arch/alpha/lib/ev67-strncat.S

Source file repositories/reference/linux-study-clean/arch/alpha/lib/ev67-strncat.S

File Facts

System
Linux kernel
Corpus path
arch/alpha/lib/ev67-strncat.S
Extension
.S
Size
2504 bytes
Lines
97
Domain
Architecture Layer
Bucket
arch/alpha
Inferred role
Architecture Layer: exported/initcall integration point
Status
integration implementation candidate

Why This File Exists

CPU and platform-specific kernel glue: boot entry, traps, syscall entry, interrupts, page tables, context switch, and low-level barriers.

Dependency Surface

Detected Declarations

Annotated Snippet

#include <linux/export.h>
	.text

	.align 4
	.globl strncat
	.ent strncat
strncat:
	.frame $30, 0, $26
	.prologue 0

	mov	$16, $0		# set up return value
	beq	$18, $zerocount	# U :
	/* Find the end of the string.  */
	ldq_u   $1, 0($16)	# L : load first quadword ($16 may be misaligned)
	lda     $2, -1($31)	# E :

	insqh   $2, $0, $2	# U :
	andnot  $16, 7, $16	# E :
	nop			# E :
	or      $2, $1, $1	# E :

	nop			# E :
	nop			# E :
	cmpbge  $31, $1, $2	# E : bits set iff byte == 0
	bne     $2, $found	# U :

$loop:	ldq     $1, 8($16)	# L :
	addq    $16, 8, $16	# E :
	cmpbge  $31, $1, $2	# E :
	beq     $2, $loop	# U :

$found:	cttz	$2, $3		# U0 :
	addq	$16, $3, $16	# E :
	nop			# E :
	bsr	$23, __stxncpy	# L0 :/* Now do the append.  */

	/* Worry about the null termination.  */

	zapnot	$1, $27, $2	# U : was last byte a null?
	cmplt	$27, $24, $5	# E : did we fill the buffer completely?
	bne	$2, 0f		# U :
	ret			# L0 :

0:	or	$5, $18, $2	# E :
	nop
	bne	$2, 2f		# U :
	and	$24, 0x80, $3	# E : no zero next byte

	nop			# E :
	bne	$3, 1f		# U :
	/* Here there are bytes left in the current word.  Clear one.  */
	addq	$24, $24, $24	# E : end-of-count bit <<= 1
	nop			# E :

2:	zap	$1, $24, $1	# U :
	nop			# E :
	stq_u	$1, 0($16)	# L :
	ret			# L0 :

1:	/* Here we must clear the first byte of the next DST word */
	stb	$31, 8($16)	# L :
	nop			# E :
	nop			# E :
	ret			# L0 :

$zerocount:
	nop			# E :
	nop			# E :
	nop			# E :
	ret			# L0 :

Annotation

Implementation Notes