The Super Mario Bros. Coding Questionnaire

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Main - ROM Hacking - The Super Mario Bros. Coding Questionnaire

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GameGenie81

Posted on 10-05-08 07:12 PM (rev. 2 of 10-05-08 07:57 PM)

Link | Quote | ID: 91754

Koopa
Level: 24

Posts: 83/100
EXP: 78085
Next: 40

Since: 08-15-07
From: Milwaukie, OR

Last post: 5432 days
Last view: 5385 days

Could you please sticky this thread, moderators?

This questionnaire is all about coding for Super Mario Bros. 1 and Super Mario Bros. 2 (Japan), whether it is easy or hard to figure out:

When I enter a cloud level in Super Mario Bros., the resulting syntaxes in the ROM code I discovered are:


ChkAreaType:
$9106: AC 4E 07 - LDY $074E = #$01
$9109: AD 43 07 - LDA $0743 = #$03
$910C: F0 02    - BEQ $9110
$910E: A0 04    - LDY #$04
StoreMusic:
$9110: B9 E7 90 - LDA $90E7,Y @ $90E7 = #$02
$9113: 85 FB    - STA $FB
ExitGetM:
$9115: 60       - RTS

Why does the RAM address that points to "CloudTypeOverride" have a result of #$03 that is loaded in the A register; which follows the previous RAM instruction that points to "AreaType" which retains the then-current result that is #$01, or "GroundMusic," that is loaded in the Y register?

Thank you,
Ben

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beneficii

Posted on 10-13-08 12:17 AM

Link | Quote | ID: 92157

Shyguy
Level: 23

Posts: 36/85
EXP: 62075
Next: 5648

Since: 02-19-07

Last post: 3133 days
Last view: 3110 days

For Super Mario Bros., here is the memory map:

http://www.romhacking.net/docs/345/

Here is the comprehensive disassembly, which will most certainly answer your specific question:

http://www.romhacking.net/docs/344/

For Super Mario Bros. 2, here is an ongoing project to complete a fully labelled disassembly:

http://sm2.beneficii.net/

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Lid

(post deleted)

ID: 92374

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