File:  [DragonFly] / src / sys / i386 / include / Attic / asmacros.h
Revision 1.6: download - view: text, annotated - select for diffs
Thu Dec 4 20:09:33 2003 UTC (10 years, 4 months ago) by dillon
Branches: MAIN
CVS tags: HEAD
General cleanups as part of the libcaps userland threading work.

    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:  * $FreeBSD: src/sys/i386/include/asmacros.h,v 1.18 1999/08/28 00:44:06 peter Exp $
   34:  * $DragonFly: src/sys/i386/include/asmacros.h,v 1.6 2003/12/04 20:09:33 dillon Exp $
   35:  */
   36: 
   37: #ifndef _MACHINE_ASMACROS_H_
   38: #define _MACHINE_ASMACROS_H_
   39: 
   40: #include <sys/cdefs.h>
   41: 
   42: #ifdef _KERNEL
   43: 
   44: /*
   45:  * Access to a per-cpu data element
   46:  */
   47: #define PCPU(x) %fs:gd_ ## x
   48: 
   49: #endif
   50: 
   51: /*
   52:  * CNAME and HIDENAME manage the relationship between symbol names in C
   53:  * and the equivalent assembly language names.  CNAME is given a name as
   54:  * it would be used in a C program.  It expands to the equivalent assembly
   55:  * language name.  HIDENAME is given an assembly-language name, and expands
   56:  * to a possibly-modified form that will be invisible to C programs.
   57:  */
   58: #define CNAME(csym)		csym
   59: #define HIDENAME(asmsym)	__CONCAT(.,asmsym)
   60: 
   61: #define ALIGN_PAGE	.p2align PAGE_SHIFT	/* page alignment */
   62: #define ALIGN_DATA	.p2align 2	/* 4 byte alignment, zero filled */
   63: #ifdef GPROF
   64: #define ALIGN_TEXT	.p2align 4,0x90	/* 16-byte alignment, nop filled */
   65: #else
   66: #define ALIGN_TEXT	.p2align 2,0x90	/* 4-byte alignment, nop filled */
   67: #endif
   68: #define SUPERALIGN_TEXT	.p2align 4,0x90	/* 16-byte alignment, nop filled */
   69: 
   70: #define GEN_ENTRY(name)		ALIGN_TEXT; .globl CNAME(name); \
   71: 				.type CNAME(name),@function; CNAME(name):
   72: #define NON_GPROF_ENTRY(name)	GEN_ENTRY(name)
   73: #define NON_GPROF_RET		.byte 0xc3	/* opcode for `ret' */
   74: 
   75: #ifdef GPROF
   76: /*
   77:  * __mcount is like [.]mcount except that doesn't require its caller to set
   78:  * up a frame pointer.  It must be called before pushing anything onto the
   79:  * stack.  gcc should eventually generate code to call __mcount in most
   80:  * cases.  This would make -pg in combination with -fomit-frame-pointer
   81:  * useful.  gcc has a configuration variable PROFILE_BEFORE_PROLOGUE to
   82:  * allow profiling before setting up the frame pointer, but this is
   83:  * inadequate for good handling of special cases, e.g., -fpic works best
   84:  * with profiling after the prologue.
   85:  *
   86:  * [.]mexitcount is a new function to support non-statistical profiling if an
   87:  * accurate clock is available.  For C sources, calls to it are generated
   88:  * by the FreeBSD extension `-mprofiler-epilogue' to gcc.  It is best to
   89:  * call [.]mexitcount at the end of a function like the MEXITCOUNT macro does,
   90:  * but gcc currently generates calls to it at the start of the epilogue to
   91:  * avoid problems with -fpic.
   92:  *
   93:  * [.]mcount and __mcount will not clobber the call-used registers or %ef.
   94:  * [.]mexitcount will not clobber the call-used registers or %ef.
   95:  *
   96:  * Cross-jumping makes non-statistical profiling timing more complicated.
   97:  * It is handled in many cases by calling [.]mexitcount before jumping.  It
   98:  * is handled for conditional jumps using CROSSJUMP() and CROSSJUMP_LABEL().
   99:  * It is handled for some fault-handling jumps by not sharing the exit
  100:  * routine.
  101:  *
  102:  * ALTENTRY() must be before a corresponding ENTRY() so that it can jump to
  103:  * the main entry point.  Note that alt entries are counted twice.  They
  104:  * have to be counted as ordinary entries for gprof to get the call times
  105:  * right for the ordinary entries.
  106:  *
  107:  * High local labels are used in macros to avoid clashes with local labels
  108:  * in functions.
  109:  *
  110:  * Ordinary `ret' is used instead of a macro `RET' because there are a lot
  111:  * of `ret's.  0xc3 is the opcode for `ret' (`#define ret ... ret' can't
  112:  * be used because this file is sometimes preprocessed in traditional mode).
  113:  * `ret' clobbers eflags but this doesn't matter.
  114:  */
  115: #define ALTENTRY(name)		GEN_ENTRY(name) ; MCOUNT ; MEXITCOUNT ; jmp 9f
  116: #define	CROSSJUMP(jtrue, label, jfalse) \
  117: 	jfalse 8f; MEXITCOUNT; jmp __CONCAT(to,label); 8:
  118: #define CROSSJUMPTARGET(label) \
  119: 	ALIGN_TEXT; __CONCAT(to,label): ; MCOUNT; jmp label
  120: #define ENTRY(name)		GEN_ENTRY(name) ; 9: ; MCOUNT
  121: #define FAKE_MCOUNT(caller)	pushl caller ; call __mcount ; addl $4,%esp
  122: #define MCOUNT			call __mcount
  123: #define MCOUNT_LABEL(name)	GEN_ENTRY(name) ; nop ; ALIGN_TEXT
  124: #define MEXITCOUNT		call HIDENAME(mexitcount)
  125: #define ret			MEXITCOUNT ; NON_GPROF_RET
  126: 
  127: #else /* !GPROF */
  128: /*
  129:  * ALTENTRY() has to align because it is before a corresponding ENTRY().
  130:  * ENTRY() has to align to because there may be no ALTENTRY() before it.
  131:  * If there is a previous ALTENTRY() then the alignment code for ENTRY()
  132:  * is empty.
  133:  */
  134: #define ALTENTRY(name)		GEN_ENTRY(name)
  135: #define	CROSSJUMP(jtrue, label, jfalse)	jtrue label
  136: #define	CROSSJUMPTARGET(label)
  137: #define ENTRY(name)		GEN_ENTRY(name)
  138: #define FAKE_MCOUNT(caller)
  139: #define MCOUNT
  140: #define MCOUNT_LABEL(name)
  141: #define MEXITCOUNT
  142: #endif /* GPROF */
  143: 
  144: #endif /* !_MACHINE_ASMACROS_H_ */