melonDS/ARM.cpp

412 lines
8.9 KiB
C++

/*
Copyright 2016-2017 StapleButter
This file is part of melonDS.
melonDS 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 3 of the License, or (at your option)
any later version.
melonDS 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 melonDS. If not, see http://www.gnu.org/licenses/.
*/
#include <stdio.h>
#include "NDS.h"
#include "ARM.h"
#include "ARMInterpreter.h"
#include "GPU3D.h"
u32 ARM::ConditionTable[16] =
{
0xF0F0, // EQ
0x0F0F, // NE
0xCCCC, // CS
0x3333, // CC
0xFF00, // MI
0x00FF, // PL
0xAAAA, // VS
0x5555, // VC
0x0C0C, // HI
0xF3F3, // LS
0xAA55, // GE
0x55AA, // LT
0x0A05, // GT
0xF5FA, // LE
0xFFFF, // AL
0x0000 // NE
};
ARM::ARM(u32 num)
{
// well uh
Num = num;
for (int i = 0; i < 16; i++)
{
Waitstates[0][i] = 1;
Waitstates[1][i] = 1;
Waitstates[2][i] = 1;
Waitstates[3][i] = 1;
}
if (!num)
{
// ARM9
Waitstates[0][0x2] = 1; // main RAM timing, assuming cache hit
Waitstates[0][0x3] = 4;
Waitstates[0][0x4] = 4;
Waitstates[0][0x5] = 5;
Waitstates[0][0x6] = 5;
Waitstates[0][0x7] = 4;
Waitstates[0][0x8] = 19;
Waitstates[0][0x9] = 19;
Waitstates[0][0xF] = 4;
Waitstates[1][0x2] = 1;
Waitstates[1][0x3] = 8;
Waitstates[1][0x4] = 8;
Waitstates[1][0x5] = 10;
Waitstates[1][0x6] = 10;
Waitstates[1][0x7] = 8;
Waitstates[1][0x8] = 38;
Waitstates[1][0x9] = 38;
Waitstates[1][0xF] = 8;
Waitstates[2][0x2] = 1;
Waitstates[2][0x3] = 2;
Waitstates[2][0x4] = 2;
Waitstates[2][0x5] = 2;
Waitstates[2][0x6] = 2;
Waitstates[2][0x7] = 2;
Waitstates[2][0x8] = 12;
Waitstates[2][0x9] = 12;
Waitstates[2][0xA] = 20;
Waitstates[2][0xF] = 2;
Waitstates[3][0x2] = 1;
Waitstates[3][0x3] = 2;
Waitstates[3][0x4] = 2;
Waitstates[3][0x5] = 4;
Waitstates[3][0x6] = 4;
Waitstates[3][0x7] = 2;
Waitstates[3][0x8] = 24;
Waitstates[3][0x9] = 24;
Waitstates[3][0xA] = 20;
Waitstates[3][0xF] = 2;
}
else
{
// ARM7
Waitstates[0][0x0] = 1;
Waitstates[0][0x2] = 1;
Waitstates[0][0x3] = 1;
Waitstates[0][0x4] = 1;
Waitstates[0][0x6] = 1;
Waitstates[0][0x8] = 6;
Waitstates[0][0x9] = 6;
Waitstates[1][0x0] = 1;
Waitstates[1][0x2] = 2;
Waitstates[1][0x3] = 1;
Waitstates[1][0x4] = 1;
Waitstates[1][0x6] = 2;
Waitstates[1][0x8] = 12;
Waitstates[1][0x9] = 12;
Waitstates[2][0x0] = 1;
Waitstates[2][0x2] = 1;
Waitstates[2][0x3] = 1;
Waitstates[2][0x4] = 1;
Waitstates[2][0x6] = 1;
Waitstates[2][0x8] = 6;
Waitstates[2][0x9] = 6;
Waitstates[2][0xA] = 10;
Waitstates[3][0x0] = 1;
Waitstates[3][0x2] = 2;
Waitstates[3][0x3] = 1;
Waitstates[3][0x4] = 1;
Waitstates[3][0x6] = 2;
Waitstates[3][0x8] = 12;
Waitstates[3][0x9] = 12;
Waitstates[3][0xA] = 10;
}
}
ARM::~ARM()
{
// dorp
}
void ARM::Reset()
{
Cycles = 0;
Halted = 0;
for (int i = 0; i < 16; i++)
R[i] = 0;
CPSR = 0x000000D3;
ExceptionBase = Num ? 0x00000000 : 0xFFFF0000;
// zorp
JumpTo(ExceptionBase);
}
void ARM::JumpTo(u32 addr, bool restorecpsr)
{
if (restorecpsr)
{
RestoreCPSR();
if (CPSR & 0x20) addr |= 0x1;
else addr &= ~0x1;
}
if (addr & 0x1)
{
addr &= ~0x1;
R[15] = addr+2;
NextInstr[0] = CodeRead16(addr);
NextInstr[1] = CodeRead16(addr+2);
CPSR |= 0x20;
}
else
{
addr &= ~0x3;
R[15] = addr+4;
NextInstr[0] = CodeRead32(addr);
NextInstr[1] = CodeRead32(addr+4);
CPSR &= ~0x20;
}
}
void ARM::RestoreCPSR()
{
u32 oldcpsr = CPSR;
