xref: /freebsd/sys/i386/include/asm.h (revision 7899f917b1c0ea178f1d2be0cfb452086d079d23)
1 /*-
2  * SPDX-License-Identifier: BSD-3-Clause
3  *
4  * Copyright (c) 1990 The Regents of the University of California.
5  * All rights reserved.
6  *
7  * This code is derived from software contributed to Berkeley by
8  * William Jolitz.
9  *
10  * Redistribution and use in source and binary forms, with or without
11  * modification, are permitted provided that the following conditions
12  * are met:
13  * 1. Redistributions of source code must retain the above copyright
14  *    notice, this list of conditions and the following disclaimer.
15  * 2. Redistributions in binary form must reproduce the above copyright
16  *    notice, this list of conditions and the following disclaimer in the
17  *    documentation and/or other materials provided with the distribution.
18  * 3. Neither the name of the University nor the names of its contributors
19  *    may be used to endorse or promote products derived from this software
20  *    without specific prior written permission.
21  *
22  * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
23  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
24  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
25  * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
26  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
27  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
28  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
29  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
30  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
31  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
32  * SUCH DAMAGE.
33  */
34 
35 #ifndef _MACHINE_ASM_H_
36 #define	_MACHINE_ASM_H_
37 
38 #include <sys/cdefs.h>
39 
40 #ifdef PIC
41 #define	PIC_PROLOGUE	\
42 	pushl	%ebx;	\
43 	call	1f;	\
44 1:			\
45 	popl	%ebx;	\
46 	addl	$_GLOBAL_OFFSET_TABLE_+[.-1b],%ebx
47 #define	PIC_EPILOGUE	\
48 	popl	%ebx
49 #define	PIC_PLT(x)	x@PLT
50 #define	PIC_GOT(x)	x@GOT(%ebx)
51 #define	PIC_GOTOFF(x)	x@GOTOFF(%ebx)
52 #else
53 #define	PIC_PROLOGUE
54 #define	PIC_EPILOGUE
55 #define	PIC_PLT(x)	x
56 #define	PIC_GOTOFF(x)	x
57 #endif
58 
59 /*
60  * CNAME and HIDENAME manage the relationship between symbol names in C
61  * and the equivalent assembly language names.  CNAME is given a name as
62  * it would be used in a C program.  It expands to the equivalent assembly
63  * language name.  HIDENAME is given an assembly-language name, and expands
64  * to a possibly-modified form that will be invisible to C programs.
65  */
66 #define CNAME(csym)		csym
67 #define HIDENAME(asmsym)	.asmsym
68 
69 /* XXX should use .p2align 4,0x90 for -m486. */
70 #define _START_ENTRY	.text; .p2align 2,0x90
71 
72 #define _ENTRY(x)	_START_ENTRY; \
73 			.globl CNAME(x); .type CNAME(x),@function; CNAME(x): \
74 			.cfi_startproc
75 #define	END(x)		.cfi_endproc; .size x, . - x
76 
77 #ifdef PROF
78 #define	ALTENTRY(x)	_ENTRY(x); \
79 			pushl %ebp; \
80 			.cfi_def_cfa_offset 8; \
81 			.cfi_offset %ebp, -8; \
82 			movl %esp,%ebp; \
83 			call PIC_PLT(HIDENAME(mcount)); \
84 			popl %ebp; \
85 			.cfi_restore %ebp; \
86 			.cfi_def_cfa_offset 4; \
87 			jmp 9f
88 #define	ENTRY(x)	_ENTRY(x); \
89 			pushl %ebp; \
90 			.cfi_def_cfa_offset 8; \
91 			.cfi_offset %ebp, -8; \
92 			movl %esp,%ebp; \
93 			call PIC_PLT(HIDENAME(mcount)); \
94 			popl %ebp; \
95 			.cfi_restore %ebp; \
96 			.cfi_def_cfa_offset 4; \
97 			9:
98 #else
99 #define	ALTENTRY(x)	_ENTRY(x)
100 #define	ENTRY(x)	_ENTRY(x)
101 #endif
102 
103 /*
104  * WEAK_REFERENCE(): create a weak reference alias from sym.
105  * The macro is not a general asm macro that takes arbitrary names,
106  * but one that takes only C names. It does the non-null name
107  * translation inside the macro.
108  */
109 
110 #define	WEAK_REFERENCE(sym, alias)					\
111 	.weak CNAME(alias);						\
112 	.equ CNAME(alias),CNAME(sym)
113 
114 /*
115  * STRONG_ALIAS: create a strong alias.
116  */
117 #define	STRONG_ALIAS(alias,sym)						\
118 	.globl alias;							\
119 	alias = sym
120 
121 #define RCSID(x)	.text; .asciz x
122 
123 #undef __FBSDID
124 #if !defined(STRIP_FBSDID)
125 #define __FBSDID(s)	.ident s
126 #else
127 #define __FBSDID(s)	/* nothing */
128 #endif /* not STRIP_FBSDID */
129 
130 #endif /* !_MACHINE_ASM_H_ */
131