xref: /onnv-gate/usr/src/lib/libc/sparcv9/gen/strncpy.s (revision 7298:b69e27387f74)
10Sstevel@tonic-gate/*
20Sstevel@tonic-gate * CDDL HEADER START
30Sstevel@tonic-gate *
40Sstevel@tonic-gate * The contents of this file are subject to the terms of the
56812Sraf * Common Development and Distribution License (the "License").
66812Sraf * You may not use this file except in compliance with the License.
70Sstevel@tonic-gate *
80Sstevel@tonic-gate * You can obtain a copy of the license at usr/src/OPENSOLARIS.LICENSE
90Sstevel@tonic-gate * or http://www.opensolaris.org/os/licensing.
100Sstevel@tonic-gate * See the License for the specific language governing permissions
110Sstevel@tonic-gate * and limitations under the License.
120Sstevel@tonic-gate *
130Sstevel@tonic-gate * When distributing Covered Code, include this CDDL HEADER in each
140Sstevel@tonic-gate * file and include the License file at usr/src/OPENSOLARIS.LICENSE.
150Sstevel@tonic-gate * If applicable, add the following below this CDDL HEADER, with the
160Sstevel@tonic-gate * fields enclosed by brackets "[]" replaced with your own identifying
170Sstevel@tonic-gate * information: Portions Copyright [yyyy] [name of copyright owner]
180Sstevel@tonic-gate *
190Sstevel@tonic-gate * CDDL HEADER END
200Sstevel@tonic-gate */
216812Sraf
220Sstevel@tonic-gate/*
236812Sraf * Copyright 2008 Sun Microsystems, Inc.  All rights reserved.
240Sstevel@tonic-gate * Use is subject to license terms.
250Sstevel@tonic-gate */
260Sstevel@tonic-gate
27*7298SMark.J.Nelson@Sun.COM	.file	"strncpy.s"
280Sstevel@tonic-gate
290Sstevel@tonic-gate/*
300Sstevel@tonic-gate * strncpy(s1, s2)
310Sstevel@tonic-gate *
320Sstevel@tonic-gate * Copy string s2 to s1, truncating or null-padding to always copy n bytes
330Sstevel@tonic-gate * return s1.
340Sstevel@tonic-gate *
350Sstevel@tonic-gate * Fast assembler language version of the following C-program for strncpy
360Sstevel@tonic-gate * which represents the `standard' for the C-library.
370Sstevel@tonic-gate *
380Sstevel@tonic-gate *	char *
390Sstevel@tonic-gate *	strncpy(char *s1, const char *s2, size_t n)
400Sstevel@tonic-gate *	{
410Sstevel@tonic-gate *		char *os1 = s1;
420Sstevel@tonic-gate *
430Sstevel@tonic-gate *		n++;
440Sstevel@tonic-gate *		while ((--n != 0) &&  ((*s1++ = *s2++) != '\0'))
450Sstevel@tonic-gate *			;
460Sstevel@tonic-gate *		if (n != 0)
470Sstevel@tonic-gate *			while (--n != 0)
480Sstevel@tonic-gate *				*s1++ = '\0';
490Sstevel@tonic-gate *		return (os1);
500Sstevel@tonic-gate *	}
510Sstevel@tonic-gate */
520Sstevel@tonic-gate
530Sstevel@tonic-gate#include <sys/asm_linkage.h>
540Sstevel@tonic-gate
550Sstevel@tonic-gate	! strncpy works similarly to strcpy, except that n bytes of s2
560Sstevel@tonic-gate	! are copied to s1. If a null character is reached in s2 yet more
570Sstevel@tonic-gate	! bytes remain to be copied, strncpy will copy null bytes into
580Sstevel@tonic-gate	! the destination string.
590Sstevel@tonic-gate	!
600Sstevel@tonic-gate	! This implementation works by first aligning the src ptr and
610Sstevel@tonic-gate	! performing small copies until it is aligned.  Then, the string
620Sstevel@tonic-gate	! is copied based upon destination alignment.  (byte, half-word,
630Sstevel@tonic-gate	! word, etc.)
