From 7431086b14781c82040059e78372c385ec74ce4e Mon Sep 17 00:00:00 2001
From: Gwilym Inzani <email@gwilym.dev>
Date: Thu, 31 Aug 2023 07:53:08 +0100
Subject: [PATCH] Try using memcpy4 for copying the tile data

---
 agb/src/agbabi/mod.rs                 |  8 ++++++++
 agb/src/display/tiled/vram_manager.rs | 12 ++++--------
 2 files changed, 12 insertions(+), 8 deletions(-)

diff --git a/agb/src/agbabi/mod.rs b/agb/src/agbabi/mod.rs
index a53823cf..1f3df5a1 100644
--- a/agb/src/agbabi/mod.rs
+++ b/agb/src/agbabi/mod.rs
@@ -4,6 +4,14 @@ global_asm!(include_str!("macros.inc"));
 global_asm!(include_str!("memcpy.s"));
 global_asm!(include_str!("memset.s"));
 
+extern "C" {
+    fn __aeabi_memcpy4(dest: *mut u32, src: *const u32, n: usize);
+}
+
+pub(crate) unsafe fn memcpy(dest: *mut u32, src: *const u32, n: usize) {
+    __aeabi_memcpy4(dest, src, n);
+}
+
 #[cfg(test)]
 mod test {
     mod memset {
diff --git a/agb/src/display/tiled/vram_manager.rs b/agb/src/display/tiled/vram_manager.rs
index 3d8c04aa..8ef68717 100644
--- a/agb/src/display/tiled/vram_manager.rs
+++ b/agb/src/display/tiled/vram_manager.rs
@@ -4,6 +4,7 @@ use alloc::{slice, vec::Vec};
 
 use crate::{
     agb_alloc::{block_allocator::BlockAllocator, bump_allocator::StartEnd},
+    agbabi,
     display::palette16,
     dma::dma_copy16,
     hash_map::{Entry, HashMap},
@@ -380,17 +381,12 @@ impl VRamManager {
         let tile_offset = (tile_id as usize) * tile_size;
         let tile_slice = &tile_set.tiles[tile_offset..(tile_offset + tile_size)];
 
-        let tile_size_in_half_words = tile_slice.len() / 2;
-
+        let tile_size = tile_slice.len();
         let target_location = tile_reference.0.as_ptr() as *mut _;
 
         unsafe {
-            dma_copy16(
-                tile_slice.as_ptr() as *const u16,
-                target_location,
-                tile_size_in_half_words,
-            );
-        };
+            agbabi::memcpy(target_location, tile_slice.as_ptr() as *const _, tile_size);
+        }
     }
 
     /// Copies raw palettes to the background palette without any checks.