glibc/sysdeps/s390/fpu/s_llrintl.c

52 lines
1.9 KiB
C

/* llrintl() - S390 version.
Copyright (C) 2019-2020 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/>. */
#if defined __s390x__ && defined HAVE_S390_MIN_Z196_ZARCH_ASM_SUPPORT
/* We only support s390x as on s390 a long long int refers to a register pair
of two 4byte registers instead of a 8byte register which is produced by the
instruction.
Note: On s390 this instruction would only be used if build with -mzarch. */
# include <math.h>
# include <math_private.h>
# include <libm-alias-ldouble.h>
long long int
__llrintl (_Float128 x)
{
long long int y;
/* The z196 zarch "convert to fixed" (cgxbra) 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__ ("cgxbra %0,0,%1,4 \n\t"
"jo 1f \n\t"
"cgxbra %0,0,%1,0 \n\t"
"1:"
: "=&d" (y) : "f" (x) : "cc");
return y;
}
libm_alias_ldouble (__llrint, llrint)
#else
# include <sysdeps/ieee754/ldbl-128/s_llrintl.c>
#endif