640Sstevel@tonic-gate
650Sstevel@tonic-gate	ENTRY(strncpy)
660Sstevel@tonic-gate
670Sstevel@tonic-gate	.align 32
680Sstevel@tonic-gate	nop				! pad to align loop on 16-byte boundary
690Sstevel@tonic-gate	subcc	%g0, %o2, %g4		! n = -n, n == 0 ?
700Sstevel@tonic-gate	bz,pn	%ncc, .done		! n == 0, done
710Sstevel@tonic-gate	add	%o1, %o2, %o3		! src = src + n
720Sstevel@tonic-gate	andcc	%o1, 7, %o4		! dword aligned ?
730Sstevel@tonic-gate	bz,pn	%ncc, .dwordaligned	! yup
740Sstevel@tonic-gate	add	%o0, %o2, %o2		! dst = dst + n
750Sstevel@tonic-gate	sub	%o4, 8, %o4		! bytes until src aligned
760Sstevel@tonic-gate
770Sstevel@tonic-gate.alignsrc:
780Sstevel@tonic-gate	ldub	[%o3 + %g4], %o1	! src[]
790Sstevel@tonic-gate	stb	%o1, [%o2 + %g4]	! dst[] = src[]
800Sstevel@tonic-gate	addcc	%g4, 1, %g4		! src++, dst++, n--
810Sstevel@tonic-gate	bz,pn	%ncc, .done		! n == 0, done
820Sstevel@tonic-gate	tst	%o1			! end of src reached (null byte) ?
830Sstevel@tonic-gate	bz,a	%ncc, .bytepad		! yes, at least one byte to pad here
840Sstevel@tonic-gate	add 	%o2, %g4, %o3		! need single dest pointer for fill
850Sstevel@tonic-gate	addcc	%o4, 1, %o4		! src aligned now?
860Sstevel@tonic-gate	bnz,a	%ncc, .alignsrc		! no, copy another byte
870Sstevel@tonic-gate	nop				! pad
880Sstevel@tonic-gate	nop				! pad
890Sstevel@tonic-gate
900Sstevel@tonic-gate.dwordaligned:
910Sstevel@tonic-gate	sethi	%hi(0x01010101), %o4	! Alan Mycroft's magic1
920Sstevel@tonic-gate	add	%o2, %g4, %g5		! dst
930Sstevel@tonic-gate	or	%o4, %lo(0x01010101),%o4!  finish loading magic1
940Sstevel@tonic-gate	and	%g5, 3, %g1		! dst<1:0> to examine offset
950Sstevel@tonic-gate	sllx	%o4, 32, %o1		! spread magic1
960Sstevel@tonic-gate	cmp	%g1, 1			! dst offset of 1 or 5
970Sstevel@tonic-gate	or	%o4, %o1, %o4		!   to all 64 bits
980Sstevel@tonic-gate	sub	%o2, 8, %o2		! adjust for dest pre-incr in cpy loops
990Sstevel@tonic-gate	be,pn	%ncc, .storebyte1241	! store 1, 2, 4, 1 bytes
1000Sstevel@tonic-gate	sllx	%o4, 7, %o5		!  Alan Mycroft's magic2
1010Sstevel@tonic-gate	cmp	%g1, 3			! dst offset of 3 or 7
1020Sstevel@tonic-gate	be,pn	%ncc, .storebyte1421	! store 1, 4, 2, 1 bytes
1030Sstevel@tonic-gate	cmp	%g1, 2			! dst halfword aligned ?
1040Sstevel@tonic-gate	be,pn	%ncc, .storehalfword	! yup, store half-word wise
1050Sstevel@tonic-gate	andcc	%g5, 7, %g0		! dst word aligned ?
