diff --git a/src/ov_SC03_124/ov_SC03_124_jr_80188544.c b/src/ov_SC03_124/ov_SC03_124_jr_80188544.c
index 4055d8c924..2c50eaa228 100644
--- a/src/ov_SC03_124/ov_SC03_124_jr_80188544.c
+++ b/src/ov_SC03_124/ov_SC03_124_jr_80188544.c
@@ -3730,7 +3730,156 @@ s32 func_80189D4C(s32 a0, s16 a1, s16 a2) {
 }
 
 
-INCLUDE_ASM("asm/ov_SC03_124/nonmatchings/ov_SC03_124_jr_80188544", func_80189F00);
+typedef struct { s16 vx, vy; } DVEC2_C974_8017BA3C_80189F00;
+typedef struct { s16 vx, vy, vz, pad; } SVEC2_C974_8017BA3C_80189F00;
+typedef struct { s16 m[3][3]; s32 t[3]; } MTX_C974_80189F00;
+
+
+/* func_80189F00 -- ov_SC03_107 / ov_SC03_107_jr_801789AC (212 ins)
+ *
+ * Decls chosen to agree VERBATIM with the destination TU
+ * (src/ov_SC03_107/ov_SC03_107_jr_801789AC.c):
+ *   func_8002D4C8  TU:168/3781/5786/5823/6444/8084 `extern void (s32,s32)`  (also `(int,int)` @999)
+ *   func_8012B030  TU:357/4991 `extern s32 (u8 *)`
+ *   func_8012CBCC  TU:452 `extern void (s32)`, TU:631 `extern void (s32)`
+ *                  -> VOID in the TU, so the return value is read through the
+ *                     §161c function-pointer cast, never through a re-decl.
+ *   func_80131C78  TU:565 `extern void (s32)`
+ *   func_80143B6C  TU:581/1143 `extern s32 (s32,s32)`
+ *   func_800291C8  TU:983 `extern void (s32,s32)`
+ *   func_80189D4C  DEFINED at TU:7981 as `s32 func_80189D4C(s32,s16,s16)` --
+ *                  the definition is above this slot, so the decl below agrees.
+ * D_801E2440 / D_801E2444 are declared nowhere in the TU (free choice).
+ */
+
+extern void func_8002D4C8(s32 a0, s32 a1);
+extern s32 func_8012B030(u8 *a0);
+extern void func_8012CBCC(s32);
+extern void func_80131C78(s32 a0);
+extern s32 func_80143B6C(s32 a0, s32 a1);
+extern void func_800291C8(s32, s32);
+extern s32 func_80189D4C(s32 a0, s16 a1, s16 a2);
+
+
+void func_80189F00(s32 a0) {
+
+    extern s32 D_801E2440;
+    extern s32 D_801E2444;
+    /* §162i1 dead-local pad: target frame 0x28 = args 0x10 + vars 0x10 + 4*2 regs;
+     * the raw draft compiles vars=0. Never read, never &-taken, >=2 elements. */
+    s32 pad[4];
+
+    if (*(s16 *)(a0 + 0xA) >= 0x10) {
+        func_80131C78(a0);
+        *(s16 *)(a0 + 0x2) = 2;
+        *(s32 *)(a0 + 0x1C) = 1;
+    }
+
+    switch (*(u8 *)(a0 + 0xC2)) {
+    case 0:
+        D_801E2440 = ((s32 (*)(s32))func_8012CBCC)(a0);
+        if (D_801E2440 & 0x6000) {
+            if (D_801E2440 & 0x1000) {
+                *(s16 *)(a0 + 0x2) = 2;
+                *(u8 *)(a0 + 0xC1) = 0;
+                *(s16 *)(a0 + 0x5E) = 0;
+                *(s32 *)(a0 + 0x1C) = 0x30;
+                func_8002D4C8(0x531, 0);
+                func_800291C8(0xA, *(s16 *)(a0 + 0xFE));
+                return;
+            }
+            func_80143B6C(a0, 1);
+            func_8002D4C8(0x754, 0);
+            *(u8 *)(a0 + 0xC2) = 1;
+            *(s32 *)(a0 + 0x14) = 0xFFF30000;
+            *(s32 *)(a0 + 0x1C) = 0;
+            *(s32 *)(a0 + 0x10) = *(s32 *)(a0 + 0x10) >> 2;
+            *(s32 *)(a0 + 0x18) = *(s32 *)(a0 + 0x18) >> 2;
+        }
