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Implement addressing mode 1 ASR register shift

This commit is contained in:
Jeffrey Pfau 2013-05-02 00:32:04 -07:00
parent 86c228f2e4
commit a635f4de4d
1 changed files with 24 additions and 1 deletions
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25
src/arm/isa-arm.c
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@ -104,7 +104,30 @@ static inline void _shiftASR(struct ARMCore* cpu, uint32_t opcode) {
static inline void _shiftASRR(struct ARMCore* cpu, uint32_t opcode) {
int rm = opcode & 0x0000000F;
ARM_STUB;
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;
}
if (!shift) {
cpu->shifterOperand = shiftVal;
cpu->shifterCarryOut = cpu->cpsr.c;
} else if (shift < 32) {
cpu->shifterOperand = shiftVal >> shift;
cpu->shifterCarryOut = (shiftVal >> (shift - 1)) & 1;
} else if (cpu->gprs[rm] >> 31) {
cpu->shifterOperand = 0xFFFFFFFF;
cpu->shifterCarryOut = 1;
} else {
cpu->shifterOperand = 0;
cpu->shifterCarryOut = 0;
}
}
static inline void _shiftROR(struct ARMCore* cpu, uint32_t opcode) {