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Unify AAA and AAS.

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This commit is contained in:
Thomas Harte 2023-11-08 22:30:39 -05:00
parent 8d2a2bcf4a
commit 5f1ea6c04c
2 changed files with 13 additions and 59 deletions
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66
InstructionSets/x86/Implementation/BCD.hpp
View File

@ -15,67 +15,21 @@
namespace InstructionSet::x86::Primitive {
template <typename ContextT>
void aaa(
CPU::RegisterPair16 &ax,
ContextT &context
) { // P. 313
/*
IF ((AL AND 0FH) > 9) OR (AF = 1)
THEN
AL ← (AL + 6);
AH ← AH + 1;
AF ← 1;
CF ← 1;
ELSE
AF ← 0;
CF ← 0;
FI;
AL ← AL AND 0FH;
*/
/*
The AF and CF flags are set to 1 if the adjustment results in a decimal carry;
otherwise they are cleared to 0. The OF, SF, ZF, and PF flags are undefined.
*/
if((ax.halves.low & 0x0f) > 9 || context.flags.template flag<Flag::AuxiliaryCarry>()) {
ax.halves.low += 6;
++ax.halves.high;
context.flags.template set_from<Flag::Carry, Flag::AuxiliaryCarry>(1);
} else {
context.flags.template set_from<Flag::Carry, Flag::AuxiliaryCarry>(0);
}
ax.halves.low &= 0x0f;
}
template <typename ContextT>
void aas(
/// If @c add is @c true, performs an AAA; otherwise perfoms an AAS.
template <bool add, typename ContextT>
void aaas(
CPU::RegisterPair16 &ax,
ContextT &context
) {
/*
IF ((AL AND 0FH) > 9) OR (AF = 1)
THEN
AL ← AL – 6;
AH ← AH – 1;
AF ← 1;
CF ← 1;
ELSE
CF ← 0;
AF ← 0;
FI;
AL ← AL AND 0FH;
*/
/*
The AF and CF flags are set to 1 if there is a decimal borrow;
otherwise, they are cleared to 0. The OF, SF, ZF, and PF flags are undefined.
*/
if((ax.halves.low & 0x0f) > 9 || context.flags.template flag<Flag::AuxiliaryCarry>()) {
ax.halves.low -= 6;
--ax.halves.high;
if constexpr (add) {
ax.halves.low += 6;
++ax.halves.high;
} else {
ax.halves.low -= 6;
--ax.halves.high;
}
context.flags.template set_from<Flag::Carry, Flag::AuxiliaryCarry>(1);
} else {
context.flags.template set_from<Flag::Carry, Flag::AuxiliaryCarry>(0);
}
ax.halves.low &= 0x0f;
}

6
InstructionSets/x86/Implementation/PerformImplementation.hpp
View File

@ -175,10 +175,10 @@ template <
case Operation::ESC:
case Operation::NOP: return;
case Operation::AAA: Primitive::aaa(context.registers.axp(), context); return;
case Operation::AAD: Primitive::aad(context.registers.axp(), instruction.operand(), context); return;
case Operation::AAM: Primitive::aam(context.registers.axp(), instruction.operand(), context); return;
case Operation::AAS: Primitive::aas(context.registers.axp(), context); return;
case Operation::AAD: Primitive::aad(context.registers.axp(), instruction.operand(), context); return;
case Operation::AAA: Primitive::aaas<true>(context.registers.axp(), context); return;
case Operation::AAS: Primitive::aaas<false>(context.registers.axp(), context); return;
case Operation::DAA: Primitive::daas<true>(context.registers.al(), context); return;
case Operation::DAS: Primitive::daas<false>(context.registers.al(), context); return;