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2016-12-01 15:45

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
.....

... 18 posts hidden. Click here to view all posts....

2016-12-02 20:19

Oswald

Registered: Apr 2002
Posts: 5094

soci, could you explain the ..= operator?

2016-12-02 20:37

Flavioweb

Registered: Nov 2011
Posts: 463

Quote: soci, could you explain the ..= operator?

http://tass64.sourceforge.net/#compound

2016-12-02 21:12

soci

Registered: Sep 2003
Posts: 480

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.

2016-12-03 14:56

Compyx

Registered: Jan 2005
Posts: 631

Quoting soci

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.

Why not remove it, with an error message when people use it. I'm sure I can change ^2016 to .text "2061" or something like it in my sources if 64tass borks and prints a clear message.

2016-12-03 16:07

soci

Registered: Sep 2003
Posts: 480

Normally it isn't used as '^2061' directly, but more as '^start'. An equivalent replacement is 'format("%d", start)' as that's what it does.

Possibly I can make a deprecation warning which directs to the use of format function instead.

It can't be changed to mean the bank byte immediately as it will compile without error if ".text $9e, ^start" was used. For ".null $9e, ^start" of course not as the result is likely 0 which is an error.

So there needs to be at least one release with the warning before it could change. And then the current "`" bank byte operator needs be there for even longer as an alias. But that's not a big problem as it's like the old "//" alias for modulo (now "%") and there's no plan to reuse it for something else yet.

Edit: It seems I have more than ~450 instances of ^xxx of which only ~50 or so is ^year, ^revision and such, rest is ^start. Oh well...

2016-12-03 18:29

Compyx

Registered: Jan 2005
Posts: 631

Sorry, I meant ^start of course.

Personally I'd rather break stuff now than later if it makes sense. Keeping old cruft around doesn't make maintaining things easier.
Deprecation warnings only serve to have people think "I'll fix that later", which they only do when stuff actually breaks.

2016-12-03 20:49

soci

Registered: Sep 2003
Posts: 480

It's not a maintenance issue as the code implementing it was refactored a few times already and is not much.

The concern is that the de facto standard notation for bank bytes still can't be used while there was a 100% replacement for years to create the exact same strings (and more).

I've added the warning for now as it helps to identify what needs to be changed and how. Especially that the breakage is hard to spot in some cases. Then sometime next year or so "^xxx" will be changed to calculate the bank bytes instead.

2016-12-03 20:52

chatGPZ

Registered: Dec 2001
Posts: 11386

Quote: