From 57f0f512b273f60d52568b8c6b77e17f5636edc0 Mon Sep 17 00:00:00 2001
From: André Fabian Silva Delgado <emulatorman@parabola.nu>
Date: Wed, 5 Aug 2015 17:04:01 -0300
Subject: Initial import

---
 arch/alpha/lib/strncat.S | 84 ++++++++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 84 insertions(+)
 create mode 100644 arch/alpha/lib/strncat.S

(limited to 'arch/alpha/lib/strncat.S')

diff --git a/arch/alpha/lib/strncat.S b/arch/alpha/lib/strncat.S
new file mode 100644
index 000000000..a8278163c
--- /dev/null
+++ b/arch/alpha/lib/strncat.S
@@ -0,0 +1,84 @@
+/*
+ * arch/alpha/lib/strncat.S
+ * Contributed by Richard Henderson (rth@tamu.edu)
+ *
+ * Append no more than COUNT characters from the null-terminated string SRC
+ * to the null-terminated string DST.  Always null-terminate the new DST.
+ *
+ * This differs slightly from the semantics in libc in that we never write
+ * past count, whereas libc may write to count+1.  This follows the generic
+ * implementation in lib/string.c and is, IMHO, more sensible.
+ */
+
+	.text
+
+	.align 3
+	.globl strncat
+	.ent strncat
+strncat:
+	.frame $30, 0, $26
+	.prologue 0
+
+	mov	$16, $0		# set up return value
+	beq	$18, $zerocount
+
+	/* Find the end of the string.  */
+
+	ldq_u   $1, 0($16)	# load first quadword ($16 may be misaligned)
+	lda     $2, -1($31)
+	insqh   $2, $16, $2
+	andnot  $16, 7, $16
+	or      $2, $1, $1
+	cmpbge  $31, $1, $2	# bits set iff byte == 0
+	bne     $2, $found
+
+$loop:	ldq     $1, 8($16)
+	addq    $16, 8, $16
+	cmpbge  $31, $1, $2
+	beq     $2, $loop
+
+$found:	negq    $2, $3		# clear all but least set bit
+	and     $2, $3, $2
+
+	and     $2, 0xf0, $3	# binary search for that set bit
+	and	$2, 0xcc, $4
+	and	$2, 0xaa, $5
+	cmovne	$3, 4, $3
+	cmovne	$4, 2, $4
+	cmovne	$5, 1, $5
+	addq	$3, $4, $3
+	addq	$16, $5, $16
+	addq	$16, $3, $16
+
+	/* Now do the append.  */
+
+	bsr	$23, __stxncpy
+
+	/* Worry about the null termination.  */
+
+	zapnot	$1, $27, $2	# was last byte a null?
+	bne	$2, 0f
+	ret
+
+0:	cmplt	$27, $24, $2	# did we fill the buffer completely?
+	or	$2, $18, $2
+	bne	$2, 2f
+
+	and	$24, 0x80, $2	# no zero next byte
+	bne	$2, 1f
+
+	/* Here there are bytes left in the current word.  Clear one.  */
+	addq	$24, $24, $24	# end-of-count bit <<= 1
+2:	zap	$1, $24, $1
+	stq_u	$1, 0($16)
+	ret
+
+1:	/* Here we must read the next DST word and clear the first byte.  */
+	ldq_u	$1, 8($16)
+	zap	$1, 1, $1
+	stq_u	$1, 8($16)
+
+$zerocount:
+	ret
+
+	.end strncat
-- 
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