projects / thirdparty / glibc.git / blame
| Commit | Line | Data |
|---|---|---|
| c7c8ca97 AJ |
1 | /* FPU control word bits. x86-64 version. |
| 2 | Copyright (C) 1993,1995,1996,1997,1998,2000,2001,2002 Free Software Foundation, Inc. | |
| 3 | This file is part of the GNU C Library. | |
| 4 | Contributed by Olaf Flebbe. | |
| 5 | ||
| 6 | The GNU C Library is free software; you can redistribute it and/or | |
| 7 | modify it under the terms of the GNU Lesser General Public | |
| 8 | License as published by the Free Software Foundation; either | |
| 9 | version 2.1 of the License, or (at your option) any later version. | |
| 10 | ||
| 11 | The GNU C Library is distributed in the hope that it will be useful, | |
| 12 | but WITHOUT ANY WARRANTY; without even the implied warranty of | |
| 13 | MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU | |
| 14 | Lesser General Public License for more details. | |
| 15 | ||
| 16 | You should have received a copy of the GNU Lesser General Public | |
| 59ba27a6 PE |
17 | License along with the GNU C Library; if not, see |
| 18 | <http://www.gnu.org/licenses/>. */ | |
| c7c8ca97 AJ |
19 | |
| 20 | #ifndef _FPU_CONTROL_H | |
| 21 | #define _FPU_CONTROL_H 1 | |
| 22 | ||
| 23 | /* Note that this file sets on x86-64 only the x87 FPU, it does not | |
| 24 | touch the SSE unit. */ | |
| 25 | ||
| 26 | /* Here is the dirty part. Set up your 387 through the control word | |
| 27 | * (cw) register. | |
| 28 | * | |
| 29 | * 15-13 12 11-10 9-8 7-6 5 4 3 2 1 0 | |
| 30 | * | reserved | IC | RC | PC | reserved | PM | UM | OM | ZM | DM | IM | |
| 31 | * | |
| 32 | * IM: Invalid operation mask | |
| 33 | * DM: Denormalized operand mask | |
| 34 | * ZM: Zero-divide mask | |
| 35 | * OM: Overflow mask | |
| 36 | * UM: Underflow mask | |
| 37 | * PM: Precision (inexact result) mask | |
| 38 | * | |
| 39 | * Mask bit is 1 means no interrupt. | |
| 40 | * | |
| 41 | * PC: Precision control | |
| 42 | * 11 - round to extended precision | |
| 43 | * 10 - round to double precision | |
| 44 | * 00 - round to single precision | |
| 45 | * | |
| 46 | * RC: Rounding control | |
| 47 | * 00 - rounding to nearest | |
| 48 | * 01 - rounding down (toward - infinity) | |
| 49 | * 10 - rounding up (toward + infinity) | |
| 50 | * 11 - rounding toward zero | |
| 51 | * | |
| 52 | * IC: Infinity control | |
| 53 | * That is for 8087 and 80287 only. | |
| 54 | * | |
| 55 | * The hardware default is 0x037f which we use. | |
| 56 | */ | |
| 57 | ||
| 58 | #include <features.h> | |
| 59 | ||
| 60 | /* masking of interrupts */ | |
| 61 | #define _FPU_MASK_IM 0x01 | |
| 62 | #define _FPU_MASK_DM 0x02 | |
| 63 | #define _FPU_MASK_ZM 0x04 | |
| 64 | #define _FPU_MASK_OM 0x08 | |
| 65 | #define _FPU_MASK_UM 0x10 | |
| 66 | #define _FPU_MASK_PM 0x20 | |
| 67 | ||
| 68 | /* precision control */ | |
| 69 | #define _FPU_EXTENDED 0x300 /* libm requires double extended precision. */ | |
| 70 | #define _FPU_DOUBLE 0x200 | |
| 71 | #define _FPU_SINGLE 0x0 | |
| 72 | ||
| 73 | /* rounding control */ | |
| 74 | #define _FPU_RC_NEAREST 0x0 /* RECOMMENDED */ | |
| 75 | #define _FPU_RC_DOWN 0x400 | |
| 76 | #define _FPU_RC_UP 0x800 | |
| 77 | #define _FPU_RC_ZERO 0xC00 | |
| 78 | ||
| 79 | #define _FPU_RESERVED 0xF0C0 /* Reserved bits in cw */ | |
| 80 | ||
| 81 | ||
| 82 | /* The fdlibm code requires strict IEEE double precision arithmetic, | |
| 83 | and no interrupts for exceptions, rounding to nearest. */ | |
| 84 | ||
| 85 | #define _FPU_DEFAULT 0x037f | |
| 86 | ||
| 87 | /* IEEE: same as above. */ | |
| 88 | #define _FPU_IEEE 0x037f | |
| 89 | ||
| 90 | /* Type of the control word. */ | |
| 91 | typedef unsigned int fpu_control_t __attribute__ ((__mode__ (__HI__))); | |
| 92 | ||
| 93 | /* Macros for accessing the hardware control word. */ | |
| 94 | #define _FPU_GETCW(cw) __asm__ ("fnstcw %0" : "=m" (*&cw)) | |
| 95 | #define _FPU_SETCW(cw) __asm__ ("fldcw %0" : : "m" (*&cw)) | |
| 96 | ||
| 97 | /* Default control word set at startup. */ | |
| 98 | extern fpu_control_t __fpu_control; | |
| 99 | ||
| 100 | #endif /* fpu_control.h */ |