patch-2.4.2 linux/include/asm-cris/bitops.h

• Lines: 185
• Date: Thu Feb 8 16:32:44 2001
• Orig file: v2.4.1/linux/include/asm-cris/bitops.h
• Orig date: Wed Dec 31 16:00:00 1969

diff -u --recursive --new-file v2.4.1/linux/include/asm-cris/bitops.h linux/include/asm-cris/bitops.h
@@ -0,0 +1,184 @@
+/* $Id: bitops.h,v 1.3 2000/10/17 14:56:27 bjornw Exp $ */
+/* all of these should probably be rewritten in assembler for speed. */
+
+#ifndef _CRIS_BITOPS_H
+#define _CRIS_BITOPS_H
+
+#include <asm/system.h>
+
+/*
+ * These have to be done with inline assembly: that way the bit-setting
+ * is guaranteed to be atomic. All bit operations return 0 if the bit
+ * was cleared before the operation and != 0 if it was not.
+ *
+ * bit 0 is the LSB of addr; bit 32 is the LSB of (addr+1).
+ */
+
+/*
+ * Some hacks to defeat gcc over-optimizations..
+ */
+struct __dummy { unsigned long a[100]; };
+#define ADDR (*(struct __dummy *) addr)
+#define CONST_ADDR (*(const struct __dummy *) addr)
+
+#define set_bit(nr, addr)    (void)test_and_set_bit(nr, addr)
+#define clear_bit(nr, addr)  (void)test_and_clear_bit(nr, addr)
+#define change_bit(nr, addr) (void)test_and_change_bit(nr, addr)
+
+extern __inline__ int test_and_set_bit(int nr, void *addr)
+{
+	unsigned int mask, retval;
+	unsigned long flags;
+	unsigned int *adr = (unsigned int *)addr;
+	
+	adr += nr >> 5;
+	mask = 1 << (nr & 0x1f);
+	save_flags(flags);
+	cli();
+	retval = (mask & *adr) != 0;
+	*adr |= mask;
+	restore_flags(flags);
+	return retval;
+}
+
+/*
+ * clear_bit() doesn't provide any barrier for the compiler.
+ */
+#define smp_mb__before_clear_bit()      barrier()
+#define smp_mb__after_clear_bit()       barrier()
+
+extern __inline__ int test_and_clear_bit(int nr, void *addr)
+{
+	unsigned int mask, retval;
+	unsigned long flags;
+	unsigned int *adr = (unsigned int *)addr;
+	
+	adr += nr >> 5;
+	mask = 1 << (nr & 0x1f);
+	save_flags(flags);
+	cli();
+	retval = (mask & *adr) != 0;
+	*adr &= ~mask;
+	restore_flags(flags);
+	return retval;
+}
+
+extern __inline__ int test_and_change_bit(int nr, void *addr)
+{
+	unsigned int mask, retval;
+	unsigned long flags;
+	unsigned int *adr = (unsigned int *)addr;
+	adr += nr >> 5;
+	mask = 1 << (nr & 0x1f);
+	save_flags(flags);
+	cli();
+	retval = (mask & *adr) != 0;
+	*adr ^= mask;
+	restore_flags(flags);
+	return retval;
+}
+
+/*
+ * This routine doesn't need to be atomic.
+ */
+extern __inline__ int test_bit(int nr, const void *addr)
+{
+	unsigned int mask;
+	unsigned int *adr = (unsigned int *)addr;
+	
+	adr += nr >> 5;
+	mask = 1 << (nr & 0x1f);
+	return ((mask & *adr) != 0);
+}
+
+/*
+ * Find-bit routines..
+ */
+
+/*
+ * ffz = Find First Zero in word. Undefined if no zero exists,
+ * so code should check against ~0UL first..
+ */
+extern __inline__ unsigned long ffz(unsigned long word)
+{
+	unsigned long result = 0;
+	
+	while(word & 1) {
+		result++;
+		word >>= 1;
+	}
+	return result;
+}
+
+/*
+ * Find first one in word. Undefined if no one exists,
+ * so code should check against 0UL first..
+ */
+extern __inline__ unsigned long find_first_one(unsigned long word)
+{
+	unsigned long result = 0;
+	
+	while(!(word & 1)) {
+		result++;
+		word >>= 1;
+	}
+	return result;
+}
+
+extern __inline__ int find_next_zero_bit (void * addr, int size, int offset)
+{
+	unsigned long *p = ((unsigned long *) addr) + (offset >> 5);
+	unsigned long result = offset & ~31UL;
+	unsigned long 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);
+}
+
+#define find_first_zero_bit(addr, size) \
+        find_next_zero_bit((addr), (size), 0)
+
+#ifdef __KERNEL__ 
+
+#define ext2_set_bit                 test_and_set_bit
+#define ext2_clear_bit               test_and_clear_bit
+#define ext2_test_bit                test_bit
+#define ext2_find_first_zero_bit     find_first_zero_bit
+#define ext2_find_next_zero_bit      find_next_zero_bit
+
+/* Bitmap functions for the minix filesystem.  */
+#define minix_set_bit(nr,addr) test_and_set_bit(nr,addr)
+#define minix_clear_bit(nr,addr) test_and_clear_bit(nr,addr)
+#define minix_test_bit(nr,addr) test_bit(nr,addr)
+#define minix_find_first_zero_bit(addr,size) find_first_zero_bit(addr,size)
+
+#endif /* __KERNEL__ */
+
+
+#endif /* _CRIS_BITOPS_H */