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+/* 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