1060Sstevel@tonic-gate	bnz,pn	%ncc, .storeword2	! yup, store word wise
1070Sstevel@tonic-gate	nop				! ensure loop is 16-byte aligned
1080Sstevel@tonic-gate
1090Sstevel@tonic-gate.storedword:
1100Sstevel@tonic-gate	ldx	[%o3 + %g4], %o1	! src dword
1110Sstevel@tonic-gate	addcc	%g4, 8, %g4		! n += 8, src += 8, dst += 8
1120Sstevel@tonic-gate	bcs,pn	%ncc,.lastword		! if counter wraps, last word
1130Sstevel@tonic-gate	andn	%o5, %o1, %g1		! ~dword & 0x8080808080808080
1140Sstevel@tonic-gate	sub	%o1, %o4, %g5		! dword - 0x0101010101010101
1150Sstevel@tonic-gate	andcc	%g5, %g1, %g0		! ((dword - 0x0101010101010101) & ~dword & 0x8080808080808080)
1160Sstevel@tonic-gate	bz,a,pt	%ncc, .storedword	! no zero byte if magic expression == 0
1170Sstevel@tonic-gate	stx	%o1, [%o2 + %g4]	! store word to dst (address pre-incremented)
1180Sstevel@tonic-gate
1190Sstevel@tonic-gate	! n has not expired, but src is at the end. we need to push out the
1200Sstevel@tonic-gate	! remaining src bytes and then start padding with null bytes
1210Sstevel@tonic-gate
1220Sstevel@tonic-gate.zerobyte:
1230Sstevel@tonic-gate	add	%o2, %g4, %o3		! pointer to dest string
1240Sstevel@tonic-gate	srlx	%o1, 56, %g1		! first byte
1250Sstevel@tonic-gate	stb	%g1, [%o3]		! store it
1260Sstevel@tonic-gate	andcc	%g1, 0xff, %g0		! end of string ?
1270Sstevel@tonic-gate	movz	%ncc, %g0, %o1		! if so, start padding with null bytes
1280Sstevel@tonic-gate	srlx	%o1, 48, %g1		! second byte
1290Sstevel@tonic-gate	stb	%g1, [%o3 + 1]		! store it
1300Sstevel@tonic-gate	andcc	%g1, 0xff, %g0		! end of string ?
1310Sstevel@tonic-gate	movz	%ncc, %g0, %o1		! if so, start padding with null bytes
1320Sstevel@tonic-gate	srlx	%o1, 40, %g1		! third byte
1330Sstevel@tonic-gate	stb	%g1, [%o3 + 2]		! store it
1340Sstevel@tonic-gate	andcc	%g1, 0xff, %g0		! end of string ?
1350Sstevel@tonic-gate	movz	%ncc, %g0, %o1		! if so, start padding with null bytes
1360Sstevel@tonic-gate	srlx	%o1, 32, %g1		! fourth byte
1370Sstevel@tonic-gate	stb	%g1, [%o3 + 3]		! store it
1380Sstevel@tonic-gate	andcc	%g1, 0xff, %g0		! end of string ?
1390Sstevel@tonic-gate	movz	%ncc, %g0, %o1		! if so, start padding with null bytes
1400Sstevel@tonic-gate	srlx	%o1, 24, %g1		! fifth byte
1410Sstevel@tonic-gate	stb	%g1, [%o3 + 4]		! store it
1420Sstevel@tonic-gate	andcc	%g1, 0xff, %g0		! end of string ?
1430Sstevel@tonic-gate	movz	%ncc, %g0, %o1		! if so, start padding with null bytes
1440Sstevel@tonic-gate	srlx	%o1, 16, %g1		! sixth byte
1450Sstevel@tonic-gate	stb	%g1, [%o3 + 5]		! store it
1460Sstevel@tonic-gate	andcc	%g1, 0xff, %g0		! end of string ?
1470Sstevel@tonic-gate	movz	%ncc, %g0, %o1		! if so, start padding with null bytes
1480Sstevel@tonic-gate	srlx	%o1, 8, %g1		! seventh byte
1490Sstevel@tonic-gate	stb	%g1, [%o3 + 6]		! store it
1500Sstevel@tonic-gate	andcc	%g1, 0xff, %g0		! end of string ?
1510Sstevel@tonic-gate	movz	%ncc, %g0, %o1		! if so, start padding with null bytes
1520Sstevel@tonic-gate	stb	%o1, [%o3 + 7]		! store eighth byte
1530Sstevel@tonic-gate	addcc	%g4, 16, %g0		! number of pad bytes < 16 ?
