Initial commit

1 files changed, 539 insertions, 0 deletions

diff --git a/asm/libgcnmultiboot.s b/asm/libgcnmultiboot.s
new file mode 100644
index 000000000..7827180e0
--- /dev/null
+++ b/asm/libgcnmultiboot.s
@@ -0,0 +1,539 @@
+; This library can be used to download and execute a multi-boot image from
+; a GameCube using the JOY Bus protocol over the link cable.
+
+	.set GCMB_STRUCT_BASE_DEST_PTR,       0x20
+	.set GCMB_STRUCT_CUR_DEST_PTR,        0x24
+	.set GCMB_STRUCT_SERIAL_INTR_HANDLER, 0x28
+
+	thumb_func_start GameCubeMultiBoot_Hash
+GameCubeMultiBoot_Hash: ; 81DCB38
+	push {r4,lr}
+	ldr r4, pool_HashVal
+	eors r3, r1
+	movs r2, 0x20
+
+$loop:
+	lsrs r3, 1
+	bcc $skipEor
+
+	eors r3, r4
+
+$skipEor:
+	subs r2, 0x1
+	bne $loop
+
+	pop {r4,pc}
+	thumb_func_end GameCubeMultiBoot_Hash
+
+	thumb_func_start GameCubeMultiBoot_Main
+; void GameCubeMultiBoot_Main(struct GameCubeMultiBoot *mb);
+GameCubeMultiBoot_Main: ; 81DCB4C
+	ldr r1, [r0, GCMB_STRUCT_SERIAL_INTR_HANDLER]
+	cmp r1, 0
+	beq _081DCB72
+	ldrb r1, [r0, 0x1]
+	adds r1, 0x1
+	strb r1, [r0, 0x1]
+	ldrb r1, [r0, 0x2]
+	cmp r1, 0x2
+	beq _081DCBBC
+	ldr r3, pool_InterruptRegs
+	ldrh r2, [r3, OFFSET_REG_IME - 0x200]
+	movs r1, 0
+	strh r1, [r3, OFFSET_REG_IME - 0x200]
+	ldrb r1, [r0]
+	cmp r1, 0xA
+	bgt _081DCB70
+	adds r1, 0x1
+	strb r1, [r0]
+_081DCB70:
+	strh r2, [r3, OFFSET_REG_IME - 0x200]
+_081DCB72:
+	bcs GameCubeMultiBoot_Init
+	ldrb r1, [r0, 0x2]
+	cmp r1, 0
+	bne _081DCBBE
+	ldr r1, [r0, GCMB_STRUCT_CUR_DEST_PTR]
+	ldr r2, [r0, GCMB_STRUCT_BASE_DEST_PTR]
+	subs r1, r2
+	beq _081DCC3E
+	cmp r1, 0xA0
+	bcc _081DCC3E
+	push {r4-r6}
+	movs r1, 0x98
+	adds r2, RomHeaderNintendoLogo - RomBase
+	ldr r4, pool_NintendoLogo
+_081DCB8E:
+	ldm r2!, {r5}
+	ldm r4!, {r6}
+	cmp r5, r6
+	bne _081DCBA4
+	subs r1, 0x4
+	bne _081DCB8E
+	ldm r2!, {r5}
+	ldm r4!, {r6}
+	eors r5, r6
+	lsrs r5, 8
+	str r2, [r0, GCMB_STRUCT_BASE_DEST_PTR]
+_081DCBA4:
+	pop {r4-r6}
+	bne GameCubeMultiBoot_Init
+	movs r1, 0x1
+	strb r1, [r0, 0x2]
+	ldr r1, [r0, 0x4]
+	ldr r2, [r0, 0x8]
+	eors r1, r2
+	str r1, [r0, 0x18]
+	ldr r2, pool_Kawa
+	muls r1, r2
+	adds r1, 0x1
+	str r1, [r0, 0x14]
+_081DCBBC:
+	bx lr
+_081DCBBE:
+	ldr r1, [r0, GCMB_STRUCT_CUR_DEST_PTR]
+	mov r12, r1
+	ldr r3, [r0, 0x18]
+	push {r4-r7}
+	ldr r4, [r0, GCMB_STRUCT_BASE_DEST_PTR]
+	ldr r5, pool_Kawa
+	ldr r6, [r0, 0x14]
+	ldr r7, pool_HashVal
+_081DCBCE:
+	cmp r4, r12
+	bcs _081DCBEE
+	ldr r1, [r4]
+	eors r1, r6
+	adds r1, r3
+	stm r4!, {r1}
+	eors r3, r1
+	movs r2, 0x20
+_081DCBDE:
