ia64/linux-2.6.18-xen.hg

view include/asm-arm/arch-pxa/bitfield.h @ 782:9ab1c319531f

merge with linux-2.6.18-xen.hg
author Isaku Yamahata <yamahata@valinux.co.jp>
date Wed Jan 28 13:07:23 2009 +0900 (2009-01-28)
parents 831230e53067
children
line source
1 /*
2 * FILE bitfield.h
3 *
4 * Version 1.1
5 * Author Copyright (c) Marc A. Viredaz, 1998
6 * DEC Western Research Laboratory, Palo Alto, CA
7 * Date April 1998 (April 1997)
8 * System Advanced RISC Machine (ARM)
9 * Language C or ARM Assembly
10 * Purpose Definition of macros to operate on bit fields.
11 */
15 #ifndef __BITFIELD_H
16 #define __BITFIELD_H
18 #ifndef __ASSEMBLY__
19 #define UData(Data) ((unsigned long) (Data))
20 #else
21 #define UData(Data) (Data)
22 #endif
25 /*
26 * MACRO: Fld
27 *
28 * Purpose
29 * The macro "Fld" encodes a bit field, given its size and its shift value
30 * with respect to bit 0.
31 *
32 * Note
33 * A more intuitive way to encode bit fields would have been to use their
34 * mask. However, extracting size and shift value information from a bit
35 * field's mask is cumbersome and might break the assembler (255-character
36 * line-size limit).
37 *
38 * Input
39 * Size Size of the bit field, in number of bits.
40 * Shft Shift value of the bit field with respect to bit 0.
41 *
42 * Output
43 * Fld Encoded bit field.
44 */
46 #define Fld(Size, Shft) (((Size) << 16) + (Shft))
49 /*
50 * MACROS: FSize, FShft, FMsk, FAlnMsk, F1stBit
51 *
52 * Purpose
53 * The macros "FSize", "FShft", "FMsk", "FAlnMsk", and "F1stBit" return
54 * the size, shift value, mask, aligned mask, and first bit of a
55 * bit field.
56 *
57 * Input
58 * Field Encoded bit field (using the macro "Fld").
59 *
60 * Output
61 * FSize Size of the bit field, in number of bits.
62 * FShft Shift value of the bit field with respect to bit 0.
63 * FMsk Mask for the bit field.
64 * FAlnMsk Mask for the bit field, aligned on bit 0.
65 * F1stBit First bit of the bit field.
66 */
68 #define FSize(Field) ((Field) >> 16)
69 #define FShft(Field) ((Field) & 0x0000FFFF)
70 #define FMsk(Field) (((UData (1) << FSize (Field)) - 1) << FShft (Field))
71 #define FAlnMsk(Field) ((UData (1) << FSize (Field)) - 1)
72 #define F1stBit(Field) (UData (1) << FShft (Field))
75 /*
76 * MACRO: FInsrt
77 *
78 * Purpose
79 * The macro "FInsrt" inserts a value into a bit field by shifting the
80 * former appropriately.
81 *
82 * Input
83 * Value Bit-field value.
84 * Field Encoded bit field (using the macro "Fld").
85 *
86 * Output
87 * FInsrt Bit-field value positioned appropriately.
88 */
90 #define FInsrt(Value, Field) \
91 (UData (Value) << FShft (Field))
94 /*
95 * MACRO: FExtr
96 *
97 * Purpose
98 * The macro "FExtr" extracts the value of a bit field by masking and
99 * shifting it appropriately.
100 *
101 * Input
102 * Data Data containing the bit-field to be extracted.
103 * Field Encoded bit field (using the macro "Fld").
104 *
105 * Output
106 * FExtr Bit-field value.
107 */
109 #define FExtr(Data, Field) \
110 ((UData (Data) >> FShft (Field)) & FAlnMsk (Field))
113 #endif /* __BITFIELD_H */