/*
 * OpenRISC string.S
 *
 * Linux architectural port borrowing liberally from similar works of
 * others.  All original copyrights apply as per the original source
 * declaration.
 *
 * Modifications for the OpenRISC architecture:
 * Copyright (C) 2003 Matjaz Breskvar <phoenix@bsemi.com>
 * Copyright (C) 2010-2011 Jonas Bonn <jonas@southpole.se>
 *
 *      This program is free software; you can redistribute it and/or
 *      modify it under the terms of the GNU General Public License
 *      as published by the Free Software Foundation; either version
 *      2 of the License, or (at your option) any later version.
 */

#include <linux/linkage.h>
#include <asm/errno.h>

        /*
         * this can be optimized by doing gcc inline assemlby with
         * proper constraints (no need to save args registers...)
         *
         */


/*
 *
 * int __copy_tofrom_user(void *to, const void *from, unsigned long size);
 *
 * NOTE: it returns number of bytes NOT copied !!!
 *
 */
        .global __copy_tofrom_user
__copy_tofrom_user:
        l.addi  r1,r1,-12
        l.sw    0(r1),r6
        l.sw    4(r1),r4
        l.sw    8(r1),r3

        l.addi  r11,r5,0
2:      l.sfeq  r11,r0
        l.bf    1f
        l.addi  r11,r11,-1
8:      l.lbz   r6,0(r4)
9:      l.sb    0(r3),r6
        l.addi  r3,r3,1
        l.j     2b
        l.addi  r4,r4,1
1:
        l.addi  r11,r11,1               // r11 holds the return value

        l.lwz   r6,0(r1)
        l.lwz   r4,4(r1)
        l.lwz   r3,8(r1)
        l.jr    r9
        l.addi  r1,r1,12

        .section .fixup, "ax"
99:
                l.j     1b
                l.nop
        .previous

        .section __ex_table, "a"
                .long 8b, 99b           // read fault
                .long 9b, 99b           // write fault
        .previous

/*
 * unsigned long clear_user(void *addr, unsigned long size) ;
 *
 * NOTE: it returns number of bytes NOT cleared !!!
 */
        .global __clear_user
__clear_user:
        l.addi  r1,r1,-8
        l.sw    0(r1),r4
        l.sw    4(r1),r3

2:      l.sfeq  r4,r0
        l.bf    1f
        l.addi  r4,r4,-1
9:      l.sb    0(r3),r0
        l.j     2b
        l.addi  r3,r3,1

1:
        l.addi  r11,r4,1

        l.lwz   r4,0(r1)
        l.lwz   r3,4(r1)
        l.jr    r9
        l.addi  r1,r1,8

        .section .fixup, "ax"
99:
                l.j     1b
                l.nop
        .previous

        .section __ex_table, "a"
                .long 9b, 99b           // write fault
        .previous

/*
 * long strncpy_from_user(char *dst, const char *src, long count)
 *
 *
 */
        .global __strncpy_from_user
__strncpy_from_user:
        l.addi  r1,r1,-16
        l.sw    0(r1),r6
        l.sw    4(r1),r5
        l.sw    8(r1),r4
        l.sw    12(r1),r3

        l.addi  r11,r5,0
2:      l.sfeq  r5,r0
        l.bf    1f
        l.addi  r5,r5,-1
8:      l.lbz   r6,0(r4)
        l.sfeq  r6,r0
        l.bf    1f
9:      l.sb    0(r3),r6
        l.addi  r3,r3,1
        l.j     2b
        l.addi  r4,r4,1
1:
        l.lwz   r6,0(r1)
        l.addi  r5,r5,1
        l.sub   r11,r11,r5              // r11 holds the return value

        l.lwz   r6,0(r1)
        l.lwz   r5,4(r1)
        l.lwz   r4,8(r1)
        l.lwz   r3,12(r1)
        l.jr    r9
        l.addi  r1,r1,16

        .section .fixup, "ax"
99:
                l.movhi r11,hi(-EFAULT)
                l.ori   r11,r11,lo(-EFAULT)

                l.lwz   r6,0(r1)
                l.lwz   r5,4(r1)
                l.lwz   r4,8(r1)
                l.lwz   r3,12(r1)
                l.jr    r9
                l.addi  r1,r1,16
        .previous

        .section __ex_table, "a"
                .long 8b, 99b           // read fault
        .previous

/*
 * extern int __strnlen_user(const char *str, long len, unsigned long top);
 *
 *
 * RTRN: - length of a string including NUL termination character
 *       - on page fault 0
 */

        .global __strnlen_user
__strnlen_user:
        l.addi  r1,r1,-8
        l.sw    0(r1),r6
        l.sw    4(r1),r3

        l.addi  r11,r0,0
2:      l.sfeq  r11,r4
        l.bf    1f
        l.addi  r11,r11,1
8:      l.lbz   r6,0(r3)
        l.sfeq  r6,r0
        l.bf    1f
        l.sfgeu r3,r5                  // are we over the top ?
        l.bf    99f
        l.j     2b
        l.addi  r3,r3,1

1:
        l.lwz   r6,0(r1)
        l.lwz   r3,4(r1)
        l.jr    r9
        l.addi  r1,r1,8

        .section .fixup, "ax"
99:
                l.addi  r11,r0,0

                l.lwz   r6,0(r1)
                l.lwz   r3,4(r1)
                l.jr    r9
                l.addi  r1,r1,8
        .previous

        .section __ex_table, "a"
                .long 8b, 99b           // read fault
        .previous