sysdep.h

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/* System call interface code for Sequent Symmetry running Dynix version 3.
Copyright (C) 1993 Free Software Foundation, Inc.
This file is part of the GNU C Library.

The GNU C Library is free software; you can redistribute it and/or
modify it under the terms of the GNU Library General Public License as
published by the Free Software Foundation; either version 2 of the
License, or (at your option) any later version.

The GNU C Library is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
Library General Public License for more details.

You should have received a copy of the GNU Library General Public
License along with the GNU C Library; see the file COPYING.LIB.  If
not, write to the Free Software Foundation, Inc., 675 Mass Ave,
Cambridge, MA 02139, USA.  */

#include <sysdeps/unix/i386/sysdep.h>

/* Get the symbols for system call interrupts.  */
#include <machine/trap.h>
  
/* Use the BSD versions of system calls, by setting the high 16 bits
   of the syscall number (see /usr/include/syscall.h).  */
#define SYS_HANDLER (SYS_bsd << 16)

/* Dynix uses an interrupt interface to system calls.
   "int $T_SVCn" are syscall interfaces for 0-6 arg functions.
   (see /usr/include/machine/trap.h).  */

#undef	DO_CALL

#ifdef	__STDC__
#define DO_CALL(syscall_name, args) 					      \
  movl $(SYS_HANDLER | SYS_##syscall_name), %eax;			      \
  int $T_SVC##args;
#else
#define DO_CALL(syscall_name, args)					      \
  movl $(SYS_HANDLER | SYS_/**/syscall_name), %eax;			      \
  int $T_SVC/**/args;
#endif

#undef	PSEUDO
#define	PSEUDO(name, syscall_name, args)				      \
  .text;								      \
  .globl syscall_error;							      \
  .align 4;								      \
  ENTRY (name)								      \
  ARGS (args)								      \
  DO_CALL (syscall_name, args)						      \
  jb syscall_error

/* For one and two-argument calls, Dynix takes the arguments in %ecx and
   %edx.  For 3-6 argument calls, Dynix takes the address of the first
   argument in %ecx.  */

#ifdef __STDC__
#define ARGS(n) ARGS_##n
#else
#define ARGS(n) ARGS_/**/n
#endif

#define ARGS_0
#define ARGS_1	movl 4(%esp), %ecx;
#define ARGS_2	movl 4(%esp), %ecx; movl 8(%esp), %edx;
#define ARGS_3	leal 4(%esp), %ecx;
#define ARGS_4	ARGS_3
#define ARGS_5	ARGS_3
#define ARGS_6	ARGS_3
  
/* Dynix reverses %ecx and %edx relative to most i386 Unices. */

#undef	r1
#define	r1		%ecx	/* Secondary return-value register.  */
#undef	scratch
#define scratch 	%edx	/* Call-clobbered register for random use.  */