+	lsrs r3, 1
+	bcc _081DCBE4
+	eors r3, r7
+_081DCBE4:
+	subs r2, 0x1
+	bne _081DCBDE
+	muls r6, r5
+	adds r6, 0x1
+	b _081DCBCE
+_081DCBEE:
+	str r4, [r0, GCMB_STRUCT_BASE_DEST_PTR]
+	str r6, [r0, 0x14]
+	pop {r4-r7}
+	str r3, [r0, 0x18]
+	ldrh r1, [r0, 0x12]
+	cmp r1, 0
+	bne _081DCC3E
+	ldr r1, [r0, GCMB_STRUCT_CUR_DEST_PTR]
+	ldr r2, [r0, GCMB_STRUCT_BASE_DEST_PTR]
+	cmp r1, r2
+	bne _081DCC3E
+	ldr r1, [r0, 0xC]
+	cmp r1, 0
+	beq _081DCC28
+	ldrh r1, [r0, 0x10]
+	cmp r1, 0
+	beq _081DCBBC
+	mov r12, lr
+	movs r1, 0xBB
+	ldr r3, [r0, 0xC]
+	bl GameCubeMultiBoot_Hash
+	ldrh r1, [r0, 0x10]
+	mov lr, r12
+	subs r1, r3
+	bne GameCubeMultiBoot_Init
+	movs r1, 0x2
+	strb r1, [r0, 0x2]
+	bx lr
+_081DCC28:
+	mov r12, lr
+	ldrb r1, [r0, 0x3]
+	lsls r1, 24
+	subs r1, 0x1
+	str r1, [r0, 0xC]
+	bl GameCubeMultiBoot_Hash
+	lsls r3, 8
+	adds r3, 0xFF
+	str r3, [r0, 0x1C]
+	bx r12
+_081DCC3E:
+	bx lr
+	thumb_func_end GameCubeMultiBoot_Main
+
+	.align 2, 0
+
+pool_HashVal: .4byte 0xa1c1
+
+pool_Kawa: .ascii "Kawa" ; name of BIOS developer
+
+pool_NintendoLogo: .4byte RomHeaderNintendoLogo
+
+	thumb_func_start GameCubeMultiBoot_ExecuteProgram
+; void GameCubeMultiBoot_ExecuteProgram(struct GameCubeMultiBoot *mb);
+GameCubeMultiBoot_ExecuteProgram: ; 81DCC4C
+	ldrb r1, [r0, 0x2]
+	cmp r1, 0x2
+	bne $unableToExecute
+	ldr r3, pool_InterruptRegs
+	movs r1, 0
+	strh r1, [r3, OFFSET_REG_IME - 0x200]
+	ldr r1, pool_MultiBootLoadAddr
+	adds r1, 0xC0
+	bx r1
+$unableToExecute:
+	bx lr
+	thumb_func_end GameCubeMultiBoot_ExecuteProgram
+
+	thumb_func_start GameCubeMultiBoot_Init
+; void GameCubeMultiBoot_Init(struct GameCubeMultiBoot *mb);
+GameCubeMultiBoot_Init: ; 81DCC60
+	ldr r3, pool_InterruptRegs
+
+; Save IME register.
+	ldrh r2, [r3, OFFSET_REG_IME - 0x200]
+
+; Disable interrupts.
+	movs r1, 0
+	strh r1, [r3, OFFSET_REG_IME - 0x200]
+
+; Set the handler to the "Stop" routine.
+; Unless the first command that is received is a device reset command, the
+; "Stop" routine will be executed and no further commands will be processed.
+	adr r3, GcMbIntrHandler_Stop
+	str r3, [r0, GCMB_STRUCT_SERIAL_INTR_HANDLER]
+
+	ldrb r3, [r0, 0x3]
+	push {r3}
+	ldrb r3, [r0, 0x1]
+	push {r0,r3}
+
+	adds r3, r0, 0
+	adds r3, GCMB_STRUCT_BASE_DEST_PTR
+
+; clear all but the last 3 fields of the struct
+$clearStructLoop:
+	stm r0!, {r1}
+	cmp r0, r3
+	blo $clearStructLoop
+
+	pop {r0,r3}
+	lsrs r3, 1
+	strb r3, [r0, 0x3]
+	pop {r3}
+	strb r3, [r0, 0x1]
+
+	ldr r3, pool_SerialRegs
+
+; Turn off JOY Bus mode.