1540Sstevel@tonic-gate	bcs,pn	%ncc, .bytepad		! yes, do simple byte wise fill
1550Sstevel@tonic-gate	add	%o3, 8, %o3		! dst += 8
1560Sstevel@tonic-gate	andcc	%o3, 7, %o4		! dst offset relative to dword boundary
1570Sstevel@tonic-gate	bz,pn	%ncc, .fillaligned	! dst already dword aligned
1580Sstevel@tonic-gate
1590Sstevel@tonic-gate	! here there is a least one more byte to zero out: otherwise we would
1600Sstevel@tonic-gate	! have exited through label .lastword
1610Sstevel@tonic-gate
1620Sstevel@tonic-gate	sub	%o4, 8, %o4		! bytes to align dst to dword boundary
1630Sstevel@tonic-gate.makealigned:
1640Sstevel@tonic-gate	stb	%g0, [%o3]		! dst[] = 0
1650Sstevel@tonic-gate	addcc	%g4, 1, %g4		! n--
1660Sstevel@tonic-gate	bz,pt	%ncc, .done		! n == 0, we are done
1670Sstevel@tonic-gate	addcc	%o4, 1, %o4		! any more byte needed to align
1680Sstevel@tonic-gate	bnz,pt	%ncc, .makealigned	! yup, pad another byte
1690Sstevel@tonic-gate	add	%o3, 1, %o3		! dst++
1700Sstevel@tonic-gate	nop				! pad to align copy loop below
1710Sstevel@tonic-gate	nop				! pad to align copy loop below
1720Sstevel@tonic-gate
1730Sstevel@tonic-gate	! here we know that there at least another 8 bytes to pad, since
1740Sstevel@tonic-gate	! we don't get here unless there were >= 16 bytes to pad to begin
1750Sstevel@tonic-gate	! with, and we have padded at most 7 bytes suring dst aligning
1760Sstevel@tonic-gate
1770Sstevel@tonic-gate.fillaligned:
1780Sstevel@tonic-gate	add	%g4, 7, %o2		! round up to next dword boundary
1790Sstevel@tonic-gate	and	%o2, -8, %o4		! pointer to next dword boundary
1800Sstevel@tonic-gate	and	%o2, 8, %o2		! dword count odd ? 8 : 0
1810Sstevel@tonic-gate	stx	%g0, [%o3]		! store first dword
1820Sstevel@tonic-gate	addcc	%o4, %o2, %o4		! dword count == 1 ?
1830Sstevel@tonic-gate	add	%g4, %o2, %g4		! if dword count odd, n -= 8
1840Sstevel@tonic-gate	bz,pt	%ncc, .bytepad		! if dword count == 1, pad leftover bytes
1850Sstevel@tonic-gate	add	%o3, %o2, %o3		! bump dst if dword count odd
1860Sstevel@tonic-gate
1870Sstevel@tonic-gate.filldword:
1880Sstevel@tonic-gate	addcc	%o4, 16, %o4		! count -= 16
1890Sstevel@tonic-gate	stx	%g0, [%o3]		! dst[n] = 0
1900Sstevel@tonic-gate	stx	%g0, [%o3 + 8]		! dst[n+8] = 0
1910Sstevel@tonic-gate	add	%o3, 16, %o3		! dst += 16
1920Sstevel@tonic-gate	bcc,pt	%ncc, .filldword	! fill dwords until count == 0
1930Sstevel@tonic-gate	addcc	%g4, 16, %g4		! n -= 16
1940Sstevel@tonic-gate	bz,pn	%ncc, .done		! if n == 0, we are done
1950Sstevel@tonic-gate
1960Sstevel@tonic-gate.bytepad:
1970Sstevel@tonic-gate	and	%g4, 1, %o2		! byte count odd ? 1 : 0
1980Sstevel@tonic-gate	stb	%g0, [%o3]		! store first byte
1990Sstevel@tonic-gate	addcc	%g4, %o2, %g4		! byte count == 1 ?
