Re: Assembler in Lex/Yacc
- From: "toby" <spamtrap@xxxxxxxxxx>
- Date: 3 Dec 2005 14:01:28 -0800
Sanky wrote:
> Hi there,
>
> I was working on an assembler for X64 architecture. I was wondering
> what are the tradeoffs in designing an assembler using lex or re2c and
> yacc? Why is that handwritten assemblers are more popular than those
> developed using lex/yacc? Developing a grammar is the toughest part,
Not particularly. As others point out, assembler grammars are not too
complex (much less so than an HLL, for instance).
> but once you have a grammar ready, I think the rest of the routines are
> pretty strightforward? Is it that code generated by Lex/Yacc is not as
> efficient?
In terms of lexing/parsing speed, it screams.
> YASM does get close, but again it resorts to hand written code at some
> places.
>
> Is it that Lex/Yacc is an overkill or is that Lex/Yacc are not the
> right tools? I'm new to compiler and assembler design, and would be
> helpful if anyone can guide.
Personally I think they are excellent tools - for systems of low to
moderate complexity. Randy's HLA probably lies well outside the sweet
spot, for reasons he goes into.
Here are two complete assemblers I implemented with lex/yacc (actually
flex and bison):
http://www.telegraphics.com.au/svn/dpa/trunk
Some rationale for choosing lex/yacc:
http://www.telegraphics.com.au/sw/info/dpa.html
One is simple, one is more complex. Error handling was not particularly
difficult (contrary to Randy's remark - but this may be because the
project is much simpler than his).
--T
>
> Thanks!
.
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- Assembler in Lex/Yacc
- From: Sanky
- Assembler in Lex/Yacc
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