/* $NetBSD: srtbegin.S,v 1.7 2005/12/11 12:17:10 christos Exp $ */
/*
* Copyright (c) 2002 Wasabi Systems, Inc.
* All rights reserved.
*
* Written by Jason R. Thorpe for Wasabi Systems, Inc.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
* 1. Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
* 2. Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in the
* documentation and/or other materials provided with the distribution.
* 3. All advertising materials mentioning features or use of this software
* must display the following acknowledgement:
* This product includes software developed for the NetBSD Project by
* Wasabi Systems, Inc.
* 4. The name of Wasabi Systems, Inc. may not be used to endorse
* or promote products derived from this software without specific prior
* written permission.
*
* THIS SOFTWARE IS PROVIDED BY WASABI SYSTEMS, INC. ``AS IS'' AND
* ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED
* TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
* PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL WASABI SYSTEMS, INC
* BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
* CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
* SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
* INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
* CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
* ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
* POSSIBILITY OF SUCH DAMAGE.
*/
#include <machine/asm.h>
#include <arm/armreg.h>
#define STACKSIZE 1024
ENTRY(start)
/*
* We assume we've been loaded VA==PA, or that the MMU
* is disabled. Make sure the MMU is disabled so that
* we don't have to care about the caches.
*/
mrc p15, 0, r2, c1, c0, 0
bic r2, r2, #CPU_CONTROL_MMU_ENABLE
mcr p15, 0, r2, c1, c0, 0
nop
nop
nop
/*
* Check to see if __text_store == &start. If not, we're most
* likely running from flash. Flash is slow, and we'd
* really like to run the code from RAM. Copy it out.
*/
adr r1, Ltext
ldmia r1, {r1-r3}
cmp r1, r2 /* __text_store == &start? */
beq relocated /* yes, in RAM */
/* Copy text segment from ROM to RAM */
1: ldrb r0, [r1], #0x01
strb r0, [r2], #0x01
cmp r2, r3 /* copy done? */
bne 1b
/*
* Okay, we are finished relocating the text segment. Now
* we need to leap to the next instruction.
*/
adr r1, Lrelocated
ldr pc, [r1]
relocated:
/*
* Check to see if __data_store == __data_start. If not,
* we're most likely built for running from flash,
* and must copy the data segment out to RAM.
*/
adr r1, Ldata
ldmia r1, {r1-r3}
cmp r1, r2 /* __data_store == __data_start? */
beq 2f /* yes, in RAM */
cmp r2, r3 /* __data_store == _edata? */
beq 2f /* yes, skip copy */
/* Copy data segment from ROM to RAM */
1: ldrb r0, [r1], #0x01
strb r0, [r2], #0x01
cmp r2, r3 /* copy done? */
bne 1b
2:
/* Clear the BSS. */
adr r1, Lbss
ldmia r1, {r1, r2}
sub r2, r2, r1
mov r3, #0
1: strb r3, [r1], #0x01
subs r2, r2, #0x01
bgt 1b
/* Set the stack pointer */
adr r1, Lstack
ldr r1, [r1]
add sp, r1, #STACKSIZE
b _C_LABEL(main)
Lrelocated:
.word relocated
Ltext:
.word _C_LABEL(__text_store)
.word _C_LABEL(start)
.word _C_LABEL(_etext)
Ldata:
.word _C_LABEL(__data_store)
.word _C_LABEL(__data_start)
Lbss:
.word _C_LABEL(_edata)
.word _C_LABEL(_end)
Lstack:
.word Lstackspace
.comm Lstackspace, STACKSIZE
