2 * Copyright (c) 1991, 1993
3 * The Regents of the University of California. All rights reserved.
5 * This code is derived from software contributed to Berkeley by
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17 * must display the following acknowledgement:
18 * This product includes software developed by the University of
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37 #include <machine/asm.h>
39 #if defined(LIBC_SCCS)
42 #endif /* LIBC_SCCS */
44 /* bcopy(s1, s2, n) */
49 addu t0, a0, a2 # t0 = end of s1 region
52 and t1, t1, t2 # t1 = true if from < to < (from+len)
53 beq t1, zero, forward # non overlapping, do forward copy
54 slt t2, a2, 12 # check for small copy
57 addu t1, a1, a2 # t1 = end of to region
59 lb v0, -1(t0) # copy bytes backwards,
60 subu t0, t0, 1 # doesnt happen often so do slow way
68 bne t2, zero, smallcpy # do a small bcopy
69 xor v0, a0, a1 # compare low two bits of addresses
71 subu a3, zero, a1 # compute # bytes to word align address
72 beq v0, zero, aligned # addresses can be word aligned
76 subu a2, a2, a3 # subtract from remaining count
77 LWHI v0, 0(a0) # get next 4 bytes (unaligned)
80 SWHI v0, 0(a1) # store 1, 2, or 3 bytes to align a1
83 and v0, a2, 3 # compute number of words left
86 addu a3, a3, a0 # compute ending address
88 LWHI v0, 0(a0) # copy words a0 unaligned, a1 aligned
98 subu a2, a2, a3 # subtract from remaining count
99 LWHI v0, 0(a0) # copy 1, 2, or 3 bytes to align
104 and v0, a2, 3 # compute number of whole words left
107 addu a3, a3, a0 # compute ending address
109 lw v0, 0(a0) # copy words
116 addu a3, a2, a0 # compute ending address
118 lbu v0, 0(a0) # copy bytes