1/*
2 * Copyright (c) 2000 Apple Computer, Inc. All rights reserved.
3 *
4 * @APPLE_OSREFERENCE_LICENSE_HEADER_START@
5 *
6 * This file contains Original Code and/or Modifications of Original Code
7 * as defined in and that are subject to the Apple Public Source License
8 * Version 2.0 (the 'License'). You may not use this file except in
9 * compliance with the License. The rights granted to you under the License
10 * may not be used to create, or enable the creation or redistribution of,
11 * unlawful or unlicensed copies of an Apple operating system, or to
12 * circumvent, violate, or enable the circumvention or violation of, any
13 * terms of an Apple operating system software license agreement.
14 *
15 * Please obtain a copy of the License at
16 * http://www.opensource.apple.com/apsl/ and read it before using this file.
17 *
18 * The Original Code and all software distributed under the License are
19 * distributed on an 'AS IS' basis, WITHOUT WARRANTY OF ANY KIND, EITHER
20 * EXPRESS OR IMPLIED, AND APPLE HEREBY DISCLAIMS ALL SUCH WARRANTIES,
21 * INCLUDING WITHOUT LIMITATION, ANY WARRANTIES OF MERCHANTABILITY,
22 * FITNESS FOR A PARTICULAR PURPOSE, QUIET ENJOYMENT OR NON-INFRINGEMENT.
23 * Please see the License for the specific language governing rights and
24 * limitations under the License.
25 *
26 * @APPLE_OSREFERENCE_LICENSE_HEADER_END@
27 */
28/* Copyright (c) 1991 NeXT Computer, Inc.  All rights reserved.
29 *
30 *	File:	architecture/i386/reg_help.h
31 *	Author:	Mike DeMoney, NeXT Computer, Inc.
32 *      Modified for i386 by: Bruce Martin, NeXT Computer, Inc.
33 *
34 *	This header file defines cpp macros useful for defining
35 *	machine register and doing machine-level operations.
36 *
37 * HISTORY
38 * 10-Mar-92  Bruce Martin (bmartin@next.com)
39 *	Adapted to i386
40 * 23-Jan-91  Mike DeMoney (mike@next.com)
41 *	Created.
42 */
43
44#ifndef	_ARCH_I386_REG_HELP_H_
45#define	_ARCH_I386_REG_HELP_H_
46
47/* Bitfield definition aid */
48#define	BITS_WIDTH(msb, lsb)	((msb)-(lsb)+1)
49#define	BIT_WIDTH(pos)		(1)	/* mostly to record the position */
50
51/* Mask creation */
52#define	MKMASK(width, offset)	(((unsigned)-1)>>(32-(width))<<(offset))
53#define	BITSMASK(msb, lsb)	MKMASK(BITS_WIDTH(msb, lsb), lsb & 0x1f)
54#define	BITMASK(pos)		MKMASK(BIT_WIDTH(pos), pos & 0x1f)
55
56/* Register addresses */
57#if	__ASSEMBLER__
58# define	REG_ADDR(type, addr)	(addr)
59#else	/* __ASSEMBLER__ */
60# define	REG_ADDR(type, addr)	(*(volatile type *)(addr))
61#endif	/* __ASSEMBLER__ */
62
63/* Cast a register to be an unsigned */
64#define	CONTENTS(foo)	(*(unsigned *) &(foo))
65
66/* Stack pointer must always be a multiple of 4 */
67#define	STACK_INCR	4
68#define	ROUND_FRAME(x)	((((unsigned)(x)) + STACK_INCR - 1) & ~(STACK_INCR-1))
69
70/* STRINGIFY -- perform all possible substitutions, then stringify */
71#define	__STR(x)	#x		/* just a helper macro */
72#define	STRINGIFY(x)	__STR(x)
73
74/*
75 * REG_PAIR_DEF -- define a register pair
76 * Register pairs are appropriately aligned to allow access via
77 * ld.d and st.d.
78 *
79 * Usage:
80 *	struct foo {
81 *		REG_PAIR_DEF(
82 *			bar_t *,	barp,
83 *			afu_t,		afu
84 *		);
85 *	};
86 *
87 * Access to individual entries of the pair is via the REG_PAIR
88 * macro (below).
89 */
90#define	REG_PAIR_DEF(type0, name0, type1, name1)		\
91	struct {						\
92		type0	name0 __attribute__(( aligned(8) ));	\
93		type1	name1;					\
94	} name0##_##name1
95
96/*
97 * REG_PAIR -- Macro to define names for accessing individual registers
98 * of register pairs.
99 *
100 * Usage:
101 *	arg0 is first element of pair
102 *	arg1 is second element of pair
103 *	arg2 is desired element of pair
104 * eg:
105 *	#define	foo_barp	REG_PAIR(barp, afu, afu)
106 */
107#define	REG_PAIR(name0, name1, the_name)			\
108	name0##_##name1.the_name
109
110#endif	/* _ARCH_I386_REG_HELP_H_ */
111