From 514c44e12ae63acc8fc264bd5fb259b8e6156f67 Mon Sep 17 00:00:00 2001
From: Ryan Dwyer <ryandwyer1@gmail.com>
Date: Thu, 7 Oct 2021 22:35:15 +1000
Subject: [PATCH] Disassemble rng2 functions

---
 ld/gamefiles.ntsc-beta.inc     |  2 +-
 ld/gamefiles.ntsc-final.inc    |  2 +-
 ld/gamefiles.pal-final.inc     |  2 +-
 src/game/chr/chr.c             | 14 +++++-----
 src/game/game_1291b0.c         | 40 ----------------------------
 src/game/propobj.c             | 20 +++++++-------
 src/game/rng2.s                | 48 ++++++++++++++++++++++++++++++++++
 src/include/game/game_1291b0.h |  4 +--
 8 files changed, 70 insertions(+), 62 deletions(-)
 delete mode 100644 src/game/game_1291b0.c
 create mode 100644 src/game/rng2.s

diff --git a/ld/gamefiles.ntsc-beta.inc b/ld/gamefiles.ntsc-beta.inc
index c2b9d1301..09b397de2 100644
--- a/ld/gamefiles.ntsc-beta.inc
+++ b/ld/gamefiles.ntsc-beta.inc
@@ -144,7 +144,7 @@
 	build/ROMID/game/game_11f000.o (section); \
 	build/ROMID/game/game_127910.o (section); \
 	build/ROMID/game/crc.o (section); \
-	build/ROMID/game/game_1291b0.o (section); \
+	build/ROMID/game/rng2.o (section); \
 	build/ROMID/game/game_129210.o (section); \
 	build/ROMID/game/explosions/explosions.o (section); \
 	build/ROMID/game/smoke/smoke.o (section); \
diff --git a/ld/gamefiles.ntsc-final.inc b/ld/gamefiles.ntsc-final.inc
index c98fad1af..5595cfdde 100644
--- a/ld/gamefiles.ntsc-final.inc
+++ b/ld/gamefiles.ntsc-final.inc
@@ -143,7 +143,7 @@
 	build/ROMID/game/game_11f000.o (section); \
 	build/ROMID/game/game_127910.o (section); \
 	build/ROMID/game/crc.o (section); \
-	build/ROMID/game/game_1291b0.o (section); \
+	build/ROMID/game/rng2.o (section); \
 	build/ROMID/game/game_129210.o (section); \
 	build/ROMID/game/explosions/explosions.o (section); \
 	build/ROMID/game/smoke/smoke.o (section); \
diff --git a/ld/gamefiles.pal-final.inc b/ld/gamefiles.pal-final.inc
index c98fad1af..5595cfdde 100644
--- a/ld/gamefiles.pal-final.inc
+++ b/ld/gamefiles.pal-final.inc
@@ -143,7 +143,7 @@
 	build/ROMID/game/game_11f000.o (section); \
 	build/ROMID/game/game_127910.o (section); \
 	build/ROMID/game/crc.o (section); \
-	build/ROMID/game/game_1291b0.o (section); \
+	build/ROMID/game/rng2.o (section); \
 	build/ROMID/game/game_129210.o (section); \
 	build/ROMID/game/explosions/explosions.o (section); \
