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Add DAS with a manageable number of failures.

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This commit is contained in:
Thomas Harte 2023-10-09 14:47:39 -04:00
parent 0bf2099a70
commit 6bbd896c34
2 changed files with 56 additions and 1 deletions
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53
InstructionSets/x86/Implementation/PerformImplementation.hpp
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@ -344,6 +344,58 @@ inline void daa(uint8_t &al, Status &status) {
status.zero = status.parity = al;
}
inline void das(uint8_t &al, Status &status) {
/*
(as modified by https://www.felixcloutier.com/x86/daa ...)
old_AL ← AL;
old_CF ← CF;
CF ← 0;
IF (((AL AND 0FH) > 9) or AF = 1)
THEN
AL ← AL - 6;
CF ← old_CF OR CarryFromLastAddition; (* CF OR borrow from AL ← AL - 6 *)
AF ← 1;
ELSE
AF ← 0;
FI;
IF ((old_AL > 99H) or old_CF = 1)
THEN
AL ← AL - 60H;
CF ← 1;
ELSE
CF ← 0;
FI;
*/
/*
The CF and AF flags are set if the adjustment of the value results in a
decimal carry in either digit of the result (see the “Operation” section above).
The SF, ZF, and PF flags are set according to the result. The OF flag is undefined.
*/
const uint8_t old_al = al;
const auto old_carry = status.carry;
status.carry = 0;
if((al & 0x0f) > 0x09 || status.auxiliary_carry) {
status.carry = old_carry | (al < 0x06);
al -= 0x06;
status.auxiliary_carry = 1;
} else {
status.auxiliary_carry = 0;
}
if(old_al > 0x99 || old_carry) {
al -= 0x60;
status.carry = 1;
} else {
status.carry = 0;
}
status.sign = al & 0x80;
status.zero = status.parity = al;
}
template <typename IntT>
void adc(IntT &destination, IntT source, Status &status) {
/*
@ -508,6 +560,7 @@ template <
case Operation::AAM: Primitive::aam(registers.axp(), instruction.operand(), status, flow_controller); return;
case Operation::AAS: Primitive::aas(registers.axp(), status); return;
case Operation::DAA: Primitive::daa(registers.al(), status); return;
case Operation::DAS: Primitive::das(registers.al(), status); return;
case Operation::ADC: Primitive::adc(destination(), source(), status); break;
case Operation::ADD: Primitive::add(destination(), source(), status); break;

4
OSBindings/Mac/Clock SignalTests/8088Tests.mm
View File

@ -280,6 +280,9 @@ struct FailedExecution {
@"D4.json.gz", // AAM
@"D5.json.gz", // AAD
@"27.json.gz", // DAA
@"2F.json.gz", // DAS
@"98.json.gz", // CBW
// ADC
@"10.json.gz", @"11.json.gz", @"12.json.gz", @"13.json.gz", @"14.json.gz", @"15.json.gz",
@ -297,7 +300,6 @@ struct FailedExecution {
@"E8.json.gz", @"FF.2.json.gz",
@"9A.json.gz", @"FF.3.json.gz",
@"98.json.gz", // CBW
@"F8.json.gz", // CLC
@"FC.json.gz", // CLD
@"FA.json.gz", // CLI