patch-2.4.19 linux-2.4.19/arch/ppc64/kernel/bitops.c

• Lines: 90
• Date: Fri Aug 2 17:39:43 2002
• Orig file: linux-2.4.18/arch/ppc64/kernel/bitops.c
• Orig date: Wed Dec 31 16:00:00 1969

diff -urN linux-2.4.18/arch/ppc64/kernel/bitops.c linux-2.4.19/arch/ppc64/kernel/bitops.c
@@ -0,0 +1,89 @@
+/*
+ * Copyright (C) 1996 Paul Mackerras.
+ * Adapted for ppc64 - Todd Inglett, Anton Blanchard
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU General Public License
+ * as published by the Free Software Foundation; either version
+ * 2 of the License, or (at your option) any later version.
+ */
+
+#include <linux/kernel.h>
+#include <asm/bitops.h>
+#include <linux/fs.h>
+#include <linux/ext2_fs.h>
+#include <linux/locks.h>
+#include <linux/quotaops.h>
+#include <asm/ppcdebug.h>
+
+#undef DEBUG_BITOPS
+
+/*
+ * Bitops are weird when viewed on big-endian systems.  They were designed
+ * on little endian so the size of the bitset doesn't matter (low order bytes
+ * come first) as long as the bit in question is valid.
+ *
+ * Bits are "tested" often using the C expression (val & (1<<nr)) so we do
+ * our best to stay compatible with that.  The assumption is that val will
+ * be unsigned long for such tests.  As such, we assume the bits are stored
+ * as an array of unsigned long (the usual case is a single unsigned long,
+ * of course).  Here's an example bitset with bit numbering:
+ *
+ *   |63..........0|127........64|195.......128|255.......196|
+ *
+ * This leads to two problems.  First, if an int, short or char is passed as
+ * a bitset it will be a bad memory reference since we want to store in chunks
+ * of unsigned long (64 bits here) size.  Second, since these could be char
+ * arrays we might have an alignment problem.  We ease the alignment problem
+ * by actually doing the operation with 32 bit values yet preserving the
+ * 64 bit long layout as shown above.  Got that?  Good.
+ */
+
+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;
+	if (tmp == ~0UL)
+		return result+size;
+found_middle:
+	return result + ffz(tmp);
+}
+
+void BUG_OUTLINE(char* file, unsigned line) 
+{
+	udbg_printf("BUG - kernel BUG at %s:%d! \n", __FILE__, __LINE__);
+	PPCDBG_ENTER_DEBUGGER();
+	printk("kernel BUG at %s:%d!\n", __FILE__, __LINE__);
+	__asm__ __volatile__(".long " BUG_ILLEGAL_INSTR);
+}
+