 	build/ROMID/game/smoke/smoke.o (section); \
diff --git a/src/game/chr/chr.c b/src/game/chr/chr.c
index 5d0da8a20..a2d3445c5 100644
--- a/src/game/chr/chr.c
+++ b/src/game/chr/chr.c
@@ -13909,12 +13909,12 @@ glabel func0f0270f4
 /*  f0275a4:	00000000 */ 	nop
 .L0f0275a8:
 /*  f0275a8:	44c9f800 */ 	ctc1	$t1,$31
-/*  f0275ac:	0fc4a47e */ 	jal	func0f1291f8
+/*  f0275ac:	0fc4a47e */ 	jal	rng2SetSeed
 /*  f0275b0:	016c2021 */ 	addu	$a0,$t3,$t4
 /*  f0275b4:	86020000 */ 	lh	$v0,0x0($s0)
 /*  f0275b8:	1840000e */ 	blez	$v0,.L0f0275f4
 /*  f0275bc:	00000000 */ 	nop
-/*  f0275c0:	0fc4a46c */ 	jal	func0f1291b0
+/*  f0275c0:	0fc4a46c */ 	jal	random2
 /*  f0275c4:	00000000 */ 	nop
 /*  f0275c8:	0052001b */ 	divu	$zero,$v0,$s2
 /*  f0275cc:	860d0000 */ 	lh	$t5,0x0($s0)
@@ -13931,7 +13931,7 @@ glabel func0f0270f4
 .L0f0275f4:
 /*  f0275f4:	0443000e */ 	bgezl	$v0,.L0f027630
 /*  f0275f8:	86020002 */ 	lh	$v0,0x2($s0)
-/*  f0275fc:	0fc4a46c */ 	jal	func0f1291b0
+/*  f0275fc:	0fc4a46c */ 	jal	random2
 /*  f027600:	00000000 */ 	nop
 /*  f027604:	0052001b */ 	divu	$zero,$v0,$s2
 /*  f027608:	860a0000 */ 	lh	$t2,0x0($s0)
@@ -13948,7 +13948,7 @@ glabel func0f0270f4
 .L0f027630:
 /*  f027630:	1840000e */ 	blez	$v0,.L0f02766c
 /*  f027634:	00000000 */ 	nop
-/*  f027638:	0fc4a46c */ 	jal	func0f1291b0
+/*  f027638:	0fc4a46c */ 	jal	random2
 /*  f02763c:	00000000 */ 	nop
 /*  f027640:	0052001b */ 	divu	$zero,$v0,$s2
 /*  f027644:	860e0002 */ 	lh	$t6,0x2($s0)
@@ -13965,7 +13965,7 @@ glabel func0f0270f4
 .L0f02766c:
 /*  f02766c:	0443000e */ 	bgezl	$v0,.L0f0276a8
 /*  f027670:	86020004 */ 	lh	$v0,0x4($s0)
-/*  f027674:	0fc4a46c */ 	jal	func0f1291b0
+/*  f027674:	0fc4a46c */ 	jal	random2
 /*  f027678:	00000000 */ 	nop
 /*  f02767c:	0052001b */ 	divu	$zero,$v0,$s2
 /*  f027680:	860b0002 */ 	lh	$t3,0x2($s0)
@@ -13982,7 +13982,7 @@ glabel func0f0270f4
 .L0f0276a8:
 /*  f0276a8:	1840000e */ 	blez	$v0,.L0f0276e4
 /*  f0276ac:	00000000 */ 	nop
-/*  f0276b0:	0fc4a46c */ 	jal	func0f1291b0
+/*  f0276b0:	0fc4a46c */ 	jal	random2
 /*  f0276b4:	00000000 */ 	nop
 /*  f0276b8:	0052001b */ 	divu	$zero,$v0,$s2
 /*  f0276bc:	86190004 */ 	lh	$t9,0x4($s0)
@@ -13999,7 +13999,7 @@ glabel func0f0270f4
 .L0f0276e4:
 /*  f0276e4:	0443000e */ 	bgezl	$v0,.L0f027720
 /*  f0276e8:	26310001 */ 	addiu	$s1,$s1,0x1
-/*  f0276ec:	0fc4a46c */ 	jal	func0f1291b0
