From f5939d862d4dcfd1fc3ae1b01c75a2883630ebda Mon Sep 17 00:00:00 2001
From: KEKW555 <152369890+KEKW555@users.noreply.github.com>
Date: Mon, 18 Dec 2023 02:47:58 +0530
Subject: [PATCH] Match sub_080803D0 (#650)

---
 asm/non_matching/scroll/sub_080803D0.inc | 290 -----------------------
 src/scroll.c                             |  86 ++++++-
 2 files changed, 85 insertions(+), 291 deletions(-)
 delete mode 100644 asm/non_matching/scroll/sub_080803D0.inc

diff --git a/asm/non_matching/scroll/sub_080803D0.inc b/asm/non_matching/scroll/sub_080803D0.inc
deleted file mode 100644
index f95374f7ef..0000000000
--- a/asm/non_matching/scroll/sub_080803D0.inc
+++ /dev/null
@@ -1,290 +0,0 @@
-	.syntax unified
-	push {r4, r5, r6, r7, lr}
-	mov r7, sl
-	mov r6, sb
-	mov r5, r8
-	push {r5, r6, r7}
-	sub sp, #0x38
-	ldr r1, _080804F0 @ =gRoomControls
-	movs r2, #0xa
-	ldrsh r0, [r1, r2]
-	ldrh r2, [r1, #6]
-	subs r0, r0, r2
-	str r0, [sp, #0x18]
-	ldr r3, [r1, #0x30]
-	movs r4, #0x2e
-	ldrsh r0, [r3, r4]
-	subs r0, r0, r2
-	str r0, [sp, #0x10]
-	movs r2, #0xc
-	ldrsh r0, [r1, r2]
-	ldrh r1, [r1, #8]
-	subs r0, r0, r1
-	str r0, [sp, #0x1c]
-	movs r4, #0x32
-	ldrsh r0, [r3, r4]
-	subs r0, r0, r1
-	str r0, [sp, #0x14]
-	movs r0, #0x3c
-	str r0, [sp, #8]
-_08080408:
-	movs r7, #0
-	ldr r1, [sp, #8]
-	adds r1, #6
-	str r1, [sp, #8]
-	adds r2, r1, #0
-	muls r2, r1, r2
-	mov sl, r2
-	lsls r4, r1, #1
-	adds r0, r4, #0
-	movs r1, #3
-	bl __divsi3
-	str r0, [sp, #0xc]
-	adds r1, r0, #0
-	muls r1, r0, r1
-	mov sb, r1
-	movs r2, #0
-	str r2, [sp, #4]
-	rsbs r4, r4, #0
-	adds r4, #1
-	mov r0, sb
-	muls r0, r4, r0
-	mov r4, sl
-	lsls r5, r4, #1
-	adds r4, r0, r5
-	ldr r0, [sp, #8]
-	mov r6, sb
-	muls r6, r0, r6
-	adds r0, r6, #0
-	mov r1, sl
-	bl __divsi3
-	adds r2, r0, #0
-	cmp r7, r2
-	bgt _08080506
-	ldr r1, [sp, #0x18]
-	adds r1, #0xf8
-	str r1, [sp, #0x20]
-	mov r1, sl
-	adds r0, r5, r1
-	lsls r3, r0, #1
-	str r6, [sp, #0x2c]
-	ldr r0, [sp, #8]
-	lsls r1, r0, #2
-	rsbs r1, r1, #0
-	adds r1, #4
-	mov r8, r1
-	rsbs r0, r0, #0
-	adds r0, #8
-	ldr r1, [sp, #0x10]
-	adds r6, r0, r1
-	ldr r0, [sp, #8]
-	adds r5, r0, r1
-	mov r0, r8
-	mov r1, sb
-	muls r1, r0, r1
-	mov r8, r1
-_0808047A:
-	ldr r1, [sp, #0x1c]
-	adds r1, #0xa8
-	mov ip, r1
-	ldr r0, [sp, #0x14]
-	ldr r1, [sp, #4]
-	adds r0, r0, r1
-	str r0, [sp, #0x34]
-	cmp ip, r0
-	ble _080804A0
-	ldr r0, [sp, #0x20]
-	cmp r0, r5
-	ble _08080496
-	movs r0, #1
-	orrs r7, r0
-_08080496:
-	ldr r1, [sp, #0x18]
-	cmp r1, r6
-	bge _080804A0
-	movs r0, #2
-	orrs r7, r0
-_080804A0:
-	ldr r0, [sp, #0x14]
-	ldr r1, [sp, #4]
-	subs r0, r0, r1
-	mov ip, r0
-	adds r0, #8
-	ldr r1, [sp, #0x1c]
-	cmp r1, r0
-	bge _080804C4
-	ldr r0, [sp, #0x20]
-	cmp r0, r5
-	ble _080804BA
-	movs r0, #4
-	orrs r7, r0
-_080804BA:
-	ldr r1, [sp, #0x18]
