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Hypnosis
Registered: Mar 2015
Posts: 36 |
Assembler with dynamic symbol creation
I have read some documentation for an assembler that allowed labels or symbols to be created dynamically, basically by concatenating strings. Which assembler was that? |
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doynax
Account closed
Registered: Oct 2004
Posts: 212 |
CA65 supports this, as do a few others I expect. If push comes to shove you can always do ad-hoc meta-programming or preprocessing by adding external tools to the build process.
In CA65 the syntax is something along these lines: .mac smc_store name
ident(.concat(.string(name), "_value")) := *+1
lda #$00
ident(.concat(.string(name), "_addr")) := *+1
sta a:$0000
.endmac |
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Hypnosis
Registered: Mar 2015
Posts: 36 |
Ah, there it is. Thanks! |
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Compyx
Registered: Jan 2005
Posts: 631 |
Why would you want to do that? Usually when I run into this, my "you're doing it wrong" alarm goes off.
There might be a valid use for this, but I'm not seeing it. |
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Oswald
Registered: Apr 2002
Posts: 5094 |
probaby some complicated speedcode, where writing native generator would take less time than macroing the shit out of it. |
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MagerValp
Registered: Dec 2001
Posts: 1078 |
For example if you want a small DSL for writing display lists, like this one here: https://twitter.com/MagerValp/status/741681367516340224 |
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doynax
Account closed
Registered: Oct 2004
Posts: 212 |
Quoting CompyxWhy would you want to do that? Usually when I run into this, my "you're doing it wrong" alarm goes off. The main place I am using it as a handy way of forwarding metadata and type information to external tools, sort of like C++ name mangling. For instance to encode breakpoints/watchpoints for VICE by running a post-processing script on the label list to transcribe magic labels into monitor commands.
Quoting Oswaldprobaby some complicated speedcode, where writing native generator would take less time than macroing the shit out of it. Indeed but also note that CA65 has scopes which often can achieve the same ends in a cleaner way, at least when operating within a single compilation unit. |
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Compyx
Registered: Jan 2005
Posts: 631 |
Quoting doynax
Quoting CompyxWhy would you want to do that? Usually when I run into this, my "you're doing it wrong" alarm goes off. The main place I am using it as a handy way of forwarding metadata and type information to external tools, sort of like C++ name mangling. For instance to encode breakpoints/watchpoints for VICE by running a post-processing script on the label list to transcribe magic labels into monitor commands.[/quote[
I stand corrected, that does indeed sound like a valid use case.
Quoting doynax
Quoting Oswaldprobaby some complicated speedcode, where writing native generator would take less time than macroing the shit out of it. Indeed but also note that CA65 has scopes which often can achieve the same ends in a cleaner way, at least when operating within a single compilation unit.
Speedcode was my first guess, but then again, when generating speedcode, you already all you need to know about entry points or whatever and just 'poke' that in other (speed)code.
I'm kind of surprised CA65 doesn't handle scopes spread over various translation units. But since it's part of a C compiler, it makes sense, C having only a couple of namespaces/scopes. |
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Hypnosis
Registered: Mar 2015
Posts: 36 |
Quoting CompyxWhy would you want to do that? Usually when I run into this, my "you're doing it wrong" alarm goes off.
I think the general case is a meta programming loop with some code that has to match and reference things in another loop. I can see if I can dig up my latest exact use case. |
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Trash
Registered: Jan 2002
Posts: 122 |
Sometimes you have speedcode that havn't got a fixed size (and the size-changes may not be cyclic), then it is nice to be able to generate labels when generating it in order to access them from another set of speedcode. |
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Oswald
Registered: Apr 2002
Posts: 5094 |
Quote: Sometimes you have speedcode that havn't got a fixed size (and the size-changes may not be cyclic), then it is nice to be able to generate labels when generating it in order to access them from another set of speedcode.
just store the "labels" into a table while generating speedcode A, then read the table while generating speedcode B that is referencing A. I do this all the time, and not much code in native 6510 either. |
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