patch-2.1.80 linux/arch/arm/lib/bitops.S

• Lines: 153
• Date: Tue Jan 20 16:39:41 1998
• Orig file: v2.1.79/linux/arch/arm/lib/bitops.S
• Orig date: Wed Dec 31 16:00:00 1969

diff -u --recursive --new-file v2.1.79/linux/arch/arm/lib/bitops.S linux/arch/arm/lib/bitops.S
@@ -0,0 +1,152 @@
+/*
+ * linux/arch/arm/lib/bitops.S
+ *
+ * Copyright (C) 1995, 1996 Russell King
+ */
+
+#include <linux/linkage.h>
+#include <asm/assembler.h>
+                .text
+
+@ Purpose  : Function to set a bit
+@ Prototype: int set_bit(int bit,int *addr)
+
+ENTRY(set_bit)
+                and     r2, r0, #7
+                mov     r3, #1
+                mov     r3, r3, lsl r2
+		SAVEIRQS(ip)
+		DISABLEIRQS(ip)
+		ldrb	r2, [r1, r0, lsr #3]
+		orr	r2, r2, r3
+		strb	r2, [r1, r0, lsr #3]
+		RESTOREIRQS(ip)
+		RETINSTR(mov,pc,lr)
+
+ENTRY(test_and_set_bit)
+		add	r1, r1, r0, lsr #3	@ Get byte offset
+		and	r3, r0, #7		@ Get bit offset
+		mov	r0, #1
+		SAVEIRQS(ip)
+		DISABLEIRQS(ip)
+		ldrb	r2, [r1]
+		tst	r2, r0, lsl r3
+		orr	r2, r2, r0, lsl r3
+		moveq	r0, #0
+		strb	r2, [r1]
+		RESTOREIRQS(ip)
+		RETINSTR(mov,pc,lr)
+
+@ Purpose  : Function to clear a bit
+@ Prototype: int clear_bit(int bit,int *addr)
+
+ENTRY(clear_bit)
+		and	r2, r0, #7
+		mov	r3, #1
+		mov	r3, r3, lsl r2
+		SAVEIRQS(ip)
+		DISABLEIRQS(ip)
+		ldrb	r2, [r1, r0, lsr #3]
+		bic	r2, r2, r3
+		strb	r2, [r1, r0, lsr #3]
+		RESTOREIRQS(ip)
+		RETINSTR(mov,pc,lr)
+
+ENTRY(test_and_clear_bit)
+		add	r1, r1, r0, lsr #3	@ Get byte offset
+		and	r3, r0, #7	@ Get bit offset
+		mov	r0, #1
+		SAVEIRQS(ip)
+		DISABLEIRQS(ip)
+		ldrb	r2, [r1]
+		tst	r2, r0, lsl r3
+		bic	r2, r2, r0, lsl r3
+		moveq	r0, #0
+		strb	r2, [r1]
+		RESTOREIRQS(ip)
+		RETINSTR(mov,pc,lr)
+
+/* Purpose  : Function to change a bit
+ * Prototype: int change_bit(int bit,int *addr)
+ */
+ENTRY(change_bit)
+                and     r2, r0, #7
+                mov     r3, #1
+                mov     r3, r3, lsl r2
+		SAVEIRQS(ip)
+		DISABLEIRQS(ip)
+		ldrb	r2, [r1, r0, lsr #3]
+		eor	r2, r2, r3
+		strb	r2, [r1, r0, lsr #3]
+		RESTOREIRQS(ip)
+		RETINSTR(mov,pc,lr)
+
+ENTRY(test_and_change_bit)
+		add	r1, r1, r0, lsr #3
+		and	r3, r0, #7
+		mov	r0, #1
+		SAVEIRQS(ip)
+		DISABLEIRQS(ip)
+		ldrb	r2, [r1]
+		tst	r2, r0, lsl r3
+		eor	r2, r2, r0, lsl r3
+		moveq	r0, #0
+		strb	r2, [r1]
+		RESTOREIRQS(ip)
+		RETINSTR(mov,pc,lr)
+
+@ 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