From 53bb78d630dcb39705ecf193bf643271ec22aca0 Mon Sep 17 00:00:00 2001
From: Ryan Dwyer <ryandwyer1@gmail.com>
Date: Sat, 18 Sep 2021 12:57:55 +1000
Subject: [PATCH] Decompile crcCalculateU32Pair

---
 src/game/game_128f30.c         | 111 +++++++--------------------------
 src/game/padhalllv.c           |   6 +-
 src/include/game/game_128f30.h |   2 +-
 src/include/lib/rng.h          |   2 +-
 src/lib/rng.c                  |   2 +-
 5 files changed, 29 insertions(+), 94 deletions(-)

diff --git a/src/game/game_128f30.c b/src/game/game_128f30.c
index 4157d47a4..38c7870cd 100644
--- a/src/game/game_128f30.c
+++ b/src/game/game_128f30.c
@@ -8,92 +8,27 @@
 u32 var8007e3c0 = 0xab8d9f77;
 u32 var8007e3c4 = 0x81280783;
 
-GLOBAL_ASM(
-glabel func0f128f30
-/*  f128f30:	27bdffa8 */ 	addiu	$sp,$sp,-88
-/*  f128f34:	3c0e8f80 */ 	lui	$t6,0x8f80
-/*  f128f38:	3c0f3108 */ 	lui	$t7,0x3108
-/*  f128f3c:	afb50028 */ 	sw	$s5,0x28($sp)
-/*  f128f40:	afb40024 */ 	sw	$s4,0x24($sp)
-/*  f128f44:	afb30020 */ 	sw	$s3,0x20($sp)
-/*  f128f48:	afb10018 */ 	sw	$s1,0x18($sp)
-/*  f128f4c:	afb00014 */ 	sw	$s0,0x14($sp)
-/*  f128f50:	35efb3c1 */ 	ori	$t7,$t7,0xb3c1
-/*  f128f54:	35ce9f47 */ 	ori	$t6,$t6,0x9f47
-/*  f128f58:	0085082b */ 	sltu	$at,$a0,$a1
-/*  f128f5c:	00a0a825 */ 	or	$s5,$a1,$zero
-/*  f128f60:	afbf002c */ 	sw	$ra,0x2c($sp)
-/*  f128f64:	afb2001c */ 	sw	$s2,0x1c($sp)
-/*  f128f68:	afa60060 */ 	sw	$a2,0x60($sp)
-/*  f128f6c:	00803825 */ 	or	$a3,$a0,$zero
-/*  f128f70:	00008825 */ 	or	$s1,$zero,$zero
-/*  f128f74:	afae0048 */ 	sw	$t6,0x48($sp)
-/*  f128f78:	afaf004c */ 	sw	$t7,0x4c($sp)
-/*  f128f7c:	00009825 */ 	or	$s3,$zero,$zero
-/*  f128f80:	0000a025 */ 	or	$s4,$zero,$zero
-/*  f128f84:	10200016 */ 	beqz	$at,.L0f128fe0
-/*  f128f88:	00808025 */ 	or	$s0,$a0,$zero
-/*  f128f8c:	afa40058 */ 	sw	$a0,0x58($sp)
-/*  f128f90:	27b20048 */ 	addiu	$s2,$sp,0x48
-.L0f128f94:
-/*  f128f94:	92180000 */ 	lbu	$t8,0x0($s0)
-/*  f128f98:	8fad004c */ 	lw	$t5,0x4c($sp)
-/*  f128f9c:	3239000f */ 	andi	$t9,$s1,0xf
-/*  f128fa0:	03384004 */ 	sllv	$t0,$t8,$t9
-/*  f128fa4:	8fac0048 */ 	lw	$t4,0x48($sp)
-/*  f128fa8:	010d7821 */ 	addu	$t7,$t0,$t5
-/*  f128fac:	000857c3 */ 	sra	$t2,$t0,0x1f
-/*  f128fb0:	01ed082b */ 	sltu	$at,$t7,$t5
-/*  f128fb4:	002a7021 */ 	addu	$t6,$at,$t2
-/*  f128fb8:	01cc7021 */ 	addu	$t6,$t6,$t4
-/*  f128fbc:	afae0048 */ 	sw	$t6,0x48($sp)
