ACWW v1.0 Bulletin Board Header code

With a lot of help in loops and general ASM stuff from Dragonboy and Demonic, I finally completed a code. This rewrites the bulletin board headers "Written by..." to "Eaten by...".

This works for me - it should replace headers that say only "Written by" and none of the other announcement posts or whatever. I'm still learning ASM though, so if you see an error, let me know.

Code:

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Rewrite BB Header (Press R)
94000130 feff0000
023ff090 012fff11
e0000000 00000040
e59f0028 e59f1028
e1df22b8 e59f3028
e7904002 e1540003
1a000000 e7801002
e24220c4 e3520000
5afffff8 e12fff1e
021e8258 1b058585
00000ab8 2e232c17
023ff090 e3520003
d2000000 00000000

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ASM source:

Code:

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ldr r0, BBHeader @Address of the first post
ldr r1, NewHeader
ldrh r2, =0x0ab8 @Last post header when added to first address
ldr r3, =0x2e232c17 @Stands for "Writ"

Loop:
ldr r4, [r0, r2] @Storing last header address to compare.
cmp r4, r3 @Check if the post starts with "Writ"
bne SkipPost @If equal, rewrite header. If not, skip it
str r1, [r0, r2]
SkipPost:
sub r2, #0xc4 @Subtracts the address to the next BB header
cmp r2, #0x0 @Checking if loop is done
bpl Loop
bx lr

BBHeader:
.long 0x021e8258
NewHeader:
.long 0x1b058585 @Not an address- it spells "__Ea"

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Technically you don't need the "cmp r2, #0x0" at the bottom.
bpl means "positive or zero" so you don't need to compare to 0, because bpl is already doing that.
so, you just need

Code:

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subs r2, #0xc4  @decrement and set conditional flag (hence the "s")
bpl Loop

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if it was bgt or blt, you'd need to define "greater than what?" or "less than what?" by comparing to something, but bpl is already defined.

Oh, I was wondering why the example I was looking at didn't have the cmp part in it. Thanks!

Brilliant. o.o Good job!

Guess I haven't been active lately. Didn't see a new, decent coder coming ;D.

Quote:

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Originally Posted by siestacat

Guess I haven't been active lately. Didn't see a new, decent coder coming ;D.

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Thanks, I used your website siestacat.wordpress.com to begin learning ASM, which was very helpful! I've been playing around with letter addresses, so my next code might involve that.

Nice. I didn't know anyone other than Demonic ever used that. Perhaps I should add some to it.

I actually recommended your tutorial to a few people Siestacat. I'm not sure if they ever got around to coding yet, though.

Thanks. 1500 + hits now. Maybe I'll add more...