-----Original Message-----
From: "B. Watson" <atari@xxxxxxxxxxxxxx>
Sent: Aug 16, 2005 6:55 AM
To: stella@xxxxxxxxxxxxxxxxxx
Subject: Re: [stella] DASM wish list
On Mon, 15 Aug 2005, C. Bond wrote:
> ...especially if your opcode list includes all
> the unofficial opcodes. In some cases you may have to rewrite your source code
> to change labels such as SAX, DCP, etc. so they don't conflict with opcodes.
> It might be better to simply separate labels from opcodes by a formatting rule.
> (Maybe not, just a thought!)
Illegal opcode support ought to be something you can turn off, either
from the command line or with a directive in your source. At one time
there was talk of doing this in DASM, but I can't remember whether it
actually happened...
> Another issue has to do with using opcode syntax such as LSR A and
> ROL A. If your assembler simply requires LSR or ROL, you can free
> up 'A' for use as a label, otherwise it becomes a reserved symbol.
I don't think anyone who codes for the VCS also smokes crack, so we
don't have to worry about that: non-crackheads know better than to use
a label that conflicts with a register name! Just because something's
allowed doesn't mean it's a good idea, and I'm willing to bet we won't
run into any old code that has labels called A, X, or Y...
[snip]
In fact, I have bet that: I unconditionally treat A, X, Y, S, and PC as
registers in the Stella debugger. I thought about it a lot, and decided
that the inconvenience of having to type a "sigil" character (maybe ".A"
or "%A" for accumulator, as opposed to just plain "A") doesn't outweigh
the possible compatibility problems dealing with a drug-influenced
label called "A"... Everyone's going to have to refer to the accumulator
a zillion times, but only the insane people are going to have a label
called "A". I won't punish the many for the crimes of the few.
---------------
Well, in my post I did not state a preference. I only pointed out that there
are tradeoffs. However, I certainly don't recommend making things easier
for "crackheads" or the "insane". You have a clear concept of what is
convenient for the many and what weighs more heavily than what in
assembler syntax specifications. I have no argument against your
preferences, I simply pointed out as you did, that some decisions involve
the selection of reserved symbols.
--
B.
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