freebsd-dev/sys/amd64/include/asmacros.h
1996-03-31 04:17:25 +00:00

128 lines
5.5 KiB
C

/*-
* Copyright (c) 1993 The Regents of the University of California.
* All rights reserved.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
* 1. Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
* 2. Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in the
* documentation and/or other materials provided with the distribution.
* 3. All advertising materials mentioning features or use of this software
* must display the following acknowledgement:
* This product includes software developed by the University of
* California, Berkeley and its contributors.
* 4. Neither the name of the University nor the names of its contributors
* may be used to endorse or promote products derived from this software
* without specific prior written permission.
*
* THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
* ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
* ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
* FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
* OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
* OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
* SUCH DAMAGE.
*
* $Id: asmacros.h,v 1.6 1995/12/29 15:28:53 bde Exp $
*/
#ifndef _MACHINE_ASMACROS_H_
#define _MACHINE_ASMACROS_H_
#ifdef KERNEL
/* XXX too much duplication in various asm*.h's and gprof.h's */
#define ALIGN_DATA .align 2 /* 4 byte alignment, zero filled */
#define ALIGN_TEXT .align 2,0x90 /* 4-byte alignment, nop filled */
#define SUPERALIGN_TEXT .align 4,0x90 /* 16-byte alignment (better for 486), nop filled */
#define GEN_ENTRY(name) ALIGN_TEXT; .globl _/**/name; _/**/name:
#define NON_GPROF_ENTRY(name) GEN_ENTRY(name)
#ifdef GPROF
/*
* __mcount is like mcount except that doesn't require its caller to set
* up a frame pointer. It must be called before pushing anything onto the
* stack. gcc should eventually generate code to call __mcount in most
* cases. This would make -pg in combination with -fomit-frame-pointer
* useful. gcc has a configuration variable PROFILE_BEFORE_PROLOGUE to
* allow profiling before setting up the frame pointer, but this is
* inadequate for good handling of special cases, e.g., -fpic works best
* with profiling after the prologue.
*
* Neither __mcount nor mcount requires %eax to point to 4 bytes of data,
* so don't waste space allocating the data or time setting it up. Changes
* to avoid the wastage in gcc-2.4.5-compiled code are available.
*
* mexitcount is a new profiling feature to allow accurate timing of all
* functions if an accurate clock is available. Changes to gcc-2.4.5 to
* support it are are available. The changes currently don't allow not
* generating mexitcounts for non-kernel code. It is best to call
* mexitcount right at the end of a function like the MEXITCOUNT macro
* does, but the changes to gcc only implement calling it as the first
* thing in the epilogue to avoid problems with -fpic.
*
* mcount and __mexitcount may clobber the call-used registers and %ef.
* mexitcount may clobber %ecx and %ef.
*
* Cross-jumping makes accurate timing more difficult. It is handled in
* many cases by calling mexitcount before jumping. It is not handled
* for some conditional jumps (e.g., in bcopyx) or for some fault-handling
* jumps. It is handled for some fault-handling jumps by not sharing the
* exit routine.
*
* ALTENTRY() must be before a corresponding ENTRY() so that it can jump to
* the main entry point. Note that alt entries are counted twice. They
* have to be counted as ordinary entries for gprof to get the call times
* right for the ordinary entries.
*
* High local labels are used in macros to avoid clashes with local labels
* in functions.
*
* "ret" is used instead of "RET" because there are a lot of "ret"s.
* 0xc3 is the opcode for "ret" (#define ret ... ret fails because this
* file is preprocessed in traditional mode). "ret" clobbers eflags
* but this doesn't matter.
*/
#define ALTENTRY(name) GEN_ENTRY(name) ; MCOUNT ; MEXITCOUNT ; jmp 9f
#define ENTRY(name) GEN_ENTRY(name) ; 9: ; MCOUNT
#define FAKE_MCOUNT(caller) pushl caller ; call __mcount ; popl %ecx
#define MCOUNT call __mcount
#define MCOUNT_LABEL(name) GEN_ENTRY(name) ; nop ; ALIGN_TEXT
#define MEXITCOUNT call mexitcount
#define ret MEXITCOUNT ; .byte 0xc3
#else /* not GPROF */
/*
* ALTENTRY() has to align because it is before a corresponding ENTRY().
* ENTRY() has to align to because there may be no ALTENTRY() before it.
* If there is a previous ALTENTRY() then the alignment code for ENTRY()
* is empty.
*/
#define ALTENTRY(name) GEN_ENTRY(name)
#define ENTRY(name) GEN_ENTRY(name)
#define FAKE_MCOUNT(caller)
#define MCOUNT
#define MCOUNT_LABEL(name)
#define MEXITCOUNT
#endif /* GPROF */
#else /* !KERNEL */
#include "/usr/src/lib/libc/i386/DEFS.h" /* XXX blech */
#ifndef RCSID
#define RCSID(a)
#endif
#endif /* KERNEL */
#endif /* !_MACHINE_ASMACROS_H_ */