2000Sstevel@tonic-gate	bz,pt	%ncc, .done		! yup, we are done
2010Sstevel@tonic-gate	add	%o3, %o2, %o3		! bump pointer if odd
2020Sstevel@tonic-gate
2030Sstevel@tonic-gate.fillbyte:
2040Sstevel@tonic-gate	addcc	%g4, 2, %g4		! n -= 2
2050Sstevel@tonic-gate	stb	%g0, [%o3]		! dst[n] = 0
2060Sstevel@tonic-gate	stb	%g0, [%o3 + 1]		! dst[n+1] = 0
2070Sstevel@tonic-gate	bnz,pt	%ncc, .fillbyte		! fill until n == 0
2080Sstevel@tonic-gate	add	%o3, 2, %o3		! dst += 2
2090Sstevel@tonic-gate
2100Sstevel@tonic-gate.done:
2110Sstevel@tonic-gate	retl				! done
2120Sstevel@tonic-gate	nop				! pad to align loops below
2130Sstevel@tonic-gate	nop				! pad to align loops below
2140Sstevel@tonic-gate
2150Sstevel@tonic-gate	! this is the last word. It may contain null bytes. store bytes
2160Sstevel@tonic-gate	! until n == 0. if null byte encountered, continue
2170Sstevel@tonic-gate
2180Sstevel@tonic-gate.lastword:
2190Sstevel@tonic-gate	sub	%g4, 8, %g4		! undo counter pre-increment
2200Sstevel@tonic-gate	add	%o2, 8, %o2		! adjust dst for counter un-bumping
2210Sstevel@tonic-gate
2220Sstevel@tonic-gate	srlx	%o1, 56, %g1		! first byte
2230Sstevel@tonic-gate	stb	%g1, [%o2 + %g4]	! store it
2240Sstevel@tonic-gate	inccc	%g4			! n--
2250Sstevel@tonic-gate	bz	.done			! if n == 0, we're done
2260Sstevel@tonic-gate	andcc	%g1, 0xff, %g0		! end of src reached ?
2270Sstevel@tonic-gate	movz	%ncc, %g0, %o1		! if so, start padding with null bytes
2280Sstevel@tonic-gate	srlx	%o1, 48, %g1		! second byte
2290Sstevel@tonic-gate	stb	%g1, [%o2 + %g4]	! store it
2300Sstevel@tonic-gate	inccc	%g4			! n--
2310Sstevel@tonic-gate	bz	.done			! if n == 0, we're done
2320Sstevel@tonic-gate	andcc	%g1, 0xff, %g0		! end of src reached ?
2330Sstevel@tonic-gate	movz	%ncc, %g0, %o1		! if so, start padding with null bytes
2340Sstevel@tonic-gate	srlx	%o1, 40, %g1		! third byte
2350Sstevel@tonic-gate	stb	%g1, [%o2 + %g4]	! store it
2360Sstevel@tonic-gate	inccc	%g4			! n--
2370Sstevel@tonic-gate	bz	.done			! if n == 0, we're done
2380Sstevel@tonic-gate	andcc	%g1, 0xff, %g0		! end of src reached ?
2390Sstevel@tonic-gate	movz	%ncc, %g0, %o1		! if so, start padding with null bytes
2400Sstevel@tonic-gate	srlx	%o1, 32, %g1		! fourth byte
2410Sstevel@tonic-gate	stb	%g1, [%o2 + %g4]	! store it
2420Sstevel@tonic-gate	inccc	%g4			! n--
2430Sstevel@tonic-gate	bz	.done			! if n == 0, we're done
2440Sstevel@tonic-gate	andcc	%g1, 0xff, %g0		! end of src reached ?
2450Sstevel@tonic-gate	movz	%ncc, %g0, %o1		! if so, start padding with null bytes
2460Sstevel@tonic-gate	srlx	%o1, 24, %g1		! fifth byte
2470Sstevel@tonic-gate	stb	%g1, [%o2 + %g4]	! store it
2480Sstevel@tonic-gate	inccc	%g4			! n--
2490Sstevel@tonic-gate	bz	.done			! if n == 0, we're done
2500Sstevel@tonic-gate	andcc	%g1, 0xff, %g0		! end of src reached ?
2510Sstevel@tonic-gate	movz	%ncc, %g0, %o1		! if so, start padding with null bytes
2520Sstevel@tonic-gate	srlx	%o1, 16, %g1		! sixth byte
2530Sstevel@tonic-gate	stb	%g1, [%o2 + %g4]	! store it
2540Sstevel@tonic-gate	inccc	%g4			! n--
2550Sstevel@tonic-gate	bz	.done			! if n == 0, we're done
2560Sstevel@tonic-gate	andcc	%g1, 0xff, %g0		! end of src reached ?
