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Diffstat (limited to 'kernel/arch/mn10300/lib/memmove.S')
| -rw-r--r-- | kernel/arch/mn10300/lib/memmove.S | 160 |
1 files changed, 160 insertions, 0 deletions
diff --git a/kernel/arch/mn10300/lib/memmove.S b/kernel/arch/mn10300/lib/memmove.S new file mode 100644 index 000000000..20b07b62b --- /dev/null +++ b/kernel/arch/mn10300/lib/memmove.S @@ -0,0 +1,160 @@ +/* MN10300 Optimised simple memory to memory copy, with support for overlapping + * regions + * + * Copyright (C) 2007 Red Hat, Inc. All Rights Reserved. + * Written by David Howells (dhowells@redhat.com) + * + * This program is free software; you can redistribute it and/or + * modify it under the terms of the GNU General Public Licence + * as published by the Free Software Foundation; either version + * 2 of the Licence, or (at your option) any later version. + */ +#include <asm/cache.h> + + .section .text + .balign L1_CACHE_BYTES + +############################################################################### +# +# void *memmove(void *dst, const void *src, size_t n) +# +############################################################################### + .globl memmove + .type memmove,@function +memmove: + # fall back to memcpy if dst < src to work bottom up + cmp d1,d0 + bcs memmove_memcpy + + # work top down + movm [d2,d3],(sp) + mov d0,(12,sp) + mov d1,(16,sp) + mov (20,sp),d2 # count + add d0,d2,a0 # dst end + add d1,d2,a1 # src end + mov d0,e3 # the return value + + cmp +0,d2 + beq memmove_done # return if zero-length copy + + # see if the three parameters are all four-byte aligned + or d0,d1,d3 + or d2,d3 + and +3,d3 + bne memmove_1 # jump if not + + # we want to transfer as much as we can in chunks of 32 bytes + add -4,a1 + cmp +31,d2 + bls memmove_4_remainder # 4-byte aligned remainder + + add -32,d2 + mov +32,d3 + +memmove_4_loop: + mov (a1),d0 + sub_sub +4,a1,+4,a0 + mov d0,(a0) + mov (a1),d1 + sub_sub +4,a1,+4,a0 + mov d1,(a0) + + mov (a1),d0 + sub_sub +4,a1,+4,a0 + mov d0,(a0) + mov (a1),d1 + sub_sub +4,a1,+4,a0 + mov d1,(a0) + + mov (a1),d0 + sub_sub +4,a1,+4,a0 + mov d0,(a0) + mov (a1),d1 + sub_sub +4,a1,+4,a0 + mov d1,(a0) + + mov (a1),d0 + sub_sub +4,a1,+4,a0 + mov d0,(a0) + mov (a1),d1 + sub_sub +4,a1,+4,a0 + mov d1,(a0) + + sub d3,d2 + bcc memmove_4_loop + + add d3,d2 + beq memmove_4_no_remainder + +memmove_4_remainder: + # cut 4-7 words down to 0-3 + cmp +16,d2 + bcs memmove_4_three_or_fewer_words + mov (a1),d0 + sub_sub +4,a1,+4,a0 + mov d0,(a0) + mov (a1),d1 + sub_sub +4,a1,+4,a0 + mov d1,(a0) + mov (a1),e0 + sub_sub +4,a1,+4,a0 + mov e0,(a0) + mov (a1),e1 + sub_sub +4,a1,+4,a0 + mov e1,(a0) + add -16,d2 + beq memmove_4_no_remainder + + # copy the remaining 1, 2 or 3 words +memmove_4_three_or_fewer_words: + cmp +8,d2 + bcs memmove_4_one_word + beq memmove_4_two_words + mov (a1),d0 + sub_sub +4,a1,+4,a0 + mov d0,(a0) +memmove_4_two_words: + mov (a1),d0 + sub_sub +4,a1,+4,a0 + mov d0,(a0) +memmove_4_one_word: + mov (a1),d0 + sub_sub +4,a1,+4,a0 + mov d0,(a0) + +memmove_4_no_remainder: + # check we copied the correct amount + # TODO: REMOVE CHECK + sub e3,a0,d2 + beq memmove_done + break + break + break + +memmove_done: + mov e3,a0 + ret [d2,d3],8 + + # handle misaligned copying +memmove_1: + add -1,a1 + add -1,d2 + mov +1,d3 + setlb # setlb requires the next insns + # to occupy exactly 4 bytes + + sub d3,d2 + movbu (a1),d0 + sub_sub d3,a1,d3,a0 + movbu d0,(a0) + lcc + + mov e3,a0 + ret [d2,d3],8 + +memmove_memcpy: + jmp memcpy + +memmove_end: + .size memmove, memmove_end-memmove |