1/* $NetBSD: srtbegin.S,v 1.4 2002/02/24 20:44:28 thorpej Exp $ */ 2 3/* 4 * Copyright (c) 2002 Wasabi Systems, Inc. 5 * All rights reserved. 6 * 7 * Written by Jason R. Thorpe for Wasabi Systems, Inc. 8 * 9 * Redistribution and use in source and binary forms, with or without 10 * modification, are permitted provided that the following conditions 11 * are met: 12 * 1. Redistributions of source code must retain the above copyright 13 * notice, this list of conditions and the following disclaimer. 14 * 2. Redistributions in binary form must reproduce the above copyright 15 * notice, this list of conditions and the following disclaimer in the 16 * documentation and/or other materials provided with the distribution. 17 * 3. All advertising materials mentioning features or use of this software 18 * must display the following acknowledgement: 19 * This product includes software developed for the NetBSD Project by 20 * Wasabi Systems, Inc. 21 * 4. The name of Wasabi Systems, Inc. may not be used to endorse 22 * or promote products derived from this software without specific prior 23 * written permission. 24 * 25 * THIS SOFTWARE IS PROVIDED BY WASABI SYSTEMS, INC. ``AS IS'' AND 26 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED 27 * TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR 28 * PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL WASABI SYSTEMS, INC 29 * BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR 30 * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF 31 * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS 32 * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN 33 * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) 34 * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE 35 * POSSIBILITY OF SUCH DAMAGE. 36 */ 37 38#include <machine/asm.h> 39#include <arm/armreg.h> 40 41#define STACKSIZE 1024 42 43ENTRY(start) 44 /* 45 * We assume we've been loaded VA==PA, or that the MMU 46 * is disabled. Make sure the MMU is disabled so that 47 * we don't have to care about the caches. 48 */ 49 mrc p15, 0, r2, c1, c0, 0 50 bic r2, r2, #CPU_CONTROL_MMU_ENABLE 51 mcr p15, 0, r2, c1, c0, 0 52 53 nop 54 nop 55 nop 56 57 /* 58 * Check to see if __text_store == &start. If not, we're most 59 * likely running from flash. Flash is slow, and we'd 60 * really like to run the code from RAM. Copy it out. 61 */ 62 add r1, pc, #(Ltext - . - 8) 63 ldmia r1, {r1-r3} 64 cmp r1, r2 /* __text_store == &start? */ 65 beq relocated /* yes, in RAM */ 66 67 /* Copy text segment from ROM to RAM */ 681: ldrb r0, [r1], #0x01 69 strb r0, [r2], #0x01 70 cmp r2, r3 /* copy done? */ 71 bne 1b 72 73 /* 74 * Okay, we are finished relocating the text segment. Now 75 * we need to leap to the next instruction. 76 */ 77 add r1, pc, #(Lrelocated - . - 8) 78 ldr pc, [r1] 79 80relocated: 81 /* 82 * Check to see if __data_store == __data_start. If not, 83 * we're most likely built for running from flash, 84 * and must copy the data segment out to RAM. 85 */ 86 add r1, pc, #(Ldata - . - 8) 87 ldmia r1, {r1-r3} 88 cmp r1, r2 /* __data_store == __data_start? */ 89 beq 2f /* yes, in RAM */ 90 91 /* Copy data segment from ROM to RAM */ 921: ldrb r0, [r1], #0x01 93 strb r0, [r2], #0x01 94 cmp r2, r3 /* copy done? */ 95 bne 1b 96 972: 98 /* Clear the BSS. */ 99 add r1, pc, #(Lbss - . - 8) 100 ldmia r1, {r1, r2} 101 sub r2, r2, r1 102 mov r3, #0 103 1041: strb r3, [r1], #0x01 105 subs r2, r2, #0x01 106 bgt 1b 107 108 /* Set the stack pointer */ 109 add r1, pc, #(Lstack - . - 8) 110 ldr r1, [r1] 111 add sp, r1, #STACKSIZE 112 113 b _C_LABEL(main) 114 115Lrelocated: 116 .word relocated 117 118Ltext: 119 .word _C_LABEL(__text_store) 120 .word _C_LABEL(start) 121 .word _C_LABEL(_etext) 122 123Ldata: 124 .word _C_LABEL(__data_store) 125 .word _C_LABEL(__data_start) 126 127Lbss: 128 .word _C_LABEL(_edata) 129 .word _C_LABEL(_end) 130 131Lstack: 132 .word Lstackspace 133 134 .comm Lstackspace, STACKSIZE 135