switch (CPSR & 0x1F)
{
case 0x11:
CPSR = R_FIQ[7];
break;
case 0x12:
CPSR = R_IRQ[2];
break;
case 0x13:
CPSR = R_SVC[2];
break;
case 0x17:
CPSR = R_ABT[2];
break;
case 0x1B:
CPSR = R_UND[2];
break;
default:
printf("!! attempt to restore CPSR under bad mode %02X, %08X\n", CPSR&0x1F, R[15]);
break;
}
UpdateMode(oldcpsr, CPSR);
}
void ARM::UpdateMode(u32 oldmode, u32 newmode)
{
u32 temp;
#define SWAP(a, b) temp = a; a = b; b = temp;
if ((oldmode & 0x1F) == (newmode & 0x1F)) return;
switch (oldmode & 0x1F)
{
case 0x11:
SWAP(R[8], R_FIQ[0]);
SWAP(R[9], R_FIQ[1]);
SWAP(R[10], R_FIQ[2]);
SWAP(R[11], R_FIQ[3]);
SWAP(R[12], R_FIQ[4]);
SWAP(R[13], R_FIQ[5]);
SWAP(R[14], R_FIQ[6]);
break;
case 0x12:
SWAP(R[13], R_IRQ[0]);
SWAP(R[14], R_IRQ[1]);
break;
case 0x13:
SWAP(R[13], R_SVC[0]);
SWAP(R[14], R_SVC[1]);
break;
case 0x17:
SWAP(R[13], R_ABT[0]);
SWAP(R[14], R_ABT[1]);
break;
case 0x1B:
SWAP(R[13], R_UND[0]);
SWAP(R[14], R_UND[1]);
break;
}
switch (newmode & 0x1F)
{
case 0x11:
SWAP(R[8], R_FIQ[0]);
SWAP(R[9], R_FIQ[1]);
SWAP(R[10], R_FIQ[2]);
SWAP(R[11], R_FIQ[3]);
SWAP(R[12], R_FIQ[4]);
SWAP(R[13], R_FIQ[5]);
SWAP(R[14], R_FIQ[6]);
break;
case 0x12:
SWAP(R[13], R_IRQ[0]);
SWAP(R[14], R_IRQ[1]);
break;
case 0x13:
SWAP(R[13], R_SVC[0]);
SWAP(R[14], R_SVC[1]);
break;
case 0x17:
SWAP(R[13], R_ABT[0]);
SWAP(R[14], R_ABT[1]);
break;
case 0x1B:
SWAP(R[13], R_UND[0]);
SWAP(R[14], R_UND[1]);
break;
}
#undef SWAP
}
void ARM::TriggerIRQ()
{
if (CPSR & 0x80)
return;
u32 oldcpsr = CPSR;
CPSR &= ~0xFF;
CPSR |= 0xD2;
UpdateMode(oldcpsr, CPSR);
R_IRQ[2] = oldcpsr;
R[14] = R[15] + (oldcpsr & 0x20 ? 2 : 0);
JumpTo(ExceptionBase + 0x18);
}
s32 ARM::Execute()
{
if (Halted)
{
if (NDS::HaltInterrupted(Num))
{
Halted = 0;
if (NDS::IME[Num]&1)
TriggerIRQ();
}
else
{
Cycles = CyclesToRun;
GPU3D::Run(CyclesToRun >> 1);
return Cycles;
}
}
Cycles = 0;
s32 lastcycles = 0;
u32 addr = R[15] - (CPSR&0x20 ? 4:8);
u32 cpsr = CPSR;
while (Cycles < CyclesToRun)
{
//if(Num==1)printf("%08X %08X\n", R[15] - (CPSR&0x20 ? 4:8), NextInstr);
if (CPSR & 0x20) // THUMB
{
// prefetch
R[15] += 2;
CurInstr = NextInstr[0];
NextInstr[0] = NextInstr[1];
NextInstr[1] = CodeRead16(R[15]);
// actually execute
u32 icode = (CurInstr >> 6);
ARMInterpreter::THUMBInstrTable[icode](this);
}
else
{
// prefetch
R[15] += 4;
CurInstr = NextInstr[0];
NextInstr[0] = NextInstr[1];
NextInstr[1] = CodeRead32(R[15]);
// actually execute
if (CheckCondition(CurInstr >> 28))
{
u32 icode = ((CurInstr >> 4) & 0xF) | ((CurInstr >> 16) & 0xFF0);
ARMInterpreter::ARMInstrTable[icode](this);
}
else if ((CurInstr & 0xFE000000) == 0xFA000000)
{
ARMInterpreter::A_BLX_IMM(this);
}
}
//if (R[15]==0x037F9364) printf("R8=%08X R9=%08X\n", R[8], R[9]);
// gross hack
// TODO, though: move timer code here too?
// quick testing shows that moving this to the NDS loop doesn't really slow things down
if (Num==0)
{
s32 diff = Cycles - lastcycles;
GPU3D::Run(diff >> 1);
lastcycles = Cycles - (diff&1);
}
// TODO optimize this shit!!!
if (Halted)
{
if (Halted == 1)
Cycles = CyclesToRun;
break;
}
if (NDS::HaltInterrupted(Num))
{
if (NDS::IME[Num]&1)
TriggerIRQ();
}
// temp. debug cruft
addr = R[15] - (CPSR&0x20 ? 4:8);
cpsr = CPSR;
}
if (Halted == 2)
Halted = 0;
return Cycles;
}