From 5f1ea6c04cd438b13144c264a402e55f1baf203d Mon Sep 17 00:00:00 2001
From: Thomas Harte <thomas.harte@gmail.com>
Date: Wed, 8 Nov 2023 22:30:39 -0500
Subject: [PATCH] Unify AAA and AAS.
---
InstructionSets/x86/Implementation/BCD.hpp | 66 +++----------------
.../Implementation/PerformImplementation.hpp | 6 +-
2 files changed, 13 insertions(+), 59 deletions(-)
diff --git a/InstructionSets/x86/Implementation/BCD.hpp b/InstructionSets/x86/Implementation/BCD.hpp
index 97519cc6a..26fd87056 100644
--- a/InstructionSets/x86/Implementation/BCD.hpp
+++ b/InstructionSets/x86/Implementation/BCD.hpp
@@ -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;
}
diff --git a/InstructionSets/x86/Implementation/PerformImplementation.hpp b/InstructionSets/x86/Implementation/PerformImplementation.hpp
index 6a13c2254..a28073a1b 100644
--- a/InstructionSets/x86/Implementation/PerformImplementation.hpp
+++ b/InstructionSets/x86/Implementation/PerformImplementation.hpp
@@ -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;