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12ddb09b | 1 | /* FPU control word bits. Alpha-mapped-to-Intel version. |
bfff8b1b | 2 | Copyright (C) 1996-2017 Free Software Foundation, Inc. |
f97d5b5f UD |
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 | |
3214b89b AJ |
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. | |
f97d5b5f UD |
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 | |
3214b89b | 14 | Lesser General Public License for more details. |
f97d5b5f | 15 | |
3214b89b | 16 | You should have received a copy of the GNU Lesser General Public |
ab84e3ff PE |
17 | License along with the GNU C Library. If not, see |
18 | <http://www.gnu.org/licenses/>. */ | |
6932e444 RM |
19 | |
20 | #ifndef _ALPHA_FPU_CONTROL_H | |
21 | #define _ALPHA_FPU_CONTROL_H | |
22 | ||
23 | /* | |
24 | * Since many programs seem to hardcode the values passed to __setfpucw() | |
25 | * (rather than using the manifest constants) we emulate the x87 interface | |
26 | * here (at least where this makes sense). | |
27 | * | |
28 | * 15-13 12 11-10 9-8 7-6 5 4 3 2 1 0 | |
29 | * | reserved | IC | RC | PC | reserved | PM | UM | OM | ZM | DM | IM | |
30 | * | |
31 | * IM: Invalid operation mask | |
32 | * DM: Denormalized operand mask | |
33 | * ZM: Zero-divide mask | |
34 | * OM: Overflow mask | |
35 | * UM: Underflow mask | |
36 | * PM: Precision (inexact result) mask | |
f04e87f2 | 37 | * |
6932e444 RM |
38 | * Mask bit is 1 means no interrupt. |
39 | * | |
40 | * PC: Precision control | |
41 | * 11 - round to extended precision | |
42 | * 10 - round to double precision | |
43 | * 00 - round to single precision | |
44 | * | |
45 | * RC: Rounding control | |
46 | * 00 - rounding to nearest | |
47 | * 01 - rounding down (toward - infinity) | |
48 | * 10 - rounding up (toward + infinity) | |
49 | * 11 - rounding toward zero | |
50 | * | |
51 | * IC: Infinity control | |
52 | * That is for 8087 and 80287 only. | |
53 | * | |
54 | * The hardware default is 0x037f. I choose 0x1372. | |
55 | */ | |
56 | ||
57 | #include <features.h> | |
58 | ||
59 | /* masking of interrupts */ | |
f04e87f2 | 60 | #define _FPU_MASK_IM 0x01 |
6932e444 RM |
61 | #define _FPU_MASK_DM 0x02 |
62 | #define _FPU_MASK_ZM 0x04 | |
63 | #define _FPU_MASK_OM 0x08 | |
64 | #define _FPU_MASK_UM 0x10 | |
65 | #define _FPU_MASK_PM 0x20 | |
66 | ||
12ddb09b | 67 | /* precision control -- without effect on Alpha */ |
6932e444 RM |
68 | #define _FPU_EXTENDED 0x300 /* RECOMMENDED */ |
69 | #define _FPU_DOUBLE 0x200 | |
70 | #define _FPU_SINGLE 0x0 /* DO NOT USE */ | |
71 | ||
72 | /* | |
73 | * rounding control---notice that on the Alpha this affects only | |
74 | * instructions with the dynamic rounding mode qualifier (/d). | |
75 | */ | |
76 | #define _FPU_RC_NEAREST 0x000 /* RECOMMENDED */ | |
77 | #define _FPU_RC_DOWN 0x400 | |
78 | #define _FPU_RC_UP 0x800 | |
79 | #define _FPU_RC_ZERO 0xC00 | |
80 | ||
81 | #define _FPU_RESERVED 0xF0C0 /* Reserved bits in cw */ | |
82 | ||
83 | ||
84 | /* Now two recommended cw */ | |
85 | ||
86 | /* Linux default: | |
87 | - extended precision | |
88 | - rounding to positive infinity. There is no /p instruction | |
89 | qualifier. By setting the dynamic rounding mode to +infinity, | |
90 | one can use /d to get round to +infinity with no extra overhead | |
91 | (so long as the default isn't changed, of course...) | |
f97d5b5f UD |
92 | - no exceptions enabled. */ |
93 | ||
94 | #define _FPU_DEFAULT 0x137f | |
6932e444 | 95 | |
2ffceb84 | 96 | /* IEEE: same as above. */ |
f97d5b5f | 97 | #define _FPU_IEEE 0x137f |
6932e444 RM |
98 | |
99 | /* Type of the control word. */ | |
100 | typedef unsigned int fpu_control_t; | |
101 | ||
102 | /* Default control word set at startup. */ | |
103 | extern fpu_control_t __fpu_control; | |
104 | ||
6932e444 | 105 | #endif /* _ALPHA_FPU_CONTROL */ |