On Fri, Feb 8, 2013 at 1:26 PM, Grobman Alexander-R53196 <R53196@xxxxxxxxxxxxx> wrote: > 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? (Plesae don't top-post. Thanks.) I don't know the PPC instruction set all that well. I don't know how the VLE instructions work; I don't even know what they are. I can tell you that GCC never recognizes instructions in an asm strings. The valid set of registers for any argument are always expressed through constraints. Ian > -----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 > >