+        *(s32 *)(a0 + 0x1C) += 1;
+        if (*(s32 *)(a0 + 0x1C) >= 0x78) {
+            func_80131C78(a0);
+            *(s16 *)(a0 + 0x2) = 2;
+            *(s32 *)(a0 + 0x1C) = 1;
+        }
+        break;
+
+    case 1:
+        D_801E2444 = *(s32 *)(a0 + 0x14);
+        D_801E2440 = ((s32 (*)(s32))func_8012CBCC)(a0);
+        if (D_801E2440 & 0x6000) {
+            if (D_801E2440 & 0x1000) {
+                *(s16 *)(a0 + 0x2) = 2;
+                *(u8 *)(a0 + 0xC1) = 0;
+                *(s16 *)(a0 + 0x5E) = 0;
+                *(s32 *)(a0 + 0x1C) = 0x30;
+                func_8002D4C8(0x531, 0);
+                func_800291C8(0xA, *(s16 *)(a0 + 0xFE));
+                return;
+            }
+            {
+                /* The read of D_801E2444 MUST precede the two pointer stores in the
+                 * source: gcc-2.7.2's scheduler cannot hoist a symbol_ref load above a
+                 * store through a register base (may-alias), so writing it inline in the
+                 * `-D_801E2444` expression leaves the load-delay slot unfilled -> a nop,
+                 * and the function is 1 instruction long. */
+                s32 t;
+                func_8002D4C8(0x754, 0);
+                func_80143B6C(a0, 1);
+                t = D_801E2444;
+                *(u8 *)(a0 + 0xC2) = 2;
+                *(s32 *)(a0 + 0x1C) = 0;
+                *(s32 *)(a0 + 0x14) = -t;
+            }
+        }
+        *(s32 *)(a0 + 0x1C) += 1;
+        if (*(s32 *)(a0 + 0x1C) >= 0x28) {
+            func_80131C78(a0);
+            *(s16 *)(a0 + 0x2) = 2;
+            *(s32 *)(a0 + 0x1C) = 1;
+        }
+        break;
+
+    case 2:
+        *(s32 *)(a0 + 0x10) = *(s32 *)(a0 + 0x10) * 15 / 16;
+        *(s32 *)(a0 + 0x18) = *(s32 *)(a0 + 0x18) * 15 / 16;
+        D_801E2440 = ((s32 (*)(s32))func_8012CBCC)(a0);
+        if (D_801E2440 & 0x6000) {
+            *(s32 *)(a0 + 0x14) = 0;
+            if (D_801E2440 & 0x1000) {
+                *(s16 *)(a0 + 0x2) = 2;
+                *(u8 *)(a0 + 0xC1) = 0;
+                *(s16 *)(a0 + 0x5E) = 0;
+                *(s32 *)(a0 + 0x1C) = 0x30;
+                func_8002D4C8(0x531, 0);
+                func_800291C8(0xA, *(s16 *)(a0 + 0xFE));
+                return;
+            }
+            if (!(*(u16 *)(a0 + 0x84) & 1)) {
+                *(u16 *)(a0 + 0x84) |= 1;
+                func_8002D4C8(0x754, 0);
+            }
+            if ((*(s32 *)(a0 + 0x1C) & 3) == 3) {
+                func_80143B6C(a0, 1);
+            }
+            *(s32 *)(a0 + 0x1C) += 1;
+            if (*(s32 *)(a0 + 0x1C) >= 0x11) {
+                func_80131C78(a0);
+                func_8012B030((u8 *)a0);
+                *(s16 *)(a0 + 0x2) = 1;
+                *(u16 *)(a0 + 0x84) &= 0xFFFE;
+            }
+        }
+        break;
+    }
+
+    func_80189D4C(a0, -0x28, 1);
+    *(s16 *)(a0 + 0x108) = *(u16 *)(a0 + 0x108) - 1;
+    if (*(s16 *)(a0 + 0x108) == 0) {
+        func_800291C8(0xA, *(s16 *)(a0 + 0xFE));
+    }
+}
+
 
 INCLUDE_ASM("asm/ov_SC03_124/nonmatchings/ov_SC03_124_jr_80188544", func_8018A250);