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From: cepurneekc@sturt.sacae.edu.au
Newsgroups: comp.sys.acorn
Subject: <None>
Message-ID: <1991Mar6.160100.2197@sturt.sacae.edu.au>
Date: 6 Mar 91 05:30:59 GMT
References: <1991Feb20.085225.11667@cl.cam.ac.uk> <5309@acorn.co.uk> <1779@svin02.info.win.tue.nl> <1991Feb26.110018.12714@abekrd.co.uk> <1991Mar1.113456.3297@ifi.uio.no>
Organization: Flinders University of South Australia - Sturt
Lines: 38

In article <1991Mar1.113456.3297@ifi.uio.no>, oystein@ifi.uio.no writes:

> In article <1991Feb26.110018.12714@abekrd.co.uk>, garyb@abekrd.co.uk writes:   

>> source, pre-processes it and emits it to the BASIC assembler for assembly.
>> Since every Archimedes comes with the ability to assemble in BASIC this
>> would result in a very small assembler....

> Sounds a bit far fetched to me, perhaps. Remember also, that quite a few
> of us need output in AOF, and the BASIC assembler can only produce absolute
> code.

??? sorry, don't know what AOF stands for, but I'm quite certain that the
BASIC assembler can produce non-absolute (relocatable) code. I too was
wondering why BASIC's assembler was not getting much mention. Back in the 
6502 days I was amazed what a hassle it was to get something done using
an Apple (editor, linker etc.) vs the BBC's [LDA ASC("a")/JSR &FFEE/RTS].
Even the Acorn BASIC manual seems to keep its ease of use a bit of a secret;
the entries for CALL and USR don't say much (for beginners :-)).

What would it take to write assembly source routines in a format that made
then reasonably usable by others? Maybe a DEFFNfoo indicating 'required'
registers -- ie R0 for SWI Write_Char, 'needed' registers -- ie. how many
are used by the procedure, and entry and exit states? If I want to use the
routine it would be my responsibility to:

STM stack,{list} ;store anything I'm using at the moment
dummy=FNfoo      ;which assembles the code for the routine
                 ;a parameter list could assign 'needed' reginters?
LDM stack,{list} ;restore the things I need.

The assembly code equivalent of PRINT "a" is presumably a bit simpler than
what most are writing, but I'd find DEFFN_256bitmultiply(x,y,p) a
useful bit of code. (where x,y & p are pointers to the data).

Are there many other BASIC/assembler fans out there?

Carl Cepurneek