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glibc/soft-fp/single.h
Joseph Myers 2004e7fb76 soft-fp: Add _FP_TO_INT_ROUND. 
Continuing the series of patches adding soft-fp features from the
kernel version of soft-fp to glibc so that glibc's version is able to
replace the old fork of soft-fp in the kernel, this patch adds the
last major such feature: _FP_TO_INT_ROUND, converting a floating-point
number to an integer with rounding according to the current rounding
direction (as opposed to truncating towards zero, which _FP_TO_INT
does).

The general structure of the implementation follows that of
_FP_TO_INT, but of course is more complicated.  As with glibc's
_FP_TO_INT it works with raw input (the kernel versions of these
macros predate the conversion of _FP_TO_INT and many other macros to
raw or semi-raw input).  I have not tried to work out what bugs there
might be in the kernel version that this might fix; it's a
from-scratch implementation based on _FP_TO_INT.

Tested for powerpc (soft-float) that there is no change to the
installed shared libraries; also tested with the libm tests with lrint
/ lrintf / llrint / llrintf made to use _FP_TO_INT_ROUND, to provide
some test of the functionality.  As we don't have benchmarks for those
functions, I haven't actually included the soft-fp versions of them,
although I expect them to be faster than the existing code (given that
the existing code involves adding and subtracting numbers such as
0x1p52 to achieve the desired rounding, which is not particularly
efficient when the underlying floating point is software floating
point).

2014-11-04  Joseph Myers  <joseph@codesourcery.com>

	* soft-fp/op-common.h (_FP_TO_INT_ROUND): New macro.
	* soft-fp/double.h [_FP_W_TYPE_SIZE < 64] (FP_TO_INT_ROUND_D): New
	macro.
	[_FP_W_TYPE_SIZE >= 64] (FP_TO_INT_ROUND_D): Likewise.
	* soft-fp/extended.h [_FP_W_TYPE_SIZE < 64] (FP_TO_INT_ROUND_E):
	New macro.
	[_FP_W_TYPE_SIZE >= 64] (FP_TO_INT_ROUND_E): Likewise.
	* soft-fp/quad.h [_FP_W_TYPE_SIZE < 64] (FP_TO_INT_ROUND_Q): New
	macro.
	[_FP_W_TYPE_SIZE >= 64] (FP_TO_INT_ROUND_Q): Likewise.
	* soft-fp/single.h (FP_TO_INT_ROUND_S): New macro.
2014-11-04 16:34:49 +00:00

