2 * Copyright (c) 1993 The Regents of the University of California.
3 * All rights reserved.
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 * 4. Neither the name of the University nor the names of its contributors
14 * may be used to endorse or promote products derived from this software
15 * without specific prior written permission.
17 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
18 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
19 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
20 * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
21 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
22 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
23 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
24 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
25 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
26 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
27 * SUCH DAMAGE.
29 * $FreeBSD: releng/6.2/sys/i386/include/asmacros.h 128019 2004-04-07 20:46:16Z imp $
32 #ifndef _MACHINE_ASMACROS_H_
33 #define _MACHINE_ASMACROS_H_
35 #include <sys/cdefs.h>
37 /* XXX too much duplication in various asm*.h's. */
40 * CNAME and HIDENAME manage the relationship between symbol names in C
41 * and the equivalent assembly language names. CNAME is given a name as
42 * it would be used in a C program. It expands to the equivalent assembly
43 * language name. HIDENAME is given an assembly-language name, and expands
44 * to a possibly-modified form that will be invisible to C programs.
46 #define CNAME(csym) csym
47 #define HIDENAME(asmsym) .asmsym
49 #define ALIGN_DATA .p2align 2 /* 4 byte alignment, zero filled */
50 #ifdef GPROF
51 #define ALIGN_TEXT .p2align 4,0x90 /* 16-byte alignment, nop filled */
53 #define ALIGN_TEXT .p2align 2,0x90 /* 4-byte alignment, nop filled */
55 #define SUPERALIGN_TEXT .p2align 4,0x90 /* 16-byte alignment, nop filled */
57 #define GEN_ENTRY(name) ALIGN_TEXT; .globl CNAME(name); \
58 .type CNAME(name),@function; CNAME(name):
59 #define NON_GPROF_ENTRY(name) GEN_ENTRY(name)
60 #define NON_GPROF_RET .byte 0xc3 /* opcode for `ret' */
62 #ifdef LOCORE
63 #define PCPU(member) %fs:PC_ ## member
64 #define PCPU_ADDR(member, reg) movl %fs:PC_PRVSPACE,reg; \
65 addl $PC_ ## member,reg
68 #ifdef GPROF
70 * __mcount is like [.]mcount except that doesn't require its caller to set
71 * up a frame pointer. It must be called before pushing anything onto the
72 * stack. gcc should eventually generate code to call __mcount in most
73 * cases. This would make -pg in combination with -fomit-frame-pointer
74 * useful. gcc has a configuration variable PROFILE_BEFORE_PROLOGUE to
75 * allow profiling before setting up the frame pointer, but this is
76 * inadequate for good handling of special cases, e.g., -fpic works best
77 * with profiling after the prologue.
79 * [.]mexitcount is a new function to support non-statistical profiling if an
80 * accurate clock is available. For C sources, calls to it are generated
81 * by the FreeBSD extension `-mprofiler-epilogue' to gcc. It is best to
82 * call [.]mexitcount at the end of a function like the MEXITCOUNT macro does,
83 * but gcc currently generates calls to it at the start of the epilogue to
84 * avoid problems with -fpic.
86 * [.]mcount and __mcount may clobber the call-used registers and %ef.
87 * [.]mexitcount may clobber %ecx and %ef.
89 * Cross-jumping makes non-statistical profiling timing more complicated.
90 * It is handled in many cases by calling [.]mexitcount before jumping. It
91 * is handled for conditional jumps using CROSSJUMP() and CROSSJUMP_LABEL().
92 * It is handled for some fault-handling jumps by not sharing the exit
93 * routine.
95 * ALTENTRY() must be before a corresponding ENTRY() so that it can jump to
96 * the main entry point. Note that alt entries are counted twice. They
97 * have to be counted as ordinary entries for gprof to get the call times
98 * right for the ordinary entries.
100 * High local labels are used in macros to avoid clashes with local labels
101 * in functions.
103 * Ordinary `ret' is used instead of a macro `RET' because there are a lot
104 * of `ret's. 0xc3 is the opcode for `ret' (`#define ret ... ret' can't
105 * be used because this file is sometimes preprocessed in traditional mode).
106 * `ret' clobbers eflags but this doesn't matter.
108 #define ALTENTRY(name) GEN_ENTRY(name) ; MCOUNT ; MEXITCOUNT ; jmp 9f
109 #define CROSSJUMP(jtrue, label, jfalse) \
110 jfalse 8f; MEXITCOUNT; jmp __CONCAT(to,label); 8:
111 #define CROSSJUMPTARGET(label) \
112 ALIGN_TEXT; __CONCAT(to,label): ; MCOUNT; jmp label
113 #define ENTRY(name) GEN_ENTRY(name) ; 9: ; MCOUNT
114 #define FAKE_MCOUNT(caller) pushl caller ; call __mcount ; popl %ecx
115 #define MCOUNT call __mcount
116 #define MCOUNT_LABEL(name) GEN_ENTRY(name) ; nop ; ALIGN_TEXT
117 #define MEXITCOUNT call HIDENAME(mexitcount)
118 #define ret MEXITCOUNT ; NON_GPROF_RET
120 #else /* !GPROF */
122 * ALTENTRY() has to align because it is before a corresponding ENTRY().
123 * ENTRY() has to align to because there may be no ALTENTRY() before it.
124 * If there is a previous ALTENTRY() then the alignment code for ENTRY()
125 * is empty.
127 #define ALTENTRY(name) GEN_ENTRY(name)
128 #define CROSSJUMP(jtrue, label, jfalse) jtrue label
129 #define CROSSJUMPTARGET(label)
130 #define ENTRY(name) GEN_ENTRY(name)
131 #define FAKE_MCOUNT(caller)
132 #define MCOUNT
133 #define MCOUNT_LABEL(name)
134 #define MEXITCOUNT
135 #endif /* GPROF */
137 #ifdef LOCORE
139 * Convenience macros for declaring interrupt entry points and trap
140 * stubs.
142 #define IDTVEC(name) ALIGN_TEXT; .globl __CONCAT(X,name); \
143 .type __CONCAT(X,name),@function; __CONCAT(X,name):
144 #define TRAP(a) pushl $(a) ; jmp alltraps
146 #endif /* LOCORE */
148 #endif /* !_MACHINE_ASMACROS_H_ */
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