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Laxity
Registered: Aug 2005
Posts: 459 |
Saving from one memory location, loading to another!
Ok.. Maybe some'o you guys know how to do this:
I wan't to save a file, say from $c000 to $ce00. The file should however load to adress $1000 to $1e00 when loaded normally (like: load "foo",8,1). How am I going about this problem?
I was thinking that I could write each byte of the data to disk, and since the two first bytes of a file is the destination memory pointer I could start by writing $00 $10 in this case and then the data from $c000 to $ce00!.. Is this correct?
Cheers! |
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cadaver
Registered: Feb 2002
Posts: 1160 |
At least IDE64 doesn't. |
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TNT
Account closed
Registered: Oct 2004
Posts: 189 |
Both IDE64 and my patch only touch vectors at $03xx. That's why you can't use direct calls which bypass these vectors. In the easiest case IDE64 fix only requires changing all those calls to their patchable versions. |
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TNT
Account closed
Registered: Oct 2004
Posts: 189 |
This one works with 1541 and clones as well as with IDE64.
setlfs = $ffba
setnam = $ffbd
open = $ffc0
close = $ffc3
chkout = $ffc9
clrchn = $ffcc
chrout = $ffd2
; make some test data
ldx #0
init txa
sta buf,x
inx
bne init
; and save it
lda #1
ldx $ba ; use last accessed device
ldy #1
jsr setlfs
lda #4
ldx #<name
ldy #>name
jsr setnam
jsr open
ldx #1 ; make it default output
jsr chkout
lda #<address ; send wanted address
jsr chrout
lda #>address
jsr chrout
lda #<memstart ; set memory start and end addresses
sta $ac
lda #>memstart
sta $ad
lda #<memend
sta $ae
lda #>memend
sta $af
ldy #0
lp1:
lda ($ac),y ; write byte to device
jsr chrout
lda $90 ; check status, exit if fail
and #%10000011 ; you could use jsr $ffb7 instead
bne fail1 ; of directly reading $90, but it
; really doesn't matter
jsr $fcdb ; bump $ac.w
jsr $fcd1 ; compare it to $ae.w
bcc lp1 ; loop if not equal
clc ; successful return
dc.b $24 ; bit $nn, hides "sec" below
fail1 sec ; error flag
php ; remember status
jsr clrchn ; restore default output
lda #1
jsr close ; and close file
plp ; restore status
rts
name dc.b "DATA"
buf ; our data will be here
address = $c000 ; it will load into this address
memstart = buf ; and these are for readability
memend = buf+256
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tlr
Registered: Sep 2003
Posts: 1790 |
@TNT: Clean and compact, nice! :) |
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Wanderer
Account closed
Registered: Apr 2003
Posts: 478 |
Why not just transfer the code?
T c000 ce00 1000
then save
s "filename" 1000 1e00
Your method of changing the first two bytes will work of course. I've used that myself since the emulator/monitor I use is very unfriendly. |
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Graham
Account closed
Registered: Dec 2002
Posts: 990 |
Why that complicated? You can use the standard LOAD vector for loading to any adress, and it is compatible with all fastloaders too. |
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Laxity
Registered: Aug 2005
Posts: 459 |
Quote: Why not just transfer the code?
T c000 ce00 1000
then save
s "filename" 1000 1e00
Your method of changing the first two bytes will work of course. I've used that myself since the emulator/monitor I use is very unfriendly.
Sure that'll work, but would be unusable in a tool. "Press F1 for instructions on how to save"!.. Nah.. don't think so! ;) |
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Laxity
Registered: Aug 2005
Posts: 459 |
tlr & TNT, thanks for sharing. I appreciate it! |
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TNT
Account closed
Registered: Oct 2004
Posts: 189 |
Quote: Why that complicated? You can use the standard LOAD vector for loading to any adress, and it is compatible with all fastloaders too.
Load instructions:
poke 43,0:poke 44,16:load"file",8:poke 43,1:poke44,8
?
Rather than have wrong load address I would rather have totally bogus one ($0000 anyone?) so it would be clear what's wrong if I don't jump through all the loops required to load file correctly. |
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hannenz
Account closed
Registered: Nov 2002
Posts: 24 |
Quote: Why that complicated? You can use the standard LOAD vector for loading to any adress, and it is compatible with all fastloaders too.
yes. just load the file as follows, this method ignores the file's load adress and will uzse the given one. and it uses kernal i/o only.
;load to ANY adress...
load_adress = $xxxx
lda #1
ldx $ba ;last used device
ldy #0
jsr $ffba ;setlfn
lda #fn1-fn
ldx #<fn
ldy #>fn
jsr $ffbd ;setnam
lda #0
ldx #<load_adress
ldy #>load_adress
jsr $ffd5 ;load
fn .text "filename"
fn1
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