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Re: CGEN: Macro insns
- To: Greg McGary <greg at mcgary dot org>
- Subject: Re: CGEN: Macro insns
- From: Dave Brolley <brolley at redhat dot com>
- Date: Fri, 06 Jul 2001 15:54:19 -0400
- CC: cgen at sources dot redhat dot com
- References: <3B448A47.4000107@redhat.com> <msae2hetwb.fsf@mcgary.org>
Greg McGary wrote:
>
> Months ago, I observed that macro-insns as currently implemented have
> very limited usefulness. The args to `emit' are error-checked, but
> otherwise completely ignored. The only thing you can do with a macro
> insn is omit some operands and have them be filled with zero, or
> change the order of operands in the syntax string.
>
> I order to define short versions collapsed src & dest regs, I needed
> to define a multi-field with an inserter that dup'ed the reg#, and
> an extractor that ignored one sub-field.
Uggggghhh.....I'll keep this in mind should I not find time to fix the
real problem. What is the ALIAS attribute? Does it keep the decode from
complaining about the ambiguity?
Dave