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ARM: Fix Addressing mode 1 shifter on rs == pc (fixes #1926)

This commit is contained in:
Vicki Pfau 2020-11-01 02:22:09 -08:00
parent 791818e9a8
commit a53b01be00
2 changed files with 5 additions and 20 deletions
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1
CHANGES
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@ -15,6 +15,7 @@ Features:
Emulation fixes:
- ARM: Fix ALU reading PC after shifting
- ARM: Fix STR storing PC after address calculation
- ARM: Fix Addressing mode 1 shifter on rs == pc (fixes mgba.io/i/1926)
- GB: Partially fix timing for skipped BIOS
- GB Audio: Fix serializing sweep time
- GB MBC: Fix MBC1 mode changing behavior

24
src/arm/isa-arm.c
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@ -19,15 +19,11 @@ static inline void _shiftLSL(struct ARMCore* cpu, uint32_t opcode) {
if (opcode & 0x00000010) {
int rs = (opcode >> 8) & 0x0000000F;
++cpu->cycles;
int shift = cpu->gprs[rs];
if (rs == ARM_PC) {
shift += 4;
}
shift &= 0xFF;
int32_t shiftVal = cpu->gprs[rm];
if (rm == ARM_PC) {
shiftVal += 4;
}
int shift = cpu->gprs[rs] & 0xFF;
if (!shift) {
cpu->shifterOperand = shiftVal;
cpu->shifterCarryOut = cpu->cpsr.c;
@ -58,15 +54,11 @@ static inline void _shiftLSR(struct ARMCore* cpu, uint32_t opcode) {
if (opcode & 0x00000010) {
int rs = (opcode >> 8) & 0x0000000F;
++cpu->cycles;
int shift = cpu->gprs[rs];
if (rs == ARM_PC) {
shift += 4;
}
shift &= 0xFF;
uint32_t shiftVal = cpu->gprs[rm];
if (rm == ARM_PC) {
shiftVal += 4;
}
int shift = cpu->gprs[rs] & 0xFF;
if (!shift) {
cpu->shifterOperand = shiftVal;
cpu->shifterCarryOut = cpu->cpsr.c;
@ -97,15 +89,11 @@ static inline void _shiftASR(struct ARMCore* cpu, uint32_t opcode) {
if (opcode & 0x00000010) {
int rs = (opcode >> 8) & 0x0000000F;
++cpu->cycles;
int shift = cpu->gprs[rs];
if (rs == ARM_PC) {
shift += 4;
}
shift &= 0xFF;
int shiftVal = cpu->gprs[rm];
if (rm == ARM_PC) {
shiftVal += 4;
}
int shift = cpu->gprs[rs] & 0xFF;
if (!shift) {
cpu->shifterOperand = shiftVal;
cpu->shifterCarryOut = cpu->cpsr.c;
@ -136,15 +124,11 @@ static inline void _shiftROR(struct ARMCore* cpu, uint32_t opcode) {
if (opcode & 0x00000010) {
int rs = (opcode >> 8) & 0x0000000F;
++cpu->cycles;
int shift = cpu->gprs[rs];
if (rs == ARM_PC) {
shift += 4;
}
shift &= 0xFF;
int shiftVal = cpu->gprs[rm];
if (rm == ARM_PC) {
shiftVal += 4;
}
int shift = cpu->gprs[rs] & 0xFF;
int rotate = shift & 0x1F;
if (!shift) {
cpu->shifterOperand = shiftVal;