From 2f7dd0b01a55073c1038558c0255625084e937bd Mon Sep 17 00:00:00 2001
From: Thomas Harte <thomas.harte@gmail.com>
Date: Sun, 30 Jul 2023 16:26:29 -0400
Subject: [PATCH] Correct stack behaviour of PLD.
---
Processors/65816/Implementation/65816Storage.cpp | 15 +++++++++++++--
1 file changed, 13 insertions(+), 2 deletions(-)
diff --git a/Processors/65816/Implementation/65816Storage.cpp b/Processors/65816/Implementation/65816Storage.cpp
index 96aeb08ae..9854df814 100644
--- a/Processors/65816/Implementation/65816Storage.cpp
+++ b/Processors/65816/Implementation/65816Storage.cpp
@@ -656,7 +656,7 @@ struct CPU::WDC65816::ProcessorStorageConstructor {
stack_exception_impl(type, is8bit, target, CycleAccessStack);
}
- // 22b. Stack; s, PLx.
+ // 22b(i). Stack; s, PLx, respecting emulation mode. E.g. PLP.
static void stack_pull(AccessType, bool is8bit, const std::function<void(MicroOp)> &target) {
target(CycleFetchPCThrowaway); // IO.
target(CycleFetchPCThrowaway); // IO.
@@ -667,6 +667,17 @@ struct CPU::WDC65816::ProcessorStorageConstructor {
target(OperationPerform);
}
+ // 22b(ii). Stack; s, PLx, ignoring emulation mode. E.g. PLD.
+ static void stack_pull_no_emulation(AccessType, bool is8bit, const std::function<void(MicroOp)> &target) {
+ target(CycleFetchPCThrowaway); // IO.
+ target(CycleFetchPCThrowaway); // IO.
+
+ if(!is8bit) target(CyclePullNotEmulation); // REG low.
+ target(CyclePullNotEmulation); // REG [high].
+
+ target(OperationPerform);
+ }
+
// 22c. Stack; s, PHx.
static void stack_push(AccessType, bool is8bit, const std::function<void(MicroOp)> &target) {
target(CycleFetchPCThrowaway); // IO.
@@ -852,7 +863,7 @@ ProcessorStorage::ProcessorStorage() {
/* 0x28 PLP s */ op(stack_pull, PLP, AccessMode::Always8Bit);
/* 0x29 AND # */ op(immediate, AND);
/* 0x2a ROL A */ op(accumulator, ROL);
- /* 0x2b PLD s */ op(stack_pull, PLD, AccessMode::Always16Bit);
+ /* 0x2b PLD s */ op(stack_pull_no_emulation, PLD, AccessMode::Always16Bit);
/* 0x2c BIT a */ op(absolute, BIT);
/* 0x2d AND a */ op(absolute, AND);
/* 0x2e ROL a */ op(absolute_rmw, ROL);