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MUL: clear V-flag and correct setting of result in registers

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folkert van heusden 2022-06-09 14:46:20 +02:00
parent bb6e599813
commit 3466cefbed
1 changed files with 6 additions and 8 deletions
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14
cpu.cpp
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@ -579,18 +579,16 @@ bool cpu::additional_double_operand_instructions(const uint16_t instr)
switch(operation) {
case 0: { // MUL
uint16_t R = getRegister(reg);
int32_t result = R * getGAM(dst_mode, dst_reg, true, false);
int16_t R1 = getRegister(reg);
int16_t R2 = getGAM(dst_mode, dst_reg, true, false);
int32_t result = R1 * R2;
if (reg & 1)
setRegister(reg, result);
else {
setRegister(reg + 1, result & 65535);
setRegister(reg, result >> 16);
}
setRegister(reg, result >> 16);
setRegister(reg | 1, result & 65535);
setPSW_n(result < 0);
setPSW_z(result == 0);
setPSW_v(false);
setPSW_c(result < -32768 || result > 32767);
return true;
}