1 /* sqrt function. PowerPC32 version.
2 Copyright (C) 2007-2017 Free Software Foundation, Inc.
3 This file is part of the GNU C Library.
5 The GNU C Library is free software; you can redistribute it and/or
6 modify it under the terms of the GNU Lesser General Public
7 License as published by the Free Software Foundation; either
8 version 2.1 of the License, or (at your option) any later version.
10 The GNU C Library is distributed in the hope that it will be useful,
11 but WITHOUT ANY WARRANTY; without even the implied warranty of
12 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
13 Lesser General Public License for more details.
15 You should have received a copy of the GNU Lesser General Public
16 License along with the GNU C Library; if not, see
17 <http://www.gnu.org/licenses/>. */
20 #include <math_ldbl_opt.h>
22 /* double [fp1] sqrt (double x [fp1])
23 Power4 (ISA V2.0) and above implement sqrt in hardware (not optional).
24 The fsqrt instruction generates the correct value for all inputs and
25 sets the appropriate floating point exceptions. Extended checking is
26 only needed to set errno (via __kernel_standard) if the input value
29 So compare the input value against the absolute value of itself.
30 This will compare equal unless the value is negative (EDOM) or a NAN,
31 in which case we branch to the extend wrapper. If equal we can return
34 This part of the function looks like a leaf routine, so no need to
35 stack a frame or execute prologue/epilogue code. It is safe to
36 branch directly to w_sqrt as long as the input value (f1) is
37 preserved. Putting the sqrt result into f2 (float parameter 2)
38 allows passing both the input value and sqrt result into the extended
39 wrapper so there is no need to recompute.
41 This tactic avoids the overhead of stacking a frame for the normal
42 (non-error) case. Until gcc supports prologue shrink-wrapping
43 this is the best we can do. */
58 cfi_adjust_cfa_offset(16)
65 SETUP_GOT_ACCESS(r30,got_label)
66 addis r30,r30,_GLOBAL_OFFSET_TABLE_-got_label@ha
67 addi r30,r30,_GLOBAL_OFFSET_TABLE_-got_label@l
68 lwz r9,_LIB_VERSION@got(30)
71 lis r9,_LIB_VERSION@ha
72 lwz r0,_LIB_VERSION@l(r9)
74 /* if (_LIB_VERSION == _IEEE_) return z; */
77 /* if (x != x) return z; !isnan*/
81 return __kernel_standard (x, x, 26) */
93 bl __kernel_standard@plt
98 weak_alias (__sqrt, sqrt)
100 #ifdef NO_LONG_DOUBLE
101 weak_alias (__sqrt, sqrtl)
102 strong_alias (__sqrt, __sqrtl)
104 #if LONG_DOUBLE_COMPAT(libm, GLIBC_2_0)
105 compat_symbol (libm, __sqrt, sqrtl, GLIBC_2_0)