| /* 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; |