/* * Copyright (C) Paul Mackerras 1997. * * 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. * * NOTE: this code runs in 32 bit mode and is packaged as ELF32. */ #include "ppc_asm.h" .text .globl _start _start: lis r9,_start@h lis r8,_etext@ha addi r8,r8,_etext@l 1: dcbf r0,r9 icbi r0,r9 addi r9,r9,0x20 cmplwi 0,r9,8 blt 1b sync 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 3f # If the size is zero, don't bother addi r8,r8,-4 # r8 -= 4 mtctr r7 # SPRN_CTR = number of words to clear li r0,0 # r0 = 0 2: stwu r0,4(r8) # Clear out a word bdnz 2b # Keep clearing until done 3: b start