strncpy_from_user.s

上传linux-jx2410的源代码

/*
 * Just like strncpy() except that if a fault occurs during copying,
 * -EFAULT is returned.
 *
 * Inputs:
 *	in0:	address of destination buffer
 *	in1:	address of string to be copied
 *	in2:	length of buffer in bytes
 * Outputs:
 *	r8:	-EFAULT in case of fault or number of bytes copied if no fault
 *
 * Copyright (C) 1998-2001 Hewlett-Packard Co
 * Copyright (C) 1998-2001 David Mosberger-Tang <[e-mail]>
 *
 * 00/03/06 D. Mosberger Fixed to return proper return value (bug found by
 *			 by Andreas Schwab <[e-mail]>).
 */

#include <asm/asmmacro.h>

GLOBAL_ENTRY(__strncpy_from_user)
	alloc r2=ar.pfs,3,0,0,0
	mov r8=0
	mov r9=in1
	;;
	add r10=in1,in2
	cmp.eq p6,p0=r0,in2
(p6)	br.ret.spnt.many rp

	// XXX braindead copy loop---this needs to be optimized
.Loop1:
	EX(.Lexit, ld1 r8=[in1],1)
	;;
	EX(.Lexit, st1 [in0]=r8,1)
	cmp.ne p6,p7=r8,r0
	;;
(p6)	cmp.ne.unc p8,p0=in1,r10
(p8)	br.cond.dpnt.few .Loop1
	;;
(p6)	mov r8=in2		// buffer filled up---return buffer length
(p7)	sub r8=in1,r9,1		// return string length (excluding NUL character)
[.Lexit:]
	br.ret.sptk.many rp
END(__strncpy_from_user)