-	cmp r1, r6
-	bge _080804C4
-	movs r0, #8
-	orrs r7, r0
-_080804C4:
-	cmp r4, #0
-	ble _080804F4
-	mov r2, r8
-	adds r0, r2, r3
-	adds r4, r4, r0
-	ldr r0, [sp, #0x2c]
-	mov r1, sb
-	subs r0, r0, r1
-	str r0, [sp, #0x2c]
-	lsls r0, r1, #2
-	add r8, r0
-	adds r6, #1
-	subs r5, #1
-	ldr r0, [sp, #0x2c]
-	mov r1, sl
-	str r3, [sp, #0x30]
-	bl __divsi3
-	adds r2, r0, #0
-	ldr r3, [sp, #0x30]
-	b _080804F6
-	.align 2, 0
-_080804F0: .4byte gRoomControls
-_080804F4:
-	adds r4, r4, r3
-_080804F6:
-	mov r1, sl
-	lsls r0, r1, #2
-	adds r3, r3, r0
-	ldr r0, [sp, #4]
-	adds r0, #1
-	str r0, [sp, #4]
-	cmp r0, r2
-	ble _0808047A
-_08080506:
-	movs r1, #0
-	str r1, [sp]
-	ldr r2, [sp, #0xc]
-	str r2, [sp, #4]
-	mov r4, sb
-	lsls r6, r4, #1
-	lsls r0, r2, #1
-	rsbs r0, r0, #0
-	adds r0, #1
-	mov r1, sl
-	muls r1, r0, r1
-	adds r0, r1, #0
-	adds r4, r6, r0
-	mov r5, sl
-	muls r5, r2, r5
-	adds r0, r5, #0
-	mov r1, sb
-	bl __divsi3
-	adds r2, r0, #0
-	ldr r0, [sp]
-	cmp r0, r2
-	bgt _080805E4
-	ldr r1, [sp, #0x18]
-	adds r1, #0xf8
-	str r1, [sp, #0x24]
-	mov r1, sb
-	adds r0, r6, r1
-	lsls r0, r0, #1
-	mov r8, r0
-	ldr r3, [sp, #0x10]
-	adds r3, #8
-	ldr r6, [sp, #0x10]
-	str r5, [sp, #0x28]
-	ldr r1, [sp, #4]
-	lsls r0, r1, #2
-	rsbs r0, r0, #0
-	adds r0, #4
-	mov r5, sl
-	muls r5, r0, r5
-_08080556:
-	ldr r0, [sp, #0x1c]
-	adds r0, #0xa8
-	mov ip, r0
-	ldr r1, [sp, #0x14]
-	ldr r0, [sp, #4]
-	adds r1, r1, r0
-	str r1, [sp, #0x34]
-	cmp ip, r1
-	ble _0808057C
-	ldr r1, [sp, #0x24]
-	cmp r1, r6
-	ble _08080572
-	movs r0, #0x10
-	orrs r7, r0
-_08080572:
-	ldr r0, [sp, #0x18]
-	cmp r0, r3
-	bge _0808057C
-	movs r0, #0x20
-	orrs r7, r0
-_0808057C:
-	ldr r1, [sp, #0x14]
-	ldr r0, [sp, #4]
-	subs r1, r1, r0
-	mov ip, r1
-	mov r0, ip
-	adds r0, #8
-	ldr r1, [sp, #0x1c]
-	cmp r1, r0
-	bge _080805A2
-	ldr r0, [sp, #0x24]
-	cmp r0, r6
-	ble _08080598
-	movs r0, #0x40
-	orrs r7, r0
-_08080598:
-	ldr r1, [sp, #0x18]
-	cmp r1, r3
-	bge _080805A2
-	movs r0, #0x80
-	orrs r7, r0
-_080805A2:
-	cmp r4, #0
-	ble _080805CE
-	mov r2, r8
-	adds r0, r2, r5
-	adds r4, r4, r0
-	ldr r0, [sp, #0x28]
-	mov r1, sl
-	subs r0, r0, r1
-	str r0, [sp, #0x28]
-	lsls r0, r1, #2
-	adds r5, r5, r0
-	ldr r2, [sp, #4]
-	subs r2, #1
-	str r2, [sp, #4]
-	ldr r0, [sp, #0x28]
-	mov r1, sb
-	str r3, [sp, #0x30]
-	bl __divsi3
-	adds r2, r0, #0
-	ldr r3, [sp, #0x30]
-	b _080805D0
-_080805CE:
-	add r4, r8
-_080805D0:
-	mov r1, sb
-	lsls r0, r1, #2
-	add r8, r0
-	subs r3, #1
-	adds r6, #1
-	ldr r0, [sp]
-	adds r0, #1
-	str r0, [sp]
-	cmp r0, r2
-	ble _08080556
-_080805E4:
-	cmp r7, #0
-	beq _080805EA
-	b _08080408
-_080805EA:
-	ldr r0, [sp, #8]
-	add sp, #0x38
-	pop {r3, r4, r5}
-	mov r8, r3
-	mov sb, r4
-	mov sl, r5
-	pop {r4, r5, r6, r7, pc}
-	.syntax divided
diff --git a/src/scroll.c b/src/scroll.c
