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micro-opt, helpful comments, trap 10 when unknown instruction

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folkert van heusden 2022-03-20 21:52:22 +01:00
parent e4432448f1
commit 9a24625b35
1 changed files with 6 additions and 4 deletions
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10
cpu.cpp
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@ -313,7 +313,7 @@ bool cpu::double_operand_instructions(const uint16_t instr)
uint16_t src_value = getGAM(src_mode, src_reg, word_mode, false);
if (word_mode) {
if (dst_mode == 0)
setRegister(dst_reg, false, int8_t(src_value));
setRegister(dst_reg, false, int8_t(src_value)); // int8_t: sign extension
else
putGAM(dst_mode, dst_reg, word_mode, src_value, false);
}
@ -903,7 +903,7 @@ bool cpu::single_operand_instructions(const uint16_t instr)
else { // SXT
uint16_t a = getGAMAddress(dst_mode, dst_reg, word_mode, false);
int32_t vl = getPSW_n() ? -1 : 0;
int32_t vl = -getPSW_n();
setPSW_z(getPSW_n() == false);
setPSW_v(false);
@ -954,7 +954,7 @@ bool cpu::conditional_branch_instructions(const uint16_t instr)
break;
case 0b00000111: // BLE
take = getPSW_n() != getPSW_v() | getPSW_z();
take = getPSW_n() != getPSW_v() || getPSW_z();
break;
case 0b10000000: // BPL
@ -970,7 +970,7 @@ bool cpu::conditional_branch_instructions(const uint16_t instr)
break;
case 0b10000011: // BLOS
take = getPSW_c() | getPSW_z();
take = getPSW_c() || getPSW_z();
break;
case 0b10000100: // BVC
@ -1600,5 +1600,7 @@ void cpu::step()
}
}
trap(010);
*event = 1;
}