From 09dc26aca0f60797a24e50265b30f00b48db6a15 Mon Sep 17 00:00:00 2001
From: Seth Barberee <seth.barberee@gmail.com>
Date: Tue, 18 Jun 2024 09:57:32 -0700
Subject: [PATCH] decomp more math funcs

---
 asm/math.s | 279 -----------------------------------------------------
 src/math.c | 166 ++++++++++++++++++++++++++++++-
 2 files changed, 164 insertions(+), 281 deletions(-)

diff --git a/asm/math.s b/asm/math.s
index dd0479918..03bf69661 100644
--- a/asm/math.s
+++ b/asm/math.s
@@ -5,285 +5,6 @@
 
 	.text
 
-	thumb_func_start u24_8_div
-u24_8_div:
-	push {r4-r7,lr}
-	mov r7, r10
-	mov r6, r9
-	mov r5, r8
-	push {r5-r7}
-	sub sp, 0x4
-	cmp r1, 0
-	bne _08009EB8
-	ldr r0, _08009EB4
-	b _08009F58
-	.align 2, 0
-_08009EB4: .4byte 0x7fffffff
-_08009EB8:
-	cmp r0, 0
-	bne _08009EC0
-	movs r0, 0
-	b _08009F58
-_08009EC0:
-	lsrs r7, r0, 24
-	lsls r6, r0, 8
-	mov r10, r1
-	movs r0, 0
-	mov r9, r0
-	movs r5, 0
-	movs r4, 0
-	movs r1, 0x1
-	mov r8, r1
-	movs r2, 0x3F
-	str r2, [sp]
-_08009ED6:
-	lsls r5, 1
-	adds r0, r4, 0
-	movs r1, 0x80
-	lsls r1, 24
-	ands r0, r1
-	cmp r0, 0
-	beq _08009EE8
-	mov r2, r8
-	orrs r5, r2
-_08009EE8:
-	movs r1, 0x2
-	negs r1, r1
-	lsls r4, 1
-	adds r0, r7, 0
-	movs r2, 0x80
-	lsls r2, 24
-	ands r0, r2
-	cmp r0, 0
-	beq _08009EFE
-	mov r0, r8
-	orrs r4, r0
-_08009EFE:
-	lsls r7, 1
-	adds r0, r6, 0
-	movs r2, 0x80
-	lsls r2, 24
-	ands r0, r2
-	cmp r0, 0
-	beq _08009F10
-	mov r0, r8
-	orrs r7, r0
-_08009F10:
-	lsls r6, 1
-	ands r6, r1
-	adds r0, r5, 0
-	adds r1, r4, 0
-	movs r2, 0
-	mov r3, r10
-	bl u32_pair_less_than
-	lsls r0, 24
-	cmp r0, 0
-	bne _08009F3A
-	adds r0, r4, 0
-	movs r1, 0x1
-	mov r2, r10
-	subs r4, r2
-	movs r2, 0
-	subs r5, r2
-	cmp r0, r4
-	bcs _08009F3C
-	subs r5, 0x1
-	b _08009F3C
-_08009F3A:
-	movs r1, 0
-_08009F3C:
-	mov r0, r9
-	lsls r0, 1
-	mov r9, r0
-	cmp r1, 0
-	beq _08009F4C
-	mov r1, r8
-	orrs r0, r1
-	mov r9, r0
-_08009F4C:
-	ldr r2, [sp]
-	subs r2, 0x1
-	str r2, [sp]
-	cmp r2, 0
-	bge _08009ED6
-	mov r0, r9
-_08009F58:
-	add sp, 0x4
-	pop {r3-r5}
-	mov r8, r3
-	mov r9, r4
-	mov r10, r5
-	pop {r4-r7}
-	pop {r1}
-	bx r1
-	thumb_func_end u24_8_div
-
-	thumb_func_start sub_8009F68
-sub_8009F68:
-	push {r4-r7,lr}
-	adds r5, r0, 0
-	adds r6, r1, 0
-	adds r4, r6, 0
-	cmp r6, 0
-	bge _08009F76
-	negs r4, r6
-_08009F76:
-	movs r7, 0x80
-	lsls r7, 1
-	cmp r4, 0
-	beq _08009FA0
-_08009F7E:
-	movs r0, 0x1
-	ands r0, r4
-	cmp r0, 0
-	beq _08009F90
-	adds r0, r7, 0
-	adds r1, r5, 0
-	bl s24_8_mul
-	adds r7, r0, 0
-_08009F90:
