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Please chime in on a proposed restructuring of the ROM hacking sections.
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Main - ROM Hacking - Another ASM Question New thread | New reply


RetroRain
Posted on 12-19-08 03:19 AM Link | Quote | ID: 97127


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Last view: 950 days 		I never fully understood this zero-page stuff. How do I change that $855C to point to something else, like $855E?

I don't really understand the first line of code here: 


$DDC4:B1 02     LDA ($02),Y @ $855C = #$96
$DDC6:9D 01 02  STA $0201,X @ $0202 = #$00


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smkdan
Posted on 12-19-08 03:52 AM Link | Quote | ID: 97128


Ninji
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Last view: 4004 days 		first line takes the 16bit address stored in $02-$03, then adds Y to it, then reads from that address. assuming Y = 0, then the stored address would be 855C. 

LDA #$5E
STA $02
LDA #$85
STA $03

LDY #$00
LDA ($02),y ;this would read 855E

INY
LDA ($02),y ;this would read 855F

RetroRain
Posted on 12-19-08 04:52 AM Link | Quote | ID: 97135


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Last view: 950 days 		Thank you, that makes it more understandable.

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