
}
}
//===========================================================================
void CpuIrqReset()
{
_ASSERT(g_bCritSectionValid);
if (g_bCritSectionValid) EnterCriticalSection(&g_CriticalSection);
g_bmIRQ = 0;
if (g_bCritSectionValid) LeaveCriticalSection(&g_CriticalSection);
}
void CpuIrqAssert(eIRQSRC Device)
{
_ASSERT(g_bCritSectionValid);
if (g_bCritSectionValid) EnterCriticalSection(&g_CriticalSection);
g_bmIRQ |= 1<<Device;
if (g_bCritSectionValid) LeaveCriticalSection(&g_CriticalSection);
}
void CpuIrqDeassert(eIRQSRC Device)
{
_ASSERT(g_bCritSectionValid);
if (g_bCritSectionValid) EnterCriticalSection(&g_CriticalSection);
g_bmIRQ &= ~(1<<Device);
if (g_bCritSectionValid) LeaveCriticalSection(&g_CriticalSection);
}
//===========================================================================
void CpuNmiReset()
{
_ASSERT(g_bCritSectionValid);
if (g_bCritSectionValid) EnterCriticalSection(&g_CriticalSection);
g_bmNMI = 0;
g_bNmiFlank = FALSE;
if (g_bCritSectionValid) LeaveCriticalSection(&g_CriticalSection);
}
void CpuNmiAssert(eIRQSRC Device)
{
_ASSERT(g_bCritSectionValid);
if (g_bCritSectionValid) EnterCriticalSection(&g_CriticalSection);
if (g_bmNMI == 0) // NMI line is just becoming active
g_bNmiFlank = TRUE;
g_bmNMI |= 1<<Device;
if (g_bCritSectionValid) LeaveCriticalSection(&g_CriticalSection);
}
void CpuNmiDeassert(eIRQSRC Device)
{
_ASSERT(g_bCritSectionValid);
if (g_bCritSectionValid) EnterCriticalSection(&g_CriticalSection);
g_bmNMI &= ~(1<<Device);
if (g_bCritSectionValid) LeaveCriticalSection(&g_CriticalSection);
}
//===========================================================================
void CpuReset()
{
// 7 cycles
regs.ps = (regs.ps | AF_INTERRUPT) & ~AF_DECIMAL;
regs.pc = * (WORD*) (mem+0xFFFC);
regs.sp = 0x0100 | ((regs.sp - 3) & 0xFF);
regs.bJammed = 0;
g_ActiveCPU = CPU_6502;
z80_reset();
}
//===========================================================================
DWORD CpuGetSnapshot(SS_CPU6502* pSS)
{
pSS->A = regs.a;
pSS->X = regs.x;
pSS->Y = regs.y;
pSS->P = regs.ps | AF_RESERVED | AF_BREAK;
pSS->S = (BYTE) (regs.sp & 0xff);
pSS->PC = regs.pc;
pSS->g_nCumulativeCycles = g_nCumulativeCycles;
return 0;
}
DWORD CpuSetSnapshot(SS_CPU6502* pSS)
{
regs.a = pSS->A;
regs.x = pSS->X;
regs.y = pSS->Y;
regs.ps = pSS->P | AF_RESERVED | AF_BREAK;
regs.sp = (USHORT)pSS->S | 0x100;
regs.pc = pSS->PC;
CpuIrqReset();
CpuNmiReset();
g_nCumulativeCycles = pSS->g_nCumulativeCycles;
return 0;
}