patch-2.2.18 linux/arch/arm/lib/findbit.S

• Lines: 66
• Date: Fri Sep 15 23:28:37 2000
• Orig file: v2.2.17/arch/arm/lib/findbit.S
• Orig date: Thu Jan 1 01:00:00 1970

diff -u --new-file --recursive --exclude-from /usr/src/exclude v2.2.17/arch/arm/lib/findbit.S linux/arch/arm/lib/findbit.S
@@ -0,0 +1,65 @@
+/*
+ * linux/arch/arm/lib/bitops.S
+ *
+ * Copyright (C) 1995-1996 Russell King
+ */
+
+#include <linux/linkage.h>
+#include <asm/assembler.h>
+                .text
+
+@ Purpose  : Find a 'zero' bit
+@ Prototype: int find_first_zero_bit(char *addr,int maxbit);
+
+ENTRY(find_first_zero_bit)
+		mov	r2, #0			@ Initialise bit position
+Lfindzbit1lp:	ldrb	r3, [r0, r2, lsr #3]	@ Check byte, if 0xFF, then all bits set
+		teq	r3, #0xFF
+		bne	Lfoundzbit
+		add	r2, r2, #8
+		cmp	r2, r1			@ Check to see if we have come to the end
+		bcc	Lfindzbit1lp
+		add	r0, r1, #1		@ Make sure that we flag an error
+		RETINSTR(mov,pc,lr)
+Lfoundzbit:	tst	r3, #1			@ Check individual bits
+		moveq	r0, r2
+		RETINSTR(moveq,pc,lr)
+		tst	r3, #2
+		addeq	r0, r2, #1
+		RETINSTR(moveq,pc,lr)
+		tst	r3, #4
+		addeq	r0, r2, #2
+		RETINSTR(moveq,pc,lr)
+		tst	r3, #8
+		addeq	r0, r2, #3
+		RETINSTR(moveq,pc,lr)
+		tst	r3, #16
+		addeq	r0, r2, #4
+		RETINSTR(moveq,pc,lr)
+		tst	r3, #32
+		addeq	r0, r2, #5
+		RETINSTR(moveq,pc,lr)
+		tst	r3, #64
+		addeq	r0, r2, #6
+		RETINSTR(moveq,pc,lr)
+		add	r0, r2, #7
+		RETINSTR(mov,pc,lr)
+
+@ Purpose  : Find next 'zero' bit
+@ Prototype: int find_next_zero_bit(char *addr,int maxbit,int offset)
+
+ENTRY(find_next_zero_bit)
+		tst	r2, #7
+		beq	Lfindzbit1lp		@ If new byte, goto old routine
+		ldrb	r3, [r0, r2, lsr#3]
+		orr	r3, r3, #0xFF00		@ Set top bits so we wont get confused
+		stmfd	sp!, {r4}
+		and	r4, r2, #7
+		mov	r3, r3, lsr r4		@ Shift right by no. of bits
+		ldmfd	sp!, {r4}
+		and	r3, r3, #0xFF
+		teq	r3, #0xFF
+		orreq	r2, r2, #7
+		addeq	r2, r2, #1
+		beq	Lfindzbit1lp		@ If all bits are set, goto old routine
+		b	Lfoundzbit