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Diffstat (limited to 'sysdeps/alpha/fpu/bits/fenv.h')
| -rw-r--r-- | sysdeps/alpha/fpu/bits/fenv.h | 133 |
1 files changed, 133 insertions, 0 deletions
diff --git a/sysdeps/alpha/fpu/bits/fenv.h b/sysdeps/alpha/fpu/bits/fenv.h new file mode 100644 index 0000000000..4dba9b59a0 --- /dev/null +++ b/sysdeps/alpha/fpu/bits/fenv.h @@ -0,0 +1,133 @@ +/* Copyright (C) 1997-2014 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_H +# error "Never use <bits/fenv.h> directly; include <fenv.h> instead." +#endif + + +/* Define the bits representing the exception. + + Note that these are the bit positions as defined by the OSF/1 + ieee_{get,set}_control_word interface and not by the hardware fpcr. + + See the Alpha Architecture Handbook section 4.7.7.3 for details, + but in summary, trap shadows mean the hardware register can acquire + extra exception bits so for proper IEEE support the tracking has to + be done in software -- in this case with kernel support. + + As to why the system call interface isn't in the same format as + the hardware register, only those crazy folks at DEC can tell you. */ + +enum + { +#ifdef __USE_GNU + FE_DENORMAL = +#define FE_DENORMAL (1 << 22) + FE_DENORMAL, +#endif + + FE_INEXACT = +#define FE_INEXACT (1 << 21) + FE_INEXACT, + + FE_UNDERFLOW = +#define FE_UNDERFLOW (1 << 20) + FE_UNDERFLOW, + + FE_OVERFLOW = +#define FE_OVERFLOW (1 << 19) + FE_OVERFLOW, + + FE_DIVBYZERO = +#define FE_DIVBYZERO (1 << 18) + FE_DIVBYZERO, + + FE_INVALID = +#define FE_INVALID (1 << 17) + FE_INVALID, + + FE_ALL_EXCEPT = +#define FE_ALL_EXCEPT (0x3f << 17) + FE_ALL_EXCEPT + }; + +/* Alpha chips support all four defined rouding modes. + + Note that code must be compiled to use dynamic rounding (/d) instructions + to see these changes. For gcc this is -mfp-rounding-mode=d; for DEC cc + this is -fprm d. The default for both is static rounding to nearest. + + These are shifted down 58 bits from the hardware fpcr because the + functions are declared to take integers. */ + +enum + { + FE_TOWARDZERO = +#define FE_TOWARDZERO 0 + FE_TOWARDZERO, + + FE_DOWNWARD = +#define FE_DOWNWARD 1 + FE_DOWNWARD, + + FE_TONEAREST = +#define FE_TONEAREST 2 + FE_TONEAREST, + + FE_UPWARD = +#define FE_UPWARD 3 + FE_UPWARD, + }; + +#ifdef __USE_GNU +/* On later hardware, and later kernels for earlier hardware, we can forcibly + underflow denormal inputs and outputs. This can speed up certain programs + significantly, usually without affecting accuracy. */ +enum + { + FE_MAP_DMZ = 1UL << 12, /* Map denorm inputs to zero */ +#define FE_MAP_DMZ FE_MAP_DMZ + + FE_MAP_UMZ = 1UL << 13, /* Map underflowed outputs to zero */ +#define FE_MAP_UMZ FE_MAP_UMZ + }; +#endif + +/* Type representing exception flags. */ +typedef unsigned long int fexcept_t; + +/* Type representing floating-point environment. */ +typedef unsigned long int fenv_t; + +/* If the default argument is used we use this value. Note that due to + architecture-specified page mappings, no user-space pointer will ever + have its two high bits set. Co-opt one. */ +#define FE_DFL_ENV ((const fenv_t *) 0x8800000000000000UL) + +#ifdef __USE_GNU +/* Floating-point environment where none of the exceptions are masked. */ +# define FE_NOMASK_ENV ((const fenv_t *) 0x880000000000003eUL) + +/* Floating-point environment with (processor-dependent) non-IEEE floating + point. In this case, mapping denormals to zero. */ +# define FE_NONIEEE_ENV ((const fenv_t *) 0x8800000000003000UL) +#endif + +/* The system calls to talk to the kernel's FP code. */ +extern unsigned long int __ieee_get_fp_control (void) __THROW; +extern void __ieee_set_fp_control (unsigned long int __value) __THROW; |