From a92e965cde3ae3f1c784d56041ecdcba1e1afa41 Mon Sep 17 00:00:00 2001
From: Franco Colmenarez <info@francoacg.com>
Date: Sun, 10 Nov 2024 17:51:49 -0500
Subject: [PATCH] fix more instructions

---
 snes-core/src/cpu/instructions/plp.rs | 5 +++++
 snes-core/src/cpu/instructions/xce.rs | 7 +++++--
 snes-core/src/ppu/registers.rs        | 1 +
 snes-frontend/src/emu_ui/debug/ppu.rs | 3 ++-
 4 files changed, 13 insertions(+), 3 deletions(-)

diff --git a/snes-core/src/cpu/instructions/plp.rs b/snes-core/src/cpu/instructions/plp.rs
index 21d1753..58eed86 100644
--- a/snes-core/src/cpu/instructions/plp.rs
+++ b/snes-core/src/cpu/instructions/plp.rs
@@ -15,6 +15,11 @@ impl CPUInstruction for PLP {
         if registers.emulation_mode {
             registers.set_memory_select_flag(true);
             registers.set_index_register_select_flag(true);
+        } else {
+            if !registers.is_16bit_index() {
+                registers.x &= 0xFF;
+                registers.y &= 0xFF;
+            }
         }
         let (bytes, cycles) = cycles::increment_cycles_plp();
         registers.increment_pc(bytes); registers.cycles += cycles;
diff --git a/snes-core/src/cpu/instructions/xce.rs b/snes-core/src/cpu/instructions/xce.rs
index 9b1cc39..87aff7d 100644
--- a/snes-core/src/cpu/instructions/xce.rs
+++ b/snes-core/src/cpu/instructions/xce.rs
@@ -10,11 +10,14 @@ pub struct XCE {}
 
 impl CPUInstruction for XCE {
     fn execute(&self, registers: &mut Registers, _bus: &mut Bus) {
-        let did_mode_change = registers.emulation_mode != registers.get_carry_flag();
         registers.exchange_carry_and_emulation();
-        if did_mode_change {
+        if registers.emulation_mode {
             registers.set_memory_select_flag(true);
             registers.set_index_register_select_flag(true);
+            registers.x &= 0xFF;
+            registers.y &= 0xFF;
+            registers.sp &= 0xFF;
+            registers.sp |= 0x100;
         }
         let (bytes, cycles) = cycles::increment_cycles_exchange();
         registers.increment_pc(bytes); registers.cycles += cycles;
diff --git a/snes-core/src/ppu/registers.rs b/snes-core/src/ppu/registers.rs
index 0a4e866..06ace9e 100644
--- a/snes-core/src/ppu/registers.rs
+++ b/snes-core/src/ppu/registers.rs
@@ -274,6 +274,7 @@ impl PPURegisters {
             _ => unreachable!(),
         };
         if address_translation_rotate > 0 {
+            println!("ADDRESS ROTATE {}", address_translation_rotate);
             // TODO: implement address translation
         }
         let increment_when_lo = (register >> 7) == 0;
diff --git a/snes-frontend/src/emu_ui/debug/ppu.rs b/snes-frontend/src/emu_ui/debug/ppu.rs
index 2a40182..d4046a8 100644
--- a/snes-frontend/src/emu_ui/debug/ppu.rs
+++ b/snes-frontend/src/emu_ui/debug/ppu.rs
@@ -190,7 +190,8 @@ fn build_vram_window(ctx: &egui::Context, ppu_debug_options: &mut PPUDebugContro
                 for row in chunks {
                     let mut address_row = format!("{:04X} | ", row[0]);
                     for address in row {
-                        address_row = format!("{}{:04X} ", address_row, ppu_registers.vram()[((*address) & 0x7FFF) as usize]);
+                        let effective_vram_address = ((*address) & 0x7FFF) as usize;
+                        address_row = format!("{}{:04X} ", address_row, ppu_registers.vram()[effective_vram_address]);
                     }
                     ui.monospace(address_row);
                 }