patch-2.1.9 linux/arch/sparc/lib/memscan.S

• Lines: 136
• Date: Sat Nov 9 10:12:04 1996
• Orig file: v2.1.8/linux/arch/sparc/lib/memscan.S
• Orig date: Thu Jan 1 02:00:00 1970

diff -u --recursive --new-file v2.1.8/linux/arch/sparc/lib/memscan.S linux/arch/sparc/lib/memscan.S
@@ -0,0 +1,135 @@
+/* $Id: memscan.S,v 1.4 1996/09/08 02:01:20 davem Exp $
+ * memscan.S: Optimized memscan for the Sparc.
+ *
+ * Copyright (C) 1996 David S. Miller (davem@caip.rutgers.edu)
+ */
+
+#include <asm/cprefix.h>
+
+/* In essence, this is just a fancy strlen. */
+
+#define LO_MAGIC 0x01010101
+#define HI_MAGIC 0x80808080
+
+	.text
+	.align	4
+	.globl	C_LABEL(__memscan_zero), C_LABEL(__memscan_generic)
+	.globl	C_LABEL(memscan)
+C_LABEL(__memscan_zero):
+	/* %o0 = addr, %o1 = size */
+	cmp	%o1, 0
+	bne,a	1f
+	 andcc	%o0, 3, %g0
+
+	retl
+	 nop
+
+1:
+	be	mzero_scan_word
+	 sethi	%hi(HI_MAGIC), %g2
+
+	ldsb	[%o0], %g3
+mzero_still_not_word_aligned:
+	cmp	%g3, 0
+	bne	1f
+	 add	%o0, 1, %o0
+
+	retl
+	 sub	%o0, 1, %o0
+
+1:
+	subcc	%o1, 1, %o1
+	bne,a	1f
+	 andcc	%o0, 3, %g0
+
+	retl
+	 nop
+
+1:
+	bne,a	mzero_still_not_word_aligned
+	 ldsb	[%o0], %g3
+
+	sethi	%hi(HI_MAGIC), %g2
+mzero_scan_word:
+	or	%g2, %lo(HI_MAGIC), %o3
+	sethi	%hi(LO_MAGIC), %g3
+	or	%g3, %lo(LO_MAGIC), %o2
+mzero_next_word:
+	ld	[%o0], %g2
+mzero_next_word_preloaded:
+	sub	%g2, %o2, %g2
+mzero_next_word_preloaded_next:
+	andcc	%g2, %o3, %g0
+	bne	mzero_byte_zero
+	 add	%o0, 4, %o0
+
+mzero_check_out_of_fuel:
+	subcc	%o1, 4, %o1
+	bg,a	1f
+	 ld	[%o0], %g2
+
+	retl
+	 nop
+
+1:
+	b	mzero_next_word_preloaded_next
+	 sub	%g2, %o2, %g2
+
+	/* Check every byte. */
+mzero_byte_zero:
+	ldsb	[%o0 - 4], %g2
+	cmp	%g2, 0
+	bne	mzero_byte_one
+	 sub	%o0, 4, %g3
+
+	retl
+	 mov	%g3, %o0
+
+mzero_byte_one:
+	ldsb	[%o0 - 3], %g2
+	cmp	%g2, 0
+	bne,a	mzero_byte_two_and_three
+	 ldsb	[%o0 - 2], %g2
+
+	retl
+	 sub	%o0, 3, %o0
+
+mzero_byte_two_and_three:
+	cmp	%g2, 0
+	bne,a	1f
+	 ldsb	[%o0 - 1], %g2
+
+	retl
+	 sub	%o0, 2, %o0
+
+1:
+	cmp	%g2, 0
+	bne,a	mzero_next_word_preloaded
+	 ld	[%o0], %g2
+
+	retl
+	 sub	%o0, 1, %o0
+
+mzero_found_it:
+	retl
+	 sub	%o0, 2, %o0
+
+C_LABEL(memscan):
+C_LABEL(__memscan_generic):
+	/* %o0 = addr, %o1 = c, %o2 = size */
+	cmp	%o2, 0
+	bne,a	0f
+	 ldub	[%o0], %g2
+
+	b,a	2f
+1:
+	ldub	[%o0], %g2
+0:
+	cmp	%g2, %o1
+	be	2f
+	 addcc	%o2, -1, %o2
+	bne	1b
+	 add	%o0, 1, %o0
+2:
+	retl
+	 nop