From 75a9396b574a6a7fc68f1f62c1ca97fbbd68324c Mon Sep 17 00:00:00 2001
From: Alex Janka <alex@alexjanka.com>
Date: Wed, 15 Feb 2023 08:25:04 +1100
Subject: [PATCH] comments and a lil fixing

---
 src/processor/memory.rs          | 13 +++++--------
 src/processor/memory/mmio/apu.rs |  2 +-
 2 files changed, 6 insertions(+), 9 deletions(-)

diff --git a/src/processor/memory.rs b/src/processor/memory.rs
index d16fc42..afed77e 100644
--- a/src/processor/memory.rs
+++ b/src/processor/memory.rs
@@ -119,6 +119,7 @@ impl Memory {
     }
 
     fn get_io(&self, address: Address) -> u8 {
+        // range: 0xFF00 - 0xFF4B inclusive
         match address {
             0xFF00 => self.joypad.as_register(),
             0xFF10..0xFF40 => self.apu.get_register(address),
@@ -127,6 +128,7 @@ impl Memory {
     }
 
     fn set_io(&mut self, address: Address, data: u8) {
+        // range: 0xFF00 - 0xFF4B inclusive
         let addr_l = (address - 0xFF00) as usize;
         if !self.user_mode {
             self.io[addr_l] = data;
@@ -150,11 +152,7 @@ impl Memory {
                     // mixed read/write
                     self.masked_io(addr_l, data, 0b01111000);
                 }
-                0xFF4D | 0xFF56 => {
-                    // cgb only
-                    self.io[addr_l] = data;
-                }
-                0xFF03 | 0xFF08..0xFF0F | 0xFF44 | 0xFF76 | 0xFF77 => {
+                0xFF03 | 0xFF08..0xFF0F | 0xFF44 => {
                     // read-only addresses
                     println!("BANNED write: {data:#X} to {address:#X}");
                 }
@@ -170,9 +168,8 @@ impl Memory {
                         self.oam[l as usize] = self.get(addr);
                     }
                 }
-                _ => {
-                    self.io[addr_l] = data;
-                }
+                0x0..0xFF00 | 0xFF4C..=u16::MAX => panic!("passed wrong address to set_io"),
+                _ => self.io[addr_l] = data,
             }
         }
     }
diff --git a/src/processor/memory/mmio/apu.rs b/src/processor/memory/mmio/apu.rs
index 1a06cc5..83a9b57 100644
--- a/src/processor/memory/mmio/apu.rs
+++ b/src/processor/memory/mmio/apu.rs
@@ -117,7 +117,7 @@ impl Apu {
             0xFF13 | 0xFF18 | 0xFF1B | 0xFF1D | 0xFF20 => 0xFF,
             // not registers
             0xFF15 | 0xFF1F | 0xFF27..0xFF30 => 0xFF,
-            0x0..0xFF10 | 0xFF40..0xFFFF | 0xFFFF => panic!("non-apu addr in apu"),
+            0x0..0xFF10 | 0xFF40..=0xFFFF => panic!("non-apu addr in apu"),
             _ => self.mem[reg(addr)],
         }
     }