guS2DInitBg OK (#426)

src/boot_O2_g3/idle.c

@@ -1,3 +1,4 @@
+#include "prevent_bss_reordering.h"
 #include "global.h"
 
 u8 D_80096B20 = 1;

src/libultra/gu/guS2DInitBg.c

@@ -1,3 +1,25 @@
 #include "global.h"
 
-#pragma GLOBAL_ASM("asm/non_matchings/boot/guS2DInitBg/guS2DInitBg.s")
+void guS2DInitBg(uObjBg* bg) {
+    u32 size;
+    s32 tmem = (bg->b.imageFmt == G_IM_FMT_CI) ? 0x100 : 0x200;
+    u16 shift = (6 - bg->b.imageSiz);
+
+    if (bg->b.imageLoad == G_BGLT_LOADBLOCK) {
+        bg->b.tmemW = bg->b.imageW >> shift;
+        bg->b.tmemH = (tmem / bg->b.tmemW) * 4;
+        bg->b.tmemSizeW = bg->b.tmemW * 2;
+        bg->b.tmemSize = bg->b.tmemH * bg->b.tmemSizeW;
+        bg->b.tmemLoadSH = (bg->b.tmemSize >> 1) - 1;
+        bg->b.tmemLoadTH = (0x7FF / bg->b.tmemW) + 1;
+    } else { // G_BGLT_LOADTILE
+        bg->b.tmemW = (bg->b.frameW >> shift) + 3;
+        bg->b.tmemH = (tmem / bg->b.tmemW) * 4;
+        bg->b.tmemSizeW = (bg->b.imageW >> shift) * 2;
+
+        size = bg->b.tmemH * bg->b.tmemSizeW;
+        bg->b.tmemSize = (size >> 16);
+        bg->b.tmemLoadSH = (size >> 0) & 0xFFFF;
+        bg->b.tmemLoadTH = bg->b.tmemH - 1;
+    }
+}