.text
.align 2
.thumb
.global walkingscript
main:
push {r4,r5,lr}
add sp, #-0x4
lsl r0, r0, #0x18 @ getQueueItemByIndex
lsr r0, r0, #0x18
lsl r1, r0, #0x2
add r1, r1, r0
lsl r1, r1, #0x3
ldr r0, exec_queue
add r5, r1, r0 @ /getQueueItemByIndex
mov r4, sp
add r4, #0x2
mov r0, sp
add r1, r4, #0x0
ldr r2, get_player_coords
bl linker @ Store player coordinates at [r0] and [r1], respectively.
mov r0, sp @ Start checking if player coordinates have changed.
ldrh r2, [r0, #0x0]
mov r3, #0x0
ldsh r1, [r0, r3]
mov r3, #0x2
ldsh r0, [r5, r3]
cmp r1, r0
bne process
mov r0, #0x0
ldsh r1, [r4, r0]
mov r3, #0x4
ldsh r0, [r5, r3]
cmp r1, r0
beq return @ Fall through to process
process:
strh r2, [r5, #0x2]
ldrh r0, [r4, #0x0]
strh r0, [r5, #0x4]
mov r0, sp
mov r1, #0x0
ldsh r0, [r0, r1]
mov r2, #0x0
ldsh r1, [r4, r2]
ldr r2, get_background_byte
bl linker @ r0: BG byte of tile the player's standing on; r4: sp + 2, pointer
lsl r0, r0, #0x18
lsr r0, r0, #0x18
@ Skip bl to return; that's what cripples the routine
lsl r0, r0, #0x18
cmp r0, #0x0
beq return @ Return if no background byte
mov r0, sp
mov r3, #0x0
ldsh r0, [r0, r3] @ r0 = player x
mov r2, #0x0
ldsh r1, [r4, r2] @ r1 = player y
ldr r2, get_tile_number
bl linker @ r0 = tile number the player's on
@ REGISTERS: see note 1
ldr r1, tile_table
mov r2, #0x0
ldr r4, table_delimiter
ldrh r4, [r4, #0x0]
loop:
ldrh r3, [r1, r2] @ Load the current value
cmp r3, r4 @ Compare the current value to our delimiter.
beq return @ And return if we finished reading the table.
cmp r3, r0 @ Compare the current value to the tile number the player's on.
bne next_entry @ Read the next entry if the two aren't equal.
ldr r0, script
ldr r2, script_executor
bl linker
return:
add sp, #0x4
pop {r4, r5}
pop {r0}
bx r0
next_entry:
add r2, r2, #0x2 @ Increase our table offset by 0x2.
b loop @ Read the next entry.
linker:
bx r2
.align 2
exec_queue: .word 0x03005098
get_player_coords: .word 0x0805C538
get_background_byte: .word 0x08058F78
get_tile_number: .word 0x08058E48
script_executor: .word 0x08069AE4
table_delimiter: .word 0x0000
tile_table: .word 0x08AAAAAA
script: .word 0x8BBBBBB
@ Tile number table: [TILE NUMBER - 2 bytes] [END - 0000]
@ note 1:
@ - r0: tile number
@ - r1: table location
@ - r2: table offset
@ - r3: table value
@ - r4: delimiter