-/*  f128fc0:	afaf004c */ 	sw	$t7,0x4c($sp)
-/*  f128fc4:	0c004b87 */ 	jal	func00012e1c
-/*  f128fc8:	02402025 */ 	or	$a0,$s2,$zero
-/*  f128fcc:	26100001 */ 	addiu	$s0,$s0,0x1
-/*  f128fd0:	26310007 */ 	addiu	$s1,$s1,0x7
-/*  f128fd4:	1615ffef */ 	bne	$s0,$s5,.L0f128f94
-/*  f128fd8:	02629826 */ 	xor	$s3,$s3,$v0
-/*  f128fdc:	8fa70058 */ 	lw	$a3,0x58($sp)
-.L0f128fe0:
-/*  f128fe0:	26b0ffff */ 	addiu	$s0,$s5,-1
-/*  f128fe4:	0207082b */ 	sltu	$at,$s0,$a3
-/*  f128fe8:	14200014 */ 	bnez	$at,.L0f12903c
-/*  f128fec:	27b20048 */ 	addiu	$s2,$sp,0x48
-/*  f128ff0:	24f5ffff */ 	addiu	$s5,$a3,-1
-.L0f128ff4:
-/*  f128ff4:	92090000 */ 	lbu	$t1,0x0($s0)
-/*  f128ff8:	8fab004c */ 	lw	$t3,0x4c($sp)
-/*  f128ffc:	3238000f */ 	andi	$t8,$s1,0xf
-/*  f129000:	0309c804 */ 	sllv	$t9,$t1,$t8
-/*  f129004:	8faa0048 */ 	lw	$t2,0x48($sp)
-/*  f129008:	032b6821 */ 	addu	$t5,$t9,$t3
-/*  f12900c:	001947c3 */ 	sra	$t0,$t9,0x1f
-/*  f129010:	01ab082b */ 	sltu	$at,$t5,$t3
-/*  f129014:	00286021 */ 	addu	$t4,$at,$t0
-/*  f129018:	018a6021 */ 	addu	$t4,$t4,$t2
-/*  f12901c:	afac0048 */ 	sw	$t4,0x48($sp)
-/*  f129020:	afad004c */ 	sw	$t5,0x4c($sp)
-/*  f129024:	0c004b87 */ 	jal	func00012e1c
-/*  f129028:	02402025 */ 	or	$a0,$s2,$zero
-/*  f12902c:	2610ffff */ 	addiu	$s0,$s0,-1
-/*  f129030:	26310003 */ 	addiu	$s1,$s1,0x3
-/*  f129034:	1615ffef */ 	bne	$s0,$s5,.L0f128ff4
-/*  f129038:	0282a026 */ 	xor	$s4,$s4,$v0
-.L0f12903c:
-/*  f12903c:	8fae0060 */ 	lw	$t6,0x60($sp)
-/*  f129040:	add30000 */ 	sw	$s3,0x0($t6)
-/*  f129044:	add40004 */ 	sw	$s4,0x4($t6)
-/*  f129048:	8fbf002c */ 	lw	$ra,0x2c($sp)
-/*  f12904c:	8fb50028 */ 	lw	$s5,0x28($sp)
-/*  f129050:	8fb40024 */ 	lw	$s4,0x24($sp)
-/*  f129054:	8fb30020 */ 	lw	$s3,0x20($sp)
-/*  f129058:	8fb2001c */ 	lw	$s2,0x1c($sp)
-/*  f12905c:	8fb10018 */ 	lw	$s1,0x18($sp)
-/*  f129060:	8fb00014 */ 	lw	$s0,0x14($sp)
-/*  f129064:	03e00008 */ 	jr	$ra
-/*  f129068:	27bd0058 */ 	addiu	$sp,$sp,0x58
-);
+void crcCalculateU32Pair(u8 *start, u8 *end, u32 *checksum)
+{
+	u8 *ptr;
+	u32 salt = 0;
+	u64 seed = 0x8f809f473108b3c1;
+	u32 sum1 = 0;
+	u32 sum2 = 0;
+
+	for (ptr = start; ptr < end; ptr++, salt += 7) {
+		seed += *ptr << (salt & 0x0f);
+		sum1 ^= rngRotateSeed(&seed);
+	}
+
+	for (ptr = end - 1; ptr >= start; ptr--, salt += 3) {
+		seed += *ptr << (salt & 0x0f);
+		sum2 ^= rngRotateSeed(&seed);
+	}
+
+	checksum[0] = sum1;
+	checksum[1] = sum2;
+}
 
