From 19ce69a2aa2fe532e5f8a9f4d8efbf18477ba825 Mon Sep 17 00:00:00 2001
From: cristian <cristian@nirvashTypeZero.local>
Date: Sun, 5 Jul 2026 16:11:29 -0400
Subject: [PATCH] Decompile func_812020C0 (tile->framebuffer blit) to C behind
 NON_MATCHING

Graphics cluster: copies a tile's set (odd) pixels from D_8122C748's plane data
into the render target at +0x5B4, 4 pixels per step over an 0xB x 0xC region;
arg1 selects source plane and scan direction. Multiplier (arg2*0x108), source
step (+/-1 u16) and framebuffer offset verified vs asm. Bare GLOBAL_ASM: 38 -> 37.

Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>
---
 src/fragments/1/fragment1_7F9A0.c | 52 +++++++++++++++++++++++++++++++
 1 file changed, 52 insertions(+)

diff --git a/src/fragments/1/fragment1_7F9A0.c b/src/fragments/1/fragment1_7F9A0.c
index 96af201..726b5b5 100644
--- a/src/fragments/1/fragment1_7F9A0.c
+++ b/src/fragments/1/fragment1_7F9A0.c
@@ -502,7 +502,59 @@ void func_81201FBC(s32 arg0, s32 arg1, s32 arg2) {
   func_812018C0(arg0 + (arg2 - 8) * 2, &D_8122C748->unk_9990, arg1, 8, 0x10);
 }
 
+#ifdef NON_MATCHING
+// Blit a tile's set (odd) pixels from D_8122C748's plane data into the render
+// target at +0x5B4, 4 pixels per step across an 0xB x 0xC region. arg1 chooses
+// the source plane and scan direction.
+void func_812020C0(s32 arg0, s32 arg1, s32 arg2) {
+    u16* src;
+    u8* base;
+    s32 step;
+    s32 row;
+    s32 col;
+    u16 p;
+
+    if (arg1 != 0) {
+        src = (u16*) ((u8*) D_8122C748 + (arg2 * 0x108) + 0x9A90);
+        step = 1;
+    } else {
+        src = (u16*) ((u8*) D_8122C748 + (arg2 * 0x108) + 0x9B96);
+        step = -1;
+    }
+    base = (u8*) arg0;
+    row = 0;
+    do {
+        col = 0;
+        do {
+            u16* dst = (u16*) (base + (row * 0x280) + (col * 2) + 0x5B4);
+            p = *src;
+            src += step;
+            if (p & 1) {
+                dst[0] = p;
+            }
+            p = *src;
+            src += step;
+            if (p & 1) {
+                dst[1] = p;
+            }
+            p = *src;
+            src += step;
+            if (p & 1) {
+                dst[2] = p;
+            }
+            p = *src;
+            src += step;
+            if (p & 1) {
+                dst[3] = p;
+            }
+            col += 4;
+        } while (col != 0xC);
+        row += 1;
+    } while (row != 0xB);
+}
+#else
 #pragma GLOBAL_ASM("asm/us/nonmatchings/fragments/1/fragment1_7F9A0/func_812020C0.s")
+#endif
 
 #pragma GLOBAL_ASM("asm/us/nonmatchings/fragments/1/fragment1_7F9A0/func_81202210.s")