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/* Software floating-point emulation.
Definitions for IEEE Single Precision.
Copyright (C) 1997-2014 Free Software Foundation, Inc.
This file is part of the GNU C Library.
Contributed by Richard Henderson (rth@cygnus.com),
Jakub Jelinek (jj@ultra.linux.cz),
David S. Miller (davem@redhat.com) and
Peter Maydell (pmaydell@chiark.greenend.org.uk).
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.
In addition to the permissions in the GNU Lesser General Public
License, the Free Software Foundation gives you unlimited
permission to link the compiled version of this file into
combinations with other programs, and to distribute those
combinations without any restriction coming from the use of this
file. (The Lesser General Public License restrictions do apply in
other respects; for example, they cover modification of the file,
and distribution when not linked into a combine executable.)
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
<http://www.gnu.org/licenses/>. */
#if _FP_W_TYPE_SIZE < 32
# error "Here's a nickel kid. Go buy yourself a real computer."
#endif
#define _FP_FRACTBITS_S _FP_W_TYPE_SIZE
#if _FP_W_TYPE_SIZE < 64
# define _FP_FRACTBITS_DW_S (2 * _FP_W_TYPE_SIZE)
#else
# define _FP_FRACTBITS_DW_S _FP_W_TYPE_SIZE
#endif
#define _FP_FRACBITS_S 24
#define _FP_FRACXBITS_S (_FP_FRACTBITS_S - _FP_FRACBITS_S)
#define _FP_WFRACBITS_S (_FP_WORKBITS + _FP_FRACBITS_S)
#define _FP_WFRACXBITS_S (_FP_FRACTBITS_S - _FP_WFRACBITS_S)
#define _FP_EXPBITS_S 8
#define _FP_EXPBIAS_S 127
#define _FP_EXPMAX_S 255
#define _FP_QNANBIT_S ((_FP_W_TYPE) 1 << (_FP_FRACBITS_S-2))
#define _FP_QNANBIT_SH_S ((_FP_W_TYPE) 1 << (_FP_FRACBITS_S-2+_FP_WORKBITS))
#define _FP_IMPLBIT_S ((_FP_W_TYPE) 1 << (_FP_FRACBITS_S-1))
#define _FP_IMPLBIT_SH_S ((_FP_W_TYPE) 1 << (_FP_FRACBITS_S-1+_FP_WORKBITS))
#define _FP_OVERFLOW_S ((_FP_W_TYPE) 1 << (_FP_WFRACBITS_S))
#define _FP_WFRACBITS_DW_S (2 * _FP_WFRACBITS_S)
#define _FP_WFRACXBITS_DW_S (_FP_FRACTBITS_DW_S - _FP_WFRACBITS_DW_S)
#define _FP_HIGHBIT_DW_S \
((_FP_W_TYPE) 1 << (_FP_WFRACBITS_DW_S - 1) % _FP_W_TYPE_SIZE)
/* The implementation of _FP_MUL_MEAT_S and _FP_DIV_MEAT_S should be
chosen by the target machine. */
typedef float SFtype __attribute__ ((mode (SF)));
union _FP_UNION_S
{
SFtype flt;
struct _FP_STRUCT_LAYOUT
{
#if __BYTE_ORDER == __BIG_ENDIAN
unsigned sign : 1;
unsigned exp : _FP_EXPBITS_S;
unsigned frac : _FP_FRACBITS_S - (_FP_IMPLBIT_S != 0);
#else
unsigned frac : _FP_FRACBITS_S - (_FP_IMPLBIT_S != 0);
unsigned exp : _FP_EXPBITS_S;
unsigned sign : 1;
#endif
} bits __attribute__ ((packed));
};
#define FP_DECL_S(X) _FP_DECL (1, X)
#define FP_UNPACK_RAW_S(X, val) _FP_UNPACK_RAW_1 (S, X, (val))
#define FP_UNPACK_RAW_SP(X, val) _FP_UNPACK_RAW_1_P (S, X, (val))
#define FP_PACK_RAW_S(val, X) _FP_PACK_RAW_1 (S, (val), X)
#define FP_PACK_RAW_SP(val, X) \
do \
{ \
if (!FP_INHIBIT_RESULTS) \
_FP_PACK_RAW_1_P (S, (val), X); \
} \
while (0)
#define FP_UNPACK_S(X, val) \
do \
{ \
_FP_UNPACK_RAW_1 (S, X, (val)); \
_FP_UNPACK_CANONICAL (S, 1, X); \
} \
while (0)
#define FP_UNPACK_SP(X, val) \
do \
{ \
_FP_UNPACK_RAW_1_P (S, X, (val)); \
_FP_UNPACK_CANONICAL (S, 1, X); \
} \
while (0)
#define FP_UNPACK_SEMIRAW_S(X, val) \
do \
{ \
_FP_UNPACK_RAW_1 (S, X, (val)); \
_FP_UNPACK_SEMIRAW (S, 1, X); \
} \
while (0)
#define FP_UNPACK_SEMIRAW_SP(X, val) \
do \
{ \
_FP_UNPACK_RAW_1_P (S, X, (val)); \
_FP_UNPACK_SEMIRAW (S, 1, X); \
} \
while (0)
#define FP_PACK_S(val, X) \
do \
{ \
_FP_PACK_CANONICAL (S, 1, X); \
_FP_PACK_RAW_1 (S, (val), X); \
} \
while (0)
#define FP_PACK_SP(val, X) \
do \
{ \
_FP_PACK_CANONICAL (S, 1, X); \
if (!FP_INHIBIT_RESULTS) \
_FP_PACK_RAW_1_P (S, (val), X); \
} \
while (0)
#define FP_PACK_SEMIRAW_S(val, X) \
do \
{ \
_FP_PACK_SEMIRAW (S, 1, X); \
_FP_PACK_RAW_1 (S, (val), X); \
} \
while (0)
#define FP_PACK_SEMIRAW_SP(val, X) \
do \
{ \
_FP_PACK_SEMIRAW (S, 1, X); \
if (!FP_INHIBIT_RESULTS) \
_FP_PACK_RAW_1_P (S, (val), X); \
} \
while (0)
#define FP_ISSIGNAN_S(X) _FP_ISSIGNAN (S, 1, X)
#define FP_NEG_S(R, X) _FP_NEG (S, 1, R, X)
#define FP_ADD_S(R, X, Y) _FP_ADD (S, 1, R, X, Y)
#define FP_SUB_S(R, X, Y) _FP_SUB (S, 1, R, X, Y)
#define FP_MUL_S(R, X, Y) _FP_MUL (S, 1, R, X, Y)
#define FP_DIV_S(R, X, Y) _FP_DIV (S, 1, R, X, Y)
#define FP_SQRT_S(R, X) _FP_SQRT (S, 1, R, X)
#define _FP_SQRT_MEAT_S(R, S, T, X, Q) _FP_SQRT_MEAT_1 (R, S, T, X, (Q))
#if _FP_W_TYPE_SIZE < 64
# define FP_FMA_S(R, X, Y, Z) _FP_FMA (S, 1, 2, R, X, Y, Z)
#else
# define FP_FMA_S(R, X, Y, Z) _FP_FMA (S, 1, 1, R, X, Y, Z)
#endif
#define FP_CMP_S(r, X, Y, un, ex) _FP_CMP (S, 1, (r), X, Y, (un), (ex))
#define FP_CMP_EQ_S(r, X, Y, ex) _FP_CMP_EQ (S, 1, (r), X, Y, (ex))
#define FP_CMP_UNORD_S(r, X, Y, ex) _FP_CMP_UNORD (S, 1, (r), X, Y, (ex))
#define FP_TO_INT_S(r, X, rsz, rsg) _FP_TO_INT (S, 1, (r), X, (rsz), (rsg))
#define FP_TO_INT_ROUND_S(r, X, rsz, rsg) \
_FP_TO_INT_ROUND (S, 1, (r), X, (rsz), (rsg))
#define FP_FROM_INT_S(X, r, rs, rt) _FP_FROM_INT (S, 1, X, (r), (rs), rt)
#define _FP_FRAC_HIGH_S(X) _FP_FRAC_HIGH_1 (X)
#define _FP_FRAC_HIGH_RAW_S(X) _FP_FRAC_HIGH_1 (X)
#if _FP_W_TYPE_SIZE < 64
# define _FP_FRAC_HIGH_DW_S(X) _FP_FRAC_HIGH_2 (X)
#else
# define _FP_FRAC_HIGH_DW_S(X) _FP_FRAC_HIGH_1 (X)
#endif
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