iPXE
pseudobit.h
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1 #ifndef _IPXE_PSEUDOBIT_H
2 #define _IPXE_PSEUDOBIT_H
3 
4 /*
5  * Copyright (C) 2008 Michael Brown <mbrown@fensystems.co.uk>.
6  *
7  * This program is free software; you can redistribute it and/or
8  * modify it under the terms of the GNU General Public License as
9  * published by the Free Software Foundation; either version 2 of the
10  * License, or any later version.
11  *
12  * This program is distributed in the hope that it will be useful, but
13  * WITHOUT ANY WARRANTY; without even the implied warranty of
14  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
15  * General Public License for more details.
16  *
17  * You should have received a copy of the GNU General Public License
18  * along with this program; if not, write to the Free Software
19  * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA
20  * 02110-1301, USA.
21  *
22  * You can also choose to distribute this program under the terms of
23  * the Unmodified Binary Distribution Licence (as given in the file
24  * COPYING.UBDL), provided that you have satisfied its requirements.
25  */
26 
27 FILE_LICENCE ( GPL2_OR_LATER_OR_UBDL );
28 
29 /**
30  * @file
31  *
32  * Pseudo-bit structures
33  *
34  */
35 
36 #include <stdint.h>
37 #include <byteswap.h>
38 
39 /* Endianness selection.
40  *
41  * This is a property of the device, not a property of the host CPU.
42  */
43 #ifdef PSEUDOBIT_LITTLE_ENDIAN
44 #define cpu_to_BIT64 cpu_to_le64
45 #define cpu_to_BIT32 cpu_to_le32
46 #define BIT64_to_cpu le64_to_cpu
47 #define BIT32_to_cpu le32_to_cpu
48 #define QWORD_SHIFT( offset, width ) (offset)
49 #endif
50 #ifdef PSEUDOBIT_BIG_ENDIAN
51 #define cpu_to_BIT64 cpu_to_be64
52 #define cpu_to_BIT32 cpu_to_be32
53 #define BIT64_to_cpu be64_to_cpu
54 #define BIT32_to_cpu be32_to_cpu
55 #define QWORD_SHIFT( offset, width ) ( 64 - (offset) - (width) )
56 #endif
57 
58 /** Datatype used to represent a bit in the pseudo-structures */
59 typedef unsigned char pseudo_bit_t;
60 
61 /**
62  * Wrapper structure for pseudo_bit_t structures
63  *
64  * This structure provides a wrapper around pseudo_bit_t structures.
65  * It has the correct size, and also encapsulates type information
66  * about the underlying pseudo_bit_t-based structure, which allows the
67  * BIT_FILL() etc. macros to work without requiring explicit type
68  * information.
69  */
70 #define PSEUDO_BIT_STRUCT( _structure ) \
71  union { \
72  uint8_t bytes[ sizeof ( _structure ) / 8 ]; \
73  uint32_t dwords[ sizeof ( _structure ) / 32 ]; \
74  uint64_t qwords[ sizeof ( _structure ) / 64 ]; \
75  _structure *dummy[0]; \
76  } __attribute__ (( packed )) u
77 
78 /** Get pseudo_bit_t structure type from wrapper structure pointer */
79 #define PSEUDO_BIT_STRUCT_TYPE( _ptr ) \
80  typeof ( *((_ptr)->u.dummy[0]) )
81 
82 /** Bit offset of a field within a pseudo_bit_t structure */
83 #define BIT_OFFSET( _ptr, _field ) \
84  offsetof ( PSEUDO_BIT_STRUCT_TYPE ( _ptr ), _field )
85 
86 /** Bit width of a field within a pseudo_bit_t structure */
87 #define BIT_WIDTH( _ptr, _field ) \
