1 files changed, 158 insertions, 0 deletions
diff --git a/include/asm-alpha/bitops.h b/include/asm-alpha/bitops.h
new file mode 100644
index 000000000..987a026e3
--- /dev/null
+++ b/include/asm-alpha/bitops.h
@@ -0,0 +1,158 @@
+#ifndef _ALPHA_BITOPS_H
+#define _ALPHA_BITOPS_H
+
+/*
+ * Copyright 1994, Linus Torvalds.
+ */
+
+/*
+ * 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 64 is the LSB of (addr+1).
+ */
+
+extern __inline__ unsigned long set_bit(unsigned long nr, void * addr)
+{
+	unsigned long oldbit;
+	unsigned long temp;
+
+	__asm__ __volatile__(
+		"\n1:\t"
+		"ldq_l %0,%1\n\t"
+		"and %0,%3,%2\n\t"
+		"bne %2,2f\n\t"
+		"xor %0,%3,%0\n\t"
+		"stq_c %0,%1\n\t"
+		"beq %0,1b\n"
+		"2:"
+		:"=&r" (temp),
+		 "=m" (((unsigned long *) addr)[nr >> 6]),
+		 "=&r" (oldbit)
+		:"r" (1UL << (nr & 63)),
+		 "m" (((unsigned long *) addr)[nr >> 6]));
+	return oldbit;
+}
+
+extern __inline__ unsigned long clear_bit(unsigned long nr, void * addr)
+{
+	unsigned long oldbit;
+	unsigned long temp;
+
+	__asm__ __volatile__(
+		"\n1:\t"
+		"ldq_l %0,%1\n\t"
+		"and %0,%3,%2\n\t"
+		"beq %2,2f\n\t"
+		"xor %0,%3,%0\n\t"
+		"stq_c %0,%1\n\t"
+		"beq %0,1b\n"
+		"2:"
+		:"=&r" (temp),
+		 "=m" (((unsigned long *) addr)[nr >> 6]),
+		 "=&r" (oldbit)
+		:"r" (1UL << (nr & 63)),
+		 "m" (((unsigned long *) addr)[nr >> 6]));
+	return oldbit;
+}
+
+extern __inline__ unsigned long change_bit(unsigned long nr, void * addr)
+{
+	unsigned long oldbit;
+	unsigned long temp;
+
+	__asm__ __volatile__(
+		"\n1:\t"
+		"ldq_l %0,%1\n\t"
+		"and %0,%3,%2\n\t"
+		"xor %0,%3,%0\n\t"
+		"stq_c %0,%1\n\t"
+		"beq %0,1b\n"
+		:"=&r" (temp),
+		 "=m" (((unsigned long *) addr)[nr >> 6]),
+		 "=&r" (oldbit)
+		:"r" (1UL << (nr & 63)),
+		 "m" (((unsigned long *) addr)[nr >> 6]));
+	return oldbit;
+}
+
+extern __inline__ unsigned long test_bit(int nr, void * addr)
+{
+	return 1UL & (((unsigned long *) addr)[nr >> 6] >> (nr & 63));
+}
+
+/*
+ * ffz = Find First Zero in word. Undefined if no zero exists,
+ * so code should check against ~0UL first..
+ *
+ * This uses the cmpbge insn to check which byte contains the zero.
+ * I don't know if that's actually a good idea, but it's fun and the
+ * resulting LBS tests should be natural on the alpha.. Besides, I'm
+ * just teaching myself the asm of the alpha anyway.
+ */
+extern inline unsigned long ffz(unsigned long word)
+{
+	unsigned long result = 0;
+	unsigned long tmp;
+
+	__asm__("cmpbge %1,%0,%0"
+		:"=r" (tmp)
+		:"r" (word), "0" (~0UL));
+	while (tmp & 1) {
+		word >>= 8;
+		tmp >>= 1;
+		result += 8;
+	}
+	while (word & 1) {
+		result++;
+		word >>= 1;
+	}
+	return result;
+}
+
+/*
+ * Find next zero bit in a bitmap reasonably efficiently..
+ */
+extern inline unsigned long find_next_zero_bit(void * addr, unsigned long size, unsigned long offset)
+{
+	unsigned long * p = ((unsigned long *) addr) + (offset >> 6);
+	unsigned long result = offset & ~63UL;
+	unsigned long tmp;
+
+	if (offset >= size)
+		return size;
+	size -= result;
+	offset &= 63UL;
+	if (offset) {
+		tmp = *(p++);
+		tmp |= ~0UL >> (64-offset);
+		if (size < 64)
+			goto found_first;
+		if (~tmp)
+			goto found_middle;
+		size -= 64;
+		result += 64;
+	}
+	while (size & ~63UL) {
+		if (~(tmp = *(p++)))
+			goto found_middle;
+		result += 64;
+		size -= 64;
+	}
+	if (!size)
+		return result;
+	tmp = *p;
+found_first:
+	tmp |= ~0UL << size;
+found_middle:
+	return result + ffz(tmp);
+}
+
+/*
+ * The optimizer actually does good code for this case..
+ */
+#define find_first_zero_bit(addr, size) \
+	find_next_zero_bit((addr), (size), 0)
+
+#endif /* _ALPHA_BITOPS_H */