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alu: Fix bug in SBC and RSC ops

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Former-commit-id: 1cb23d6280e1816395c46a7571dd9f48df870202
This commit is contained in:
Michel Heily 2019-07-09 01:29:34 +03:00
parent 19e4196384
commit 34233fa654
1 changed files with 3 additions and 3 deletions
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6
src/arm7tdmi/alu.rs
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@ -239,7 +239,7 @@ impl Core {
fn alu_add_flags(a: i32, b: i32, carry: &mut bool, overflow: &mut bool) -> i32 { fn alu_add_flags(a: i32, b: i32, carry: &mut bool, overflow: &mut bool) -> i32 {
let res = a.wrapping_add(b) as u32; let res = a.wrapping_add(b) as u32;
*carry = res < a as u32|| res < b as u32; *carry = res < a as u32 || res < b as u32;
let (_, would_overflow) = a.overflowing_add(b); let (_, would_overflow) = a.overflowing_add(b);
*overflow = would_overflow; *overflow = would_overflow;
res as i32 res as i32
@ -267,8 +267,8 @@ impl Core {
RSB => Self::alu_sub_flags(op2, op1, &mut carry, &mut overflow), RSB => Self::alu_sub_flags(op2, op1, &mut carry, &mut overflow),
ADD | CMN => Self::alu_add_flags(op1, op2, &mut carry, &mut overflow), ADD | CMN => Self::alu_add_flags(op1, op2, &mut carry, &mut overflow),
ADC => Self::alu_add_flags(op1, op2.wrapping_add(C), &mut carry, &mut overflow), ADC => Self::alu_add_flags(op1, op2.wrapping_add(C), &mut carry, &mut overflow),
SBC => Self::alu_sub_flags(op1, op2.wrapping_sub(1 - C), &mut carry, &mut overflow), SBC => Self::alu_sub_flags(op1, op2, &mut carry, &mut overflow).wrapping_sub(1 - C),
RSC => Self::alu_sub_flags(op2, op1.wrapping_sub(1 - C), &mut carry, &mut overflow), RSC => Self::alu_sub_flags(op2, op1, &mut carry, &mut overflow).wrapping_sub(1 - C),
ORR => op1 | op2, ORR => op1 | op2,
MOV => op2, MOV => op2,
BIC => op1 & (!op2), BIC => op1 & (!op2),