1/* SPDX-License-Identifier: GPL-2.0 */
2/*
3 *	FILE    	bitfield.h
4 *
5 *	Version 	1.1
6 *	Author  	Copyright (c) Marc A. Viredaz, 1998
7 *	        	DEC Western Research Laboratory, Palo Alto, CA
8 *	Date    	April 1998 (April 1997)
9 *	System  	Advanced RISC Machine (ARM)
10 *	Language	C or ARM Assembly
11 *	Purpose 	Definition of macros to operate on bit fields.
12 */
13
14
15
16#ifndef __BITFIELD_H
17#define __BITFIELD_H
18
19#ifndef __ASSEMBLY__
20#define UData(Data)	((unsigned long) (Data))
21#else
22#define UData(Data)	(Data)
23#endif
24
25
26/*
27 * MACRO: Fld
28 *
29 * Purpose
30 *    The macro "Fld" encodes a bit field, given its size and its shift value
31 *    with respect to bit 0.
32 *
33 * Note
34 *    A more intuitive way to encode bit fields would have been to use their
35 *    mask. However, extracting size and shift value information from a bit
36 *    field's mask is cumbersome and might break the assembler (255-character
37 *    line-size limit).
38 *
39 * Input
40 *    Size      	Size of the bit field, in number of bits.
41 *    Shft      	Shift value of the bit field with respect to bit 0.
42 *
43 * Output
44 *    Fld       	Encoded bit field.
45 */
46
47#define Fld(Size, Shft)	(((Size) << 16) + (Shft))
48
49
50/*
51 * MACROS: FSize, FShft, FMsk, FAlnMsk, F1stBit
52 *
53 * Purpose
54 *    The macros "FSize", "FShft", "FMsk", "FAlnMsk", and "F1stBit" return
55 *    the size, shift value, mask, aligned mask, and first bit of a
56 *    bit field.
57 *
58 * Input
59 *    Field     	Encoded bit field (using the macro "Fld").
60 *
61 * Output
62 *    FSize     	Size of the bit field, in number of bits.
63 *    FShft     	Shift value of the bit field with respect to bit 0.
64 *    FMsk      	Mask for the bit field.
65 *    FAlnMsk   	Mask for the bit field, aligned on bit 0.
66 *    F1stBit   	First bit of the bit field.
67 */
68
69#define FSize(Field)	((Field) >> 16)
70#define FShft(Field)	((Field) & 0x0000FFFF)
71#define FMsk(Field)	(((UData (1) << FSize (Field)) - 1) << FShft (Field))
72#define FAlnMsk(Field)	((UData (1) << FSize (Field)) - 1)
73#define F1stBit(Field)	(UData (1) << FShft (Field))
74
75
76/*
77 * MACRO: FInsrt
78 *
79 * Purpose
80 *    The macro "FInsrt" inserts a value into a bit field by shifting the
81 *    former appropriately.
82 *
83 * Input
84 *    Value     	Bit-field value.
85 *    Field     	Encoded bit field (using the macro "Fld").
86 *
87 * Output
88 *    FInsrt    	Bit-field value positioned appropriately.
89 */
90
91#define FInsrt(Value, Field) \
92                	(UData (Value) << FShft (Field))
93
94
95/*
96 * MACRO: FExtr
97 *
98 * Purpose
99 *    The macro "FExtr" extracts the value of a bit field by masking and
100 *    shifting it appropriately.
101 *
102 * Input
103 *    Data      	Data containing the bit-field to be extracted.
104 *    Field     	Encoded bit field (using the macro "Fld").
105 *
106 * Output
107 *    FExtr     	Bit-field value.
108 */
109
110#define FExtr(Data, Field) \
111                	((UData (Data) >> FShft (Field)) & FAlnMsk (Field))
112
113
114#endif /* __BITFIELD_H */
115