sysdeps/powerpc/fpu/e_hypotf.c

   1 /* Pythagorean addition using floats
   2    Copyright (C) 2011-2017 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 /* __ieee754_hypotf(x,y)
  25
  26    This a FP only version without any FP->INT conversion.
  27    It is similar to default C version, making appropriates
  28    overflow and underflows checks as using double precision
  29    instead of scaling.  */
  30
  31 #ifdef _ARCH_PWR7
  32 /* POWER7 isinf and isnan optimizations are fast. */
  33 # define TEST_INF_NAN(x, y)                                      \
  34    if ((isinff(x) || isinff(y))                                  \
  35        && !issignaling (x) && !issignaling (y))                  \
  36      return INFINITY;                                            \
  37    if (isnanf(x) || isnanf(y))                                   \
  38      return x + y;
  39 # else
  40 /* For POWER6 and below isinf/isnan triggers LHS and PLT calls are
  41  * costly (especially for POWER6). */
  42 # define GET_TWO_FLOAT_WORD(f1,f2,i1,i2)                         \
  43  do {                                                            \
  44    ieee_float_shape_type gf_u1;                                  \
  45    ieee_float_shape_type gf_u2;                                  \
  46    gf_u1.value = (f1);                                           \
  47    gf_u2.value = (f2);                                           \
  48    (i1) = gf_u1.word & 0x7fffffff;                               \
  49    (i2) = gf_u2.word & 0x7fffffff;                               \
  50  } while (0)
  51
  52 # define TEST_INF_NAN(x, y)                                      \
  53  do {                                                            \
  54    uint32_t hx, hy;                                              \
  55    GET_TWO_FLOAT_WORD(x, y, hx, hy);                             \
  56    if (hy > hx) {                                                \
  57      uint32_t ht = hx; hx = hy; hy = ht;                         \
  58    }                                                             \
  59    if (hx >= 0x7f800000) {                                       \
  60      if ((hx == 0x7f800000 || hy == 0x7f800000)                  \
  61          && !issignaling (x) && !issignaling (y))                \
  62        return INFINITY;                                          \
  63      return x + y;                                               \
  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)