ARM assembly syntax (was Re: [patch 03/36] Hexagon: Add bitopssupport)

From: Linas Vepstas (Code Aurora)
Date: Tue Aug 30 2011 - 17:14:59 EST


On Fri, Aug 26, 2011 at 10:34:10PM +0200, Pavel Machek wrote:
> Hi!
>
> > + __asm__ __volatile__ (
> > + " {R10 = %1; R11 = asr(%2,#5); }\n"
> > + " {R10 += asl(R11,#2); R11 = and(%2,#0x1f)}\n"
> > + "1: R12 = memw_locked(R10);\n"
> > + " { P0 = tstbit(R12,R11); R12 = clrbit(R12,R11); }\n"
> > + " memw_locked(R10,P1) = R12;\n"
> > + " {if !P1 jump 1b; %0 = mux(P0,#1,#0);}\n"
>
> Nice assembly syntax, btw. I can only wish architectures such as arm
> used something as readable...

Yes, I, too, was very pleasantly surprised when I first saw this.

Of course, one *could* alter binutils to accept something similar
for ARM, and then alter gcc to spit it out. Whether anyone would use
this isn't clear .. and I can already almost hear certain maintainers
telling us how much of a bad idea this is from the maintainership
point-of-view ....

--linas

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