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ready.
Registered: Feb 2003
Posts: 441 |
64tass: labels inside FOR ... NEXT loops
hello,
does 64tass have the possibility to use indexed labels, like inside a FOR...NEXT loop?
Something like:
.FOR X=0, X<X_MAX-1, X=X+1
LABEL(X)
LDA #ABC
STA ZXY
.NEXT
so to have X_MAX labels.
Unrolled:
LABEL1
LDA #ABC
STA ZXY
LABEL2
LDA #ABC
STA ZXY
..... |
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soci
Registered: Sep 2003
Posts: 473 |
The "^" prefix for macro parameters is gone since r98. It did an expression evaluation and the result was converted to a decimal string which in turn was used for textual replacement. Similar to the "^" operator.
While it could be resurrected I'd like to see it dead and buried. Unfortunately the non-macro operator variant of this can't go away that easy due to it's common use in basic start lines. The sad thing is there's no other useful use of it at all. It should have been assigned as the bank byte operator but it couldn't due to it's 1.3x legacy.
As macro parameters are text replacements you're out of luck to use the value of the loop variable this way.
The alternative to numbered labels is lists. Simplest is to collect addresses into a list:
*= $1000
lista := [] ; empty
.for i=0,i<8,i=i+1
lista ..= [*] ; collect
lda #i
.if i>3
nop
.fi
.next
.word lista ;all
.word lista[4];5thGives:
.1000 a9 00 lda #$00 lda #i
.1002 a9 01 lda #$01 lda #i
.1004 a9 02 lda #$02 lda #i
.1006 a9 03 lda #$03 lda #i
.1008 a9 04 lda #$04 lda #i
.100a ea nop nop
.100b a9 05 lda #$05 lda #i
.100d ea nop nop
.100e a9 06 lda #$06 lda #i
.1010 ea nop nop
.1011 a9 07 lda #$07 lda #i
.1013 ea nop nop
>1014 00 10 02 10 04 10 06 10 .word lista ;all
>101c 08 10 0b 10 0e 10 11 10
>1024 08 10 .word lista[4];5th
Something similar can be done a bit more complicated using a list of anonymous scopes (not exactly the same as above):
*= $1000
lista := []
.for i=0,i<8,i=i+1
lista ..= [+]
+ .block
label lda #i
.if i>3
lbl2 nop
.fi
.bend
.next
.word lista.label
.word lista[4].lbl2
Results in:
.1000 a9 00 lda #$00 label lda #i
.1002 a9 01 lda #$01 label lda #i
.1004 a9 02 lda #$02 label lda #i
.1006 a9 03 lda #$03 label lda #i
.1008 a9 04 lda #$04 label lda #i
.100a ea nop lbl2 nop
.100b a9 05 lda #$05 label lda #i
.100d ea nop lbl2 nop
.100e a9 06 lda #$06 label lda #i
.1010 ea nop lbl2 nop
.1011 a9 07 lda #$07 label lda #i
.1013 ea nop lbl2 nop
>1014 00 10 02 10 04 10 06 10 .word lista.label
>101c 08 10 0b 10 0e 10 11 10
>1024 0a 10 .word lista[4].lbl2
This has an advantage that proper referencable labels can be used for each instance of code using only one list.
