From c6d7c40dfcad34d3a0ec0c005d6b1133a23f2f50 Mon Sep 17 00:00:00 2001
From: Vicki Pfau <vi@endrift.com>
Date: Tue, 24 May 2022 19:23:39 -0700
Subject: [PATCH] GBA: Fix booting multiboot ROMs with no JOY entrypoint

---
 CHANGES            |  1 +
 src/gba/hle-bios.c | 17 +++++++++++------
 src/gba/hle-bios.s | 33 ++++++++++++++++++++++++---------
 3 files changed, 36 insertions(+), 15 deletions(-)

diff --git a/CHANGES b/CHANGES
index 304577ecf..faaf2c15d 100644
--- a/CHANGES
+++ b/CHANGES
@@ -25,6 +25,7 @@ Emulation fixes:
  - GB Video: Draw SGB border pieces that overlap GB graphics (fixes mgba.io/i/1339)
  - GBA: Improve timing when not booting from BIOS
  - GBA: Fix expected entry point for multiboot ELFs (fixes mgba.io/i/2450)
+ - GBA: Fix booting multiboot ROMs with no JOY entrypoint
  - GBA BIOS: Work around IRQ handling hiccup in Mario & Luigi (fixes mgba.io/i/1059)
  - GBA BIOS: Initial HLE timing estimation of UnLz77 functions (fixes mgba.io/i/2141)
  - GBA DMA: Fix DMA source direction bits being cleared (fixes mgba.io/i/2410)
diff --git a/src/gba/hle-bios.c b/src/gba/hle-bios.c
index 91a48711b..67424c196 100644
--- a/src/gba/hle-bios.c
+++ b/src/gba/hle-bios.c
@@ -3,11 +3,11 @@
 #include <mgba/internal/gba/memory.h>
 
