xref: /freebsd/sys/amd64/include/asmacros.h (revision 7f3dea244c40159a41ab22da77a434d7c5b5e85a)
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 1.16 1997/04/22 06:55:32 jdp Exp $
34  */
35 
36 #ifndef _MACHINE_ASMACROS_H_
37 #define _MACHINE_ASMACROS_H_
38 
39 #include <sys/cdefs.h>
40 #include <machine/asnames.h>
41 
42 /* XXX too much duplication in various asm*.h's. */
43 
44 /*
45  * CNAME and HIDENAME manage the relationship between symbol names in C
46  * and the equivalent assembly language names.  CNAME is given a name as
47  * it would be used in a C program.  It expands to the equivalent assembly
48  * language name.  HIDENAME is given an assembly-language name, and expands
49  * to a possibly-modified form that will be invisible to C programs.
50  */
51 #if defined(__ELF__)
52 #define CNAME(csym)		csym
53 #define HIDENAME(asmsym)	__CONCAT(.,asmsym)
54 #else
55 #define CNAME(csym)		__CONCAT(_,csym)
56 #define HIDENAME(asmsym)	asmsym
57 #endif
58 
59 #define ALIGN_DATA	.p2align 2	/* 4 byte alignment, zero filled */
60 #ifdef GPROF
61 #define ALIGN_TEXT	.p2align 4,0x90	/* 16-byte alignment, nop filled */
62 #else
63 #define ALIGN_TEXT	.p2align 2,0x90	/* 4-byte alignment, nop filled */
64 #endif
65 #define SUPERALIGN_TEXT	.p2align 4,0x90	/* 16-byte alignment, nop filled */
66 
67 #define GEN_ENTRY(name)		ALIGN_TEXT; .globl CNAME(name); \
68 				.type CNAME(name),@function; CNAME(name):
69 #define NON_GPROF_ENTRY(name)	GEN_ENTRY(name)
70 #define NON_GPROF_RET		.byte 0xc3	/* opcode for `ret' */
71 
72 #ifdef GPROF
73 /*
74  * __mcount is like [.]mcount except that doesn't require its caller to set
75  * up a frame pointer.  It must be called before pushing anything onto the
76  * stack.  gcc should eventually generate code to call __mcount in most
77  * cases.  This would make -pg in combination with -fomit-frame-pointer
78  * useful.  gcc has a configuration variable PROFILE_BEFORE_PROLOGUE to
79  * allow profiling before setting up the frame pointer, but this is
80  * inadequate for good handling of special cases, e.g., -fpic works best
81  * with profiling after the prologue.
82  *
83  * [.]mexitcount is a new function to support non-statistical profiling if an
84  * accurate clock is available.  For C sources, calls to it are generated
85  * by the FreeBSD extension `-mprofiler-epilogue' to gcc.  It is best to
86  * call [.]mexitcount at the end of a function like the MEXITCOUNT macro does,
87  * but gcc currently generates calls to it at the start of the epilogue to
88  * avoid problems with -fpic.
89  *
90  * [.]mcount and __mcount may clobber the call-used registers and %ef.
91  * [.]mexitcount may clobber %ecx and %ef.
92  *
93  * Cross-jumping makes non-statistical profiling timing more complicated.
94  * It is handled in many cases by calling [.]mexitcount before jumping.  It
95  * is handled for conditional jumps using CROSSJUMP() and CROSSJUMP_LABEL().
96  * It is handled for some fault-handling jumps by not sharing the exit
97  * routine.
98  *
99  * ALTENTRY() must be before a corresponding ENTRY() so that it can jump to
100  * the main entry point.  Note that alt entries are counted twice.  They
101  * have to be counted as ordinary entries for gprof to get the call times
102  * right for the ordinary entries.
103  *
104  * High local labels are used in macros to avoid clashes with local labels
105  * in functions.
106  *
107  * Ordinary `ret' is used instead of a macro `RET' because there are a lot
108  * of `ret's.  0xc3 is the opcode for `ret' (`#define ret ... ret' can't
109  * be used because this file is sometimes preprocessed in traditional mode).
110  * `ret' clobbers eflags but this doesn't matter.
111  */
112 #define ALTENTRY(name)		GEN_ENTRY(name) ; MCOUNT ; MEXITCOUNT ; jmp 9f
113 #define	CROSSJUMP(jtrue, label, jfalse) \
114 	jfalse 8f; MEXITCOUNT; jmp __CONCAT(to,label); 8:
115 #define CROSSJUMPTARGET(label) \
116 	ALIGN_TEXT; __CONCAT(to,label): ; MCOUNT; jmp label
117 #define ENTRY(name)		GEN_ENTRY(name) ; 9: ; MCOUNT
118 #define FAKE_MCOUNT(caller)	pushl caller ; call __mcount ; popl %ecx
119 #define MCOUNT			call __mcount
120 #define MCOUNT_LABEL(name)	GEN_ENTRY(name) ; nop ; ALIGN_TEXT
121 #define MEXITCOUNT		call HIDENAME(mexitcount)
122 #define ret			MEXITCOUNT ; NON_GPROF_RET
123 
124 #else /* !GPROF */
125 /*
126  * ALTENTRY() has to align because it is before a corresponding ENTRY().
127  * ENTRY() has to align to because there may be no ALTENTRY() before it.
128  * If there is a previous ALTENTRY() then the alignment code for ENTRY()
129  * is empty.
130  */
131 #define ALTENTRY(name)		GEN_ENTRY(name)
132 #define	CROSSJUMP(jtrue, label, jfalse)	jtrue label
133 #define	CROSSJUMPTARGET(label)
134 #define ENTRY(name)		GEN_ENTRY(name)
135 #define FAKE_MCOUNT(caller)
136 #define MCOUNT
137 #define MCOUNT_LABEL(name)
138 #define MEXITCOUNT
139 #endif /* GPROF */
140 
141 #endif /* !_MACHINE_ASMACROS_H_ */
142