romboot.S revision 1.2
1 /* $NetBSD: romboot.S,v 1.2 2002/01/03 11:22:17 shin Exp $ */ 2 3 /*- 4 * Copyright (c) 2001 Takao Shinohara. 5 * All rights reserved. 6 * 7 * Redistribution and use in source and binary forms, with or without 8 * modification, are permitted provided that the following conditions 9 * are met: 10 * 1. Redistributions of source code must retain the above copyright 11 * notice, this list of conditions and the following disclaimer. 12 * 2. Redistributions in binary form must reproduce the above copyright 13 * notice, this list of conditions and the following disclaimer in the 14 * documentation and/or other materials provided with the distribution. 15 * 16 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND 17 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 18 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 19 * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE 20 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 21 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 22 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 23 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 24 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 25 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 26 * SUCH DAMAGE. 27 */ 28 29 /* 30 * simple boot loader for ROM 31 * 32 * supported platform: LASER5 L-Router(L-Board) 33 */ 34 35 #define zero $0 36 #define AT $at 37 #define v0 $2 38 #define v1 $3 39 #define a0 $4 40 #define a1 $5 41 #define a2 $6 42 #define a3 $7 43 #define t0 $8 44 #define t1 $9 45 #define t2 $10 46 #define t3 $11 47 #define t4 $12 48 #define t5 $13 49 #define t6 $14 50 #define t7 $15 51 #define s0 $16 52 #define s1 $17 53 #define s2 $18 54 #define s3 $19 55 #define s4 $20 56 #define s5 $21 57 #define s6 $22 58 #define s7 $23 59 #define t8 $24 60 #define t9 $25 61 #define k0 $26 62 #define k1 $27 63 #define gp $28 64 #define sp $29 65 #define s8 $30 66 #define ra $31 67 68 #define MIPS_KSEG1_START 0xa0000000 69 #define KERNEL_LOADADDR 0x80030000 70 71 .text 72 .set noreorder 73 .globl _start 74 _start: 75 bal 1f # ra = ROM address + 8 76 nop 77 1: subu a0, ra, 8 # a0 = ROM address 78 move s0, a0 # keep it in s0 79 la t0, _etext 80 la t1, _ftext 81 subu t0, t1 # t0 = size of boot loader 82 addu a0, t0 # a0 = kernel address in ROM 83 li a1, KERNEL_LOADADDR 84 li t2, (1024*1024*3) # max kernel size = 3MB - boot 85 subu t2, t0 86 addu t2, a1 # kernel end address 87 or a1, MIPS_KSEG1_START # convert to kseg1 addr 88 or t2, MIPS_KSEG1_START # convert to kseg1 addr 89 2: 90 lw v0, 0(a0) 91 sw v0, 0(a1) 92 addu a0, 4 93 bltu a1, t2, 2b 94 addu a1, 4 # BDSLOT 95 96 li a0, 1 # argc = 1 97 addu a1, sp, -16 # argv 98 la t0, argv0 99 addu t0, s0 100 sw t0, 0(a1) # argv[0] = "netbsd" 101 sw zero, 4(a1) # argv[1] = NULL 102 la a2, bootinfo 103 addu a2, s0 104 move a3, zero 105 li t9, KERNEL_LOADADDR 106 jr t9 107 nop 108 109 argv0: .asciiz "netbsd" 110 111 bootinfo: 112 .word 34 # len 113 .word 0x13536135 # magic 114 .word 0 # fb_addr 115 .word 0, 0 # fb_line_bytes, fb_width, fb_height, fb_type 116 .word 2 # BI_CNUSE_SERIAL 117 .word 0x04104500 # VR4122 118 .word 0x03810200 # LASER5 L-BOARD 119 /* 120 * kernel binary image begins here. 121 */ 122
Indexes created Mon Oct 20 16:09:52 GMT 2025