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Fix DAA

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This commit is contained in:
Kevin Hamacher 2016-06-02 13:49:21 +02:00
parent 9508244447
commit a58e599c7a
1 changed files with 21 additions and 20 deletions
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41
src/cpu.rs
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@ -1083,38 +1083,39 @@ impl CPU {
0x26 => self.ld_r_v(REG_N_H),
0x27 => {
// Logic copied from some other emulator
let mut v = self.regs[REG_A] as u16;
let a = self.regs[REG_A];
if self.debug {
println!("DAA");
}
if self.flags & FLAG_N == 0 {
// Lower nibble
if ((self.flags & FLAG_H) == FLAG_H) || (v & 0xF) > 9 {
v += 0x06;
}
let mut cor: u8 = 0;
if (self.flags & FLAG_H) == FLAG_H {
cor |= 0x06;
}
if (self.flags & FLAG_C) == FLAG_C {
cor |= 0x60;
}
// Higher nibble
if ((self.flags & FLAG_C) == FLAG_C) || v > 0x9F {
v += 0x60;
}
if (self.flags & FLAG_N) == FLAG_N {
self.regs[REG_A] = a.wrapping_sub(cor);
} else {
// Lower nibble
if (self.flags & FLAG_H) == FLAG_H {
v = v.wrapping_sub(6) & 0xFF;
if (a & 0x0F) > 0x09 {
cor |= 0x06;
}
// Higher nibble
if (self.flags & FLAG_C) == FLAG_C {
v = v.wrapping_sub(0x60);
if a > 0x99 {
cor |= 0x60;
}
self.regs[REG_A] = a.wrapping_add(cor);
}
self.clear_flag(FLAG_H);
self.set_clear_flag(FLAG_C, (v & 0x100) == 0x100);
self.set_clear_flag(FLAG_Z, v as u8 == 0);
self.regs[REG_A] = v as u8;
if cor & 0x60 == 0x60 {
self.set_flag(FLAG_C);
}
let a = self.regs[REG_A];
self.set_clear_flag(FLAG_Z, a == 0);
4
},