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/* Internal libc stuff for floating point environment routines.
Copyright (C) 1997-2016 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
<http://www.gnu.org/licenses/>. */
#ifndef _FENV_LIBC_H
#define _FENV_LIBC_H 1
#include <fenv.h>
#include <ldsodefs.h>
#include <sysdep.h>
extern const fenv_t *__fe_nomask_env_priv (void);
extern const fenv_t *__fe_mask_env (void) attribute_hidden;
/* The sticky bits in the FPSCR indicating exceptions have occurred. */
#define FPSCR_STICKY_BITS ((FE_ALL_EXCEPT | FE_ALL_INVALID) & ~FE_INVALID)
/* Equivalent to fegetenv, but returns a fenv_t instead of taking a
pointer. */
#define fegetenv_register() \
({ fenv_t env; asm volatile ("mffs %0" : "=f" (env)); env; })
/* Equivalent to fesetenv, but takes a fenv_t instead of a pointer. */
#define fesetenv_register(env) \
do { \
double d = (env); \
if(GLRO(dl_hwcap) & PPC_FEATURE_HAS_DFP) \
asm volatile (".machine push; " \
".machine \"power6\"; " \
"mtfsf 0xff,%0,1,0; " \
".machine pop" : : "f" (d)); \
else \
asm volatile ("mtfsf 0xff,%0" : : "f" (d)); \
} while(0)
/* This very handy macro:
- Sets the rounding mode to 'round to nearest';
- Sets the processor into IEEE mode; and
- Prevents exceptions from being raised for inexact results.
These things happen to be exactly what you need for typical elementary
functions. */
#define relax_fenv_state() \
do { \
if (GLRO(dl_hwcap) & PPC_FEATURE_HAS_DFP) \
asm (".machine push; .machine \"power6\"; " \
"mtfsfi 7,0,1; .machine pop"); \
asm ("mtfsfi 7,0"); \
} while(0)
/* Set/clear a particular FPSCR bit (for instance,
reset_fpscr_bit(FPSCR_VE);
prevents INVALID exceptions from being raised). */
#define set_fpscr_bit(x) asm volatile ("mtfsb1 %0" : : "i"(x))
#define reset_fpscr_bit(x) asm volatile ("mtfsb0 %0" : : "i"(x))
typedef union
{
fenv_t fenv;
unsigned long long l;
} fenv_union_t;
static inline int
__fesetround_inline (int round)
{
if ((unsigned int) round < 2)
{
asm volatile ("mtfsb0 30");
if ((unsigned int) round == 0)
asm volatile ("mtfsb0 31");
else
asm volatile ("mtfsb1 31");
}
else
{
asm volatile ("mtfsb1 30");
if ((unsigned int) round == 2)
asm volatile ("mtfsb0 31");
else
asm volatile ("mtfsb1 31");
}
return 0;
}
/* Definitions of all the FPSCR bit numbers */
enum {
FPSCR_FX = 0, /* exception summary */
FPSCR_FEX, /* enabled exception summary */
FPSCR_VX, /* invalid operation summary */
FPSCR_OX, /* overflow */
FPSCR_UX, /* underflow */
FPSCR_ZX, /* zero divide */
FPSCR_XX, /* inexact */
FPSCR_VXSNAN, /* invalid operation for sNaN */
FPSCR_VXISI, /* invalid operation for Inf-Inf */
FPSCR_VXIDI, /* invalid operation for Inf/Inf */
FPSCR_VXZDZ, /* invalid operation for 0/0 */
FPSCR_VXIMZ, /* invalid operation for Inf*0 */
FPSCR_VXVC, /* invalid operation for invalid compare */
FPSCR_FR, /* fraction rounded [fraction was incremented by round] */
FPSCR_FI, /* fraction inexact */
FPSCR_FPRF_C, /* result class descriptor */
FPSCR_FPRF_FL, /* result less than (usually, less than 0) */
FPSCR_FPRF_FG, /* result greater than */
FPSCR_FPRF_FE, /* result equal to */
FPSCR_FPRF_FU, /* result unordered */
FPSCR_20, /* reserved */
FPSCR_VXSOFT, /* invalid operation set by software */
FPSCR_VXSQRT, /* invalid operation for square root */
FPSCR_VXCVI, /* invalid operation for invalid integer convert */
FPSCR_VE, /* invalid operation exception enable */
FPSCR_OE, /* overflow exception enable */
FPSCR_UE, /* underflow exception enable */
FPSCR_ZE, /* zero divide exception enable */
FPSCR_XE, /* inexact exception enable */
#ifdef _ARCH_PWR6
FPSCR_29, /* Reserved in ISA 2.05 */
#else
FPSCR_NI /* non-IEEE mode (typically, no denormalised numbers) */
#endif /* _ARCH_PWR6 */
/* the remaining two least-significant bits keep the rounding mode */
};
static inline int
fenv_reg_to_exceptions (unsigned long long l)
{
int result = 0;
if (l & (1 << (31 - FPSCR_XE)))
result |= FE_INEXACT;
if (l & (1 << (31 - FPSCR_ZE)))
result |= FE_DIVBYZERO;
if (l & (1 << (31 - FPSCR_UE)))
result |= FE_UNDERFLOW;
if (l & (1 << (31 - FPSCR_OE)))
result |= FE_OVERFLOW;
if (l & (1 << (31 - FPSCR_VE)))
result |= FE_INVALID;
return result;
}
#ifdef _ARCH_PWR6
/* Not supported in ISA 2.05. Provided for source compat only. */
# define FPSCR_NI 29
#endif /* _ARCH_PWR6 */
/* This operation (i) sets the appropriate FPSCR bits for its
parameter, (ii) converts sNaN to the corresponding qNaN, and (iii)
otherwise passes its parameter through unchanged (in particular, -0
and +0 stay as they were). The `obvious' way to do this is optimised
out by gcc. */
#define f_wash(x) \
({ double d; asm volatile ("fmul %0,%1,%2" \
: "=f"(d) \
: "f" (x), "f"((float)1.0)); d; })
#define f_washf(x) \
({ float f; asm volatile ("fmuls %0,%1,%2" \
: "=f"(f) \
: "f" (x), "f"((float)1.0)); f; })
#endif /* fenv_libc.h */
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