-	adds r0, r5, 0
-	adds r1, r5, 0
-	bl s24_8_mul
-	adds r5, r0, 0
-	asrs r4, 1
-	cmp r4, 0
-	bne _08009F7E
-_08009FA0:
-	cmp r6, 0
-	bge _08009FB0
-	movs r0, 0x80
-	lsls r0, 1
-	adds r1, r7, 0
-	bl s24_8_div
-	b _08009FB2
-_08009FB0:
-	adds r0, r7, 0
-_08009FB2:
-	pop {r4-r7}
-	pop {r1}
-	bx r1
-	thumb_func_end sub_8009F68
-
-	thumb_func_start sub_8009FB8
-sub_8009FB8:
-	push {r4-r7,lr}
-	adds r5, r0, 0
-	adds r6, r1, 0
-	cmp r5, 0
-	bge _08009FC4
-	negs r5, r5
-_08009FC4:
-	cmp r6, 0
-	bge _08009FCA
-	negs r6, r6
-_08009FCA:
-	cmp r5, r6
-	bge _08009FD4
-	adds r4, r5, 0
-	adds r5, r6, 0
-	adds r6, r4, 0
-_08009FD4:
-	cmp r6, 0
-	beq _0800A016
-	movs r7, 0x2
-_08009FDA:
-	adds r0, r6, 0
-	adds r1, r5, 0
-	bl s24_8_div
-	adds r4, r0, 0
-	adds r1, r4, 0
-	bl s24_8_mul
-	adds r4, r0, 0
-	movs r0, 0x80
-	lsls r0, 3
-	adds r1, r4, r0
-	adds r0, r4, 0
-	bl s24_8_div
-	adds r4, r0, 0
-	adds r0, r5, 0
-	adds r1, r4, 0
-	bl s24_8_mul
-	lsls r0, 1
-	adds r5, r0
-	adds r0, r6, 0
-	adds r1, r4, 0
-	bl s24_8_mul
-	adds r6, r0, 0
-	subs r7, 0x1
-	cmp r7, 0
-	bge _08009FDA
-_0800A016:
-	adds r0, r5, 0
-	pop {r4-r7}
-	pop {r1}
-	bx r1
-	thumb_func_end sub_8009FB8
-
-	thumb_func_start sub_800A020
-sub_800A020:
-	push {r4,lr}
-	adds r3, r0, 0
-	ldr r4, _0800A044
-	lsrs r2, r1, 16
-	str r2, [r3]
-	lsls r0, r1, 16
-	str r0, [r3, 0x4]
-	movs r0, 0x80
-	lsls r0, 8
-	ands r0, r1
-	cmp r0, 0
-	beq _0800A03C
-	orrs r2, r4
-	str r2, [r3]
-_0800A03C:
-	pop {r4}
-	pop {r0}
-	bx r0
-	.align 2, 0
-_0800A044: .4byte 0xffff0000
-	thumb_func_end sub_800A020
-
-	thumb_func_start sub_800A048
-sub_800A048:
-	push {lr}
-	ldrh r1, [r0]
-	lsls r2, r1, 16
-	ldr r0, [r0, 0x4]
-	lsrs r1, r0, 16
-	orrs r2, r1
-	movs r1, 0x80
-	lsls r1, 8
-	ands r0, r1
-	cmp r0, 0
-	beq _0800A060
-	adds r2, 0x1
-_0800A060:
-	adds r0, r2, 0
-	pop {r1}
-	bx r1
-	thumb_func_end sub_800A048
-
-	thumb_func_start sub_800A068
-sub_800A068:
-	push {lr}
-	ldrb r1, [r0]
-	lsls r2, r1, 24
-	ldr r0, [r0, 0x4]
-	lsrs r1, r0, 8
-	orrs r2, r1
-	movs r1, 0x80
-	lsls r1, 8
-	ands r0, r1
-	cmp r0, 0
-	beq _0800A080
-	adds r2, 0x1
-_0800A080:
-	adds r0, r2, 0
-	pop {r1}
-	bx r1
-	thumb_func_end sub_800A068
-
 	thumb_func_start sub_800A088
 sub_800A088:
 	push {lr}
diff --git a/src/math.c b/src/math.c
index de958007a..e7b4816b7 100644
--- a/src/math.c
+++ b/src/math.c
@@ -2,10 +2,10 @@
 #include "globaldata.h"
 #include "math.h"
 
-extern u24_8 u24_8_div(u24_8 x, u24_8 y); // decomp in progress: https://decomp.me/scratch/pMyGD
-
 #include "data/math.h"
 
