1 /* FPU control word bits. C-SKY version.
2 Copyright (C) 2018-2023 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 /* C-SKY FPU floating point control register bits.
23
24 31-28 -> Reserved (read as 0, write with 0).
25 27 -> 0: Flush denormalized results to zero.
26 1: Flush denormalized results to signed minimal normal number.
27 26 -> Reserved (read as 0, write with 0).
28 25-24 -> Rounding control.
29 23-6 -> Reserved (read as 0, write with 0).
30 5 -> Enable exception for input denormalized exception.
31 4 -> Enable exception for inexact exception.
32 3 -> Enable exception for underflow exception.
33 2 -> Enable exception for overflow exception.
34 1 -> Enable exception for division by zero exception.
35 0 -> Enable exception for invalid operation exception.
36
37 Rounding Control:
38 00 - Rounding to nearest (RN).
39 01 - Rounding toward zero (RZ).
40 10 - Rounding (up) toward plus infinity (RP).
41 11 - Rounding (down)toward minus infinity (RM).
42
43 C-SKY FPU floating point exception status register bits.
44
45 15 -> Accumulate bit for any exception.
46 14 -> Reserved (read as 0, write with 0).
47 13 -> Cause bit for input denormalized exception.
48 12 -> Cause bit for inexact exception.
49 11 -> Cause bit for underflow exception.
50 10 -> Cause bit for overflow exception.
51 9 -> Cause bit for division by zero exception.
52 8 -> Cause bit for invalid operation exception.
53 7 -> Flag bit for any exception.
54 6 -> Reserved (read as 0, write with 0).
55 5 -> Flag exception for input denormalized exception.
56 4 -> Flag exception for inexact exception.
57 3 -> Flag exception for underflow exception.
58 2 -> Flag exception for overflow exception.
59 1 -> Flag exception for division by zero exception.
60 0 -> Flag exception for invalid operation exception. */
61
62 #include <features.h>
63
64 #ifdef __csky_soft_float__
65
66 # define _FPU_RESERVED 0xffffffff
67 # define _FPU_DEFAULT 0x00000000
68 typedef unsigned int fpu_control_t;
69 # define _FPU_GETCW(cw) (cw) = 0
70 # define _FPU_SETCW(cw) (void) (cw)
71 # define _FPU_GETFPSR(cw) (cw) = 0
72 # define _FPU_SETFPSR(cw) (void) (cw)
73 extern fpu_control_t __fpu_control;
74
75 #else /* __csky_soft_float__ */
76
77 /* Masking of interrupts. */
78 # define _FPU_MASK_IDE (1 << 5) /* Input denormalized exception. */
79 # define _FPU_MASK_IXE (1 << 4) /* Inexact exception. */
80 # define _FPU_MASK_UFE (1 << 3) /* Underflow exception. */
81 # define _FPU_MASK_OFE (1 << 2) /* Overflow exception. */
82 # define _FPU_MASK_DZE (1 << 1) /* Division by zero exception. */
83 # define _FPU_MASK_IOE (1 << 0) /* Invalid operation exception. */
84
85 # define _FPU_MASK_FEA (1 << 15) /* Case for any exception. */
86 # define _FPU_MASK_FEC (1 << 7) /* Flag for any exception. */
87
88 /* Flush denormalized numbers to zero. */
89 # define _FPU_FLUSH_TZ 0x8000000
90
91 /* Rounding control. */
92 # define _FPU_RC_NEAREST (0x0 << 24) /* RECOMMENDED. */
93 # define _FPU_RC_ZERO (0x1 << 24)
94 # define _FPU_RC_UP (0x2 << 24)
95 # define _FPU_RC_DOWN (0x3 << 24)
96
97 # define _FPU_RESERVED 0xf460ffc0 /* Reserved bits in cw. */
98 # define _FPU_FPSR_RESERVED 0xffff4040
99
100 /* The fdlibm code requires strict IEEE double precision arithmetic,
101 and no interrupts for exceptions, rounding to nearest. */
102
103 # define _FPU_DEFAULT 0x00000000
104 # define _FPU_FPSR_DEFAULT 0x00000000
105
106 /* IEEE: same as above, but exceptions. */
107 # define _FPU_FPCR_IEEE 0x0000001F
108 # define _FPU_FPSR_IEEE 0x00000000
109
110 /* Type of the control word. */
111 typedef unsigned int fpu_control_t;
112
113 /* Macros for accessing the hardware control word. */
114 # if (__CSKY__ == 2)
115 # define _FPU_GETCW(cw) __asm__ volatile ("mfcr %0, cr<1, 2>" : "=a" (cw))
116 # define _FPU_SETCW(cw) __asm__ volatile ("mtcr %0, cr<1, 2>" : : "a" (cw))
117 # define _FPU_GETFPSR(cw) __asm__ volatile ("mfcr %0, cr<2, 2>" : "=a" (cw))
118 # define _FPU_SETFPSR(cw) __asm__ volatile ("mtcr %0, cr<2, 2>" : : "a" (cw))
119 # else
120 # define _FPU_GETCW(cw) __asm__ volatile ("1: cprcr %0, cpcr2 \n" \
121 " btsti %0, 31 \n" \
122 " bt 1b \n" \
123 " cprcr %0, cpcr1\n" : "=b" (cw))
124
125 # define _FPU_SETCW(cw) __asm__ volatile ("1: cprcr r7, cpcr2 \n" \
126 " btsti r7, 31 \n" \
127 " bt 1b \n" \
128 " cpwcr %0, cpcr1 \n" \
129 : : "b" (cw) : "r7")
130
131 # define _FPU_GETFPSR(cw) __asm__ volatile ("1: cprcr %0, cpcr2 \n" \
132 " btsti %0, 31 \n" \
133 " bt 1b \n" \
134 " cprcr %0, cpcr4\n" : "=b" (cw))
135
136 # define _FPU_SETFPSR(cw) __asm__ volatile ("1: cprcr r7, cpcr2 \n" \
137 " btsti r7, 31 \n" \
138 " bt 1b \n" \
139 " cpwcr %0, cpcr4 \n" \
140 : : "b" (cw) : "r7")
141 # endif /* __CSKY__ != 2 */
142
143 /* Default control word set at startup. */
144 extern fpu_control_t __fpu_control;
145
146 #endif /* !__csky_soft_float__ */
147
148 #endif /* fpu_control.h */