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/*
* memmove routine for Z8000
* Copyright (C) 2004 Christian Groessler <chris@groessler.org>
*
* Permission to use, copy, modify, and distribute this file
* for any purpose is hereby granted without fee, provided that
* the above copyright notice and this notice appears in all
* copies.
*
* This file is distributed WITHOUT ANY WARRANTY; without even the implied
* warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.
*/
/* void *memmove(void *dest, const void *src, size_t length);
*/
name "memmove.S"
.text
even
global _memmove
_memmove:
#ifdef __Z8001__
segm
#ifdef __STD_CALL__
ldl rr6,rr14(#4)
ldl rr4,rr14(#8)
ldl rr2,rr14(#12)
#else
pushl @rr14,rr6
#endif
/* rr2 - length (high word ignored)
* rr4 - src
* rr6 - dest
*/
testl rr2
jr z,finish
/* check for destructive overlap (src < dest && dest < src + length) */
cpl rr6,rr4
jp ule,memmove_entry /* non-destructive, let memcpy do the work */
ldl rr0,rr2
addl rr0,rr4 /* rr0 = src + length */
cpl rr0,rr6
jp ult,memmove_entry /* non-destructive, let memcpy do the work */
/* set-up pointers to copy backwards, add (length - 1) */
addl rr4,rr2 /* src + length */
addl rr6,rr2 /* dest + length */
subl rr4,#1
subl rr6,#1
/* check alignment */
bitb rl7,#0 /* odd destination address? */
jr z,testsrc
bitb rl5,#0 /* odd source address? */
jr z,odd_copy
jr even_copy
testsrc:
bitb rl5,#0
jr nz,odd_copy /* src even, dest odd */
lddb @rr6,@rr4,r3
jr ov,finish /* jump if r5 is zero now */
/* copy words */
even_copy:
ld r2,r3 /* remember length */
srl r3,#1
/* jr z,no_words it cannot be zero here */
dec r5,#1
dec r7,#1
lddr @rr6,@rr4,r3
no_words:
bitb rl2,#0 /* odd length? */
jr z,finish
inc r5,#1
inc r7,#1
lddb @rr6,@rr4,r2 /* yes, copy last byte */
jr finish
/* copy bytes */
odd_copy:
lddrb @rr6,@rr4,r3
finish:
#ifdef __STD_CALL__
ldl rr6,rr14(#4)
#else
popl rr2,@rr14
#endif
#else /* above Z8001, below Z8002 */
unsegm
#ifdef __STD_CALL__
ld r7,r15(#2)
ld r6,r15(#4)
ld r5,r15(#6)
#else
ld r2,r7 /* buffer pointer return value */
#endif
/* r5 - length
* r6 - src
* r7 - dest
*/
test r5
jr z,finish
/* check for destructive overlap (src < dest && dest < src + length) */
cp r7,r6
jp ule,memmove_entry /* non-destructive, let memcpy do the work */
ld r0,r5
add r0,r6 /* r0 = src + length */
cp r0,r7
jp ult,memmove_entry /* non-destructive, let memcpy do the work */
/* set-up pointers to copy backwards, add (length - 1) */
add r6,r5 /* src + length */
add r7,r5 /* dest + length */
dec r6,#1
dec r7,#1
/* check alignment */
bitb rl7,#0 /* odd destination address? */
jr z,testsrc
bitb rl6,#0 /* odd source address? */
jr z,odd_copy
jr even_copy
testsrc:
bitb rl6,#0
jr nz,odd_copy /* src even, dest odd */
lddb @r7,@r6,r5
jr ov,finish /* jump if r5 is zero now */
/* copy words */
even_copy:
ld r4,r5 /* remember length */
srl r5,#1
/* jr z,no_words it cannot be zero here */
dec r6,#1
dec r7,#1
lddr @r7,@r6,r5
no_words:
bitb rl4,#0 /* odd length? */
jr z,finish
inc r6,#1
inc r7,#1
lddb @r7,@r6,r4 /* yes, copy last byte */
jr finish
/* copy bytes */
odd_copy:
lddrb @r7,@r6,r5
finish:
#ifdef __STD_CALL__
ld r7,r15(#2)
#endif
#endif /* Z8002 */
ret
.end
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