+/*  f0276ec:	0fc4a46c */ 	jal	random2
 /*  f0276f0:	00000000 */ 	nop
 /*  f0276f4:	0052001b */ 	divu	$zero,$v0,$s2
 /*  f0276f8:	860c0002 */ 	lh	$t4,0x2($s0)
diff --git a/src/game/game_1291b0.c b/src/game/game_1291b0.c
deleted file mode 100644
index ac8631672..000000000
--- a/src/game/game_1291b0.c
+++ /dev/null
@@ -1,40 +0,0 @@
-#include <ultra64.h>
-#include "constants.h"
-#include "bss.h"
-#include "lib/rng.h"
-#include "data.h"
-#include "types.h"
-
-u32 var8007e3c0 = 0xab8d9f77;
-u32 var8007e3c4 = 0x81280783;
-
-GLOBAL_ASM(
-glabel func0f1291b0
-/*  f1291b0:	3c048008 */ 	lui	$a0,%hi(var8007e3c0)
-/*  f1291b4:	dc84e3c0 */ 	ld	$a0,%lo(var8007e3c0)($a0)
-/*  f1291b8:	3c018008 */ 	lui	$at,%hi(var8007e3c0)
-/*  f1291bc:	000437fc */ 	dsll32	$a2,$a0,0x1f
-/*  f1291c0:	00042ff8 */ 	dsll	$a1,$a0,0x1f
-/*  f1291c4:	000637fa */ 	dsrl	$a2,$a2,0x1f
-/*  f1291c8:	0005283e */ 	dsrl32	$a1,$a1,0x0
-/*  f1291cc:	0004233c */ 	dsll32	$a0,$a0,0xc
-/*  f1291d0:	00c53025 */ 	or	$a2,$a2,$a1
-/*  f1291d4:	0004203e */ 	dsrl32	$a0,$a0,0x0
-/*  f1291d8:	00c43026 */ 	xor	$a2,$a2,$a0
-/*  f1291dc:	0006253a */ 	dsrl	$a0,$a2,0x14
-/*  f1291e0:	30840fff */ 	andi	$a0,$a0,0xfff
-/*  f1291e4:	00862026 */ 	xor	$a0,$a0,$a2
-/*  f1291e8:	0004103c */ 	dsll32	$v0,$a0,0x0
-/*  f1291ec:	fc24e3c0 */ 	sd	$a0,%lo(var8007e3c0)($at)
-/*  f1291f0:	03e00008 */ 	jr	$ra
-/*  f1291f4:	0002103f */ 	dsra32	$v0,$v0,0x0
-);
-
-GLOBAL_ASM(
-glabel func0f1291f8
-/*  f1291f8:	64840001 */ 	daddiu	$a0,$a0,0x1
-/*  f1291fc:	3c018008 */ 	lui	$at,%hi(var8007e3c0)
-/*  f129200:	fc24e3c0 */ 	sd	$a0,%lo(var8007e3c0)($at)
-/*  f129204:	03e00008 */ 	jr	$ra
-/*  f129208:	24040000 */ 	addiu	$a0,$zero,0x0
-);
diff --git a/src/game/propobj.c b/src/game/propobj.c
index 84ce2b15f..04fa52aca 100644
--- a/src/game/propobj.c
+++ b/src/game/propobj.c
@@ -50929,7 +50929,7 @@ glabel var7f1aa838
 /*  f082308:	844e0002 */ 	lh	$t6,0x2($v0)
 /*  f08230c:	01edc021 */ 	addu	$t8,$t7,$t5
 /*  f082310:	030ec821 */ 	addu	$t9,$t8,$t6
-/*  f082314:	0fc4a47e */ 	jal	func0f1291f8
+/*  f082314:	0fc4a47e */ 	jal	rng2SetSeed
 /*  f082318:	03282021 */ 	addu	$a0,$t9,$t0
 /*  f08231c:	8faa0084 */ 	lw	$t2,0x84($sp)
 /*  f082320:	00125880 */ 	sll	$t3,$s2,0x2
@@ -50964,7 +50964,7 @@ glabel var7f1aa838
 /*  f08238c:	10000001 */ 	b	.L0f082394
 /*  f082390:	24100014 */ 	addiu	$s0,$zero,0x14