I think I've showed Oswald once in private message how to prototype 25 parametrized IRQs with a for loop generator so that each of them sets the vector to the next one and the last one back to the first. With on-demand high byte update to spare cycles/bytes (variable length instances) and initial setup. It used this latter anonymous scope+list method. |
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Oswald
Registered: Apr 2002
Posts: 5017 |
for the record:
*= $801
.word +, 2016
.null $9e, ^start
+ .word 0
start
sei
lda #<irqlist[0].addr ; elso cim
sta $314
lda #>irqlist[0].addr
sta $315
lda #irqlist[0].raster ; elso pozicio
sta $d012
lda $d011
and #~$80
sta $d011
lda #1
sta $dc0d
sta $d01a
bit $dc0d
sta $d019
cli
rts
irqlist2 := [] ; ures lista a rutinoknak
.for this = 0, this < 50, this = this + 1; 50 db
irqlist2 ..= [+] ; aktualis irq rutin listaba rakasa
+ .block ; irq rutin blokk
addr = * ; cim
raster = (this & 1) == 0 ? (this/2)*8+53 : (this/2)*8+55; raster pozicio effekthez
nextirq = irqlist[len(irqlist2) % len(irqlist)];a kovetkezo irq rutin
lda #this & 15 ; hogy legyen valami effekt is
sta $d020
lda #nextirq.raster ; kovetkezo pozicio
sta $d012
inc $d019
lda #<nextirq.addr ; kovetkezo cim
sta $314
.if (>nextirq.addr) != (>addr); csak ha kell
lda #>nextirq.addr
sta $315
.fi
jmp this == 49 ? $ea31 : $ea81; hogy lehessen gepelni ;)
.bend
.next
irqlist = irqlist2 ; hogy lehessen hasznalni fent |
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soci
Registered: Sep 2003
Posts: 473 |
Thanks! Next time I'll comment in English, one can never know ;) |
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Radiant
Registered: Sep 2004
Posts: 639 |
Parenthetical: A great example of why code comments and symbols always should be in English - you never know who is going to read the code down the line.
I take it one step further and keep all design documents, Trello boards et cetera in English as well, even though at the moment everyone in the group speaks Swedish. |
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Oswald
Registered: Apr 2002
Posts: 5017 |
*= $801
.word +, 2016
.null $9e, ^start
+ .word 0
start
sei
lda #<irqlist[0].addr ; first adress
sta $314
lda #>irqlist[0].addr
sta $315
lda #irqlist[0].raster ; first raster pos
sta $d012
lda $d011
and #~$80
sta $d011
lda #1
sta $dc0d
sta $d01a
bit $dc0d
sta $d019
cli
rts
irqlist2 := [] ; empty list for the routines
.for this = 0, this < 50, this = this + 1; 50 pcs
irqlist2 ..= [+] ;put current irq routine into list
+ .block ; irq routine block
addr = * ; address
raster = (this & 1) == 0 ? (this/2)*8+53 : (this/2)*8+55; raster position for effect
nextirq = irqlist[len(irqlist2) % len(irqlist)];the next irq routine
lda #this & 15 ; so some effect is shown
sta $d020
lda #nextirq.raster ; next position
sta $d012
inc $d019
lda #<nextirq.addr ; next adress
sta $314
.if (>nextirq.addr) != (>addr); only if needed
lda #>nextirq.addr
sta $315
.fi
jmp this == 49 ? $ea31 : $ea81; so you can type ;)
.bend
.next
irqlist = irqlist2 ; so it is possible to use up there |
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chatGPZ
Registered: Dec 2001
Posts: 11110 |
Quote:A great example of why code comments and symbols always should be in English
come on.... at least its not japanese :) |
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Hein
Registered: Apr 2004
Posts: 933 |
Quoting soci
*= $1000
lista := [] ; empty
.for i=0,i<8,i=i+1
lista ..= [*] ; collect
lda #i
.if i>3
nop
.fi
.next
.word lista ;all
.word lista[4];5th
Thanks, will try that. |
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Oswald
Registered: Apr 2002
Posts: 5017 |
soci, could you explain the ..= operator? |
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Flavioweb
Registered: Nov 2011
Posts: 447 |
Quote: soci, could you explain the ..= operator?
http://tass64.sourceforge.net/#compound |
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soci
Registered: Sep 2003
Posts: 473 |
Yes, "..=" is the compound assignment version of the concatenate operator "..".
So "a ..= b" is the shorter form of "a := a .. b" or "a .var a .. b". Just like "a += b" is "a := a + b".
Btw. compound assignments for ".for" loops are only available since r1245. The last release was r1237 which is the reason I still used "i = i + 1" instead of the shorter "i += 1" in the example. |
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