This is really strange that such option does not exist. VLE instruction set does not use r8-r24 for many 16bit instructions. How do people use inline assembly with these? Or does compiler recognize these limitations for "known" instructions by itself? Alex. -----Original Message----- From: Ian Lance Taylor [mailto:iant@xxxxxxxxxx] Sent: Friday, February 08, 2013 3:19 PM To: Grobman Alexander-R53196 Cc: gcc-help@xxxxxxxxxxx Subject: Re: builtin assembler constraints On Fri, Feb 8, 2013 at 10:15 AM, Grobman Alexander-R53196 <R53196@xxxxxxxxxxxxx> wrote: > > I'm trying to incorporate new PPC instructions into a C code. These > instructions use limited set of GPRs as operands i.e. only even > registers can be used as a source, > > Is there way to specify that in the asm() statement? As far as I know there is no constraint that describes only the even registers of the general register set. It would not be very difficult to add one to the PPC backend. I can't think of any other way to approach this. Ian
