/*
   * arch/alpha/lib/strncpy.S
   * Contributed by Richard Henderson (rth@tamu.edu)
   *
   * Copy no more than COUNT bytes of the null-terminated string from
   * SRC to DST.  If SRC does not cover all of COUNT, the balance is
   * zeroed.
   *
   * Or, rather, if the kernel cared about that weird ANSI quirk.  This
   * version has cropped that bit o' nastiness as well as assuming that
   * __stxncpy is in range of a branch.
   */
  
  	.set noat
  	.set noreorder
  
  	.text
  
  	.align 4
  	.globl strncpy
  	.ent strncpy
  strncpy:
  	.frame $30, 0, $26
  	.prologue 0
  
  	mov	$16, $0		# set return value now
  	beq	$18, $zerolen
  	unop
  	bsr	$23, __stxncpy	# do the work of the copy
  
  	unop
  	bne	$18, $multiword	# do we have full words left?
  	subq	$24, 1, $3	# nope
  	subq	$27, 1, $4
  
  	or	$3, $24, $3	# clear the bits between the last
  	or	$4, $27, $4	# written byte and the last byte in COUNT
  	andnot	$3, $4, $4
  	zap	$1, $4, $1
  
  	stq_u	$1, 0($16)
  	ret
  
  	.align	4
  $multiword:
  	subq	$27, 1, $2	# clear the final bits in the prev word
  	or	$2, $27, $2
  	zapnot	$1, $2, $1
  	subq	$18, 1, $18
  
  	stq_u	$1, 0($16)
  	addq	$16, 8, $16
  	unop
  	beq	$18, 1f
  
  	nop
  	unop
  	nop
  	blbc	$18, 0f
  
  	stq_u	$31, 0($16)	# zero one word
  	subq	$18, 1, $18
  	addq	$16, 8, $16
  	beq	$18, 1f
  
  0:	stq_u	$31, 0($16)	# zero two words
  	subq	$18, 2, $18
  	stq_u	$31, 8($16)
  	addq	$16, 16, $16
  	bne	$18, 0b
  
  1:	ldq_u	$1, 0($16)	# clear the leading bits in the final word
  	subq	$24, 1, $2
  	or	$2, $24, $2
  
  	zap	$1, $2, $1
  	stq_u	$1, 0($16)
  $zerolen:
  	ret
  
  	.end	strncpy