| yuezonghe | 824eb0c | 2024-06-27 02:32:26 -0700 | [diff] [blame^] | 1 | # |
| 2 | # __mmap.S, part of the i960 support for the uClibc library. |
| 3 | # |
| 4 | # Copyright (C) 2002 by Okiok Data Ltd. http://www.okiok.com/ |
| 5 | # |
| 6 | # This program is free software; you can redistribute it and/or modify it under |
| 7 | # the terms of the GNU Library General Public License as published by the Free |
| 8 | # Software Foundation; either version 2 of the License, or (at your option) any |
| 9 | # later version. |
| 10 | # |
| 11 | # This program is distributed in the hope that it will be useful, but WITHOUT |
| 12 | # ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS |
| 13 | # FOR A PARTICULAR PURPOSE. See the GNU Library General Public License for more |
| 14 | # details. |
| 15 | # |
| 16 | # You should have received a copy of the GNU Library General Public License |
| 17 | # along with this program; if not, write to the Free Software Foundation, Inc., |
| 18 | # at 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA |
| 19 | # |
| 20 | # Derived from an old port of uC-libc to the i960 by Keith Adams (kma@cse.ogi.edu). |
| 21 | # |
| 22 | |
| 23 | #include <sys/syscall.h> |
| 24 | |
| 25 | /* This is a plain system call. The 6 arguments are already set up correctly */ |
| 26 | /* void * mmap(void *start, size_t length, int prot , int flags, int fd, off_t offset) */ |
| 27 | |
| 28 | |
| 29 | .globl _mmap |
| 30 | _mmap: |
| 31 | mov g13, r3 |
| 32 | ldconst __NR_mmap, g13 |
| 33 | calls 0 |
| 34 | mov r3, g13 |
| 35 | |
| 36 | /* We now need to check if the return value is a small negative integer. */ |
| 37 | /* This is somewhat tricky as the return code (normally an address) is an */ |
| 38 | /* unsigned type, or an ordinal in i960 assembler. */ |
| 39 | /* We'll use the fact that, integers from -256 to -1 are ordinals 0xFFFFFF00 to 0xFFFFFFFF. */ |
| 40 | /* So by checking that the return address is in the top range of the ordinals, we'll */ |
| 41 | /* in fact be checking if it's not an encoded negated erro code. */ |
| 42 | |
| 43 | /* The range -256 to -1 should be enough since that in uClinux 2.0.39, there are */ |
| 44 | /* 124 system calls for the i960. */ |
| 45 | |
| 46 | ldconst 0xFFFFFF00, r3 /* This is the integer's -256 representation */ |
| 47 | cmpobl g0, r3, 1f /* Something smaller than this means it's out of the range, and a valid address */ |
| 48 | subi g0, 0, r3 /* If it's an errno, save its negated (now positive) value in _errno. */ |
| 49 | st r3, _errno |
| 50 | subi 1, 0, g0 /* And return -1. */ |
| 51 | 1: |
| 52 | ret |