start.S revision 302408
1/*- 2 * Copyright (c) 2016 Stanislav Galabov 3 * All rights reserved. 4 * 5 * Redistribution and use in source and binary forms, with or without 6 * modification, are permitted provided that the following conditions 7 * are met: 8 * 1. Redistributions of source code must retain the above copyright 9 * notice, this list of conditions and the following disclaimer. 10 * 2. Redistributions in binary form must reproduce the above copyright 11 * notice, this list of conditions and the following disclaimer in the 12 * documentation and/or other materials provided with the distribution. 13 * 14 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND 15 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 16 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 17 * ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE 18 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 19 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 20 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 21 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 22 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 23 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 24 * SUCH DAMAGE. 25 * 26 * $FreeBSD: stable/11/sys/boot/mips/uboot/start.S 296183 2016-02-29 07:47:04Z sgalabov $ 27 */ 28 29#include <machine/asm.h> 30 31 .text 32 .extern _C_LABEL(main) 33 .weak _DYNAMIC 34 35/* 36 * Entry point to the loader that U-Boot passes control to. 37 */ 38ENTRY(_start) 39 PTR_S sp, uboot_address 40 j main 41 nop 42END(_start) 43 44/* 45 * syscall() 46 */ 47ENTRY(syscall) 48 PTR_S ra, ret_address 49 PTR_L t9, syscall_ptr 50 jalr t9 51 nop 52 PTR_L ra, ret_address 53 jr ra 54 nop 55END(syscall) 56 57/* 58 * Data section 59 */ 60 .data 61 .align 8 62 .globl syscall_ptr 63syscall_ptr: 64 .dword 0 65 66 .globl uboot_address 67uboot_address: 68 .dword 0 69 70ret_address: 71 .dword 0 72