update from netbsd

1 files changed, 110 insertions, 0 deletions

diff --git a/sys/lib/libkern/arch/alpha/bzero.S b/sys/lib/libkern/arch/alpha/bzero.S
new file mode 100644
index 00000000000..3bf1e75a9f8
--- /dev/null
+++ b/sys/lib/libkern/arch/alpha/bzero.S
@@ -0,0 +1,110 @@
+/*	$NetBSD: bzero.S,v 1.1 1995/10/20 01:16:02 cgd Exp $	*/
+
+/*
+ * Copyright (c) 1995 Carnegie-Mellon University.
+ * All rights reserved.
+ *
+ * Author: Trevor Blackwell
+ *
+ * Permission to use, copy, modify and distribute this software and
+ * its documentation is hereby granted, provided that both the copyright
+ * notice and this permission notice appear in all copies of the
+ * software, derivative works or modified versions, and any portions
+ * thereof, and that both notices appear in supporting documentation.
+ *
+ * CARNEGIE MELLON ALLOWS FREE USE OF THIS SOFTWARE IN ITS "AS IS"
+ * CONDITION.  CARNEGIE MELLON DISCLAIMS ANY LIABILITY OF ANY KIND
+ * FOR ANY DAMAGES WHATSOEVER RESULTING FROM THE USE OF THIS SOFTWARE.
+ *
+ * Carnegie Mellon requests users of this software to return to
+ *
+ *  Software Distribution Coordinator  or  Software.Distribution@CS.CMU.EDU
+ *  School of Computer Science
+ *  Carnegie Mellon University
+ *  Pittsburgh PA 15213-3890
+ *
+ * any improvements or extensions that they make and grant Carnegie the
+ * rights to redistribute these changes.
+ */
+
+#include "DEFS.h"
+
+LEAF(bzero,2)
+	ble	a1,bzero_done
+	bic	a1,63,t3	/* t3 is # bytes to do 64 bytes at a time */
+
+	/* If nothing in first word, ignore it */
+	subq	zero,a0,t0
+	and	t0,7,t0		/* t0 = (0-size)%8 */
+	beq	t0,bzero_nostart1
+
+	cmpult	a1,t0,t1	/* if size > size%8 goto noshort */
+	beq	t1,bzero_noshort
+
+	/*
+	 * The whole thing is less than a word.
+	 * Mask off 1..7 bytes, and finish.
+	 */
+	ldq_u	t2,0(a0)
+	lda	t0,-1(zero)	/* t0=-1 */
+	mskql	t0,a1,t0	/* Get ff in bytes (a0%8)..((a0+a1-1)%8) */
+	insql	t0,a0,t0
+	bic	t2,t0,t2	/* zero those bytes in word */
+	stq_u	t2,0(a0)
+	RET
+
+bzero_noshort:
+	/* Handle the first partial word */
+	ldq_u	t2,0(a0)
+	subq	a1,t0,a1
+	mskql	t2,a0,t2	/* zero bytes (a0%8)..7 in word */
+	stq_u	t2,0(a0)
+
+	addq	a0,t0,a0	/* round a0 up to next word */
+	bic	a1,63,t3	/* recalc t3 (# bytes to do 64 bytes at a
+				   time) */
+
+bzero_nostart1:
+	/*
+	 * Loop, zeroing 64 bytes at a time
+	 */
+	beq	t3,bzero_lp_done
+bzero_lp:
+	stq	zero,0(a0)
+	stq	zero,8(a0)
+	stq	zero,16(a0)
+	stq	zero,24(a0)
+	subq	t3,64,t3
+	stq	zero,32(a0)
+	stq	zero,40(a0)
+	stq	zero,48(a0)
+	stq	zero,56(a0)
+	addq	a0,64,a0
+	bne	t3,bzero_lp
+
+bzero_lp_done:
+	/*
+	 * Handle the last 0..7 words.
+	 * We mask off the low bits, so we don't need an extra
+	 * compare instruction for the loop (just a bne. heh-heh)
+	 */
+	and	a1,0x38,t4
+	beq	t4,bzero_finish_lp_done
+bzero_finish_lp:
+	stq	zero,0(a0)
+	subq	t4,8,t4
+	addq	a0,8,a0
+	bne	t4,bzero_finish_lp
+
+	/* Do the last partial word */
+bzero_finish_lp_done:
+	and	a1,7,t5		/* 0..7 bytes left */
+	beq	t5,bzero_done	/* mskqh won't change t0 if t5==0, but I
+				   don't want to touch, say, a new VM page */
+	ldq	t0,0(a0)
+	mskqh	t0,t5,t0
+	stq	t0,0(a0)
+bzero_done:
+	RET
+
+	END(bzero)