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ASH, MTPS and MFPS fixes

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folkert van heusden 2022-03-20 17:50:58 +01:00
parent 6f7f65c915
commit 35a797e8dd
1 changed files with 11 additions and 4 deletions
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15
cpu.cpp
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@ -481,10 +481,13 @@ bool cpu::additional_double_operand_instructions(const uint16_t instr)
R <<= 1;
}
else if (shift < 0) {
R >>= -(shift - 1);
R >>= -(shift + 1);
setPSW_c(R & 1);
R >>= 1;
}
else {
setPSW_c(false);
}
setPSW_n(R < 0);
setPSW_z(R == 0);
@ -839,16 +842,20 @@ bool cpu::single_operand_instructions(const uint16_t instr)
break;
case 0b000110100: // MTPS (put something in PSW)
psw = getGAM(dst_mode, dst_reg, word_mode, false);
psw &= 0xff00; // only alter lower 8 bits
psw |= getGAM(dst_mode, dst_reg, word_mode, false) & 0xef; // can't change bit 4
break;
case 0b000110111: // MFPS (get PSW to something) / SXT
if (word_mode) { // MFPS
putGAM(dst_mode, dst_reg, word_mode, psw, false);
uint16_t temp = psw & 0xff;
if (dst_mode == 0 && sign(temp))
temp |= 0xff00;
putGAM(dst_mode, dst_reg, word_mode, temp, false);
}
else { // SXT
a = getGAMAddress(dst_mode, dst_reg, word_mode, false);
v = b -> read(a, word_mode);
vl = getPSW_n() ? -1 : 0;