 const uint8_t hleBios[SIZE_BIOS] = {
-	0x06, 0x00, 0x00, 0xea, 0x66, 0x00, 0x00, 0xea, 0x0c, 0x00, 0x00, 0xea,
+	0xd3, 0x00, 0x00, 0xea, 0x66, 0x00, 0x00, 0xea, 0x0c, 0x00, 0x00, 0xea,
 	0xfe, 0xff, 0xff, 0xea, 0xfe, 0xff, 0xff, 0xea, 0x00, 0x00, 0xa0, 0xe1,
-	0x59, 0x00, 0x00, 0xea, 0xfe, 0xff, 0xff, 0xea, 0x58, 0x01, 0x9f, 0xe5,
-	0x00, 0x10, 0x90, 0xe5, 0x00, 0x00, 0x51, 0xe3, 0x02, 0x03, 0xa0, 0x03,
-	0x10, 0xff, 0x2f, 0xe1, 0x00, 0x00, 0x00, 0x00, 0x00, 0xf0, 0x29, 0xe1,
+	0x59, 0x00, 0x00, 0xea, 0xfe, 0xff, 0xff, 0xea, 0x00, 0x00, 0x00, 0x00,
+	0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
+	0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
 	0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x5d, 0xe3, 0x01, 0xd3, 0xa0, 0x03,
 	0x20, 0xd0, 0x4d, 0x02, 0x00, 0x58, 0x2d, 0xe9, 0x02, 0xc0, 0x5e, 0xe5,
 	0xd4, 0xb0, 0xa0, 0xe3, 0x0c, 0xc1, 0x9b, 0xe7, 0xd2, 0xbf, 0xa0, 0xe3,
@@ -35,7 +35,7 @@ const uint8_t hleBios[SIZE_BIOS] = {
 	0xb0, 0x01, 0x00, 0x00, 0xb0, 0x01, 0x00, 0x00, 0xb0, 0x01, 0x00, 0x00,
 	0xb0, 0x01, 0x00, 0x00, 0xb0, 0x01, 0x00, 0x00, 0xb0, 0x01, 0x00, 0x00,
 	0xb0, 0x01, 0x00, 0x00, 0xb0, 0x01, 0x00, 0x00, 0x00, 0x03, 0x00, 0x00,
-	0xc0, 0x00, 0x00, 0x02, 0x0f, 0x50, 0x2d, 0xe9, 0x01, 0x03, 0xa0, 0xe3,
+	0x00, 0x00, 0x00, 0x00, 0x0f, 0x50, 0x2d, 0xe9, 0x01, 0x03, 0xa0, 0xe3,
 	0x00, 0xe0, 0x8f, 0xe2, 0x04, 0xf0, 0x10, 0xe5, 0x0f, 0x50, 0xbd, 0xe8,
 	0x04, 0xf0, 0x5e, 0xe2, 0x00, 0x00, 0x00, 0x00, 0x02, 0xc0, 0x5e, 0xe5,
 	0x04, 0xf0, 0x5e, 0xe2, 0x00, 0x00, 0x00, 0x00, 0x04, 0xe0, 0xa0, 0x03,
@@ -73,5 +73,10 @@ const uint8_t hleBios[SIZE_BIOS] = {
 	0x01, 0xa0, 0xa0, 0xe1, 0xfa, 0x07, 0xa0, 0xe8, 0xfa, 0x07, 0xa0, 0xe8,
 	0xfa, 0x07, 0xa0, 0xe8, 0xfa, 0x07, 0xa0, 0xe8, 0x00, 0x10, 0xa0, 0xe3,
 	0xf0, 0x07, 0xbd, 0xe8, 0x1e, 0xff, 0x2f, 0xe1, 0xb0, 0x01, 0x00, 0x00,
-	0x04, 0xb0, 0x5b, 0xe2, 0xfd, 0xff, 0xff, 0x8a, 0x1e, 0xff, 0x2f, 0xe1
+	0x04, 0xb0, 0x5b, 0xe2, 0xfd, 0xff, 0xff, 0x8a, 0x1e, 0xff, 0x2f, 0xe1,
+	0xc2, 0x03, 0xa0, 0xe3, 0x03, 0x10, 0x50, 0xe4, 0x00, 0x00, 0x51, 0xe3,
+	0x00, 0x10, 0xa0, 0x13, 0x10, 0xff, 0x2f, 0x11, 0x1c, 0x00, 0x9f, 0xe5,
+	0x00, 0x10, 0x90, 0xe5, 0x00, 0x00, 0x51, 0xe3, 0x00, 0x10, 0xa0, 0xe3,
+	0x10, 0xff, 0x2f, 0x11, 0xc0, 0x00, 0x40, 0xe2, 0x10, 0xff, 0x2f, 0xe1,
+	0x00, 0x00, 0x00, 0x00, 0x00, 0xf0, 0x29, 0xe1, 0xc0, 0x00, 0x00, 0x02
 };
diff --git a/src/gba/hle-bios.s b/src/gba/hle-bios.s
index 3f9ae905e..85c963157 100644
--- a/src/gba/hle-bios.s
+++ b/src/gba/hle-bios.s
@@ -16,16 +16,14 @@ nop
 b irqBase
 b fiqBase
 
-resetBase:
-ldr r0, =0x20000C0
-ldr r1, [r0]
-cmp r1, #0
-moveq r0, #0x8000000
-bx r0
-.word 0
-.word 0xE129F000
-
 .word 0 @ Padding for back-compat
+.word 0
+.word 0
+.word 0
+.word 0
+.word 0
+.word 0
+.word 0
 
 swiBase:
 cmp    sp, #0
@@ -113,6 +111,7 @@ swiTable:
 .word SoundDriverGetJumpList  @ 0x2A
 
 .ltorg
+.word 0 @ Padding for back-compat
 
 irqBase:
 stmfd  sp!, {r0-r3, r12, lr}
@@ -313,3 +312,19 @@ StallCall:
 subs r11, #4
 bhi StallCall
 bx lr
+
+resetBase:
+mov r0, #0x8000003
+ldrb r1, [r0], #-3
+cmp r1, #0
+movne r1, #0
+bxne r0
+ldr r0, =0x20000C0
+ldr r1, [r0]
+cmp r1, #0
+mov r1, #0
+bxne r0
+sub r0, #0xC0
+bx r0
+.word 0
+.word 0xE129F000