gnupic: use of labels in macros in gpasm - howto and maybe bug?
Subject:
use of labels in macros in gpasm - howto and maybe bug?
From:
Jesse Lackey ####@####.####
Date:
28 Mar 2002 18:23:47 -0000
Message-Id: <3CA35F03.9020403@celestialaudio.com>
Hello all,
I'm writing a couple of semi-gnarly macros that require labels. I need
to have a way for each instance of the macro to have unique labels,
since labels definted in macros have global scope.
For example, the macro:
FooMac macro Arg0, Arg1
some code
btfss etc
goto _hopover
more code
btfss etc2
goto _anotherBranch
return
_hopover
other code
return
_anotherBranch
yet more code
return
endm
needs to have _hopover be different each instance.
The two schemes I've come up with:
(1) pass unique symbols in for each labels in for each instance
(2) pass a unique number in for each instance
(1) would be to have _hopover and _anotherBranch themselves be arguments
to the macro, and unique symbols would be passed in. This is a bit ugly
in that one of my macros has 4 labels in it, and there could be any
number of labels required for arbitrarily complex macros.
(2) is a bit of cleverness: pass in a unique number, and use it to
synthesize unique lables with #v(). i.e. pass in another argument,
"Arg2" say, as a number, and use _#v(Arg2)_hopover, etc. to make
_4_hopover if Arg2 is 4.
Okay.
(a) is there a better way than all this tomfoolery? I could use goto $1
+- number, but I'd have to calculate number each time the code changed
and if number is wrong it would produce hard to diagnose bugs.
(b) I'm having problems with method (2) that don't make sense and may be
gpasm bugs. Specifically, for one of the synthesized labels the first
two goto _(label) assemble fine, but the third idential goto _(label)
gives a parse error. Some of the parse errors give line numbers that
are blank, also, so I suspect gpasm.
Suggestions?
I'm going to go back to (1) to work around these problems, but if anyone
wants to give a serious look at the problem, if indeed it seems that
gpasm has a bug, I'll put together a test case.
Thanks in advance!
Jesse
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