1 /* FPU control word bits. Nios2 version.
2 Copyright (C) 1996, 1997, 1998, 1999, 2000 Free Software Foundation, Inc.
3 This file is part of the GNU C Library.
5 The GNU C Library is free software; you can redistribute it and/or
6 modify it under the terms of the GNU Lesser General Public
7 License as published by the Free Software Foundation; either
8 version 2.1 of the License, or (at your option) any later version.
10 The GNU C Library is distributed in the hope that it will be useful,
11 but WITHOUT ANY WARRANTY; without even the implied warranty of
12 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
13 Lesser General Public License for more details.
15 You should have received a copy of the GNU Lesser General Public
16 License along with the GNU C Library; if not, see
17 <http://www.gnu.org/licenses/>. */
19 #ifndef _FPU_CONTROL_H
20 #define _FPU_CONTROL_H
22 /* MIPS FPU floating point control register bits.
24 * 31-25 -> floating point conditions code bits 7-1. These bits are only
25 * available in MIPS IV.
26 * 24 -> flush denormalized results to zero instead of
27 * causing unimplemented operation exception. This bit is only
28 * available for MIPS III and newer.
30 * 22-18 -> reserved (read as 0, write with 0)
31 * 17 -> cause bit for unimplemented operation
32 * 16 -> cause bit for invalid exception
33 * 15 -> cause bit for division by zero exception
34 * 14 -> cause bit for overflow exception
35 * 13 -> cause bit for underflow exception
36 * 12 -> cause bit for inexact exception
37 * 11 -> enable exception for invalid exception
38 * 10 -> enable exception for division by zero exception
39 * 9 -> enable exception for overflow exception
40 * 8 -> enable exception for underflow exception
41 * 7 -> enable exception for inexact exception
42 * 6 -> flag invalid exception
43 * 5 -> flag division by zero exception
44 * 4 -> flag overflow exception
45 * 3 -> flag underflow exception
46 * 2 -> flag inexact exception
47 * 1-0 -> rounding control
51 * 00 - rounding to nearest (RN)
52 * 01 - rounding toward zero (RZ)
53 * 10 - rounding (up) toward plus infinity (RP)
54 * 11 - rounding (down)toward minus infinity (RM)
59 /* masking of interrupts */
60 #define _FPU_MASK_V 0x0800 /* Invalid operation */
61 #define _FPU_MASK_Z 0x0400 /* Division by zero */
62 #define _FPU_MASK_O 0x0200 /* Overflow */
63 #define _FPU_MASK_U 0x0100 /* Underflow */
64 #define _FPU_MASK_I 0x0080 /* Inexact operation */
66 /* flush denormalized numbers to zero */
67 #define _FPU_FLUSH_TZ 0x1000000
69 /* rounding control */
70 #define _FPU_RC_NEAREST 0x0 /* RECOMMENDED */
71 #define _FPU_RC_ZERO 0x1
72 #define _FPU_RC_UP 0x2
73 #define _FPU_RC_DOWN 0x3
75 #define _FPU_RESERVED 0xfe3c0000 /* Reserved bits in cw */
78 /* The fdlibm code requires strict IEEE double precision arithmetic,
79 and no interrupts for exceptions, rounding to nearest. */
81 #define _FPU_DEFAULT 0x00000000
83 /* IEEE: same as above, but exceptions */
84 #define _FPU_IEEE 0x00000F80
86 /* Type of the control word. */
87 typedef unsigned int fpu_control_t __attribute__ ((__mode__ (__SI__)));
89 /* Macros for accessing the hardware control word. */
90 #define _FPU_GETCW(cw) __asm__ ("cfc1 %0,$31" : "=r" (cw))
91 #define _FPU_SETCW(cw) __asm__ ("ctc1 %0,$31" : : "r" (cw))
94 /* Default control word set at startup. */
95 extern fpu_control_t __fpu_control;
98 #endif /* fpu_control.h */