diff options
Diffstat (limited to 'libc/sysdeps/linux/i960/mmap.S')
| -rw-r--r-- | libc/sysdeps/linux/i960/mmap.S | 52 |
1 files changed, 52 insertions, 0 deletions
diff --git a/libc/sysdeps/linux/i960/mmap.S b/libc/sysdeps/linux/i960/mmap.S new file mode 100644 index 000000000..bc4267948 --- /dev/null +++ b/libc/sysdeps/linux/i960/mmap.S @@ -0,0 +1,52 @@ +# +# __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 <sys/syscall.h> + +/* 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 |