Apply asie's patch 4 for performance modifications

This patch removes the need for a backbuffer on EWRAM and instead store
them on the VRAM.

1 files changed, 21 insertions, 11 deletions

diff --git a/src/uxn/devices/ppu.c b/src/uxn/devices/ppu.c
index 97b5e4f..61e4d26 100644
--- a/src/uxn/devices/ppu.c
+++ b/src/uxn/devices/ppu.c
@@ -142,10 +142,6 @@ static Uint32 unpack_icon_lut_flipx[256] = {
     0x11111111
 };
 
-EWRAM_BSS
-static u32 *backbuffer_bg0[32 * 20 * sizeof(Tile) / 4];
-EWRAM_BSS
-static u32 *backbuffer_bg1[32 * 20 * sizeof(Tile) / 4];
 static u32 dirty_tiles[20] = {0};
 
 void
@@ -194,13 +190,13 @@ puticn(Ppu *p, Uint32 *layer, Uint16 x, Uint16 y, Uint8 *sprite, Uint8 color, Ui
 
         if (flipy) flipy = 7;
 
-        if (x >= 240 || y >= 160) return;
+        if (x >= SCREEN_WIDTH || y >= SCREEN_HEIGHT) return;
 
         if (color != 0x05 && color != 0x0a && color != 0x0f) {
                 u64 mask = ~((u64)0xFFFFFFFF << shift);
 
                 for (v = 0; v < 8; v++, layerptr++) {
-                        if ((y + v) >= 160) break;
+                        if ((y + v) >= SCREEN_HEIGHT) break;
 
                         sprline = sprite[v ^ flipy];
                         u64 data = (u64)(lut_expand[sprline] * (color & 3)) << shift;
@@ -213,7 +209,7 @@ puticn(Ppu *p, Uint32 *layer, Uint16 x, Uint16 y, Uint8 *sprite, Uint8 color, Ui
                 }
         } else {
                 for (v = 0; v < 8; v++, layerptr++) {
-                        if ((y + v) >= 160) break;
+                        if ((y + v) >= SCREEN_HEIGHT) break;
 
                         sprline = sprite[v ^ flipy];
                         u64 mask = ~((u64)(lut_expand[sprline] * 0xF) << shift);
@@ -246,13 +242,13 @@ putchr(Ppu *p, Uint32 *layer, Uint16 x, Uint16 y, Uint8 *sprite, Uint8 color,
 
         if (flipy) flipy = 7;
 
-        if (x >= 240 || y >= 160) return;
+        if (x >= SCREEN_WIDTH || y >= SCREEN_HEIGHT) return;
 
         u64 mask = ~((u64)0xFFFFFFFF << shift);
         u32 colconst = (color >> 2) * 0x11111111;
 
         for (v = 0; v < 8; v++, layerptr++) {
-                if ((y + v) >= 160) break;
+                if ((y + v) >= SCREEN_HEIGHT) break;
 
                 sprline1 = sprite[v ^ flipy];
                 sprline2 = sprite[(v ^ flipy) | 8];
@@ -315,13 +311,27 @@ initppu(Ppu *p, Uint8 hor, Uint8 ver, Uint8 pad) {
     BG_CTRL(1) = BG_CHARBLOCK(cb_bg) | BG_SCREENBLOCK(sb_idx) | BG_PRIORITY(2);
 
     // Clear tile memory.
-    p->fg = backbuffer_bg0;
-    p->bg = backbuffer_bg1;
     for (size_t i = 0; i < 32 * 20 * 8; ++i) {
         p->fg[i] = 0;
         p->bg[i] = 0;
     }
 
+    // Use DMA to clear VRAM.
+    u32 fill = 0;
+    u32 tile_clear_ctrl = (32 * 20 * 8) | DMA_DST_INC | DMA_SRC_FIXED | DMA_NOW | DMA_CHUNK_32 | DMA_ENABLE;
+    DMA_SRC(3) = &fill;
+    DMA_DST(3) = p->fg;
+    DMA_CTRL(3) = tile_clear_ctrl;
+    DMA_DST(3) = p->bg;
+    DMA_CTRL(3) = tile_clear_ctrl;
+
+    p->fg = (u32*) (MEM_VRAM + (56 * 1024));
+    p->bg = (u32*) (MEM_VRAM + (76 * 1024));
+    DMA_DST(3) = p->fg;
+    DMA_CTRL(3) = tile_clear_ctrl;
+    DMA_DST(3) = p->bg;
+    DMA_CTRL(3) = tile_clear_ctrl;
+
     // Initialize default palette.
     PAL_BUFFER_BG[0] = COLOR_BLACK;
     PAL_BUFFER_BG[1] = COLOR_WHITE;