Re: A89: Starting out assembly, need help


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Re: A89: Starting out assembly, need help




>
>In a message dated 11/30/98 10:08:39 PM Eastern Standard Time,
>assets@eden.rutgers.edu writes:
>
>> just define space in your program:
>>
>>  xCoordinate:
>>   dc.w 0
>
>How does this work?  lf l wanted to store a1 to a place in mem, can l use
any
>mem in $0000 to wherever?  l don't understand this quite well...
>

$5800 is part of the unused video memory, so you would define an equate like
this:

xCoordinate    equ    $5800

then you would access it like this:

 move.w a1,xCoordinate

on the other hand, if you defined xCoordinate in your code using a label and
dc.w, then you would be changing an area of user memory that is occupied by
your program; you would access it w/ relative addressing:

move.w a1,xCoordinate(pc)