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#

# __mmap.S, part of the i960 support for the uClibc library.

#

# Copyright (C) 2002 by Okiok Data Ltd.  http://www.okiok.com/

#

# This program 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.

#

# This program 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 this program; if not, write to the Free Software Foundation, Inc.,

# at 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA

#

# Derived from an old port of uC-libc to the i960 by Keith Adams (kma@cse.ogi.edu).

#

#include 

/* This is a plain system call.  The 6 arguments are already set up correctly */

/* void  *  mmap(void  *start,  size_t length, int prot , int flags, int fd, off_t offset) */

        .globl _mmap

_mmap:

        mov     g13, r3

        ldconst __NR_mmap, g13

        calls   0

        mov     r3, g13

        /* We now need to check if the return value is a small negative integer.                    */

        /* This is somewhat tricky as the return code (normally an address) is an                   */

        /* unsigned type, or an ordinal in i960 assembler.                                          */

        /* We'll use the fact that, integers from -256 to -1 are ordinals 0xFFFFFF00 to 0xFFFFFFFF. */

        /* So by checking that the return address is in the top range of the ordinals, we'll        */

        /* in fact be checking if it's not an encoded negated erro code.                            */

        /* The range -256 to -1 should be enough since that in uClinux 2.0.39, there are            */

        /* 124 system calls for the i960.                                                           */

        ldconst 0xFFFFFF00, r3  /* This is the integer's -256 representation */

        cmpobl  g0, r3, 1f      /* Something smaller than this means it's out of the range, and a valid address */

        subi    g0, 0, r3       /* If it's an errno, save its negated (now positive) value in _errno. */

        st      r3, _errno

        subi    1, 0, g0        /* And return -1. */

1:

        ret