From 2b7958f5f36feb6bf68c65bc29617bf3a272a610 Mon Sep 17 00:00:00 2001
From: Rekai Musuka <rekai@musuka.dev>
Date: Wed, 9 Jun 2021 20:48:31 -0500
Subject: [PATCH] chore(bus): add a select few read/write guards

---
 src/bus.rs | 41 +++++++++++++++--------------------------
 1 file changed, 15 insertions(+), 26 deletions(-)

diff --git a/src/bus.rs b/src/bus.rs
index 70789b0..bd8180c 100644
--- a/src/bus.rs
+++ b/src/bus.rs
@@ -158,14 +158,10 @@ impl BusIo for Bus {
             }
             0x8000..=0x9FFF => {
                 // 8KB Video RAM
-
-                // TODO: Fix Timing issues in PPU
-                // match self.ppu.stat.mode() {
-                //     PpuMode::VBlank => 0xFF,
-                //     _ => self.ppu.read_byte(addr),
-                // }
-
-                self.ppu.read_byte(addr)
+                match self.ppu.stat.mode() {
+                    PpuMode::VBlank => 0xFF,
+                    _ => self.ppu.read_byte(addr),
+                }
             }
             0xA000..=0xBFFF => match self.cartridge.as_ref() {
                 // 8KB External RAM
@@ -195,16 +191,12 @@ impl BusIo for Bus {
             }
             0xFE00..=0xFE9F => {
                 // Sprite Attribute Table
+                use PpuMode::{HBlank, VBlank};
 
-                // TODO: Fix timing issues in the PPU
-                // use PpuMode::{HBlank, VBlank};
-
-                // match self.ppu.stat.mode() {
-                //     HBlank | VBlank => self.ppu.oam.read_byte(addr),
-                //     _ => 0xFF,
-                // }
-
-                self.ppu.oam.read_byte(addr)
+                match self.ppu.stat.mode() {
+                    HBlank | VBlank => self.ppu.oam.read_byte(addr),
+                    _ => 0xFF,
+                }
             }
             0xFEA0..=0xFEFF => {
                 // Prohibited Memory
@@ -313,15 +305,12 @@ impl BusIo for Bus {
             }
             0xFE00..=0xFE9F => {
                 // Sprite Attribute Table
-                // use PpuMode::{HBlank, VBlank};
+                use PpuMode::{HBlank, VBlank};
 
-                // TODO: Fix Timing issues in the PPU
-                // match self.ppu.stat.mode() {
-                //     HBlank | VBlank => self.ppu.oam.write_byte(addr, byte),
-                //     _ => {}
-                // }
-
-                self.ppu.oam.write_byte(addr, byte)
+                match self.ppu.stat.mode() {
+                    HBlank | VBlank => self.ppu.oam.write_byte(addr, byte),
+                    _ => {}
+                }
             }
             0xFEA0..=0xFEFF => {} // TODO: As far as I know, writes to here do nothing.
             0xFF00..=0xFF7F => {
@@ -376,7 +365,7 @@ impl BusIo for Bus {
                             self.boot = None;
                         }
                     }
-                    _ => unimplemented!("Unable to write to {:#06X} in I/O Registers", addr),
+                    _ => {} // unimplemented!("Unable to write to {:#06X} in I/O Registers", addr),
                 };
             }
             0xFF80..=0xFFFE => {