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If compiled with z196 zarch support, the convert-to-fixed instruction is used to implement llround, llroundf, llroundl. Otherwise the common-code implementation is used.
43 lines
1.6 KiB
C
43 lines
1.6 KiB
C
/* llround() - S390 version.
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Copyright (C) 2019 Free Software Foundation, Inc.
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This file is part of the GNU C Library.
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The GNU C Library is free software; you can redistribute it and/or
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modify it under the terms of the GNU Lesser General Public License as
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published by the Free Software Foundation; either version 2.1 of the
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License, or (at your option) any later version.
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The GNU C Library is distributed in the hope that it will be useful,
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but WITHOUT ANY WARRANTY; without even the implied warranty of
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MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
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Lesser General Public License for more details.
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You should have received a copy of the GNU Lesser General Public
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License along with the GNU C Library; if not, see
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<https://www.gnu.org/licenses/>. */
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#if defined __s390x__ && defined HAVE_S390_MIN_Z196_ZARCH_ASM_SUPPORT
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/* We only support s390x as on s390 a long long int refers to a register pair
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of two 4byte registers instead of a 8byte register which is produced by the
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instruction.
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Note: On s390 this instruction would only be used if build with -mzarch. */
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# include <math.h>
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# include <libm-alias-double.h>
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long long int
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__llround (double x)
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{
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long long int y;
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/* The z196 zarch "convert to fixed" (cgdbra) instruction is rounding
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x to the nearest integer with "ties away from 0" rounding mode
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(M3-field: 1) where inexact exceptions are suppressed (M4-field: 4). */
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__asm__ ("cgdbra %0,1,%1,4" : "=d" (y) : "f" (x) : "cc");
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return y;
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}
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libm_alias_double (__llround, llround)
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#else
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# include <sysdeps/ieee754/dbl-64/s_llround.c>
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#endif
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