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Carry is set by left- or right-most bits

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Don't rely on modify_status() to get it right.
This commit is contained in:
Peter Evans 2018-01-21 16:21:15 -06:00
parent 3206332a7d
commit d119854631
1 changed files with 6 additions and 2 deletions
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8
src/mos6502.bits.c
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@ -142,11 +142,13 @@ DEFINE_INST(rol)
carry = 1; carry = 1;
} }
cpu->P &= ~MOS_CARRY;
if (carry) { if (carry) {
result |= 0x01; result |= 0x01;
cpu->P |= MOS_CARRY;
} }
mos6502_modify_status(cpu, MOS_NZC, oper, result); mos6502_modify_status(cpu, MOS_NZ, oper, result);
if (cpu->eff_addr) { if (cpu->eff_addr) {
mos6502_set(cpu, cpu->eff_addr, result & 0xff); mos6502_set(cpu, cpu->eff_addr, result & 0xff);
@ -168,11 +170,13 @@ DEFINE_INST(ror)
carry = 1; carry = 1;
} }
cpu->P &= ~MOS_CARRY;
if (carry) { if (carry) {
result |= 0x80; result |= 0x80;
cpu->P |= MOS_CARRY;
} }
mos6502_modify_status(cpu, MOS_NZC, oper, result); mos6502_modify_status(cpu, MOS_NZ, oper, result);
if (cpu->eff_addr) { if (cpu->eff_addr) {
mos6502_set(cpu, cpu->eff_addr, result & 0xff); mos6502_set(cpu, cpu->eff_addr, result & 0xff);