1/* FPU control word bits.
2 Copyright (C) 2022-2026 Free Software Foundation, Inc.
3 This file is part of the GNU C Library.
4
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.
9
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.
14
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 <https://www.gnu.org/licenses/>. */
18
19#ifndef _FPU_CONTROL_H
20#define _FPU_CONTROL_H
21
22/* LoongArch FPU floating point control register bits.
23 *
24 * 31-29 -> reserved (read as 0, can not changed by software)
25 * 28 -> cause bit for invalid exception
26 * 27 -> cause bit for division by zero exception
27 * 26 -> cause bit for overflow exception
28 * 25 -> cause bit for underflow exception
29 * 24 -> cause bit for inexact exception
30 * 23-21 -> reserved (read as 0, can not changed by software)
31 * 20 -> flag invalid exception
32 * 19 -> flag division by zero exception
33 * 18 -> flag overflow exception
34 * 17 -> flag underflow exception
35 * 16 -> flag inexact exception
36 * 9-8 -> rounding control
37 * 7-5 -> reserved (read as 0, can not changed by software)
38 * 4 -> enable exception for invalid exception
39 * 3 -> enable exception for division by zero exception
40 * 2 -> enable exception for overflow exception
41 * 1 -> enable exception for underflow exception
42 * 0 -> enable exception for inexact exception
43 *
44 *
45 * Rounding Control:
46 * 00 - rounding ties to even (RNE)
47 * 01 - rounding toward zero (RZ)
48 * 10 - rounding (up) toward plus infinity (RP)
49 * 11 - rounding (down) toward minus infinity (RM)
50 */
51
52#include <features.h>
53
54#ifdef __loongarch_soft_float
55
56#define _FPU_RESERVED 0xffffffff
57#define _FPU_DEFAULT 0x00000000
58typedef unsigned int fpu_control_t;
59#define _FPU_GETCW(cw) (cw) = 0
60#define _FPU_SETCW(cw) (void) (cw)
61extern fpu_control_t __fpu_control;
62
63#else /* __loongarch_soft_float */
64
65/* Masks for interrupts. */
66#define _FPU_MASK_V 0x10 /* Invalid operation */
67#define _FPU_MASK_Z 0x08 /* Division by zero */
68#define _FPU_MASK_O 0x04 /* Overflow */
69#define _FPU_MASK_U 0x02 /* Underflow */
70#define _FPU_MASK_I 0x01 /* Inexact operation */
71
72/* Flush denormalized numbers to zero. */
73#define _FPU_FLUSH_TZ 0x1000000
74
75/* Rounding control. */
76#define _FPU_RC_NEAREST 0x000 /* RECOMMENDED */
77#define _FPU_RC_ZERO 0x100
78#define _FPU_RC_UP 0x200
79#define _FPU_RC_DOWN 0x300
80/* Mask for rounding control. */
81#define _FPU_RC_MASK 0x300
82
83#define _FPU_RESERVED 0x0
84
85#define _FPU_DEFAULT 0x0
86#define _FPU_IEEE 0x1F
87
88/* Type of the control word. */
89typedef unsigned int fpu_control_t __attribute__ ((__mode__ (__SI__)));
90
91/* Macros for accessing the hardware control word. */
92extern fpu_control_t __loongarch_fpu_getcw (void) __THROW;
93extern void __loongarch_fpu_setcw (fpu_control_t) __THROW;
94#define _FPU_GETCW(cw) __asm__ volatile ("movfcsr2gr %0,$fcsr0" : "=r"(cw))
95#define _FPU_SETCW(cw) __asm__ volatile ("movgr2fcsr $fcsr0,%0" : : "r"(cw))
96
97#define _FPU_GET_ENABLES(cw) __asm__ volatile ("movfcsr2gr %0,$fcsr1" : "=r"(cw))
98#define _FPU_SET_ENABLES(cw) __asm__ volatile ("movgr2fcsr $fcsr1,%0" : : "r"(cw))
99
100#define _FPU_GET_FLAGS_CAUSE(cw) __asm__ volatile ("movfcsr2gr %0,$fcsr2" : "=r"(cw))
101#define _FPU_SET_FLAGS_CAUSE(cw) __asm__ volatile ("movgr2fcsr $fcsr2,%0" : : "r"(cw))
102
103#define _FPU_GET_RM(cw) __asm__ volatile ("movfcsr2gr %0,$fcsr3" : "=r"(cw))
104#define _FPU_SET_RM(cw) __asm__ volatile ("movgr2fcsr $fcsr3,%0" : : "r"(cw))
105
106/* Default control word set at startup. */
107extern fpu_control_t __fpu_control;
108
109# define _FCLASS_SNAN (1 << 0)
110# define _FCLASS_QNAN (1 << 1)
111# define _FCLASS_MINF (1 << 2)
112# define _FCLASS_MNORM (1 << 3)
113# define _FCLASS_MSUBNORM (1 << 4)
114# define _FCLASS_MZERO (1 << 5)
115# define _FCLASS_PINF (1 << 6)
116# define _FCLASS_PNORM (1 << 7)
117# define _FCLASS_PSUBNORM (1 << 8)
118# define _FCLASS_PZERO (1 << 9)
119
120# define _FCLASS_ZERO (_FCLASS_MZERO | _FCLASS_PZERO)
121# define _FCLASS_SUBNORM (_FCLASS_MSUBNORM | _FCLASS_PSUBNORM)
122# define _FCLASS_NORM (_FCLASS_MNORM | _FCLASS_PNORM)
123# define _FCLASS_INF (_FCLASS_MINF | _FCLASS_PINF)
124# define _FCLASS_NAN (_FCLASS_SNAN | _FCLASS_QNAN)
125
126#endif /* __loongarch_soft_float */
127
128#endif /* fpu_control.h */