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/* dlentry.s
*
* $Id$
*
* This file contains the entry veneer for RTEMS programs
* downloaded to the eth-comm board.
*
* This file was written by Jay Monkman (jmonkman@fracsa.com)
* It was based on the dlentry.s file for the Papyrus BSP,
* written by:
*
* Author: Andrew Bray <andy@i-cubed.co.uk>
*
* COPYRIGHT (c) 1995 by i-cubed ltd.
*
* To anyone who acknowledges that this file is provided "AS IS"
* without any express or implied warranty:
* permission to use, copy, modify, and distribute this file
* for any purpose is hereby granted without fee, provided that
* the above copyright notice and this notice appears in all
* copies, and that the name of i-cubed limited not be used in
* advertising or publicity pertaining to distribution of the
* software without specific, written prior permission.
* i-cubed limited makes no representations about the suitability
* of this software for any purpose.
*
*/
#include <rtems/asm.h>
/*
* The initial stack is set to run BELOW the code base address.
* (between the vectors and text sections)
*
* All the entry veneer has to do is to clear the BSS.
*/
/*
* GDB likes to have debugging information for the entry veneer.
* Here is some DWARF information.
*/
/*
* There was some debugging info here, but I removed it because I
* couldn't get it to work. It isn't really necessary as far as I
* can tell. It should still be in the papyrus BSP. -Jay
*/
/*
* On entry to download_entry, R3 will hold a pointer to a Board Info
* Block (boardinfo_t). This should be copied as soon as possible
* to the global M860_binfo. (The block should be copied, _NOT_
* the pointer)
*/
.section ".entry" /* This might have to be the first thing in the
* text section. At one time, it had to be
* first, but I don't believe it is true
* andy more. */
PUBLIC_VAR (start)
SYM(start):
bl .startup
base_addr:
/*
* Parameters from linker
*/
toc_pointer:
.long s.got
bss_length:
.long bss.size
bss_addr:
.long bss.start
PUBLIC_VAR (text_addr)
text_addr:
.long text.start
PUBLIC_VAR (text_length)
text_length:
.long text.size
/*
* Initialization code
*/
.startup:
/* Get start address */
mflr r1
/* clear the bss section */
bl bssclr
/*
* Copy the Board Info Block
*/
.extern SYM(M860_binfo)
lis r6, SYM(M860_binfo)@ha
addi r6, r6, SYM(M860_binfo)@l
lhz r4, 0(r3) /* Load the size of the block */
rlwinm. r4, r4, 30, 0x3fffffff /* get number of words */
mtctr r4
cpy_b: lwz r5, 0(r3) /* In with the old ... */
stw r5, 0(r6) /* ... Out with the new */
addi r6, r6, 0x4 /* Go to the next word */
addi r3, r3, 0x4
bdnz cpy_b /* decrement counter and loop */
/*
* C_setup.
*/
/* set toc */
lwz r2, toc_pointer-base_addr(r1)
/* Set up stack pointer = beginning of text section - 56 */
addi r1, r1, -56-4
lis r9, 0xff00
addi r10, 0, -16384
sth r10, 0x950(r9)
lis r9, 0x0000
addi r9, r9, 0x0007
mtspr 0x9e, r9
lis r5,environ@ha
la r5,environ@l(r5) /* environp */
li r4, 0 /* argv */
li r3, 0 /* argc */
.extern SYM (boot_card)
bl SYM (boot_card) /* call the first C routine */
loopstop:
b loopstop
/*
* bssclr - zero out bss
*/
bssclr:
lwz r4, bss_addr-base_addr(r1) /* Start of bss */
lwz r5, bss_length-base_addr(r1) /* Length of bss */
rlwinm. r5,r5,30,0x3FFFFFFF /* form length/4 */
beqlr /* no bss */
mtctr r5 /* set ctr reg */
xor r6,r6,r6 /* r6 = 0 */
clear_bss:
stswi r6,r4,0x4 /* store r6 */
addi r4,r4,0x4 /* update r2 */
bdnz clear_bss /* dec counter and loop */
blr /* return */
.comm environ,4,4
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