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Diffstat (limited to 'arch/ppc64/boot/crt0.S')
| -rw-r--r-- | arch/ppc64/boot/crt0.S | 48 |
1 files changed, 48 insertions, 0 deletions
diff --git a/arch/ppc64/boot/crt0.S b/arch/ppc64/boot/crt0.S new file mode 100644 index 000000000000..04d3e74cd72f --- /dev/null +++ b/arch/ppc64/boot/crt0.S @@ -0,0 +1,48 @@ +/* + * 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 <asm/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 + |