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authorRalf Baechle <ralf@linux-mips.org>1997-01-07 02:33:00 +0000
committer <ralf@linux-mips.org>1997-01-07 02:33:00 +0000
commitbeb116954b9b7f3bb56412b2494b562f02b864b1 (patch)
tree120e997879884e1b9d93b265221b939d2ef1ade1 /include/asm-ppc/bitops.h
parent908d4681a1dc3792ecafbe64265783a86c4cccb6 (diff)
Import of Linux/MIPS 2.1.14
Diffstat (limited to 'include/asm-ppc/bitops.h')
-rw-r--r--include/asm-ppc/bitops.h130
1 files changed, 130 insertions, 0 deletions
diff --git a/include/asm-ppc/bitops.h b/include/asm-ppc/bitops.h
new file mode 100644
index 000000000..5e0407abd
--- /dev/null
+++ b/include/asm-ppc/bitops.h
@@ -0,0 +1,130 @@
+#ifndef _ASM_PPC_BITOPS_H_
+#define _ASM_PPC_BITOPS_H_
+
+/*
+ * For the benefit of those who are trying to port Linux to another
+ * architecture, here are some C-language equivalents. You should
+ * recode these in the native assembly language, if at all possible.
+ * To guarantee atomicity, these routines call cli() and sti() to
+ * disable interrupts while they operate. (You have to provide inline
+ * routines to cli() and sti().)
+ *
+ * Also note, these routines assume that you have 32 bit integers.
+ * You will have to change this if you are trying to port Linux to the
+ * Alpha architecture or to a Cray. :-)
+ *
+ * C language equivalents written by Theodore Ts'o, 9/26/92
+ */
+
+#include "asm/system.h" /* For cli/sti declaration */
+
+#define BIT(n) 1<<(n&0x1F)
+typedef unsigned long BITFIELD;
+
+extern __inline__ int set_bit(int nr, void * add)
+{
+ int mask, oldbit;
+ BITFIELD *addr = add;
+
+ int s = _disable_interrupts();
+ addr += nr >> 5;
+ mask = BIT(nr);
+ oldbit = (mask & *addr) != 0;
+ *addr |= mask;
+ _enable_interrupts(s);
+
+
+ return oldbit;
+}
+
+extern __inline__ int change_bit(int nr, void *add)
+{
+ BITFIELD *addr = add;
+ int mask, retval;
+ int s = _disable_interrupts();
+ addr += nr >> 5;
+ mask = BIT(nr);
+ retval = (mask & *addr) != 0;
+ *addr ^= mask;
+ _enable_interrupts(s);
+ return retval;
+}
+
+extern __inline__ int clear_bit(int nr, void *add)
+{
+ BITFIELD *addr = add;
+ int mask, retval;
+ int s = _disable_interrupts();
+ addr += nr >> 5;
+ mask = BIT(nr);
+ retval = (mask & *addr) != 0;
+ *addr &= ~mask;
+ _enable_interrupts(s);
+ return retval;
+}
+
+extern __inline__ int test_bit(int nr, void *add)
+{
+ int mask;
+ BITFIELD *addr = add;
+
+ addr += nr >> 5;
+ mask = BIT(nr);
+ return ((mask & *addr) != 0);
+}
+#if 0
+extern __inline__ int find_first_zero_bit(void *add, int len)
+{
+ int mask, nr, i;
+ BITFIELD *addr = add;
+ nr = 0;
+ while (len)
+ {
+ if (~*addr != 0)
+ { /* Contains at least one zero */
+ for (i = 0; i < 32; i++, nr++)
+ {
+ mask = BIT(nr);
+ if ((mask & *addr) == 0)
+ {
+ return (nr);
+ }
+ }
+ }
+ len -= 32;
+ addr++;
+ nr += 32;
+ }
+ return (0); /* Shouldn't happen */
+}
+
+extern __inline__ int find_next_zero_bit(void *add, int len, int nr)
+{
+ int mask, i;
+ BITFIELD *addr = add;
+ addr += nr >> 5;
+ len -= nr;
+ while (len)
+ {
+ if (*addr != 0xFFFFFFFF)
+ { /* Contains at least one zero */
+ for (i = 0; i < 32; i++, nr++)
+ {
+ mask = BIT(nr);
+ if ((mask & *addr) == 0)
+ {
+printk("Bit: %d(%d), Pat: %x\n", nr, nr&0x1F, *addr);
+ return (nr);
+ }
+ }
+ }
+ len -= 32;
+ addr++;
+ nr += 32;
+ }
+ return (0); /* Shouldn't happen */
+}
+#endif
+#endif /* _ASM_PPC_BITOPS_H */
+
+