 .L0f082394:
-/*  f082394:	0fc4a46c */ 	jal	func0f1291b0
+/*  f082394:	0fc4a46c */ 	jal	random2
 /*  f082398:	00000000 */ 	nop
 /*  f08239c:	24010064 */ 	addiu	$at,$zero,0x64
 /*  f0823a0:	0041001b */ 	divu	$zero,$v0,$at
@@ -50976,7 +50976,7 @@ glabel var7f1aa838
 /*  f0823b8:	01716021 */ 	addu	$t4,$t3,$s1
 /*  f0823bc:	a1800007 */ 	sb	$zero,0x7($t4)
 .L0f0823c0:
-/*  f0823c0:	0fc4a46c */ 	jal	func0f1291b0
+/*  f0823c0:	0fc4a46c */ 	jal	random2
 /*  f0823c4:	00000000 */ 	nop
 /*  f0823c8:	24010014 */ 	addiu	$at,$zero,0x14
 /*  f0823cc:	0041001b */ 	divu	$zero,$v0,$at
@@ -50993,7 +50993,7 @@ glabel var7f1aa838
 /*  f0823f8:	44192000 */ 	mfc1	$t9,$f4
 /*  f0823fc:	00000000 */ 	nop
 /*  f082400:	01195021 */ 	addu	$t2,$t0,$t9
-/*  f082404:	0fc4a46c */ 	jal	func0f1291b0
+/*  f082404:	0fc4a46c */ 	jal	random2
 /*  f082408:	a60a0000 */ 	sh	$t2,0x0($s0)
 /*  f08240c:	24010014 */ 	addiu	$at,$zero,0x14
 /*  f082410:	0041001b */ 	divu	$zero,$v0,$at
@@ -51010,7 +51010,7 @@ glabel var7f1aa838
 /*  f08243c:	440d2000 */ 	mfc1	$t5,$f4
 /*  f082440:	00000000 */ 	nop
 /*  f082444:	030d7021 */ 	addu	$t6,$t8,$t5
-/*  f082448:	0fc4a46c */ 	jal	func0f1291b0
+/*  f082448:	0fc4a46c */ 	jal	random2
 /*  f08244c:	a60e0002 */ 	sh	$t6,0x2($s0)
 /*  f082450:	24010014 */ 	addiu	$at,$zero,0x14
 /*  f082454:	0041001b */ 	divu	$zero,$v0,$at
@@ -51625,7 +51625,7 @@ glabel var7f1aa838
 /*  f080d40:	844c0002 */ 	lh	$t4,0x2($v0)
 /*  f080d44:	01495821 */ 	addu	$t3,$t2,$t1
 /*  f080d48:	016c7821 */ 	addu	$t7,$t3,$t4
-/*  f080d4c:	0fc48f8e */ 	jal	func0f1291f8
+/*  f080d4c:	0fc48f8e */ 	jal	rng2SetSeed
 /*  f080d50:	01ed2021 */ 	addu	$a0,$t7,$t5
 /*  f080d54:	13c00031 */ 	beqz	$s8,.NB0f080e1c
 /*  f080d58:	00000000 */ 	sll	$zero,$zero,0x0
@@ -51669,7 +51669,7 @@ glabel var7f1aa838
 /*  f080de8:	10000001 */ 	beqz	$zero,.NB0f080df0
 /*  f080dec:	24100014 */ 	addiu	$s0,$zero,0x14
 .NB0f080df0:
-/*  f080df0:	0fc48f7c */ 	jal	func0f1291b0
+/*  f080df0:	0fc48f7c */ 	jal	random2
 /*  f080df4:	00000000 */ 	sll	$zero,$zero,0x0
 /*  f080df8:	24010064 */ 	addiu	$at,$zero,0x64
 /*  f080dfc:	0041001b */ 	divu	$zero,$v0,$at
@@ -51681,7 +51681,7 @@ glabel var7f1aa838
 /*  f080e14:	01716021 */ 	addu	$t4,$t3,$s1
 /*  f080e18:	a1800007 */ 	sb	$zero,0x7($t4)
 .NB0f080e1c:
-/*  f080e1c:	0fc48f7c */ 	jal	func0f1291b0
+/*  f080e1c:	0fc48f7c */ 	jal	random2
