# # __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