2570Sstevel@tonic-gate	movz	%ncc, %g0, %o1		! if so, start padding with null bytes
2580Sstevel@tonic-gate	srlx	%o1, 8, %g1		! seventh byte
2590Sstevel@tonic-gate	stb	%g1, [%o2 + %g4]	! store it
2600Sstevel@tonic-gate	inccc	%g4			! n--
2610Sstevel@tonic-gate	bz	.done			! if n == 0, we're done
2620Sstevel@tonic-gate	andcc	%g1, 0xff, %g0		! end of src reached ?
2630Sstevel@tonic-gate	movz	%ncc, %g0, %o1		! if so, start padding with null bytes
2640Sstevel@tonic-gate	ba	.done			! here n must be zero, we are done
2650Sstevel@tonic-gate	stb	%o1, [%o2 + %g4]	! store eigth byte
2660Sstevel@tonic-gate	nop				! pad to align loops below
2670Sstevel@tonic-gate	nop				! pad to align loops below
2680Sstevel@tonic-gate
2690Sstevel@tonic-gate.storebyte1421:
2700Sstevel@tonic-gate	ldx	[%o3 + %g4], %o1	! x = src[]
2710Sstevel@tonic-gate	addcc	%g4, 8, %g4		! src += 8, dst += 8
2720Sstevel@tonic-gate	bcs,pn	%ncc,.lastword		! if counter wraps, last word
2730Sstevel@tonic-gate	andn	%o5, %o1, %g1		! ~x & 0x8080808080808080
2740Sstevel@tonic-gate	sub	%o1, %o4, %g5		! x - 0x0101010101010101
2750Sstevel@tonic-gate	andcc	%g5, %g1, %g0		! ((x - 0x0101010101010101) & ~x & 0x8080808080808080)
2760Sstevel@tonic-gate	bnz,pn	%ncc, .zerobyte		! end of src found, may need to pad
2770Sstevel@tonic-gate	add	%o2, %g4, %g5		! dst (in pointer form)
2780Sstevel@tonic-gate	srlx	%o1, 56, %g1		! %g1<7:0> = first byte; word aligned now
2790Sstevel@tonic-gate	stb	%g1, [%g5]		! store first byte
2800Sstevel@tonic-gate	srlx	%o1, 24, %g1		! %g1<31:0> = bytes 2, 3, 4, 5
2810Sstevel@tonic-gate	stw	%g1, [%g5 + 1]		! store bytes 2, 3, 4, 5
2820Sstevel@tonic-gate	srlx	%o1, 8, %g1		! %g1<15:0> = bytes 6, 7
2830Sstevel@tonic-gate	sth	%g1, [%g5 + 5]		! store bytes 6, 7
2840Sstevel@tonic-gate	ba	.storebyte1421		! next dword
2850Sstevel@tonic-gate	stb	%o1, [%g5 + 7]		! store eigth byte
2860Sstevel@tonic-gate
2870Sstevel@tonic-gate.storebyte1241:
2880Sstevel@tonic-gate	ldx	[%o3 + %g4], %o1	! x = src[]
2890Sstevel@tonic-gate	addcc	%g4, 8, %g4		! src += 8, dst += 8
2900Sstevel@tonic-gate	bcs,pn	%ncc,.lastword		! if counter wraps, last word
2910Sstevel@tonic-gate	andn	%o5, %o1, %g1		! ~x & 0x8080808080808080
2920Sstevel@tonic-gate	sub	%o1, %o4, %g5		! x - 0x0101010101010101
2930Sstevel@tonic-gate	andcc	%g5, %g1, %g0		! ((x - 0x0101010101010101) & ~x & 0x8080808080808080)
2940Sstevel@tonic-gate	bnz,pn	%ncc, .zerobyte		! x has zero byte, handle end cases
2950Sstevel@tonic-gate	add	%o2, %g4, %g5		! dst (in pointer form)
2960Sstevel@tonic-gate	srlx	%o1, 56, %g1		! %g1<7:0> = first byte; half-word aligned now
2970Sstevel@tonic-gate	stb	%g1, [%g5]		! store first byte
2980Sstevel@tonic-gate	srlx	%o1, 40, %g1		! %g1<15:0> = bytes 2, 3
