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SOB: code reduction / RTS: fix for "RTS R6"

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folkert van heusden 2024-03-31 14:31:28 +02:00
parent 8abdda5066
commit 7fe3949307
Signed by untrusted user who does not match committer: folkert
GPG key ID: 6B6455EDFEED3BD1
1 changed files with 8 additions and 6 deletions
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14
cpu.cpp
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@ -796,9 +796,7 @@ bool cpu::additional_double_operand_instructions(const uint16_t instr)
}
case 7: { // SOB
addRegister(reg, rm_cur, -1);
if (getRegister(reg)) {
if (addRegister(reg, rm_cur, -1)) {
uint16_t newPC = getPC() - dst * 2;
setPC(newPC);
@ -1643,13 +1641,17 @@ bool cpu::misc_operations(const uint16_t instr)
if ((instr & 0b1111111111111000) == 0b0000000010000000) { // RTS
const int link_reg = instr & 7;
uint16_t v = popStack();
// MOVE link, PC
setPC(getRegister(link_reg));
// POP link
setRegister(link_reg, v);
uint16_t word_on_stack = b->readWord(getRegister(6), d_space);
setRegister(link_reg, word_on_stack);
// do not overwrite SP when it was just set
if (link_reg != 6)
addRegister(6, rm_cur, 2);
return true;
}