[MKDS] ARM9 Code Handler

;A very simple and minimal code handler for ARM9 addresses created for Mario Kart DS by Fishguy6564
;R0 = code list address
;R1 = address to write to
;R2 = instruction to write to address
;R3 = code handler terminator value

.set codelist, 0x2001E54
.set terminator, 0xDEADBEEF
    STMDB       SP!, {R0-R3}    ;PUSH
    LDR         R0, =codelist   ;R0 contains the address of the beginning of the code list
    LDR         R3, =terminator ;R3 contains the expected code list terminator
LOOP:
    LDR         R1, [R0]        ;Load the address to write to or terminator from the codelist into R1
    CMP         R1, R3          ;Check if terminator is present
    BEQ         END             ;End iteration through code list if the entry was the code list terminator
    LDR         R2, [R0, #4]    ;Load value to be written from the code list into R2
    STR         R2, [R1]        ;Write value to the address
    ADD         R0, R0, #8      ;Increase to the next entry in code list
    B           LOOP            ;Loop again
END:
    LDMIA       SP!, {R0-R3}    ;POP
    BX          LR

[ARM9 Codehandler by Fishguy6564]
02039988 EAFF1D88
E2000FB0 00000038
E92D000F E59F0024
E59F3024 E5901000
E1510003 0A000003
E5902004 E5812000
E2800008 EAFFFFF8
E8BD000F E12FFF1E
02001E54 DEADBEEF

[Empty Code List]
E2001E54 YYYYYYYY
<-----Codes----->
DEADBEEF 00000000

Calculate in hex
Y = (8 * code amount) + 4

Example:
[Code List With ARM9 Infinite Speed]
E2001E54 00000014 <- Instructions are included on how we calculated 0x14
01002E98 E3500470 ;1 Code
01003E40 E3A02470 ;2 Codes
DEADBEEF 00000000

Total of two codes we want to use.
Plug into the equation to calculate the Y value
Y = (8 * 2) + 4
Y = 20
convert it to hex
20 = 0x14 in hex so..
Y = 0x14 this is our value for Y
Zero extend the calculated value, so YYYYYYYY = 00000014

Note: Infinite speed was not made by me!

Instructions on porting to other games:
I've tried to make this source as clean and descriptive as possible by adding comments and assembly directives. To port this to another game, simply change the .set directive for the code list to an unused region in ram. From there, just hook this code to a base address that is in constant execution for best results. The content after the POP (LDMIA) may differ depending on where you hook to. Always remember to include a return branch at the end of your code, in this case, it was BX LR. Again, this may differ depending on where you hook it. This is my first ever DS code, so if you find any bugs then please feel free to report them :P