[uClibc]Subject: libc/sysdeps/linux/mips/syscall.S

[Marshall M. Midden]

There were a number of problems with the file for 32 bit mips.
a) It was mixing new and old format calling conventions.
   (the new mips calling abi uses registers a0,a1,a2,a3,a4,a5,a6,a7 ...,
   whereas the original one for linux uses a0,a1,a2,a3,stack ... .
   linux/arch/mips/kernel/scall_o32.S, look for stackargs.
b) "a3" is missed.
c) Missing the .end and .size at the end of the file.
d) system calls that restart must do a reload of v0.

Here is my version of the file -- did not touch 64 bit mips.

/* Copyright (C) 1996, 1997 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 Lesser General Public
   License as published by the Free Software Foundation; either
   version 2.1 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
   Lesser General Public License for more details.

   You should have received a copy of the GNU Lesser General Public
   License along with the GNU C Library; if not, write to the Free
   Software Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA
   02111-1307 USA.  */

#include <features.h>
#include <asm/asm.h>
#include <asm/regdef.h>

#ifdef PIC
	.option	pic2
#endif
	.text
	.globl	syscall
	.ent	syscall, 0
syscall:
	move	v0, a0		/* Load system call number from first arg. */
	move	a0, a1		/* Move the next three args up a register. */
	move	a1, a2
	move	a2, a3
	/* Load the remaining possible args (up to 11) from the stack. */
#ifdef __mips64
	ld	t0,4*8(sp)
	ld	t1,5*8(sp)
	ld	t2,6*8(sp)
	ld	t3,7*8(sp)
	ld	t4,8*8(sp)
	ld	t5,9*8(sp)
	ld	t6,10*8(sp)
#else
	lw	a3,4*4(sp)
	lw	t0,5*4(sp)
	lw	t1,6*4(sp)
	lw	t2,7*4(sp)
	lw	t3,8*4(sp)
	addiu	sp,sp,36
	sw	t0,4*4(sp)
	sw	t1,5*4(sp)
	sw	t2,6*4(sp)
	sw	t3,7*4(sp)
	sw	v0,8*4(sp)
	lw	v0,8*4(sp)	/* for system call restarts */
#endif
	syscall			/* Do the system call. */
#ifndef __mips64
	addiu	sp,sp,36
#endif
	j	ra		/* Return to caller. */
	.end	syscall
	.size	syscall,.-syscall