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 | | From: | sanjaya | | Subject: | Assembler code | | Date: | 14 Jan 2005 20:38:45 -0800 |
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 | > >>can someone help me with the assembler code to move memory contents
> >>from $DA00-$DBFF (Bank 1 main memory) to $8000-$81ff (main memory).
> >>
> >>thanks,
> >>sanjaya
> >
> >
Don't we have to activate soft switches to copy from Bank 1, Main meory?
thanks,
sanjaya
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| | From: | Laine Houghton | | Subject: | Re: Assembler code | | Date: | Sat, 15 Jan 2005 09:49:46 -0700 |
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"sanjaya" wrote in message
news:95bec359.0501142038.7cf17bad@posting.google.com...
>> >>can someone help me with the assembler code to move memory contents
>> >>from $DA00-$DBFF (Bank 1 main memory) to $8000-$81ff (main memory).
>> >>
>> >>thanks,
>> >>sanjaya
>> >
>> >
>
> Don't we have to activate soft switches to copy from Bank 1, Main meory?
>
> thanks,
> sanjaya
Yes.
On powerup bank 2 is switched in. Reading $C08B (TWICE) sets $D000-$DFFF to
bank 1 read/write
lda $DA00 ;get byte in bank 2
sta $300 ;save byte
bit $C08B
bit $C08B ;switch in bank 1
lda $DA00 ;get byte in bank 1
sta $301 ; save byte
bit $C083
bit $C083 ; switch bank 2 back in
lda $DA00
cmp $300
bne ERROR
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