index 3b70936d57..c4c43f77e8 100644
--- a/src/scroll.c
+++ b/src/scroll.c
@@ -502,7 +502,91 @@ void sub_08080368(void) {
     }
 }
 
-ASM_FUNC("asm/non_matching/scroll/sub_080803D0.inc", u32 sub_080803D0())
+u32 sub_080803D0(void) {
+    s32 sp00, sp04, sp08, sp0c, sp10, sp14, sp18, sp1c;
+    s32 r2, r4, r7, r8, r9, r10;
+
+    sp18 = gRoomControls.scroll_x - gRoomControls.origin_x;
+    sp10 = gRoomControls.camera_target->x.HALF.HI - gRoomControls.origin_x;
+    sp1c = gRoomControls.scroll_y - gRoomControls.origin_y;
+    sp14 = gRoomControls.camera_target->y.HALF.HI - gRoomControls.origin_y;
+    sp08 = 0x3c;
+    do {
+        r7 = 0;
+        sp08 += 6;
+        r10 = sp08 * sp08;
+        sp0c = sp08 * 2 / 3;
+        r9 = sp0c * sp0c;
+
+        sp00 = sp08;
+        sp04 = 0;
+        r4 = (-(sp08 * 2) + 1) * r9 + r10 * 2;
+        r2 = sp00 * r9 / r10;
+        while (sp04 <= r2) {
+
+            if ((sp1c + 0xa8) > sp14 + sp04) {
+                if (sp18 + 0xf8 > sp00 + sp10) {
+                    r7 |= 1;
+                }
+                if (sp18 < sp10 - sp00 + 8) {
+                    r7 |= 2;
+                }
+            }
+            if (sp1c < (sp14 - sp04) + 8) {
+                if (sp18 + 0xf8 > sp00 + sp10) {
+                    r7 |= 4;
+                }
+                if (sp18 < sp10 - sp00 + 8) {
+                    r7 |= 8;
+                }
+            }
+
+            if (r4 > 0) {
+                r4 += ((-(sp00 << 0x2) + 4) * r9) + (r10 * (6 + 4 * sp04));
+                sp00--;
+                r2 = sp00 * r9 / r10;
+            } else {
+                r4 += (r10 * (6 + 4 * sp04));
+            }
+
+            sp04++;
+        }
+
+        sp00 = 0;
+        sp04 = sp0c;
+        r4 = r9 * 2 + (sp04 * -2 + 1) * r10;
+        r2 = sp04 * r10 / r9;
+        while (sp00 <= r2) {
+            if (sp1c + 0xa8 > sp14 + sp04) {
+                if (sp18 + 0xf8 > sp10 + sp00) {
+                    r7 |= 0x10;
+                }
+                if (sp18 < sp10 + 8 - sp00) {
+                    r7 |= 0x20;
+                }
+            }
+            if (sp1c < (sp14 - sp04) + 8) {
+                if (sp18 + 0xf8 > sp10 + sp00) {
+                    r7 |= 0x40;
+                }
+                if (sp18 < sp10 + 8 - sp00) {
+                    r7 |= 0x80;
+                }
+            }
+
+            if (r4 > 0) {
+                r4 += r9 * (6 + (4 * sp00)) + (sp04 * -4 + 4) * r10;
+                sp04--;
+                r2 = sp04 * r10 / r9;
+            } else {
+                r4 += r9 * (6 + (4 * sp00));
+            }
+            sp00++;
+        }
+    } while (r7 != 0);
+
+    return sp08;
+}
 
 void UpdateIsDiggingCave(void) {
     switch (gRoomControls.area) {