Re: mips64 inline question

[d p chang <weasel at meer dot net>]

Richard Henderson <rth@redhat.com> writes:

> On Wed, Jan 23, 2002 at 03:46:27PM -0800, d p chang wrote:
> > The code in question is in delay.h as:
> >
> > extern __inline__ void __udelay(unsigned long usecs, unsigned long lpj)
> > {
> > 	unsigned long lo;
> >
> > 	usecs *= 0x00068db8bac710cbUL;		/* 2**64 / (1000000 / HZ) */
> > 	__asm__ ("dmultu\t%2,%3"
> >                  :"=h" (usecs), "=l" (lo)
> >                  :"r" (usecs),"r" (lpj));
> > 	__delay(hi);
> > }
>
> This should work.  You should provide a complete compilable
> example that shows the problem.

ok, first I configured my cross compiler like this (just in case this
is the root of my prolblems):

        ../../../gcc/configure
        --target=mips64-linux --host=i686-linux --build=i686-linux
        --prefix=/home/dpc/src/cross-mips
        --with-as=/home/dpc/src/cross-mips/bin/mips64-linux-as
        --with-ld=/home/dpc/src/cross-mips/bin/mips64-linux-ld
        --enable-languages=c,c++ --disable-multilib --disable-nls
        --disable-shared --enable-newlib

The simple test I used was this:

static __inline__ void __udelay(unsigned long usecs, unsigned long lpj)
{
        unsigned long lo;

#if 0 
// doesn't work
 	__asm__ ("dmultu\t%2,%3"
                  :"=h" (usecs), "=l" (lo)
                  :"r" (usecs),"r" (lpj));
#else
// seems to generate the code i expect
        {
        unsigned long hi;
        __asm__ ("dmultu\t%2,%3 ; mfhi %0 ; mflo %1"
                 : "=r" (hi), "=r" (lo)
                 : "r" (usecs),"r" (lpj)
                 : "hi", "lo");
        }
#endif
}

int
main(int argc, char** argv)
{
  __udelay(1313, 0x1313);
  return 0;
}