+	lsls r0, r3, 10
+	strh r0, [r3, OFFSET_REG_RCNT - 0x120]
+
+; Turn on JOY Bus mode.
+	movs r0, 0xC0
+	lsls r0, 8
+	strh r0, [r3, OFFSET_REG_RCNT - 0x120]
+
+; Init JOY Bus registers.
+	movs r0, 0x47
+	strh r0, [r3, OFFSET_REG_JOYCNT - 0x120]
+	strh r1, [r3, OFFSET_REG_JOYSTAT - 0x120]
+
+	ldr r3, pool_InterruptRegs
+
+; Acknowledge serial interrupt.
+	movs r0, INTR_FLAG_SERIAL
+	strh r0, [r3, OFFSET_REG_IF - 0x200]
+
+; Enable serial interrupt.
+	ldrh r1, [r3, OFFSET_REG_IE - 0x200]
+	orrs r1, r0
+	strh r1, [r3, OFFSET_REG_IE - 0x200]
+
+; Restore IME register.
+	strh r2, [r3, OFFSET_REG_IME - 0x200]
+
+	bx lr
+	thumb_func_end GameCubeMultiBoot_Init
+
+	non_word_aligned_thumb_func_start GameCubeMultiBoot_HandleSerialInterrupt
+; void GameCubeMultiBoot_HandleSerialInterrupt(struct GameCubeMultiBoot *mb);
+GameCubeMultiBoot_HandleSerialInterrupt: ; 81DCCAA
+	ldr r3, pool_SerialRegs
+
+; Acknowledge reset/receive/send flags.
+	ldrh r1, [r3, OFFSET_REG_JOYCNT - 0x120]
+	strh r1, [r3, OFFSET_REG_JOYCNT - 0x120]
+
+	movs r2, 0
+	strb r2, [r0]
+
+	ldr r2, [r0, GCMB_STRUCT_SERIAL_INTR_HANDLER]
+	cmp r2, 0
+	beq GameCubeMultiBoot_HandleSerialInterruptDone
+
+	lsrs r1, 1 ; was a device reset command received?
+	bcs GameCubeMultiBoot_BeginHandshake ; branch if so
+
+	mov pc, r2
+
+	.align 2, 0
+
+; Zero the status and the interrupt handler pointer.
+; Commands from the GameCube will not be processed after this is executed
+; unless GameCubeMultiBoot_Init() is called again.
+GcMbIntrHandler_Stop:
+	movs r2, 0
+	strh r2, [r3, OFFSET_REG_JOYSTAT - 0x120]
+
+GameCubeMultiBoot_SetInterruptHandler:
+	str r2, [r0, GCMB_STRUCT_SERIAL_INTR_HANDLER]
+
+GameCubeMultiBoot_ReadVCount:
+	ldr r3, pool_RegDispstat
+	ldrh r1, [r3, OFFSET_REG_VCOUNT - OFFSET_REG_DISPSTAT]
+	strb r1, [r0, 0x3]
+
+GameCubeMultiBoot_HandleSerialInterruptDone:
+	bx lr
+
+GameCubeMultiBoot_BeginHandshake:
+	ldr r1, [r3, OFFSET_REG_JOY_RECV - 0x120]
+	ldr r1, pool_RubyUSAGameCode
+	str r1, [r3, OFFSET_REG_JOY_TRANS - 0x120]
+	movs r1, 0x10
+	strh r1, [r3, OFFSET_REG_JOYSTAT - 0x120]
+	ldrb r1, [r0, 0x3]
+	strb r1, [r0, 0x9]
+	ldrb r1, [r0, 0x2]
+	cmp r1, 0
+	bne GcMbIntrHandler_Stop
+	ldr r1, pool_MultiBootLoadAddr
+	str r1, [r0, GCMB_STRUCT_BASE_DEST_PTR]
+	str r1, [r0, GCMB_STRUCT_CUR_DEST_PTR]
+	adr r2, GcMbIntrHandler_CheckGameCodeSent
+	b GameCubeMultiBoot_SetInterruptHandler
+
+	.align 2, 0
+
+GcMbIntrHandler_CheckGameCodeSent: ; 81DCCEC
+	lsls r1, 31
+	bcc GcMbIntrHandler_Stop ; stop if send failed
+	bmi GameCubeMultiBoot_CheckHandshakeResponse ; branch if receive is complete
+
+; If the response hasn't been fully received yet,
+; check again upon the next interrupt.