+u24_8 u24_8_div(u24_8 x, u24_8 y);
+
 u32 fast_mod_3(s32 x) {
     if (x < 0x100) {
         return gFastMod3Lookup[x];
@@ -159,3 +159,165 @@ u24_8 u24_8_mul(u24_8 x, u24_8 y) {
 
     return out_l;
 }
+
+u24_8 u24_8_div(u24_8 x, u24_8 y)
+{
+  bool8 bVar1;
+  u32 r9;
+  u32 r2;
+  u32 r4;
+  u32 r5;
+  u32 r6;
+  u32 r7;
+  u32 r8;
+  int counter;
+  s32 sl;
+  s32 flag;
+  s32 save;
+  
+  if (y == 0) {
+    return 0x7fffffff;
+  }
+  else if (x == 0) {
+    return 0;
+  }
+  else {
+    r7 = x >> 0x18;
+    r6 = x << 8;
+    sl = y;
+    r9 = 0;
+    r5 = 0;
+    r4 = 0;
+    r2 = 0;
+    r8 = 1;
+
+      
+    for(counter = 0x3f; counter >= 0; counter--)
+    {
+      r5 <<= 1;
+      if ((r4 & 0x80000000) != 0) {
+        r5 |= r8;
+      }
+      flag = -2;
+      r4 <<= 1;
+      if ((r7 & 0x80000000) != 0) {
+        r4 |= r8;
+      }
+      r7 <<= 1;
+      if ((r6 & 0x80000000) != 0) {
+        r7 |= r8;
+      }
+      r6 <<= 1;
+      r6 &= flag;
+      if (u32_pair_less_than(r5,r4,0,sl) == 0) {
+        save = r4;
+        bVar1 = 1;
+        r4 = r4 - sl;
+        r5 = r5 - r2;  // WHY????
+        if (save < r4) {
+          r5--;
+        }
+      }
+      else {
+        bVar1 = 0;
+      }
+      r9 <<= 1;
+      if (bVar1) {
+        r9 |= r8;
+      }
+    }
+  }
+  return r9;
+}
+
+s32 sub_8009F68(s32 x, s32 y)
+{
+    s32 uVar1;
+    s32 sVar1;
+
+    uVar1 = y;
+    if (y < 0) {
+        uVar1 = -y;
+    }
+    sVar1 = 0x100;
+    for (; uVar1 != 0; uVar1 >>= 1) {
+        if ((uVar1 & 1) != 0) {
+            sVar1 = s24_8_mul(sVar1, x);
+        }
+        x = s24_8_mul(x, x);
+    }
+    if (y >= 0) {
+        return sVar1;
+    }
+    else
+        return s24_8_div(0x100,sVar1);
+}
+
+s32 sub_8009FB8(s32 x, s32 y)
+{
+    s32 r4;
+    s32 counter;
+
+    s32 r5;
+    s32 r6;
+
+    r5 = x;
+    r6 = y;
+
+    if (r5 < 0) {
+        r5 = -r5;
+    }
+    if (r6 < 0) {
+        r6 = -r6;
+    }
+    if (r5 < r6) {
+        r4 = r5;
+        r5 = r6;
+        r6 = r4;
+    }
+    if (r6 != 0) {
+        for(counter = 2; counter >= 0; counter--)
+        {
+            r4 = s24_8_div(r6,r5);
+            r4 = s24_8_mul(r4,r4);
+            r4 = s24_8_div(r4,r4 + 0x400);
+            r5 = r5 + s24_8_mul(r5,r4) * 2;
+            r6 = s24_8_mul(r6,r4);
+        }
+    }
+    return r5;
+}
+
+void sub_800A020(s32 *param_1, u32 param_2)
+{
+  register u32 temp asm("r4");
+    
+  temp = 0xffff0000;
+  param_1[0] = param_2 >> 0x10;
+  param_1[1] = param_2 << 0x10;
+  if ((param_2 & 0x8000) != 0) {
+    param_1[0] |= temp;
+  }
+}
+
+u32 sub_800A048(u32 *param_1)
+{
+  u32 uVar1;
+  
+  uVar1 = ((u16)param_1[0] << 0x10) | (param_1[1] >> 0x10);
+  if ((param_1[1] & 0x8000) != 0) {
+    uVar1++;
+  }
+  return uVar1;
+}
+
+UNUSED u32 sub_800A068(u32 *param_1)
+{
+  u32 uVar1;
+  
+  uVar1 = ((u8)param_1[0] << 0x18) | param_1[1] >> 8;
+  if ((param_1[1] & 0x8000) != 0) {
+    uVar1++;
+  }
+  return uVar1;
+}