Home | History | Annotate | Download | only in gen
      1 /*
      2  * CDDL HEADER START
      3  *
      4  * The contents of this file are subject to the terms of the
      5  * Common Development and Distribution License (the "License").
      6  * You may not use this file except in compliance with the License.
      7  *
      8  * You can obtain a copy of the license at usr/src/OPENSOLARIS.LICENSE
      9  * or http://www.opensolaris.org/os/licensing.
     10  * See the License for the specific language governing permissions
     11  * and limitations under the License.
     12  *
     13  * When distributing Covered Code, include this CDDL HEADER in each
     14  * file and include the License file at usr/src/OPENSOLARIS.LICENSE.
     15  * If applicable, add the following below this CDDL HEADER, with the
     16  * fields enclosed by brackets "[]" replaced with your own identifying
     17  * information: Portions Copyright [yyyy] [name of copyright owner]
     18  *
     19  * CDDL HEADER END
     20  */
     21 
     22 /*
     23  * Copyright 2008 Sun Microsystems, Inc.  All rights reserved.
     24  * Use is subject to license terms.
     25  */
     26 
     27 	.file	"memcpy.s"
     28 
     29 /*
     30  * memcpy(s1, s2, len)
     31  *
     32  * Copy s2 to s1, always copy n bytes.
     33  * Note: this does not work for overlapped copies, bcopy() does
     34  *
     35  * Added entry __align_cpy_1 is generally for use of the compilers.
     36  *
     37  *
     38  * Fast assembler language version of the following C-program for memcpy
     39  * which represents the `standard' for the C-library.
     40  *
     41  *	void *
     42  *	memcpy(void *s, const void *s0, size_t n)
     43  *	{
     44  *		if (n != 0) {
     45  *			char *s1 = s;
     46  *			const char *s2 = s0;
     47  *			do {
     48  *				*s1++ = *s2++;
     49  *			} while (--n != 0);
     50  *		}
     51  *		return (s);
     52  *	}
     53  */
     54 
     55 #include <sys/asm_linkage.h>
     56 
     57 	ANSI_PRAGMA_WEAK(memcpy,function)
     58 
     59 	ENTRY(memcpy)
     60 	ENTRY(__align_cpy_1)
     61 	mov	%o0, %g5		! save des address for return val
     62 	cmp	%o2, 17			! for small counts copy bytes
     63 	bleu,pn	%xcc, .dbytecp
     64 	andcc	%o1, 3, %o5		! is src word aligned
     65 	bz,pn	%icc, .aldst
     66 	cmp	%o5, 2			! is src half-word aligned
     67 	be,pt	%xcc, .s2algn
     68 	cmp	%o5, 3			! src is byte aligned
     69 .s1algn:ldub	[%o1], %o3		! move 1 or 3 bytes to align it
     70 	inc	1, %o1
     71 	stb	%o3, [%g5]		! move a byte to align src
     72 	inc	1, %g5
     73 	bne,pt	%icc, .s2algn
     74 	dec	%o2
     75 	b	.ald			! now go align dest
     76 	andcc	%g5, 3, %o5
     77 
     78 .s2algn:lduh	[%o1], %o3		! know src is 2 byte alinged
     79 	inc	2, %o1
     80 	srl	%o3, 8, %o4
     81 	stb	%o4, [%g5]		! have to do bytes,
     82 	stb	%o3, [%g5 + 1]		! don't know dst alingment
     83 	inc	2, %g5
     84 	dec	2, %o2
     85 
     86 .aldst:	andcc	%g5, 3, %o5		! align the destination address
