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author | Stefan Liebler <stli@linux.ibm.com> | 2019-12-11 15:09:29 +0100 |
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committer | Stefan Liebler <stli@linux.ibm.com> | 2019-12-11 15:12:22 +0100 |
commit | e3f07622209c1b4436ef364b134dfd2cd4ca9976 (patch) | |
tree | 363f2be23fae1b1a138f7541bb2c027018bb8b1c /sysdeps/s390/fpu/s_lrintf.c | |
parent | 4399b163376b331773e43917dcf56ce68e43e6a0 (diff) | |
download | glibc-e3f07622209c1b4436ef364b134dfd2cd4ca9976.tar.gz glibc-e3f07622209c1b4436ef364b134dfd2cd4ca9976.tar.xz glibc-e3f07622209c1b4436ef364b134dfd2cd4ca9976.zip |
S390: Use convert-to-fixed instruction for lrint functions.
If compiled with z196 zarch support, the convert-to-fixed instruction is used to implement lrint, lrintf, lrintl. Otherwise the common-code implementation is used.
Diffstat (limited to 'sysdeps/s390/fpu/s_lrintf.c')
-rw-r--r-- | sysdeps/s390/fpu/s_lrintf.c | 55 |
1 files changed, 55 insertions, 0 deletions
diff --git a/sysdeps/s390/fpu/s_lrintf.c b/sysdeps/s390/fpu/s_lrintf.c new file mode 100644 index 0000000000..d6a2a4081a --- /dev/null +++ b/sysdeps/s390/fpu/s_lrintf.c @@ -0,0 +1,55 @@ +/* lrintf() - S390 version. + Copyright (C) 2019 Free Software Foundation, Inc. + + This file is part of the GNU C Library. + + The GNU C Library is free software; you can redistribute it and/or + modify it under the terms of the GNU Lesser General Public License as + published by the Free Software Foundation; either version 2.1 of the + License, or (at your option) any later version. + + The GNU C Library is distributed in the hope that it will be useful, + but WITHOUT ANY WARRANTY; without even the implied warranty of + MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU + Lesser General Public License for more details. + + You should have received a copy of the GNU Lesser General Public + License along with the GNU C Library; if not, see + <https://www.gnu.org/licenses/>. */ + +#ifdef HAVE_S390_MIN_Z196_ZARCH_ASM_SUPPORT +# include <math.h> +# include <libm-alias-float.h> + +/* The sizeof (long int) differs between s390x (8byte) and s390 (4byte). + Thus we need different instructions as the target size is encoded there. + Note: On s390 this instruction is only used if build with -mzarch. */ +# ifdef __s390x__ +# define INSN "cgebra" +# else +# define INSN "cfebra" +# endif + +long int +__lrintf (float x) +{ + long int y; + /* The z196 zarch "convert to fixed" (cgebra) instruction is rounding + according to current rounding mode (M3-field: 0). + First convert x with suppressed inexact exception and check if the + resulting value is beyond the target limits (indicated by cc=3; + Note: a nan is also indicated by cc=3). + If the resulting value is within the target limits, redo + without suppressing the inexact exception. */ + __asm__ (INSN " %0,0,%1,4 \n\t" + "jo 1f \n\t" + INSN " %0,0,%1,0 \n\t" + "1:" + : "=&d" (y) : "f" (x) : "cc"); + return y; +} +libm_alias_float (__lrint, lrint) + +#else +# include <sysdeps/ieee754/flt-32/s_lrintf.c> +#endif |