From 44e074a15e9651481f7f652ac006a7c9d58cbeb9 Mon Sep 17 00:00:00 2001
From: Vicki Pfau <vi@endrift.com>
Date: Tue, 4 Jul 2023 23:23:17 -0700
Subject: [PATCH] GBA BIOS: Add DACS compatibility to HLE BIOS (closes #2972)

---
 src/gba/hle-bios.c | 16 ++++++++++++----
 src/gba/hle-bios.s | 31 ++++++++++++++++++++++++++++++-
 2 files changed, 42 insertions(+), 5 deletions(-)

diff --git a/src/gba/hle-bios.c b/src/gba/hle-bios.c
index f82d01f64..841caf543 100644
--- a/src/gba/hle-bios.c
+++ b/src/gba/hle-bios.c
@@ -3,9 +3,9 @@
 #include <mgba/internal/gba/memory.h>
 
 const uint8_t hleBios[GBA_SIZE_BIOS] = {
-	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, 0x00, 0x00, 0x00, 0x00,
+	0xd3, 0x00, 0x00, 0xea, 0xe1, 0x00, 0x00, 0xea, 0x0c, 0x00, 0x00, 0xea,
+	0xdf, 0x00, 0x00, 0xea, 0xde, 0x00, 0x00, 0xea, 0x00, 0x00, 0xa0, 0xe1,
+	0x59, 0x00, 0x00, 0xea, 0xdb, 0x00, 0x00, 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,
@@ -78,5 +78,13 @@ const uint8_t hleBios[GBA_SIZE_BIOS] = {
 	0x00, 0x10, 0xa0, 0x13, 0x1e, 0xff, 0x2f, 0x11, 0x1c, 0xe0, 0x9f, 0xe5,
 	0x00, 0x10, 0x9e, 0xe5, 0x00, 0x00, 0x51, 0xe3, 0x00, 0x10, 0xa0, 0xe3,
 	0x1e, 0xff, 0x2f, 0x11, 0xc0, 0xe0, 0x4e, 0xe2, 0x1e, 0xff, 0x2f, 0xe1,
-	0x00, 0x00, 0x00, 0x00, 0x00, 0xf0, 0x29, 0xe1, 0xc0, 0x00, 0x00, 0x02
+	0x00, 0x00, 0x00, 0x00, 0x00, 0xf0, 0x29, 0xe1, 0xc0, 0x00, 0x00, 0x02,
+	0x4c, 0xd0, 0x9f, 0xe5, 0x00, 0x50, 0x2d, 0xe9, 0x00, 0xc0, 0x4f, 0xe1,
+	0x00, 0xe0, 0x0f, 0xe1, 0x00, 0x50, 0x2d, 0xe9, 0x02, 0xe3, 0xa0, 0xe3,
+	0x9c, 0xc0, 0xde, 0xe5, 0xa5, 0x00, 0x5c, 0xe3, 0x04, 0x00, 0x00, 0x1a,
+	0xb4, 0xc0, 0xde, 0xe5, 0x80, 0x00, 0x1c, 0xe3, 0x04, 0xe0, 0x8f, 0xe2,
+	0x20, 0xf0, 0x9f, 0x15, 0x20, 0xf0, 0x9f, 0x05, 0x14, 0xd0, 0x9f, 0xe5,
+	0x10, 0xc0, 0x1d, 0xe5, 0x0c, 0xf0, 0x69, 0xe1, 0x00, 0x50, 0x3d, 0xe9,
+	0x04, 0xf0, 0x5e, 0xe2, 0x00, 0x00, 0x00, 0x00, 0x04, 0xe0, 0xa0, 0x03,
+	0xf0, 0x7f, 0x00, 0x03, 0x00, 0x20, 0xfe, 0x09, 0x00, 0xc0, 0xff, 0x09
 };
diff --git a/src/gba/hle-bios.s b/src/gba/hle-bios.s
index 36e18790b..07f827b26 100644
--- a/src/gba/hle-bios.s
+++ b/src/gba/hle-bios.s
@@ -123,7 +123,7 @@ subs   pc, lr, #4
 .word 0
 .word 0xE55EC002
 
-undefBase:
+@ Padding for back compat
 subs   pc, lr, #4
 .word 0
 .word 0x03A0E004
@@ -328,3 +328,32 @@ sub lr, #0xC0
 bx lr
 .word 0
 .word 0xE129F000
+
+.ltorg
+
+undefBase:
+pabtBase:
+dabtBase:
+fiqBase:
+ldr sp, =0x03007FF0
+stmdb sp!, {r12, lr}
+mrs r12, spsr
+mrs lr, cpsr
+stmdb sp!, {r12, lr}
+mov lr, #0x08000000
+ldrb r12, [lr, #0x9C]
+cmp r12, #0xA5
+bne 1f
+ldrb r12, [lr, #0xB4]
+tst r12, #0x80
+adr lr, 1f
+ldrne pc, =0x09FE2000
+ldreq pc, =0x09FFC000
+1:
+ldr sp, =0x03007FF0
+ldr r12, [sp, #-0x10]
+msr spsr, r12
+ldmdb sp!, {r12, lr}
+subs pc, lr, #4
+.word 0
+.word 0x03A0E004