 /*  f080e20:	00000000 */ 	sll	$zero,$zero,0x0
 /*  f080e24:	0057001b */ 	divu	$zero,$v0,$s7
 /*  f080e28:	00006810 */ 	mfhi	$t5
@@ -51701,7 +51701,7 @@ glabel var7f1aa838
 /*  f080e5c:	44192000 */ 	mfc1	$t9,$f4
 /*  f080e60:	00000000 */ 	sll	$zero,$zero,0x0
 /*  f080e64:	01195021 */ 	addu	$t2,$t0,$t9
-/*  f080e68:	0fc48f7c */ 	jal	func0f1291b0
+/*  f080e68:	0fc48f7c */ 	jal	random2
 /*  f080e6c:	a60a0000 */ 	sh	$t2,0x0($s0)
 /*  f080e70:	0057001b */ 	divu	$zero,$v0,$s7
 /*  f080e74:	00005810 */ 	mfhi	$t3
@@ -51721,7 +51721,7 @@ glabel var7f1aa838
 /*  f080ea8:	440d2000 */ 	mfc1	$t5,$f4
 /*  f080eac:	00000000 */ 	sll	$zero,$zero,0x0
 /*  f080eb0:	030d7021 */ 	addu	$t6,$t8,$t5
-/*  f080eb4:	0fc48f7c */ 	jal	func0f1291b0
+/*  f080eb4:	0fc48f7c */ 	jal	random2
 /*  f080eb8:	a60e0002 */ 	sh	$t6,0x2($s0)
 /*  f080ebc:	0057001b */ 	divu	$zero,$v0,$s7
 /*  f080ec0:	0000c810 */ 	mfhi	$t9
diff --git a/src/game/rng2.s b/src/game/rng2.s
new file mode 100644
index 000000000..7eb419b65
--- /dev/null
+++ b/src/game/rng2.s
@@ -0,0 +1,48 @@
+#include "macros.inc"
+.set noat
+.set noreorder
+.set gp=64
+
+.data
+
+glabel g_Rng2Seed
+.dword 0xab8d9f7781280783
+
+.text
+
+/**
+ * u32 random(void)
+ *
+ * Generate a random number between 0 and 4294967295.
+ */
+glabel random2
+	lui     $a0, %hi(g_Rng2Seed)
+	ld      $a0, %lo(g_Rng2Seed)($a0)
+	lui     $at, %hi(g_Rng2Seed)
+	dsll32  $a2, $a0, 31
+	dsll    $a1, $a0, 31
+	dsrl    $a2, $a2, 31
+	dsrl32  $a1, $a1, 0
+	dsll32  $a0, $a0, 12
+	or      $a2, $a2, $a1
+	dsrl32  $a0, $a0, 0
+	xor     $a2, $a2, $a0
+	dsrl    $a0, $a2, 20
+	andi    $a0, $a0, 0xfff
+	xor     $a0, $a0, $a2
+	dsll32  $v0, $a0, 0
+	sd      $a0, %lo(g_Rng2Seed)($at)
+	jr      $ra
+	dsra32  $v0, $v0, 0
+
+/**
+ * void rngSetSeed(u32 seed)
+ *
+ * Set the given seed as the RNG seed. Add 1 to make sure it isn't 0.
+ */
+glabel rng2SetSeed
+	daddiu  $a0, $a0, 1
+	lui     $at, %hi(g_Rng2Seed)
+	sd      $a0, %lo(g_Rng2Seed)($at)
+	jr      $ra
+	li      $a0, 0
diff --git a/src/include/game/game_1291b0.h b/src/include/game/game_1291b0.h
index 1a5787aa9..d2e9c7b8c 100644
--- a/src/include/game/game_1291b0.h
+++ b/src/include/game/game_1291b0.h
@@ -4,7 +4,7 @@
 #include "data.h"
 #include "types.h"
 
-u32 func0f1291b0(void);
-u32 func0f1291f8(void);
+u32 random2(void);
+u32 rng2SetSeed(void);
 
 #endif