xref: /freebsd/sys/amd64/include/asmacros.h (revision 952d112864d8008aa87278a30a539d888a8493cd)
1 /*-
2  * Copyright (c) 1993 The Regents of the University of California.
3  * All rights reserved.
4  *
5  * Redistribution and use in source and binary forms, with or without
6  * modification, are permitted provided that the following conditions
7  * are met:
8  * 1. Redistributions of source code must retain the above copyright
9  *    notice, this list of conditions and the following disclaimer.
10  * 2. Redistributions in binary form must reproduce the above copyright
11  *    notice, this list of conditions and the following disclaimer in the
12  *    documentation and/or other materials provided with the distribution.
13  * 3. All advertising materials mentioning features or use of this software
14  *    must display the following acknowledgement:
15  *	This product includes software developed by the University of
16  *	California, Berkeley and its contributors.
17  * 4. Neither the name of the University nor the names of its contributors
18  *    may be used to endorse or promote products derived from this software
19  *    without specific prior written permission.
20  *
21  * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
22  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
23  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
24  * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
25  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
26  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
27  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
28  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
29  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
30  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
31  * SUCH DAMAGE.
32  *
33  *	$Id: asmacros.h,v 1.14 1997/02/22 09:33:56 peter Exp $
34  */
35 
36 #ifndef _MACHINE_ASMACROS_H_
37 #define _MACHINE_ASMACROS_H_
38 
39 #include <sys/cdefs.h>
40 
41 /* XXX too much duplication in various asm*.h's. */
42 
43 #define ALIGN_DATA	.align	2	/* 4 byte alignment, zero filled */
44 #ifdef GPROF
45 #define ALIGN_TEXT	.align	4,0x90	/* 16-byte alignment, nop filled */
46 #else
47 #define ALIGN_TEXT	.align	2,0x90	/* 4-byte alignment, nop filled */
48 #endif
49 #define SUPERALIGN_TEXT	.align	4,0x90	/* 16-byte alignment, nop filled */
50 
51 #define GEN_ENTRY(name)		ALIGN_TEXT; .globl __CONCAT(_,name); \
52 				__CONCAT(_,name):
53 #define NON_GPROF_ENTRY(name)	GEN_ENTRY(name)
54 #define NON_GPROF_RET		.byte 0xc3	/* opcode for `ret' */
55 
56 #ifdef GPROF
57 /*
58  * __mcount is like mcount except that doesn't require its caller to set
59  * up a frame pointer.  It must be called before pushing anything onto the
60  * stack.  gcc should eventually generate code to call __mcount in most
61  * cases.  This would make -pg in combination with -fomit-frame-pointer
62  * useful.  gcc has a configuration variable PROFILE_BEFORE_PROLOGUE to
63  * allow profiling before setting up the frame pointer, but this is
64  * inadequate for good handling of special cases, e.g., -fpic works best
65  * with profiling after the prologue.
66  *
67  * mexitcount is a new function to support non-statistical profiling if an
68  * accurate clock is available.  For C sources, calls to it are generated
69  * by the FreeBSD extension `-mprofiler-epilogue' to gcc.  It is best to
70  * call mexitcount at the end of a function like the MEXITCOUNT macro does,
71  * but gcc currently generates calls to it at the start of the epilogue to
72  * avoid problems with -fpic.
73  *
74  * mcount and __mexitcount may clobber the call-used registers and %ef.
75  * mexitcount may clobber %ecx and %ef.
76  *
77  * Cross-jumping makes non-statistical profiling timing more complicated.
78  * It is handled in many cases by calling mexitcount before jumping.  It is
79  * handled for conditional jumps using CROSSJUMP() and CROSSJUMP_LABEL().
80  * It is handled for some fault-handling jumps by not sharing the exit
81  * routine.
82  *
83  * ALTENTRY() must be before a corresponding ENTRY() so that it can jump to
84  * the main entry point.  Note that alt entries are counted twice.  They
85  * have to be counted as ordinary entries for gprof to get the call times
86  * right for the ordinary entries.
87  *
88  * High local labels are used in macros to avoid clashes with local labels
89  * in functions.
90  *
91  * Ordinary `ret' is used instead of a macro `RET' because there are a lot
92  * of `ret's.  0xc3 is the opcode for `ret' (`#define ret ... ret' can't
93  * be used because this file is sometimes preprocessed in traditional mode).
94  * `ret' clobbers eflags but this doesn't matter.
95  */
96 #define ALTENTRY(name)		GEN_ENTRY(name) ; MCOUNT ; MEXITCOUNT ; jmp 9f
97 #define	CROSSJUMP(jtrue, label, jfalse) \
98 	jfalse 8f; MEXITCOUNT; jmp __CONCAT(to,label); 8:
99 #define CROSSJUMPTARGET(label) \
100 	ALIGN_TEXT; __CONCAT(to,label): ; MCOUNT; jmp label
101 #define ENTRY(name)		GEN_ENTRY(name) ; 9: ; MCOUNT
102 #define FAKE_MCOUNT(caller)	pushl caller ; call __mcount ; popl %ecx
103 #define MCOUNT			call __mcount
104 #define MCOUNT_LABEL(name)	GEN_ENTRY(name) ; nop ; ALIGN_TEXT
105 #define MEXITCOUNT		call mexitcount
106 #define ret			MEXITCOUNT ; NON_GPROF_RET
107 
108 #else /* !GPROF */
109 /*
110  * ALTENTRY() has to align because it is before a corresponding ENTRY().
111  * ENTRY() has to align to because there may be no ALTENTRY() before it.
112  * If there is a previous ALTENTRY() then the alignment code for ENTRY()
113  * is empty.
114  */
115 #define ALTENTRY(name)		GEN_ENTRY(name)
116 #define	CROSSJUMP(jtrue, label, jfalse)	jtrue label
117 #define	CROSSJUMPTARGET(label)
118 #define ENTRY(name)		GEN_ENTRY(name)
119 #define FAKE_MCOUNT(caller)
120 #define MCOUNT
121 #define MCOUNT_LABEL(name)
122 #define MEXITCOUNT
123 #endif /* GPROF */
124 
125 #endif /* !_MACHINE_ASMACROS_H_ */
126