![Jörn Engel](/assets/img/avatar_default.png)
Signed-off-by: Jörn Engel <joern@wohnheim.fh-wedel.de> Signed-off-by: Adrian Bunk <bunk@stusta.de>
81 lines
2.3 KiB
ArmAsm
81 lines
2.3 KiB
ArmAsm
/* Copyright (c) 1997 Paul Mackerras <paulus@cs.anu.edu.au>
|
|
* Initial Power Macintosh COFF version.
|
|
* Copyright (c) 1999 Grant Erickson <grant@lcse.umn.edu>
|
|
* Modifications for IBM PowerPC 400-class processor evaluation
|
|
* boards.
|
|
*
|
|
* Module name: crt0.S
|
|
*
|
|
* Description:
|
|
* Boot loader execution entry point. Clears out .bss section as per
|
|
* ANSI C requirements. Invalidates and flushes the caches over the
|
|
* range covered by the boot loader's .text section. Sets up a stack
|
|
* below the .text section entry point.
|
|
*
|
|
* This program is free software; you can redistribute it and/or
|
|
* modify it under the terms of the GNU General Public License
|
|
* as published by the Free Software Foundation; either version
|
|
* 2 of the License, or (at your option) any later version.
|
|
*/
|
|
|
|
#include <asm/ppc_asm.h>
|
|
|
|
.text
|
|
|
|
.globl _start
|
|
_start:
|
|
#ifdef XCOFF
|
|
.long __start,0,0
|
|
|
|
.globl __start
|
|
__start:
|
|
#endif
|
|
|
|
## Flush and invalidate the caches for the range in memory covering
|
|
## the .text section of the boot loader
|
|
|
|
lis r9,_start@h # r9 = &_start
|
|
lis r8,_etext@ha #
|
|
addi r8,r8,_etext@l # r8 = &_etext
|
|
3: dcbf r0,r9 # Flush the data cache
|
|
icbi r0,r9 # Invalidate the instruction cache
|
|
addi r9,r9,0x10 # Increment by one cache line
|
|
cmplw cr0,r9,r8 # Are we at the end yet?
|
|
blt 3b # No, keep flushing and invalidating
|
|
sync # sync ; isync after flushing the icache
|
|
isync
|
|
|
|
## Clear out the BSS as per ANSI C requirements
|
|
|
|
lis r7,_end@ha
|
|
addi r7,r7,_end@l # r7 = &_end
|
|
lis r8,__bss_start@ha #
|
|
addi r8,r8,__bss_start@l # r8 = &_bss_start
|
|
|
|
## Determine how large an area, in number of words, to clear
|
|
|
|
subf r7,r8,r7 # r7 = &_end - &_bss_start + 1
|
|
addi r7,r7,3 # r7 += 3
|
|
srwi. r7,r7,2 # r7 = size in words.
|
|
beq 2f # If the size is zero, do not bother
|
|
addi r8,r8,-4 # r8 -= 4
|
|
mtctr r7 # SPRN_CTR = number of words to clear
|
|
li r0,0 # r0 = 0
|
|
1: stwu r0,4(r8) # Clear out a word
|
|
bdnz 1b # If we are not done yet, keep clearing
|
|
2:
|
|
|
|
#ifdef CONFIG_40x
|
|
## Set up the stack
|
|
|
|
lis r9,_start@h # r9 = &_start (text section entry)
|
|
ori r9,r9,_start@l
|
|
subi r1,r9,64 # Start the stack 64 bytes below _start
|
|
clrrwi r1,r1,4 # Make sure it is aligned on 16 bytes.
|
|
li r0,0
|
|
stwu r0,-16(r1)
|
|
mtlr r9
|
|
#endif
|
|
|
|
b start # All done, start the real work.
|