+	adr r2, GcMbIntrHandler_CheckHandshakeResponse
+	b GameCubeMultiBoot_SetInterruptHandler
+
+	.align 2, 0
+
+GcMbIntrHandler_CheckHandshakeResponse: ; 81DCCF8
+	lsrs r1, 1 ; is receive complete?
+	bcc GcMbIntrHandler_Stop ; stop if not
+
+GameCubeMultiBoot_CheckHandshakeResponse:
+	ldr r1, [r3, OFFSET_REG_JOY_RECV - 0x120]
+	ldr r2, pool_RubyUSAGameCode
+	cmp r1, r2
+	bne GcMbIntrHandler_Stop ; stop if the GameCube didn't reply with the same game code
+	ldrb r1, [r0, 0x3]
+	strb r1, [r0, 0xB]
+	adr r2, GcMbIntrHandler_81DCD0C
+	b GameCubeMultiBoot_SetInterruptHandler
+
+	.align 2, 0
+
+GcMbIntrHandler_81DCD0C: ; 81DCD0C
+	lsrs r1, 1 ; is receive complete?
+	bcc GcMbIntrHandler_Stop ; branch if not
+	ldr r1, [r3, OFFSET_REG_JOY_RECV - 0x120]
+	lsrs r2, r1, 24
+	cmp r2, 0xDD
+	bne GcMbIntrHandler_Stop
+	str r1, [r0, 0x4]
+	ldrb r1, [r0, 0x1]
+	strb r1, [r0, 0xA]
+	movs r2, 0
+	movs r3, 0
+	ldr r1, [r0, 0x8]
+	lsrs r1, 8
+_081DCD26:
+	lsrs r1, 1
+	adcs r2, r3
+	cmp r1, 0
+	bne _081DCD26
+	cmp r2, 0xE
+	bgt _081DCD38
+	cmp r2, 0x7
+	bge _081DCD3A
+	movs r1, 0xFF
+_081DCD38:
+	strb r1, [r0, 0xA]
+_081DCD3A:
+	ldr r1, [r0, 0x8]
+	adds r1, 0xEE
+	ldr r3, pool_SerialRegs
+	str r1, [r3, OFFSET_REG_JOY_TRANS - 0x120]
+	movs r1, 0x30
+	strh r1, [r3, OFFSET_REG_JOYSTAT - 0x120]
+	adr r2, GcMbIntrHandler_81DCD4C
+	b GameCubeMultiBoot_SetInterruptHandler
+
+	.align 2, 0
+
+GcMbIntrHandler_81DCD4C: ; 81DCD4C
+	lsls r1, 31
+	bcc GcMbIntrHandler_Stop ; stop if send failed
+	bmi _081DCD5C ; branch if receive is complete
+	adr r2, GcMbIntrHandler_81DCD58
+	b GameCubeMultiBoot_SetInterruptHandler
+
+	.align 2, 0
+
+GcMbIntrHandler_81DCD58: ; 81DCD58
+	lsrs r1, 1 ; is receive complete?
+	bcc GcMbIntrHandler_Stop ; branch if not
+_081DCD5C:
+	ldr r1, [r3, OFFSET_REG_JOY_RECV - 0x120]
+	ldr r2, _081DCDFC
+	cmp r1, r2
+	bhs GcMbIntrHandler_Stop
+	adds r1, 0x1
+	adds r1, r1
+	strh r1, [r0, 0x12]
+	ldrb r1, [r0, 0x2]
+	cmp r1, 0
+_081DCD6E:
+	bne GcMbIntrHandler_Stop
+	ldr r1, pool_MultiBootLoadAddr
+	str r1, [r0, GCMB_STRUCT_BASE_DEST_PTR]
+	str r1, [r0, GCMB_STRUCT_CUR_DEST_PTR]
+	adr r2, GcMbIntrHandler_81DCD7C
+	b GameCubeMultiBoot_SetInterruptHandler
+
+	.align 2, 0
+
+GcMbIntrHandler_81DCD7C: ; 81DCD7C
+	lsrs r1, 1 ; is receive complete?
