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e47308c98d
This patches consolidates all the powerpc nearbyint{f} implementations
on the generic sysdeps/powerpc/fpu/s_nearbyint{f}.
* sysdeps/powerpc/fpu/round_to_integer.h (set_fenv_mode): Add
NEARBYINT handling.
* sysdeps/powerpc/fpu/s_nearbyint.c: New file.
* sysdeps/powerpc/fpu/s_nearbyintf.c: Likewise.
* sysdeps/powerpc/powerpc32/fpu/s_nearbyint.S: Remove file.
* sysdeps/powerpc/powerpc32/fpu/s_nearbyintf.S: Likewise.
* sysdeps/powerpc/powerpc64/fpu/s_nearbyint.S: Likewise.
* sysdeps/powerpc/powerpc64/fpu/s_nearbyintf.S: Likewise.
136 lines
3.2 KiB
C
136 lines
3.2 KiB
C
/* Round to integer generic implementation.
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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 Library General Public License as
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published by the Free Software Foundation; either version 2 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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Library General Public License for more details.
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You should have received a copy of the GNU Library General Public
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License along with the GNU C Library; see the file COPYING.LIB. If
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not, see <http://www.gnu.org/licenses/>. */
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#ifndef _ROUND_TO_INTEGER_H
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#define _ROUND_TO_INTEGER_H
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#include <fenv_private.h>
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enum round_mode
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{
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CEIL,
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FLOOR,
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ROUND,
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TRUNC,
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NEARBYINT
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};
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static inline void
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set_fenv_mode (enum round_mode mode)
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{
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switch (mode)
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{
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case CEIL:
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__fesetround_inline_nocheck (FE_UPWARD);
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break;
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case FLOOR:
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__fesetround_inline_nocheck (FE_DOWNWARD);
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break;
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case TRUNC:
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case ROUND:
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__fesetround_inline_nocheck (FE_TOWARDZERO);
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break;
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case NEARBYINT:
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/* Disable FE_INEXACT exception */
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reset_fpscr_bit (FPSCR_XE);
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break;
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}
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}
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static inline float
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round_to_integer_float (enum round_mode mode, float x)
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{
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/* Ensure sNaN input is converted to qNaN. */
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if (__glibc_unlikely (isnan (x)))
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return x + x;
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if (fabs (x) > 0x1p+23)
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return x;
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float r = x;
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/* Save current FPU rounding mode and inexact state. */
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fenv_t fe = fegetenv_register ();
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set_fenv_mode (mode);
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if (x > 0.0)
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{
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/* IEEE 1003.1 round function. IEEE specifies "round to the nearest
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integer value, rounding halfway cases away from zero, regardless of
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the current rounding mode." However PowerPC Architecture defines
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"Round to Nearest" as "Choose the best approximation. In case of a
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tie, choose the one that is even (least significant bit o).".
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So we can't use the PowerPC "Round to Nearest" mode. Instead we set
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"Round toward Zero" mode and round by adding +-0.5 before rounding
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to the integer value. */
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if (mode == ROUND)
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r += 0.5f;
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r += 0x1p+23;
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r -= 0x1p+23;
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r = fabs (r);
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}
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else if (x < 0.0)
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{
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if (mode == ROUND)
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r -= 0.5f;
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r -= 0x1p+23;
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r += 0x1p+23;
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r = -fabs (r);
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}
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__builtin_mtfsf (0xff, fe);
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return r;
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}
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static inline double
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round_to_integer_double (enum round_mode mode, double x)
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{
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/* Ensure sNaN input is converted to qNaN. */
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if (__glibc_unlikely (isnan (x)))
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return x + x;
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if (fabs (x) > 0x1p+52)
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return x;
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double r = x;
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/* Save current FPU rounding mode and inexact state. */
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fenv_t fe = fegetenv_register ();
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set_fenv_mode (mode);
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if (x > 0.0)
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{
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if (mode == ROUND)
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r += 0.5;
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r += 0x1p+52;
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r -= 0x1p+52;
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r = fabs (r);
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}
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else if (x < 0.0)
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{
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if (mode == ROUND)
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r -= 0.5;
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r -= 0x1p+52;
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r += 0x1p+52;
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r = -fabs (r);
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}
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__builtin_mtfsf (0xff, fe);
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return r;
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}
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#endif
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