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/*
* memcmp 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.
*/
/* int memcmp(const void *b1, const void *b2, size_t length);
*/
name "memcmp.S"
.text
even
global _memcmp
_memcmp:
#ifdef __Z8001__
segm
#ifdef __STD_CALL__
ldl rr6,rr14(#4)
ldl rr4,rr14(#8)
ldl rr2,rr14(#12)
#endif
/* rr2 - length (high word ignored)
* rr4 - b2
* rr6 - b1
*/
clr r1 /* initialize return value */
testl rr2
jr z,finish
bitb rl7,#0 /* odd b1? */
jr nz,testb2
bitb rl5,#0 /* odd b2? */
jr nz,odd_cmp /* b1 even, b2 odd */
jr t,even_cmp
testb2:
bitb rl5,#0
jr z,odd_cmp /* b2 even, b1 odd */
cpsib @rr6,@rr4,r3,eq
jr z,beq /* bytes are the same */
jr t,byte_diff
beq: jr ov,finish /* jump if r3 is zero now */
/* compare words */
even_cmp:
ld r2,r3 /* remember length */
srl r3,#1
jr z,no_words
cpsir @rr6,@rr4,r3,ne
jr nz,no_words
dec r7,#2
dec r5,#2 /* point to different bytes */
ldk r3,#2
jr t,odd_cmp
no_words:
bitb rl2,#0 /* odd length? */
jr z,finish
cpsib @rr6,@rr4,r3,eq
jr z,finish /* last bytes are the same */
jr t,byte_diff
/* compare bytes */
odd_cmp:
cpsirb @rr6,@rr4,r3,ne
jr nz,finish
byte_diff:
dec r7,#1
dec r5,#1 /* point to different bytes */
ldb rl1,@rr6
clr r0
ldb rl0,@rr4
sub r1,r0
finish: /* set return value */
#ifdef __STD_CALL__
ld r7,r1
#else
ld r2,r1
#endif
#else /* above Z8001, below Z8002 */
unsegm
#ifdef __STD_CALL__
ld r7,r15(#2)
ld r6,r15(#4)
ld r5,r15(#6)
#endif
/* r5 - length
* r6 - b2
* r7 - b1
*/
clr r1 /* initialize return value */
test r5
jr z,finish
bitb rl7,#0 /* odd destination address? */
jr nz,testb2
bitb rl6,#0 /* odd source address? */
jr nz,odd_cmp /* b1 even, b2 odd */
jr t,even_cmp
testb2:
bitb rl6,#0
jr z,odd_cmp /* b2 even, b1 odd */
cpsib @r7,@r6,r5,eq
jr z,beq /* bytes are the same */
jr t,byte_diff
beq: jr ov,finish /* jump if r3 is zero now */
/* compare words */
even_cmp:
ld r4,r5 /* remember length */
srl r5,#1
jr z,no_words
cpsir @r7,@r6,r5,ne
jr nz,no_words
dec r7,#2
dec r6,#2 /* point to different bytes */
ldk r5,#2
jr t,odd_cmp
no_words:
bitb rl4,#0 /* odd length? */
jr z,finish
cpsib @r7,@r6,r4,eq
jr z,finish /* last bytes are the same */
jr t,byte_diff
/* compare bytes */
odd_cmp:
cpsirb @r7,@r6,r5,ne
jr nz,finish
byte_diff:
dec r7,#1
dec r6,#1 /* point to different bytes */
ldb rl1,@r7
clr r0
ldb rl0,@r6
sub r1,r0
finish:
#ifdef __STD_CALL__
ld r7,r1
#else
ld r2,r1
#endif
#endif /* Z8002 */
ret
.end
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