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85036fe67f
pokeemerald/asm/libgcnmultiboot.s
YamaArashi 85036fe67f partially comment GameCube multi-boot library
2015-11-27 01:33:50 -08:00

540 lines
12 KiB
ArmAsm
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; 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: ; 82DED70
push {r4,lr}
ldr r4, pool_HashVal
eors r3, r1
movs r2, 0x20
@loop:
lsrs r3, 1
bcc @skipExclusiveOr
eors r3, r4
@skipExclusiveOr:
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: ; 82DED84
ldr r1, [r0, GCMB_STRUCT_SERIAL_INTR_HANDLER]
cmp r1, 0
beq _082DEDAA
ldrb r1, [r0, 0x1]
adds r1, 0x1
strb r1, [r0, 0x1]
ldrb r1, [r0, 0x2]
cmp r1, 0x2
beq _082DEDF4
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 _082DEDA8
adds r1, 0x1
strb r1, [r0]
_082DEDA8:
strh r2, [r3, OFFSET_REG_IME - 0x200]
_082DEDAA:
bcs GameCubeMultiBoot_Init
ldrb r1, [r0, 0x2]
cmp r1, 0
bne _082DEDF6
ldr r1, [r0, GCMB_STRUCT_CUR_DEST_PTR]
ldr r2, [r0, GCMB_STRUCT_BASE_DEST_PTR]
subs r1, r2
beq _082DEE76
cmp r1, 0xA0
bcc _082DEE76
push {r4-r6}
movs r1, 0x98
adds r2, RomHeaderNintendoLogo - RomBase
ldr r4, pool_NintendoLogo
_082DEDC6:
ldm r2!, {r5}
ldm r4!, {r6}
cmp r5, r6
bne _082DEDDC
subs r1, 0x4
bne _082DEDC6
ldm r2!, {r5}
ldm r4!, {r6}
eors r5, r6
lsrs r5, 8
str r2, [r0, GCMB_STRUCT_BASE_DEST_PTR]
_082DEDDC:
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]
_082DEDF4:
bx lr
_082DEDF6:
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
_082DEE06:
cmp r4, r12
bcs _082DEE26
ldr r1, [r4]
eors r1, r6
adds r1, r3
stm r4!, {r1}
eors r3, r1
movs r2, 0x20
_082DEE16:
lsrs r3, 1
bcc _082DEE1C
eors r3, r7
_082DEE1C:
subs r2, 0x1
bne _082DEE16
muls r6, r5
adds r6, 0x1
b _082DEE06
_082DEE26:
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 _082DEE76
ldr r1, [r0, GCMB_STRUCT_CUR_DEST_PTR]
ldr r2, [r0, GCMB_STRUCT_BASE_DEST_PTR]
cmp r1, r2
bne _082DEE76
ldr r1, [r0, 0xC]
cmp r1, 0
beq _082DEE60
ldrh r1, [r0, 0x10]
cmp r1, 0
beq _082DEDF4
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
_082DEE60:
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
_082DEE76:
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: ; 82DEE84
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: ; 82DEE98
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: ; 82DEEE2
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: ; 82DEF24
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: ; 82DEF30
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_82DEF44
b GameCubeMultiBoot_SetInterruptHandler
.align 2, 0
GcMbIntrHandler_82DEF44: ; 82DEF44
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
_082DEF5E:
lsrs r1, 1
adcs r2, r3
cmp r1, 0
bne _082DEF5E
cmp r2, 0xE
bgt _082DEF70
cmp r2, 0x7
bge _082DEF72
movs r1, 0xFF
_082DEF70:
strb r1, [r0, 0xA]
_082DEF72:
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_82DEF84
b GameCubeMultiBoot_SetInterruptHandler
.align 2, 0
GcMbIntrHandler_82DEF84: ; 82DEF84
lsls r1, 31
bcc GcMbIntrHandler_Stop ; stop if send failed
bmi _082DEF94 ; branch if receive is complete
adr r2, GcMbIntrHandler_82DEF90
b GameCubeMultiBoot_SetInterruptHandler
.align 2, 0
GcMbIntrHandler_82DEF90: ; 82DEF90
lsrs r1, 1 ; is receive complete?
bcc GcMbIntrHandler_Stop ; branch if not
_082DEF94:
ldr r1, [r3, OFFSET_REG_JOY_RECV - 0x120]
ldr r2, _082DF034
cmp r1, r2
bhs GcMbIntrHandler_Stop
adds r1, 0x1
adds r1, r1
strh r1, [r0, 0x12]
ldrb r1, [r0, 0x2]
cmp r1, 0
_082DEFA6:
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_82DEFB4
b GameCubeMultiBoot_SetInterruptHandler
.align 2, 0
GcMbIntrHandler_82DEFB4: ; 82DEFB4
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
_082DEFD2:
ldrb r1, [r0, 0x1]
lsls r1, 8
adds r1, 0xCC
str r1, [r3, OFFSET_REG_JOY_TRANS - 0x120]
adr r2, _082DEFE0
b GameCubeMultiBoot_SetInterruptHandler
.align 2, 0
_082DEFE0:
lsls r1, 31
_082DEFE2:
bcc GcMbIntrHandler_Stop
ldr r1, [r0, 0x1C]
cmp r1, 0
beq _082DEFD2
str r1, [r3, OFFSET_REG_JOY_TRANS - 0x120]
adr r2, GcMbIntrHandler_82DEFF0
b GameCubeMultiBoot_SetInterruptHandler
.align 2, 0
GcMbIntrHandler_82DEFF0: ; 82DEFF0
lsls r1, 31
bcc _082DEFE2 ; branch if send failed
bmi _082DF000 ; branch if receive is complete
adr r2, GcMbIntrHandler_82DEFFC
b GameCubeMultiBoot_SetInterruptHandler
.align 2, 0
GcMbIntrHandler_82DEFFC: ; 82DEFFC
lsrs r1, 1 ; is receive complete?
bcc _082DEFE2 ; branch if not
_082DF000:
ldr r1, [r3, OFFSET_REG_JOY_RECV - 0x120]
lsrs r2, r1, 24
cmp r2, 0xBB
bne _082DEFA6
strh r1, [r0, 0x10]
adr r2, GcMbIntrHandler_82DF010
b GameCubeMultiBoot_SetInterruptHandler
.align 2, 0
GcMbIntrHandler_82DF010: ; 82DF010
b GcMbIntrHandler_Stop
thumb_func_end GameCubeMultiBoot_HandleSerialInterrupt
non_word_aligned_thumb_func_start GameCubeMultiBoot_Quit
; void GameCubeMultiBoot_Quit();
GameCubeMultiBoot_Quit: ; 82DF012
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
_082DF034: .4byte 0x4000
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
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