| # |
| # __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 |