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nomistake
Registered: Apr 2011
Posts: 29 |
$a000 drives me nuts
hello everyone,
so i've had this problem quite often and i don't know how to manage it: everytime i use the memory between $a000 and $bfff i am in trouble :-) somehow i can't read from it with lda $a000,x - i have switched off the basic and kernal with lda #$35 sta $01. what am i doing wrong?
thanks for any advice. |
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tlr
Registered: Sep 2003
Posts: 1790 |
There's nothing special with $a000 if rom is banked out and code is running from ram. Is $00 properly set up? |
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nomistake
Registered: Apr 2011
Posts: 29 |
$00 ??
i thought setting $01 to #$35 would be enough... |
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chatGPZ
Registered: Dec 2001
Posts: 11386 |
yes and no.. for the cpu port $00 is data direction and $01 is data - $00 must be $2f (which is the default set by kernal, so usually you dont have to set it up) |
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nomistake
Registered: Apr 2011
Posts: 29 |
lol - i copied the wrong data to $a000 (again) - no wonder why i didn't get the results i expected. sorry for bothering you guys with this but thanks a lot for the help! |
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ChristopherJam
Registered: Aug 2004
Posts: 1409 |
I did get caught out by the DDR ($00) being vandalised the other day; my loader wasn't respecting the length byte of the last block of a file that was loading to near the end of ram, so I overwrote it without realising. |
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enthusi
Registered: May 2004
Posts: 677 |
Also some TASS versions are molesting $00:
Turbo Assembler 5.2 FIX |
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nomistake
Registered: Apr 2011
Posts: 29 |
oh! i am using the +60k version of tass Turbo Assembler Professional 1.2 [+60K] 20051017 since i like to have all the regular memory available for my programm. do i just need to look for something that changes $00 and set it to #$2f or is there more to fix this??
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EDIT: i checked, this version is already fixed ($00 @ #$2f) |
