20060303a

1 files changed, 73 insertions, 0 deletions

diff --git a/libkern/memset-power.s b/libkern/memset-power.s
new file mode 100644
index 00000000..fa6e8d92
--- /dev/null
+++ b/libkern/memset-power.s
@@ -0,0 +1,73 @@
+	TEXT	memset(SB),$0
+#define	BDNZ	BC	16,0,
+	MOVW R3, p+0(FP)		/* R3 is pointer */
+
+/*
+ * performance:
+ *	about 100mbytes/sec (8k blocks) on a 603/105 without L2 cache
+ *	drops to 40mbytes/sec (10k blocks) and 28mbytes/sec with 32k blocks
+ */
+
+	MOVW	n+8(FP), R4		/* R4 is count */
+	CMP	R4, $0
+	BLE	ret
+	MOVW	c+4(FP), R5		/* R5 is char */
+
+/*
+ * create 16 copies of c in R5 .. R8
+ */
+	RLWNM	$0, R5, $0xff, R5
+	RLWMI	$8, R5, $0xff00, R5
+	RLWMI	$16, R5, $0xffff0000, R5
+	MOVW	R5, R6
+	MOVW	R5, R7
+	MOVW	R5, R8
+
+/*
+ * let STSW do the work for 16 characters or less; aligned and unaligned
+ */
+	CMP	R4, $16
+	BLE	out
+
+/*
+ * store enough bytes to align pointer
+ */
+	ANDCC	$7,R3, R9
+	BEQ	l2
+	SUBC	R9, $8, R9
+	MOVW	R9, XER
+	STSW	R5, (R3)
+	ADD	R9, R3
+	SUB	R9, R4
+
+/*
+ * store 16 at a time while there's room
+ * STSW was used here originally, but it's `completion serialised'
+ */
+l2:
+	SRAWCC	$4, R4, R9
+	BLE	out
+	MOVW	R9, CTR
+l3:
+	MOVW	R5, 0(R3)
+	ADD	$8, R3, R10
+	MOVW	R6, 4(R3)
+	MOVW	R7, 0(R10)
+	ADD	$8, R10, R3
+	MOVW	R8, 4(R10)
+	BDNZ	l3
+	RLWNMCC	$0, R4, $15, R4	/* residue */
+	BEQ	ret
+
+/*
+ * store up to 16 bytes from R5 .. R8; aligned and unaligned
+ */
+
+out:
+	MOVW	R4, XER
+	STSW	R5, (R3)
+
+ret:
+	MOVW	0(FP), R3
+	RETURN
+	END