From 885bfea43409a3d5438bbde59f8d40014fd7cbbf Mon Sep 17 00:00:00 2001
From: Franco Colmenarez <info@francoacg.com>
Date: Wed, 12 Oct 2022 08:07:25 -0500
Subject: [PATCH] Small PPU refactor for HDMA addresses

---
 src/ppu.rs | 29 +++++++++++++++++------------
 1 file changed, 17 insertions(+), 12 deletions(-)

diff --git a/src/ppu.rs b/src/ppu.rs
index 8677b33..d8b5a32 100644
--- a/src/ppu.rs
+++ b/src/ppu.rs
@@ -390,17 +390,14 @@ impl PPU {
     }
 
     pub fn get_register(&self, address: u16) -> u8 {
-        if address >= 0xFF51 && address <= 0xFF55 {
-            if address == HDMA1_ADDRESS {
-                return self.hdma_source.to_be_bytes()[0];
-            } else if address == HDMA2_ADDRESS {
-                return self.hdma_source.to_be_bytes()[1];
-            } else if address == HDMA3_ADDRESS {
-                return self.hdma_destination.to_be_bytes()[0];
-            } else if address == HDMA4_ADDRESS {
-                return self.hdma_destination.to_be_bytes()[1];
-            } else if address == HDMA5_ADDRESS {
-                return self.hdma_start;
+        if address >= HDMA1_ADDRESS && address <= HDMA5_ADDRESS {
+            return match address {
+                HDMA1_ADDRESS => self.hdma_source.to_be_bytes()[0],
+                HDMA2_ADDRESS => self.hdma_source.to_be_bytes()[1],
+                HDMA3_ADDRESS => self.hdma_destination.to_be_bytes()[0],
+                HDMA4_ADDRESS => self.hdma_destination.to_be_bytes()[1],
+                HDMA5_ADDRESS => self.hdma_start,
+                _ => 0x00,
             }
         } else if address >= 0xFF68 && address <= 0xFF6B {
             return self.cram_registers[(address as usize) - 0xFF68];
@@ -415,7 +412,15 @@ impl PPU {
     }
 
     pub fn set_register(&mut self, address: u16, data: u8) {
-        if address >= 0xFF51 && address <= 0xFF55 {
+        if address >= HDMA1_ADDRESS && address <= HDMA5_ADDRESS {
+            match address {
+                HDMA1_ADDRESS => self.hdma_source = (self.hdma_source & 0xFF) | ((data as u16) << 8),
+                HDMA2_ADDRESS => self.hdma_source = (self.hdma_source & 0xFF00) | (data as u16),
+                HDMA3_ADDRESS => self.hdma_destination = (self.hdma_destination & 0xFF) | ((data as u16) << 8),
+                HDMA4_ADDRESS => self.hdma_destination = (self.hdma_destination & 0xFF00) | (data as u16),
+                HDMA5_ADDRESS => self.hdma_start = data,
+                _ => (),
+            };
             if address == HDMA1_ADDRESS {
                 self.hdma_source = (self.hdma_source & 0xFF) | ((data as u16) << 8);
             } else if address == HDMA2_ADDRESS {