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Took a shot at DAA, seemingly not to Fuse's liking though.

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This commit is contained in:
Thomas Harte 2017-05-25 22:17:48 -04:00
parent ff3c60c0e1
commit ea0ad9fd87
1 changed files with 62 additions and 1 deletions
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63
Processors/Z80/Z80.hpp
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@ -126,6 +126,7 @@ struct MicroOp {
CalculateIndexAddress,
DJNZ,
DAA,
None
};
@ -371,7 +372,7 @@ template <class T> class Processor: public MicroOpScheduler<MicroOp> {
/* 0x23 INC HL; 0x24 INC H; 0x25 DEC H; 0x26 LD H, n */
INC_INC_DEC_LD(index, index.bytes.high),
/* 0x27 DAA */ XX,
/* 0x27 DAA */ Program({MicroOp::DAA}),
/* 0x28 JR Z */ JR(TestZ), /* 0x29 ADD HL, HL */ ADD16(index, index),
/* 0x2a LD HL, (nn) */ Program(FETCH16(temp16_, pc_), FETCH16L(index, temp16_)),
@ -755,6 +756,66 @@ template <class T> class Processor: public MicroOpScheduler<MicroOp> {
subtract_flag_ = Flag::Subtract;
} break;
case MicroOp::DAA: {
int lowNibble = a_ & 0xf;
int highNibble = a_ >> 4;
int amountToAdd = 0;
if(carry_flag_)
{
amountToAdd = (lowNibble > 0x9 || half_carry_flag_) ? 0x66 : 0x60;
}
else
{
if(half_carry_flag_)
{
amountToAdd = (highNibble > 0x9) ? 0x66 : 0x06;
}
else
{
if(lowNibble > 0x9)
{
amountToAdd = (highNibble > 0x8) ? 0x66 : 0x06;
}
else
{
amountToAdd = (highNibble > 0x9) ? 0x60 : 0x00;
}
}
}
if(!carry_flag_)
{
if(lowNibble > 0x9)
{
if(highNibble > 0x8) carry_flag_ = Flag::Carry;
}
else
{
if(highNibble > 0x9) carry_flag_ = Flag::Carry;
}
}
if(subtract_flag_)
{
a_ -= amountToAdd;
if(half_carry_flag_ && lowNibble < 0x6) half_carry_flag_ = 0;
}
else
{
a_ += amountToAdd;
half_carry_flag_ = (lowNibble > 0x9) ? Flag::HalfCarry : 0;
}
sign_result_ = zero_result_ = bit3_result_ = bit5_result_ = a_;
uint8_t parity = a_;
parity ^= (parity >> 4);
parity ^= (parity >> 2);
parity ^= (parity >> 1);
parity_overflow_flag_ = (parity & 1) << 3;
} break;
#pragma mark - 16-bit arithmetic