     87 .ald:	bz,pn	%icc, .w4cp
     88 	cmp	%o5, 2
     89 	bz,pn	%icc, .w2cp
     90 	cmp	%o5, 3
     91 .w3cp:	lduw	[%o1], %o4
     92 	inc	4, %o1
     93 	srl	%o4, 24, %o5
     94 	stb	%o5, [%g5]
     95 	bne,pt	%icc, .w1cp
     96 	inc	%g5
     97 	dec	1, %o2
     98 	andn	%o2, 3, %o3		! o3 is aligned word count
     99 	dec	4, %o3			! avoid reading beyond tail of src
    100 	sub	%o1, %g5, %o1		! o1 gets the difference
    101 
    102 1:	sll	%o4, 8, %g1		! save residual bytes
    103 	lduw	[%o1+%g5], %o4
    104 	deccc	4, %o3
    105 	srl	%o4, 24, %o5		! merge with residual
    106 	or	%o5, %g1, %g1
    107 	st	%g1, [%g5]
    108 	bnz,pt	%xcc, 1b
    109 	inc	4, %g5
    110 	sub	%o1, 3, %o1		! used one byte of last word read
    111 	and	%o2, 3, %o2
    112 	b	7f
    113 	inc	4, %o2
    114 
    115 .w1cp:	srl	%o4, 8, %o5
    116 	sth	%o5, [%g5]
    117 	inc	2, %g5
    118 	dec	3, %o2
    119 	andn	%o2, 3, %o3		! o3 is aligned word count
    120 	dec	4, %o3			! avoid reading beyond tail of src
    121 	sub	%o1, %g5, %o1		! o1 gets the difference
    122 
    123 2:	sll	%o4, 24, %g1		! save residual bytes
    124 	lduw	[%o1+%g5], %o4
    125 	deccc	4, %o3
    126 	srl	%o4, 8, %o5		! merge with residual
    127 	or	%o5, %g1, %g1
    128 	st	%g1, [%g5]
    129 	bnz,pt	%xcc, 2b
    130 	inc	4, %g5
    131 	sub	%o1, 1, %o1		! used three bytes of last word read
    132 	and	%o2, 3, %o2
    133 	b	7f
    134 	inc	4, %o2
    135 
    136 .w2cp:	lduw	[%o1], %o4
    137 	inc	4, %o1
    138 	srl	%o4, 16, %o5
    139 	sth	%o5, [%g5]
    140 	inc	2, %g5
    141 	dec	2, %o2
    142 	andn	%o2, 3, %o3		! o3 is aligned word count
    143 	dec	4, %o3			! avoid reading beyond tail of src
    144 	sub	%o1, %g5, %o1		! o1 gets the difference
    145 
    146 3:	sll	%o4, 16, %g1		! save residual bytes
    147 	lduw	[%o1+%g5], %o4
    148 	deccc	4, %o3
    149 	srl	%o4, 16, %o5		! merge with residual
    150 	or	%o5, %g1, %g1
    151 	st	%g1, [%g5]
    152 	bnz,pt	%xcc, 3b
    153 	inc	4, %g5
    154 	sub	%o1, 2, %o1		! used two bytes of last word read
    155 	and	%o2, 3, %o2
    156 	b	7f
    157 	inc	4, %o2
    158 
    159 .w4cp:	andn	%o2, 3, %o3		! o3 is aligned word count
    160 	sub	%o1, %g5, %o1		! o1 gets the difference
    161 
    162 1:	lduw	[%o1+%g5], %o4		! read from address
    163 	deccc	4, %o3			! decrement count
    164 	st	%o4, [%g5]		! write at destination address
    165 	bgu,pt	%xcc, 1b
    166 	inc	4, %g5			! increment to address
    167 	b	7f
    168 	and	%o2, 3, %o2		! number of leftover bytes, if any
    169 
    170 	!
    171 	! differenced byte copy, works with any alignment
    172 	!
    173 .dbytecp:
    174 	b	7f
    175 	sub	%o1, %g5, %o1		! o1 gets the difference
    176 
    177 4:	stb	%o4, [%g5]		! write to address
    178 	inc	%g5			! inc to address
    179 7:	deccc	%o2			! decrement count
    180 	bgeu,a,pt %xcc,4b		! loop till done
    181 	ldub	[%o1+%g5], %o4		! read from address
    182 	retl
    183 	nop
    184 
    185 	SET_SIZE(memcpy)
    186 	SET_SIZE(__align_cpy_1)
    187