2990Sstevel@tonic-gate	sth	%g1, [%g5 + 1]		! store bytes 2, 3
3000Sstevel@tonic-gate	srlx	%o1, 8, %g1		! %g1<31:0> = bytes 4, 5, 6, 7
3010Sstevel@tonic-gate	stw	%g1, [%g5 + 3]		! store bytes 4, 5, 6, 7
3020Sstevel@tonic-gate	ba	.storebyte1241		! next dword
3030Sstevel@tonic-gate	stb	%o1, [%g5 + 7]		! store eigth byte
3040Sstevel@tonic-gate
3050Sstevel@tonic-gate.storehalfword:
3060Sstevel@tonic-gate	ldx	[%o3 + %g4], %o1	! x = src[]
3070Sstevel@tonic-gate	addcc	%g4, 8, %g4		! src += 8, dst += 8
3080Sstevel@tonic-gate	bcs,pn	%ncc,.lastword		! if counter wraps, last word
3090Sstevel@tonic-gate	andn	%o5, %o1, %g1		! ~x & 0x8080808080808080
3100Sstevel@tonic-gate	sub	%o1, %o4, %g5		! x - 0x0101010101010101
3110Sstevel@tonic-gate	andcc	%g5, %g1, %g0		! ((x - 0x0101010101010101) & ~x & 0x8080808080808080)
3120Sstevel@tonic-gate	bnz,pn	%ncc, .zerobyte		! x has zero byte, handle end cases
3130Sstevel@tonic-gate	add	%o2, %g4, %g5		! dst (in pointer form)
3140Sstevel@tonic-gate	srlx	%o1, 48, %g1		! %g1<15:0> = bytes 1, 2; word aligned now
3150Sstevel@tonic-gate	sth	%g1, [%g5]		! store bytes 1, 2
3160Sstevel@tonic-gate	srlx	%o1, 16, %g1		! %g1<31:0> = bytes 3, 4, 5, 6
3170Sstevel@tonic-gate	stw	%g1, [%g5 + 2]		! store bytes 3, 4, 5, 6
3180Sstevel@tonic-gate	ba	.storehalfword		! next dword
3190Sstevel@tonic-gate	sth	%o1, [%g5 + 6]		! store bytes 7, 8
3200Sstevel@tonic-gate	nop				! align next loop to 16-byte boundary
3210Sstevel@tonic-gate	nop				! align next loop to 16-byte boundary
3220Sstevel@tonic-gate
3230Sstevel@tonic-gate.storeword2:
3240Sstevel@tonic-gate	ldx	[%o3 + %g4], %o1	! x = src[]
3250Sstevel@tonic-gate	addcc	%g4, 8, %g4		! src += 8, dst += 8
3260Sstevel@tonic-gate	bcs,pn	%ncc,.lastword		! if counter wraps, last word
3270Sstevel@tonic-gate	andn	%o5, %o1, %g1		! ~x & 0x8080808080808080
3280Sstevel@tonic-gate	sub	%o1, %o4, %g5		! x - 0x0101010101010101
3290Sstevel@tonic-gate	andcc	%g5, %g1, %g0		! ((x - 0x0101010101010101) & ~x & 0x8080808080808080)
3300Sstevel@tonic-gate	bnz,pn	%ncc, .zerobyte		! x has zero byte, handle end cases
3310Sstevel@tonic-gate	add	%o2, %g4, %g5		! dst (in pointer form)
3320Sstevel@tonic-gate	srlx	%o1, 32, %g1		! %g1<31:0> = bytes 1, 2, 3, 4
3330Sstevel@tonic-gate	stw	%g1, [%g5]		! store bytes 1, 2, 3, 4
3340Sstevel@tonic-gate	ba	.storeword2		! next dword
3350Sstevel@tonic-gate	stw	%o1, [%g5 + 4]		! store bytes 5, 6, 7, 8
3360Sstevel@tonic-gate
3370Sstevel@tonic-gate	! do not remove these pads, loop above may slow down otherwise
3380Sstevel@tonic-gate
3390Sstevel@tonic-gate	nop				! pad
3400Sstevel@tonic-gate	nop				! pad
3410Sstevel@tonic-gate
3420Sstevel@tonic-gate	SET_SIZE(strncpy)
343