Hi Bill.

16-Apr-04 20:16:00, Bill Birrell wrote to Jasen Betts


 BB> After I wrote that screed, I dug out the assembler and things and had a 
 BB> look.
 BB> This is what worked like strlen():


 BB>     Obviously it would need a C interface around it to be useful, but I
 BB> just
 BB> wanted to confirm that I hadn't got it completely arse about face

I couldn't get my real mode dos compiler (tc2) and assembler (arrow) to
cooperate (they used to cooperate ok... dunno what went wrong)

here's one as inline assenmmbler (GCC)

int sleng( char *c)
 {
 asm(
   "  movl %0 ,%%edi;          "
   "  xorl %%eax ,%%eax;       "
   "  movl %%eax ,%%ecx;       "
   "  notl %%ecx;              "
   "  cld;                     "
   "  repnz ; scasb;           "
   "  movl $-2,%%eax;          "
   "  subl %%ecx,%%eax;        "
     : /* no outputs - eax becomes the function's return value */
     :"rm"(c)
     :"eax","ecx","edi","cc");
  }

This is my first attempt at gcc style inline asm, I'd welcome any
comments...

hmm, if I had the glibc source I could see how the experts did it.

is the syntax for inline asm described somewhere in the GCC info tree?
(where?)

 -=> Bye <=-

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