alpha/lib/memchr.S

17    write to the Free Software Foundation, Inc., 59 Temple Place - Suite 330,
18    Boston, MA 02111-1307, USA.  */
22       - memory accessed as aligned quadwords only
23       - uses cmpbge to compare 8 bytes in parallel
24       - does binary search to find 0 byte in last
31       - only minimum number of quadwords may be accessed
32       - the third argument is an unsigned long
44 	# Hack -- if someone passes in (size_t)-1, hoping to just
47 	# that we will never have a 56-bit address space, cropping
49 	zap	$18, 0x80, $5	#-e0	:
54 	and	$17, 0xff, $17	#-e0    : $17 = 00000000000000ch
57         lda     $3, -1($31)	# .. e1 :
58 	sll	$17, 16, $2	#-e0    : $2 = 00000000chch0000
62 	sll	$17, 32, $2	#-e0    : $2 = chchchch00000000
67 	ldq_u	$6, -1($5)	#-e1	: eight or less bytes to search
77 	negq	$18, $6		#-e0	:
81 	and	$2, $6, $2	#-e0	:
89         and     $2, 0x0f, $1	#-e0	:
94         and     $2, 0x33, $1	#-e0	:
99         cmoveq  $1, $3, $0	#-e0	:
104 	# searched.  $16 may not be aligned.
107 	andnot	$16, 0x7, $0	#-e1	:
111         cmpbge  $31, $1, $2	#-e0	:
114 	# At least one byte left to process.
118 	addq	$0, 8, $0	#-e0	:
129 	subq	$18, $0, $4	#-e0	: $4 <- nr quads to be processed
139 	ldq	$1, 8($0)	#-e0	: prefetch $1
144 	addq	$0, 8, $0	#-e0	:
149 	addq	$0, 8, $6	#-e0	:
154 	bne	$6, $unrolled_loop #-e1 :
157 $final:	subq	$5, $0, $18	# .. e1	: $18 <- number of bytes left to do
161 	mov	$31, $0		#-e0	: