sysdeps/powerpc/fpu/e_hypotf.c

   1 /* Pythagorean addition using floats
   2    Copyright (C) 2011-2014 Free Software Foundation, Inc.
   3    This file is part of the GNU C Library.
   4    Contributed by Adhemerval Zanella <azanella@br.ibm.com>, 2011
   5
   6    The GNU C Library is free software; you can redistribute it and/or
   7    modify it under the terms of the GNU Library General Public License as
   8    published by the Free Software Foundation; either version 2 of the
   9    License, or (at your option) any later version.
  10
  11    The GNU C Library is distributed in the hope that it will be useful,
  12    but WITHOUT ANY WARRANTY; without even the implied warranty of
  13    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  14    Library General Public License for more details.
  15
  16    You should have received a copy of the GNU Library General Public
  17    License along with the GNU C Library; see the file COPYING.LIB.  If
  18    not, see <http://www.gnu.org/licenses/>.  */
  19
  20 #include <math.h>
  21 #include <math_private.h>
  22 #include <stdint.h>
  23
  24 static const float two30  = 1.0737418e09;
  25
  26 /* __ieee754_hypotf(x,y)
  27
  28    This a FP only version without any FP->INT conversion.
  29    It is similar to default C version, making appropriates
  30    overflow and underflows checks as using double precision
  31    instead of scaling.  */
  32
  33 #ifdef _ARCH_PWR7
  34 /* POWER7 isinf and isnan optimizations are fast. */
  35 # define TEST_INF_NAN(x, y)                                      \
  36    if (isinff(x) || isinff(y))                                   \
  37      return INFINITY;                                            \
  38    if (isnanf(x) || isnanf(y))                                   \
  39      return NAN;
  40 # else
  41 /* For POWER6 and below isinf/isnan triggers LHS and PLT calls are
  42  * costly (especially for POWER6). */
  43 # define GET_TWO_FLOAT_WORD(f1,f2,i1,i2)                         \
  44  do {                                                            \
  45    ieee_float_shape_type gf_u1;                                  \
  46    ieee_float_shape_type gf_u2;                                  \
  47    gf_u1.value = (f1);                                           \
  48    gf_u2.value = (f2);                                           \
  49    (i1) = gf_u1.word & 0x7fffffff;                               \
  50    (i2) = gf_u2.word & 0x7fffffff;                               \
  51  } while (0)
  52
  53 # define TEST_INF_NAN(x, y)                                      \
  54  do {                                                            \
  55    uint32_t hx, hy;                                              \
  56    GET_TWO_FLOAT_WORD(x, y, hx, hy);                             \
  57    if (hy > hx) {                                                \
  58      uint32_t ht = hx; hx = hy; hy = ht;                         \
  59    }                                                             \
  60    if (hx >= 0x7f800000) {                                       \
  61      if (hx == 0x7f800000 || hy == 0x7f800000)                   \
  62        return INFINITY;                                          \
  63      return NAN;                                                 \
  64    }                                                             \
  65  } while (0)
  66 #endif
  67
  68
  69 float
  70 __ieee754_hypotf (float x, float y)
  71 {
  72   TEST_INF_NAN (x, y);
  73
  74   return __ieee754_sqrt ((double) x * x + (double) y * y);
  75 }
  76 strong_alias (__ieee754_hypotf, __hypotf_finite)