libc/sysdeps/linux/powerpc/copysignl.c

   1 /* s_copysignl.c -- long double version of s_copysign.c.
   2  * Conversion to long double by Ulrich Drepper,
   3  * Cygnus Support, drepper@cygnus.com.
   4  */
   5
   6 /*
   7  * ====================================================
   8  * Copyright (C) 1993 by Sun Microsystems, Inc. All rights reserved.
   9  *
  10  * Developed at SunPro, a Sun Microsystems, Inc. business.
  11  * Permission to use, copy, modify, and distribute this
  12  * software is freely granted, provided that this notice
  13  * is preserved.
  14  * ====================================================
  15  */
  16
  17 /*
  18  * copysignl(long double x, long double y)
  19  * copysignl(x,y) returns a value with the magnitude of x and
  20  * with the sign bit of y.
  21  */
  22
  23 #include <endian.h>
  24 #include <stdint.h>
  25
  26 #if __FLOAT_WORD_ORDER == BIG_ENDIAN
  27
  28 typedef union
  29 {
  30   long double value;
  31   struct
  32   {
  33     int sign_exponent:16;
  34     unsigned int empty:16;
  35     uint32_t msw;
  36     uint32_t lsw;
  37   } parts;
  38 } ieee_long_double_shape_type;
  39
  40 #endif
  41
  42 #if __FLOAT_WORD_ORDER == LITTLE_ENDIAN
  43
  44 typedef union
  45 {
  46   long double value;
  47   struct
  48   {
  49     uint32_t lsw;
  50     uint32_t msw;
  51     int sign_exponent:16;
  52     unsigned int empty:16;
  53   } parts;
  54 } ieee_long_double_shape_type;
  55
  56 #endif
  57
  58 /* Get int from the exponent of a long double.  */
  59
  60 #define GET_LDOUBLE_EXP(exp,d)                                  \
  61 do {                                                            \
  62   ieee_long_double_shape_type ge_u;                             \
  63   ge_u.value = (d);                                             \
  64   (exp) = ge_u.parts.sign_exponent;                             \
  65 } while (0)
  66
  67 /* Set exponent of a long double from an int.  */
  68
  69 #define SET_LDOUBLE_EXP(d,exp)                                  \
  70 do {                                                            \
  71   ieee_long_double_shape_type se_u;                             \
  72   se_u.value = (d);                                             \
  73   se_u.parts.sign_exponent = (exp);                             \
  74   (d) = se_u.value;                                             \
  75 } while (0)
  76
  77 long double copysignl(long double x, long double y);
  78 libc_hidden_proto(copysignl);
  79
  80 long double copysignl(long double x, long double y)
  81 {
  82         uint32_t es1,es2;
  83         GET_LDOUBLE_EXP(es1,x);
  84         GET_LDOUBLE_EXP(es2,y);
  85         SET_LDOUBLE_EXP(x,(es1&0x7fff)|(es2&0x8000));
  86         return x;
  87 }
  88
  89 libc_hidden_def(copysignl);