88  sizeof ( ( ( PSEUDO_BIT_STRUCT_TYPE ( _ptr ) * ) NULL )->_field )
89 
90 /** Qword offset of a field within a pseudo_bit_t structure */
91 #define QWORD_OFFSET( _ptr, _field ) \
92  ( BIT_OFFSET ( _ptr, _field ) / 64 )
93 
94 /** Qword bit offset of a field within a pseudo_bit_t structure */
95 #define QWORD_BIT_OFFSET( _ptr, _index, _field ) \
96  ( BIT_OFFSET ( _ptr, _field ) - ( 64 * (_index) ) )
97 
98 /** Qword bit shift for a field within a pseudo_bit_t structure */
99 #define QWORD_BIT_SHIFT( _ptr, _index, _field ) \
100  QWORD_SHIFT ( QWORD_BIT_OFFSET ( _ptr, _index, _field ), \
101  BIT_WIDTH ( _ptr, _field ) )
102 
103 /** Bit mask for a field within a pseudo_bit_t structure */
104 #define BIT_MASK( _ptr, _field ) \
105  ( ( ~( ( uint64_t ) 0 ) ) >> \
106  ( 64 - BIT_WIDTH ( _ptr, _field ) ) )
107 
108 /*
109  * Assemble native-endian qword from named fields and values
110  *
111  */
112 
113 #define BIT_ASSEMBLE_1( _ptr, _index, _field, _value ) \
114  ( ( ( uint64_t) (_value) ) << \
115  QWORD_BIT_SHIFT ( _ptr, _index, _field ) )
116 
117 #define BIT_ASSEMBLE_2( _ptr, _index, _field, _value, ... ) \
118  ( BIT_ASSEMBLE_1 ( _ptr, _index, _field, _value ) | \
119  BIT_ASSEMBLE_1 ( _ptr, _index, __VA_ARGS__ ) )
120 
121 #define BIT_ASSEMBLE_3( _ptr, _index, _field, _value, ... ) \
122  ( BIT_ASSEMBLE_1 ( _ptr, _index, _field, _value ) | \
123  BIT_ASSEMBLE_2 ( _ptr, _index, __VA_ARGS__ ) )
124 
125 #define BIT_ASSEMBLE_4( _ptr, _index, _field, _value, ... ) \
126  ( BIT_ASSEMBLE_1 ( _ptr, _index, _field, _value ) | \
127  BIT_ASSEMBLE_3 ( _ptr, _index, __VA_ARGS__ ) )
128 
129 #define BIT_ASSEMBLE_5( _ptr, _index, _field, _value, ... ) \
130  ( BIT_ASSEMBLE_1 ( _ptr, _index, _field, _value ) | \
131  BIT_ASSEMBLE_4 ( _ptr, _index, __VA_ARGS__ ) )
132 
133 #define BIT_ASSEMBLE_6( _ptr, _index, _field, _value, ... ) \
134  ( BIT_ASSEMBLE_1 ( _ptr, _index, _field, _value ) | \
135  BIT_ASSEMBLE_5 ( _ptr, _index, __VA_ARGS__ ) )
136 
137 #define BIT_ASSEMBLE_7( _ptr, _index, _field, _value, ... ) \
138  ( BIT_ASSEMBLE_1 ( _ptr, _index, _field, _value ) | \
139  BIT_ASSEMBLE_6 ( _ptr, _index, __VA_ARGS__ ) )
140 
141 /*
142  * Build native-endian (positive) qword bitmasks from named fields
143  *
144  */
145 
146 #define BIT_MASK_1( _ptr, _index, _field ) \
147  ( BIT_MASK ( _ptr, _field ) << \
148  QWORD_BIT_SHIFT ( _ptr, _index, _field ) )
149 
150 #define BIT_MASK_2( _ptr, _index, _field, ... ) \
151  ( BIT_MASK_1 ( _ptr, _index, _field ) | \
152  BIT_MASK_1 ( _ptr, _index, __VA_ARGS__ ) )
153 
154 #define BIT_MASK_3( _ptr, _index, _field, ... ) \
155  ( BIT_MASK_1 ( _ptr, _index, _field ) | \
156  BIT_MASK_2 ( _ptr, _index, __VA_ARGS__ ) )
157 
158 #define BIT_MASK_4( _ptr, _index, _field, ... ) \
159  ( BIT_MASK_1 ( _ptr, _index, _field ) | \
160  BIT_MASK_3 ( _ptr, _index, __VA_ARGS__ ) )
161 
162 #define BIT_MASK_5( _ptr, _index, _field, ... ) \
163  ( BIT_MASK_1 ( _ptr, _index, _field ) | \
164  BIT_MASK_4 ( _ptr, _index, __VA_ARGS__ ) )
165 
166 #define BIT_MASK_6( _ptr, _index, _field, ... ) \
167  ( BIT_MASK_1 ( _ptr, _index, _field ) | \
168  BIT_MASK_5 ( _ptr, _index, __VA_ARGS__ ) )
169 
