From 6a4d1cbcc7b13b295ada64c0e939ca6fb11b0213 Mon Sep 17 00:00:00 2001
From: Zur3l <90565581+Zur3l@users.noreply.github.com>
Date: Sat, 11 Jul 2026 15:59:32 -0400
Subject: [PATCH] Decomp sub_02001AB0

---
 .../{main_02001AB0.inc => main_02001B0C.inc}  |  0
 asm/{main_02001AB0.s => main_02001B0C.s}      | 29 +-------------
 include/main_02001A54.h                       |  1 +
 main.lsf                                      |  2 +-
 src/main_02001A54.c                           | 40 +++++++++++++++++++
 5 files changed, 43 insertions(+), 29 deletions(-)
 rename asm/include/{main_02001AB0.inc => main_02001B0C.inc} (100%)
 rename asm/{main_02001AB0.s => main_02001B0C.s} (95%)

diff --git a/asm/include/main_02001AB0.inc b/asm/include/main_02001B0C.inc
similarity index 100%
rename from asm/include/main_02001AB0.inc
rename to asm/include/main_02001B0C.inc
diff --git a/asm/main_02001AB0.s b/asm/main_02001B0C.s
similarity index 95%
rename from asm/main_02001AB0.s
rename to asm/main_02001B0C.s
index 17e3eeb4..9c3483fe 100644
--- a/asm/main_02001AB0.s
+++ b/asm/main_02001B0C.s
@@ -1,35 +1,8 @@
 	.include "asm/macros.inc"
-	.include "main_02001AB0.inc"
+	.include "main_02001B0C.inc"
 
 	.text
 
-	arm_func_start sub_02001AB0
-sub_02001AB0: ; 0x02001AB0
-	stmdb sp!, {r3, r4, r5, lr}
-	tst r0, #0x80000000
-	movne r2, #1
-	moveq r2, #0
-	tst r1, #0x80000000
-	and r4, r2, #0xff
-	movne r2, #1
-	moveq r2, #0
-	cmp r1, #0
-	and r5, r2, #0xff
-	mvneq r0, #0x80000000
-	ldmeqia sp!, {r3, r4, r5, pc}
-	cmp r0, #0
-	moveq r0, #0
-	ldmeqia sp!, {r3, r4, r5, pc}
-	cmp r4, #0
-	rsbne r0, r0, #0
-	cmp r5, #0
-	rsbne r1, r1, #0
-	bl sub_02001BB4
-	cmp r4, r5
-	rsbne r0, r0, #0
-	ldmia sp!, {r3, r4, r5, pc}
-	arm_func_end sub_02001AB0
-
 	arm_func_start UMultiplyByFixedPoint
 UMultiplyByFixedPoint: ; 0x02001B0C
 	stmdb sp!, {r3, r4, r5, lr}
diff --git a/include/main_02001A54.h b/include/main_02001A54.h
index af2881b4..4be3412c 100644
--- a/include/main_02001A54.h
+++ b/include/main_02001A54.h
@@ -4,5 +4,6 @@
 #include "util.h"
 
 s32 MultiplyByFixedPoint(s32 x, s32 y);
+s32 sub_02001AB0(s32 x, s32 y);
 
 #endif //PMDSKY_MAIN_02001A54_H
diff --git a/main.lsf b/main.lsf
index 3c17a76e..2ad6e721 100644
--- a/main.lsf
+++ b/main.lsf
@@ -19,7 +19,7 @@ Static main
 	Object src/main_020018D0.o
 	Object asm/main_02001A30.o
 	Object src/main_02001A54.o
-	Object asm/main_02001AB0.o
+	Object asm/main_02001B0C.o
 	Object src/main_0200224C.o
 	Object asm/main_020022C4.o
 	Object src/main_0200330C.o
diff --git a/src/main_02001A54.c b/src/main_02001A54.c
index 5a103714..e6f33a0a 100644
--- a/src/main_02001A54.c
+++ b/src/main_02001A54.c
@@ -1,6 +1,7 @@
 #include "main_02001A54.h"
 
 extern s32 UMultiplyByFixedPoint(s32, s32);
+extern s32 sub_02001BB4(s32, s32);
 
 s32 MultiplyByFixedPoint(s32 x, s32 y)
 {
@@ -40,3 +41,42 @@ s32 MultiplyByFixedPoint(s32 x, s32 y)
     }
     return result;
 }
+
+s32 sub_02001AB0(s32 x, s32 y)
+{
+    s32 result;
+    bool8 xNeg;
+    bool8 yNeg;
+
+    // Same as checking if x < 0 and y < 0
+    if (x & 0x80000000) {
+        xNeg = TRUE;
+    } else {
+        xNeg = FALSE;
+    }
+    if (y & 0x80000000) {
+        yNeg = TRUE;
+    } else {
+        yNeg = FALSE;
+    }
+    
+    if (y == 0) {
+        return 0x7FFFFFFF;
+    }
+    if (x == 0) {
+        return 0;
+    }
+    
+    if (xNeg) {
+        x = -x;
+    }
+    if (yNeg) {
+        y = -y;
+    }
+    
+    result = sub_02001BB4(x, y);
+    if (xNeg != yNeg) {
+        result = -result;
+    }
+    return result;
+}