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authorwdenk <wdenk>2002-11-03 00:24:07 +0000
committerwdenk <wdenk>2002-11-03 00:24:07 +0000
commitc609719b8d1b2dca590e0ed499016d041203e403 (patch)
tree7ea1755d80903ff972f312a249eb856061d40e15 /include/asm-arm/bitops.h
parent5b1d713721c3ea02549940133f09236783dda1f9 (diff)
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Initial revision
Diffstat (limited to 'include/asm-arm/bitops.h')
-rw-r--r--include/asm-arm/bitops.h144
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diff --git a/include/asm-arm/bitops.h b/include/asm-arm/bitops.h
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+/*
+ * Copyright 1995, Russell King.
+ * Various bits and pieces copyrights include:
+ * Linus Torvalds (test_bit).
+ *
+ * bit 0 is the LSB of addr; bit 32 is the LSB of (addr+1).
+ *
+ * Please note that the code in this file should never be included
+ * from user space. Many of these are not implemented in assembler
+ * since they would be too costly. Also, they require priviledged
+ * instructions (which are not available from user mode) to ensure
+ * that they are atomic.
+ */
+
+#ifndef __ASM_ARM_BITOPS_H
+#define __ASM_ARM_BITOPS_H
+
+#ifdef __KERNEL__
+
+#define smp_mb__before_clear_bit() do { } while (0)
+#define smp_mb__after_clear_bit() do { } while (0)
+
+/*
+ * Function prototypes to keep gcc -Wall happy.
+ */
+extern void set_bit(int nr, volatile void * addr);
+
+static inline void __set_bit(int nr, volatile void *addr)
+{
+ ((unsigned char *) addr)[nr >> 3] |= (1U << (nr & 7));
+}
+
+extern void clear_bit(int nr, volatile void * addr);
+
+static inline void __clear_bit(int nr, volatile void *addr)
+{
+ ((unsigned char *) addr)[nr >> 3] &= ~(1U << (nr & 7));
+}
+
+extern void change_bit(int nr, volatile void * addr);
+
+static inline void __change_bit(int nr, volatile void *addr)
+{
+ ((unsigned char *) addr)[nr >> 3] ^= (1U << (nr & 7));
+}
+
+extern int test_and_set_bit(int nr, volatile void * addr);
+
+static inline int __test_and_set_bit(int nr, volatile void *addr)
+{
+ unsigned int mask = 1 << (nr & 7);
+ unsigned int oldval;
+
+ oldval = ((unsigned char *) addr)[nr >> 3];
+ ((unsigned char *) addr)[nr >> 3] = oldval | mask;
+ return oldval & mask;
+}
+
+extern int test_and_clear_bit(int nr, volatile void * addr);
+
+static inline int __test_and_clear_bit(int nr, volatile void *addr)
+{
+ unsigned int mask = 1 << (nr & 7);
+ unsigned int oldval;
+
+ oldval = ((unsigned char *) addr)[nr >> 3];
+ ((unsigned char *) addr)[nr >> 3] = oldval & ~mask;
+ return oldval & mask;
+}
+
+extern int test_and_change_bit(int nr, volatile void * addr);
+
+static inline int __test_and_change_bit(int nr, volatile void *addr)
+{
+ unsigned int mask = 1 << (nr & 7);
+ unsigned int oldval;
+
+ oldval = ((unsigned char *) addr)[nr >> 3];
+ ((unsigned char *) addr)[nr >> 3] = oldval ^ mask;
+ return oldval & mask;
+}
+
+extern int find_first_zero_bit(void * addr, unsigned size);
+extern int find_next_zero_bit(void * addr, int size, int offset);
+
+/*
+ * This routine doesn't need to be atomic.
+ */
+static inline int test_bit(int nr, const void * addr)
+{
+ return ((unsigned char *) addr)[nr >> 3] & (1U << (nr & 7));
+}
+
+/*
+ * ffz = Find First Zero in word. Undefined if no zero exists,
+ * so code should check against ~0UL first..
+ */
+static inline unsigned long ffz(unsigned long word)
+{
+ int k;
+
+ word = ~word;
+ k = 31;
+ if (word & 0x0000ffff) { k -= 16; word <<= 16; }
+ if (word & 0x00ff0000) { k -= 8; word <<= 8; }
+ if (word & 0x0f000000) { k -= 4; word <<= 4; }
+ if (word & 0x30000000) { k -= 2; word <<= 2; }
+ if (word & 0x40000000) { k -= 1; }
+ return k;
+}
+
+/*
+ * ffs: find first bit set. This is defined the same way as
+ * the libc and compiler builtin ffs routines, therefore
+ * differs in spirit from the above ffz (man ffs).
+ */
+
+#define ffs(x) generic_ffs(x)
+
+/*
+ * hweightN: returns the hamming weight (i.e. the number
+ * of bits set) of a N-bit word
+ */
+
+#define hweight32(x) generic_hweight32(x)
+#define hweight16(x) generic_hweight16(x)
+#define hweight8(x) generic_hweight8(x)
+
+#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_test_and_set_bit(nr,addr) test_and_set_bit(nr,addr)
+#define minix_set_bit(nr,addr) set_bit(nr,addr)
+#define minix_test_and_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 /* _ARM_BITOPS_H */