 void crcCalculateU16Pair(u8 *start, u8 *end, u16 *checksum)
 {
@@ -105,12 +40,12 @@ void crcCalculateU16Pair(u8 *start, u8 *end, u16 *checksum)
 
 	for (ptr = start; ptr < end; ptr++, salt += 7) {
 		seed += *ptr << (salt & 0x0f);
-		sum1 ^= func00012e1c(&seed);
+		sum1 ^= rngRotateSeed(&seed);
 	}
 
 	for (ptr = end - 1; ptr >= start; ptr--, salt += 3) {
 		seed += *ptr << (salt & 0x0f);
-		sum2 ^= func00012e1c(&seed);
+		sum2 ^= rngRotateSeed(&seed);
 	}
 
 	checksum[0] = sum1 & 0xffff;
diff --git a/src/game/padhalllv.c b/src/game/padhalllv.c
index 9bef4308e..d322ad915 100644
--- a/src/game/padhalllv.c
+++ b/src/game/padhalllv.c
@@ -446,7 +446,7 @@ struct waygroup *func0f114810(s32 *groupnums, s32 value, u32 mask)
 				} else {
 					u64 sp50 = ((u64)g_WaypointHashes[0] << 32) | g_WaypointHashes[1];
 
-					if (func00012e1c(&sp50) % 2 == 0) {
+					if (rngRotateSeed(&sp50) % 2 == 0) {
 						break;
 					}
 				}
@@ -567,7 +567,7 @@ struct waypoint *func0f114b7c(s32 *pointnums, s32 arg1, s32 groupnum, u32 mask)
 				} else {
 					u64 sp50 = ((u64)g_WaypointHashes[0] << 32) | g_WaypointHashes[1];
 
-					if (func00012e1c(&sp50) % 2 == 0) {
+					if (rngRotateSeed(&sp50) % 2 == 0) {
 						break;
 					}
 				}
@@ -727,7 +727,7 @@ void func0f11505c(struct waygroup *groupa, struct waygroup *groupb, struct waypo
 					} else {
 						u64 sp50 = ((u64)g_WaypointHashes[0] << 32) | g_WaypointHashes[1];
 
-						if ((func00012e1c(&sp50) % 2) == 0) {
+						if ((rngRotateSeed(&sp50) % 2) == 0) {
 							break;
 						}
 					}
diff --git a/src/include/game/game_128f30.h b/src/include/game/game_128f30.h
index 0153c70d3..d63393c23 100644
--- a/src/include/game/game_128f30.h
+++ b/src/include/game/game_128f30.h
@@ -4,7 +4,7 @@
 #include "data.h"
 #include "types.h"
 
-u32 func0f128f30(void);
+void crcCalculateU32Pair(u8 *start, u8 *end, u32 *checksum);
 void crcCalculateU16Pair(u8 *start, u8 *end, u16 *checksum);
 u32 func0f1291b0(void);
 u32 func0f1291f8(void);
diff --git a/src/include/lib/rng.h b/src/include/lib/rng.h
index 467ed9c93..d5231d39d 100644
--- a/src/include/lib/rng.h
+++ b/src/include/lib/rng.h
@@ -6,6 +6,6 @@
 
 u32 random(void);
 void rngSetSeed(u32 seed);
-u32 func00012e1c(u64 *value);
+u32 rngRotateSeed(u64 *value);
 
 #endif
diff --git a/src/lib/rng.c b/src/lib/rng.c
index c55f83268..ddd9e66c7 100644
--- a/src/lib/rng.c
+++ b/src/lib/rng.c
@@ -49,7 +49,7 @@ glabel rngSetSeed
 );
 
 GLOBAL_ASM(
-glabel func00012e1c
+glabel rngRotateSeed
 /*    12e1c:	dc870000 */ 	ld	$a3,0x0($a0)
 /*    12e20:	000737fc */ 	dsll32	$a2,$a3,0x1f
 /*    12e24:	00072ff8 */ 	dsll	$a1,$a3,0x1f