+	bcc GcMbIntrHandler_Stop ; branch if not
+	ldr r2, [r0, GCMB_STRUCT_CUR_DEST_PTR]
+	movs r1, 0x4
+	ands r1, r2
+	adds r1, 0x8
+	lsls r1, 2
+	strh r1, [r3, OFFSET_REG_JOYSTAT - 0x120]
+	ldr r1, [r3, OFFSET_REG_JOY_RECV - 0x120]
+	stm r2!, {r1}
+	str r2, [r0, GCMB_STRUCT_CUR_DEST_PTR]
+	ldrh r1, [r0, 0x12]
+	subs r1, 0x1
+	strh r1, [r0, 0x12]
+	bne GameCubeMultiBoot_ReadVCount
+
+_081DCD9A:
+	ldrb r1, [r0, 0x1]
+	lsls r1, 8
+	adds r1, 0xCC
+	str r1, [r3, OFFSET_REG_JOY_TRANS - 0x120]
+	adr r2, _081DCDA8
+	b GameCubeMultiBoot_SetInterruptHandler
+
+	.align 2, 0
+
+_081DCDA8:
+	lsls r1, 31
+
+_081DCDAA:
+	bcc GcMbIntrHandler_Stop
+	ldr r1, [r0, 0x1C]
+	cmp r1, 0
+	beq _081DCD9A
+	str r1, [r3, OFFSET_REG_JOY_TRANS - 0x120]
+	adr r2, GcMbIntrHandler_81DCDB8
+	b GameCubeMultiBoot_SetInterruptHandler
+
+	.align 2, 0
+
+GcMbIntrHandler_81DCDB8: ; 81DCDB8
+	lsls r1, 31
+	bcc _081DCDAA ; branch if send failed
+	bmi _081DCDC8 ; branch if receive is complete
+	adr r2, GcMbIntrHandler_81DCDC4
+	b GameCubeMultiBoot_SetInterruptHandler
+
+	.align 2, 0
+
+GcMbIntrHandler_81DCDC4: ; 81DCDC4
+	lsrs r1, 1 ; is receive complete?
+	bcc _081DCDAA ; branch if not
+
+_081DCDC8:
+	ldr r1, [r3, OFFSET_REG_JOY_RECV - 0x120]
+	lsrs r2, r1, 24
+	cmp r2, 0xBB
+	bne _081DCD6E
+	strh r1, [r0, 0x10]
+	adr r2, GcMbIntrHandler_81DCDD8
+	b GameCubeMultiBoot_SetInterruptHandler
+
+	.align 2, 0
+
+GcMbIntrHandler_81DCDD8: ; 81DCDD8
+	b GcMbIntrHandler_Stop
+
+	thumb_func_end GameCubeMultiBoot_HandleSerialInterrupt
+
+	non_word_aligned_thumb_func_start GameCubeMultiBoot_Quit
+; void GameCubeMultiBoot_Quit();
+GameCubeMultiBoot_Quit: ; 81DCDDA
+	ldr r3, pool_InterruptRegs
+
+; Save IME register.
+	ldrh r2, [r3, OFFSET_REG_IME - 0x200]
+
+; Disable interrupts.
+	movs r1, 0
+	strh r1, [r3, OFFSET_REG_IME - 0x200]
+
+	ldr r3, pool_SerialRegs
+
+; Acknowledge all JOYCNT flags.
+	movs r0, 0x7
+	strh r0, [r3, OFFSET_REG_JOYCNT - 0x120]
+
+; Turn off JOY Bus mode.
+	lsls r0, r3, 10
+	strh r0, [r3, OFFSET_REG_RCNT - 0x120] ; store 0x8000
+
+	ldr r3, pool_InterruptRegs
+
+; Acknowledge serial interrupt.
+	movs r0, INTR_FLAG_SERIAL
+	strh r0, [r3, OFFSET_REG_IF - 0x200]
+
+; Disable serial interrupt.
+	ldrh r1, [r3, OFFSET_REG_IE - 0x200]
+	bics r1, r0
+	strh r1, [r3, OFFSET_REG_IE - 0x200]
+
+; Restore IME register.
+	strh r2, [r3, OFFSET_REG_IME - 0x200]
+
+	bx lr
+	thumb_func_end GameCubeMultiBoot_Quit
+
+	.align 2, 0
+
+_081DCDFC: .4byte 0x00004000
+
+pool_InterruptRegs: .4byte REG_BASE + 0x200
+
+pool_SerialRegs: .4byte REG_BASE + 0x120
+
+pool_RegDispstat: .4byte REG_DISPSTAT
+
+pool_RubyUSAGameCode: .ascii "AXVE"
+
+pool_MultiBootLoadAddr: .4byte EWRAM_START