patch-2.1.48 linux/arch/ppc/kernel/bitops.c

• Lines: 202
• Date: Thu Jul 31 13:09:17 1997
• Orig file: v2.1.47/linux/arch/ppc/kernel/bitops.c
• Orig date: Wed Dec 31 16:00:00 1969

diff -u --recursive --new-file v2.1.47/linux/arch/ppc/kernel/bitops.c linux/arch/ppc/kernel/bitops.c
@@ -0,0 +1,201 @@
+/*
+ * Copyright (C) 1996 Paul Mackerras.
+ */
+
+#include <linux/kernel.h>
+#include <asm/bitops.h>
+
+/*
+ * I left these here since the problems with "cc" make it difficult to keep
+ * them in bitops.h -- Cort
+ */
+void set_bit(int nr, volatile void *addr)
+{
+	unsigned int t;
+	unsigned int mask = 1 << (nr & 0x1f);
+	volatile unsigned int *p = ((volatile unsigned int *)addr) + (nr >> 5);
+
+	if ((unsigned long)addr & 3)
+		printk(KERN_ERR "set_bit(%x, %p)\n", nr, addr);
+	__asm__ __volatile__("\n\
+1:	lwarx	%0,0,%2
+	or	%0,%0,%1
+	stwcx.	%0,0,%2
+	bne	1b"
+	: "=&r" (t)		/*, "=m" (*p)*/
+	: "r" (mask), "r" (p)
+	: "cc");
+}
+
+void clear_bit(int nr, volatile void *addr)
+{
+	unsigned int t;
+	unsigned int mask = 1 << (nr & 0x1f);
+	volatile unsigned int *p = ((volatile unsigned int *)addr) + (nr >> 5);
+
+	if ((unsigned long)addr & 3)
+		printk(KERN_ERR "clear_bit(%x, %p)\n", nr, addr);
+	__asm__ __volatile__("\n\
+1:	lwarx	%0,0,%2
+	andc	%0,%0,%1
+	stwcx.	%0,0,%2
+	bne	1b"
+	: "=&r" (t)		/*, "=m" (*p)*/
+	: "r" (mask), "r" (p)
+	: "cc");
+}
+
+void change_bit(int nr, volatile void *addr)
+{
+	unsigned int t;
+	unsigned int mask = 1 << (nr & 0x1f);
+	volatile unsigned int *p = ((volatile unsigned int *)addr) + (nr >> 5);
+
+	if ((unsigned long)addr & 3)
+		printk(KERN_ERR "change_bit(%x, %p)\n", nr, addr);
+	__asm__ __volatile__("\n\
+1:	lwarx	%0,0,%2
+	xor	%0,%0,%1
+	stwcx.	%0,0,%2
+	bne	1b"
+	: "=&r" (t)		/*, "=m" (*p)*/
+	: "r" (mask), "r" (p)
+	: "cc");
+}
+
+int test_and_set_bit(int nr, volatile void *addr)
+{
+	unsigned int old, t;
+	unsigned int mask = 1 << (nr & 0x1f);
+	volatile unsigned int *p = ((volatile unsigned int *)addr) + (nr >> 5);
+
+	if ((unsigned long)addr & 3)
+		printk(KERN_ERR "test_and_set_bit(%x, %p)\n", nr, addr);
+	__asm__ __volatile__("\n\
+1:	lwarx	%0,0,%3
+	or	%1,%0,%2
+	stwcx.	%1,0,%3
+	bne	1b"
+	: "=&r" (old), "=&r" (t)	/*, "=m" (*p)*/
+	: "r" (mask), "r" (p)
+	: "cc");
+
+	return (old & mask) != 0;
+}
+
+int test_and_clear_bit(int nr, volatile void *addr)
+{
+	unsigned int old, t;
+	unsigned int mask = 1 << (nr & 0x1f);
+	volatile unsigned int *p = ((volatile unsigned int *)addr) + (nr >> 5);
+
+	if ((unsigned long)addr & 3)
+		printk(KERN_ERR "test_and_clear_bit(%x, %p)\n", nr, addr);
+	__asm__ __volatile__("\n\
+1:	lwarx	%0,0,%3
+	andc	%1,%0,%2
+	stwcx.	%1,0,%3
+	bne	1b"
+	: "=&r" (old), "=&r" (t)	/*, "=m" (*p)*/
+	: "r" (mask), "r" (p)
+	: "cc");
+
+	return (old & mask) != 0;
+}
+
+int test_and_change_bit(int nr, volatile void *addr)
+{
+	unsigned int old, t;
+	unsigned int mask = 1 << (nr & 0x1f);
+	volatile unsigned int *p = ((volatile unsigned int *)addr) + (nr >> 5);
+
+	if ((unsigned long)addr & 3)
+		printk(KERN_ERR "test_and_change_bit(%x, %p)\n", nr, addr);
+	__asm__ __volatile__("\n\
+1:	lwarx	%0,0,%3
+	xor	%1,%0,%2
+	stwcx.	%1,0,%3
+	bne	1b"
+	: "=&r" (old), "=&r" (t)	/*, "=m" (*p)*/
+	: "r" (mask), "r" (p)
+	: "cc");
+
+	return (old & mask) != 0;
+}
+
+/* I put it in bitops.h -- Cort */
+#if 0
+int ffz(unsigned int x)
+{
+	int n;
+
+	x = ~x & (x+1);		/* set LS zero to 1, other bits to 0 */
+	__asm__ ("cntlzw %0,%1" : "=r" (n) : "r" (x));
+	return 31 - n;
+}
+
+/*
+ * This implementation of find_{first,next}_zero_bit was stolen from
+ * Linus' asm-alpha/bitops.h.
+ */
+
+int find_first_zero_bit(void * addr, int size)
+{
+	unsigned int * p = ((unsigned int *) addr);
+	unsigned int result = 0;
+	unsigned int tmp;
+
+	if (size == 0)
+		return 0;
+	while (size & ~31UL) {
+		if (~(tmp = *(p++)))
+			goto found_middle;
+		result += 32;
+		size -= 32;
+	}
+	if (!size)
+		return result;
+	tmp = *p;
+	tmp |= ~0UL << size;
+found_middle:
+	return result + ffz(tmp);
+}
+
+/*
+ * Find next zero bit in a bitmap reasonably efficiently..
+ */
+int find_next_zero_bit(void * addr, int size, int offset)
+{
+	unsigned int * p = ((unsigned int *) addr) + (offset >> 5);
+	unsigned int result = offset & ~31UL;
+	unsigned int tmp;
+
+	if (offset >= size)
+		return size;
+	size -= result;
+	offset &= 31UL;
+	if (offset) {
+		tmp = *(p++);
+		tmp |= ~0UL >> (32-offset);
+		if (size < 32)
+			goto found_first;
+		if (~tmp)
+			goto found_middle;
+		size -= 32;
+		result += 32;
+	}
+	while (size & ~31UL) {
+		if (~(tmp = *(p++)))
+			goto found_middle;
+		result += 32;
+		size -= 32;
+	}
+	if (!size)
+		return result;
+	tmp = *p;
+found_first:
+	tmp |= ~0UL << size;
+found_middle:
+	return result + ffz(tmp);
+}
+#endif