170 #define BIT_MASK_7( _ptr, _index, _field, ... ) \
171  ( BIT_MASK_1 ( _ptr, _index, _field ) | \
172  BIT_MASK_6 ( _ptr, _index, __VA_ARGS__ ) )
173 
174 /*
175  * Populate device-endian qwords from named fields and values
176  *
177  */
178 
179 #define BIT_FILL( _ptr, _index, _assembled ) do { \
180  uint64_t *__ptr = &(_ptr)->u.qwords[(_index)]; \
181  uint64_t __assembled = (_assembled); \
182  *__ptr = cpu_to_BIT64 ( __assembled ); \
183  } while ( 0 )
184 
185 #define BIT_FILL_1( _ptr, _field1, ... ) \
186  BIT_FILL ( _ptr, QWORD_OFFSET ( _ptr, _field1 ), \
187  BIT_ASSEMBLE_1 ( _ptr, QWORD_OFFSET ( _ptr, _field1 ), \
188  _field1, __VA_ARGS__ ) )
189 
190 #define BIT_FILL_2( _ptr, _field1, ... ) \
191  BIT_FILL ( _ptr, QWORD_OFFSET ( _ptr, _field1 ), \
192  BIT_ASSEMBLE_2 ( _ptr, QWORD_OFFSET ( _ptr, _field1 ), \
193  _field1, __VA_ARGS__ ) )
194 
195 #define BIT_FILL_3( _ptr, _field1, ... ) \
196  BIT_FILL ( _ptr, QWORD_OFFSET ( _ptr, _field1 ), \
197  BIT_ASSEMBLE_3 ( _ptr, QWORD_OFFSET ( _ptr, _field1 ), \
198  _field1, __VA_ARGS__ ) )
199 
200 #define BIT_FILL_4( _ptr, _field1, ... ) \
201  BIT_FILL ( _ptr, QWORD_OFFSET ( _ptr, _field1 ), \
202  BIT_ASSEMBLE_4 ( _ptr, QWORD_OFFSET ( _ptr, _field1 ), \
203  _field1, __VA_ARGS__ ) )
204 
205 #define BIT_FILL_5( _ptr, _field1, ... ) \
206  BIT_FILL ( _ptr, QWORD_OFFSET ( _ptr, _field1 ), \
207  BIT_ASSEMBLE_5 ( _ptr, QWORD_OFFSET ( _ptr, _field1 ), \
208  _field1, __VA_ARGS__ ) )
209 
210 #define BIT_FILL_6( _ptr, _field1, ... ) \
211  BIT_FILL ( _ptr, QWORD_OFFSET ( _ptr, _field1 ), \
212  BIT_ASSEMBLE_6 ( _ptr, QWORD_OFFSET ( _ptr, _field1 ), \
213  _field1, __VA_ARGS__ ) )
214 
215 #define BIT_QWORD_PTR( _ptr, _field ) \
216  ( { \
217  unsigned int __index = QWORD_OFFSET ( _ptr, _field ); \
218  uint64_t *__ptr = &(_ptr)->u.qwords[__index]; \
219  __ptr; \
220  } )
221 
222 /** Extract value of named field */
223 #define BIT_GET64( _ptr, _field ) \
224  ( { \
225  unsigned int __index = QWORD_OFFSET ( _ptr, _field ); \
226  uint64_t *__ptr = &(_ptr)->u.qwords[__index]; \
227  uint64_t __value = BIT64_to_cpu ( *__ptr ); \
228  __value >>= \
229  QWORD_BIT_SHIFT ( _ptr, __index, _field ); \
230  __value &= BIT_MASK ( _ptr, _field ); \
231  __value; \
232  } )
233 
234 /** Extract value of named field (for fields up to the size of a long) */
235 #define BIT_GET( _ptr, _field ) \
236  ( ( unsigned long ) BIT_GET64 ( _ptr, _field ) )
237 
238 #define BIT_SET( _ptr, _field, _value ) do { \
239  unsigned int __index = QWORD_OFFSET ( _ptr, _field ); \
240  uint64_t *__ptr = &(_ptr)->u.qwords[__index]; \
241  unsigned int __shift = \
242  QWORD_BIT_SHIFT ( _ptr, __index, _field ); \
243  uint64_t __value = (_value); \
244  *__ptr &= cpu_to_BIT64 ( ~( BIT_MASK ( _ptr, _field ) << \
245  __shift ) ); \
246  *__ptr |= cpu_to_BIT64 ( __value << __shift ); \
247  } while ( 0 )
248 
249 #endif /* _IPXE_PSEUDOBIT_H */
FILE_LICENCE
FILE_LICENCE(GPL2_OR_LATER_OR_UBDL)
pseudo_bit_t
unsigned char pseudo_bit_t
Datatype used to represent a bit in the pseudo-structures.
Definition: pseudobit.h:59
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