1 files changed, 120 insertions, 0 deletions
diff --git a/lib/libc/mips/string/bcmp.S b/lib/libc/mips/string/bcmp.S
new file mode 100644
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+++ b/lib/libc/mips/string/bcmp.S
@@ -0,0 +1,120 @@
+/*-
+ * Copyright (c) 1991, 1993
+ *	The Regents of the University of California.  All rights reserved.
+ *
+ * This code is derived from software contributed to Berkeley by
+ * Ralph Campbell.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions
+ * are met:
+ * 1. Redistributions of source code must retain the above copyright
+ *    notice, this list of conditions and the following disclaimer.
+ * 2. Redistributions in binary form must reproduce the above copyright
+ *    notice, this list of conditions and the following disclaimer in the
+ *    documentation and/or other materials provided with the distribution.
+ * 3. All advertising materials mentioning features or use of this software
+ *    must display the following acknowledgement:
+ *	This product includes software developed by the University of
+ *	California, Berkeley and its contributors.
+ * 4. Neither the name of the University nor the names of its contributors
+ *    may be used to endorse or promote products derived from this software
+ *    without specific prior written permission.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
+ * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
+ * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
+ * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
+ * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
+ * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
+ * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
+ * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
+ * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
+ * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
+ * SUCH DAMAGE.
+ */
+
+#include <machine/asm.h>
+
+#if defined(LIBC_SCCS)
+	.text
+	.asciz "$OpenBSD$"
+#endif /* LIBC_SCCS */
+
+/* bcmp(s1, s2, n) */
+
+LEAF(bcmp)
+	.set	noreorder
+	blt	a2, 16, small		# is it worth any trouble?
+	xor	v0, a0, a1		# compare low two bits of addresses
+	and	v0, v0, 3
+	subu	a3, zero, a1		# compute # bytes to word align address
+	bne	v0, zero, unaligned	# not possible to align addresses
+	and	a3, a3, 3
+
+	beq	a3, zero, 1f
+	subu	a2, a2, a3		# subtract from remaining count
+	move	v0, v1			# init v0,v1 so unmodified bytes match
+	LWHI	v0, 0(a0)		# read 1, 2, or 3 bytes
+	LWHI	v1, 0(a1)
+	addu	a1, a1, a3
+	bne	v0, v1, nomatch
+	addu	a0, a0, a3
+1:
+	and	a3, a2, ~3		# compute number of whole words left
+	subu	a2, a2, a3		#   which has to be >= (16-3) & ~3
+	addu	a3, a3, a0		# compute ending address
+2:
+	lw	v0, 0(a0)		# compare words
+	lw	v1, 0(a1)
+	addu	a0, a0, 4
+	bne	v0, v1, nomatch
+	addu	a1, a1, 4
+	bne	a0, a3, 2b
+	nop
+	b	small			# finish remainder
+	nop
+unaligned:
+	beq	a3, zero, 2f
+	subu	a2, a2, a3		# subtract from remaining count
+	addu	a3, a3, a0		# compute ending address
+1:
+	lbu	v0, 0(a0)		# compare bytes until a1 word aligned
+	lbu	v1, 0(a1)
+	addu	a0, a0, 1
+	bne	v0, v1, nomatch
+	addu	a1, a1, 1
+	bne	a0, a3, 1b
+	nop
+2:
+	and	a3, a2, ~3		# compute number of whole words left
+	subu	a2, a2, a3		#   which has to be >= (16-3) & ~3
+	addu	a3, a3, a0		# compute ending address
+3:
+	LWHI	v0, 0(a0)		# compare words a0 unaligned, a1 aligned
+	LWLO	v0, 3(a0)
+	lw	v1, 0(a1)
+	addu	a0, a0, 4
+	bne	v0, v1, nomatch
+	addu	a1, a1, 4
+	bne	a0, a3, 3b
+	nop
+small:
+	ble	a2, zero, match
+	addu	a3, a2, a0		# compute ending address
+1:
+	lbu	v0, 0(a0)
+	lbu	v1, 0(a1)
+	addu	a0, a0, 1
+	bne	v0, v1, nomatch
+	addu	a1, a1, 1
+	bne	a0, a3, 1b
+	nop
+match:
+	j	ra
+	move	v0, zero
+nomatch:
+	j	ra
+	li	v0, 1
+	.set	reorder
+END(bcmp)