winsup/cygwin/math/modfl.c

   1 /**
   2  * This file has no copyright assigned and is placed in the Public Domain.
   3  * This file is part of the mingw-w64 runtime package.
   4  * No warranty is given; refer to the file DISCLAIMER.PD within this package.
   5  */
   6 #include <fenv.h>
   7 #include <math.h>
   8 #include <errno.h>
   9
  10 long double
  11 modfl (long double value, long double* iptr)
  12 {
  13   long double int_part = 0.0L;
  14   /* truncate */
  15 #if defined(_AMD64_) || defined(__x86_64__)
  16   asm volatile ("subq $8, %%rsp\n"
  17     "fnstcw 4(%%rsp)\n"
  18     "movzwl 4(%%rsp), %%eax\n"
  19     "orb $12, %%ah\n"
  20     "movw %%ax, (%%rsp)\n"
  21     "fldcw (%%rsp)\n"
  22     "frndint\n"
  23     "fldcw 4(%%rsp)\n"
  24     "addq $8, %%rsp\n" : "=t" (int_part) : "0" (value) : "eax"); /* round */
  25 #elif defined(_X86_) || defined(__i386__)
  26   asm volatile ("push %%eax\n\tsubl $8, %%esp\n"
  27     "fnstcw 4(%%esp)\n"
  28     "movzwl 4(%%esp), %%eax\n"
  29     "orb $12, %%ah\n"
  30     "movw %%ax, (%%esp)\n"
  31     "fldcw (%%esp)\n"
  32     "frndint\n"
  33     "fldcw 4(%%esp)\n"
  34     "addl $8, %%esp\n\tpop %%eax\n" : "=t" (int_part) : "0" (value) : "eax"); /* round */
  35 #else
  36   int_part = truncl(value);
  37 #endif
  38   if (iptr)
  39     *iptr = int_part;
  40   return (isinf (value) ?  0.0L : value - int_part);
  41 }