diff --git a/src/arm/isa-arm.c b/src/arm/isa-arm.c index 196bf4453..2e141e535 100644 --- a/src/arm/isa-arm.c +++ b/src/arm/isa-arm.c @@ -76,7 +76,28 @@ static inline void _shiftROR(struct ARMCore* cpu, uint32_t opcode) { static inline void _shiftRORR(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; + } + int rotate = shift & 0x1F; + if (!shift) { + cpu->shifterOperand = shiftVal; + cpu->shifterCarryOut = cpu->cpsr.c; + } else if (rotate) { + cpu->shifterOperand = ARM_ROR(shiftVal, rotate); + cpu->shifterCarryOut = (shiftVal >> (rotate - 1)) & 1; + } else { + cpu->shifterOperand = shiftVal; + cpu->shifterCarryOut = ARM_SIGN(shiftVal); + } } static inline void _immediate(struct ARMCore* cpu, uint32_t opcode) {