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-rw-r--r--arch/s390/include/asm/bitops.h81
1 files changed, 81 insertions, 0 deletions
diff --git a/arch/s390/include/asm/bitops.h b/arch/s390/include/asm/bitops.h
index 6f573890fb28..15422933c60b 100644
--- a/arch/s390/include/asm/bitops.h
+++ b/arch/s390/include/asm/bitops.h
@@ -640,6 +640,87 @@ static inline unsigned long find_first_bit(const unsigned long * addr,
}
#define find_first_bit find_first_bit
+/*
+ * Big endian variant whichs starts bit counting from left using
+ * the flogr (find leftmost one) instruction.
+ */
+static inline unsigned long __flo_word(unsigned long nr, unsigned long val)
+{
+ register unsigned long bit asm("2") = val;
+ register unsigned long out asm("3");
+
+ asm volatile (
+ " .insn rre,0xb9830000,%[bit],%[bit]\n"
+ : [bit] "+d" (bit), [out] "=d" (out) : : "cc");
+ return nr + bit;
+}
+
+/*
+ * 64 bit special left bitops format:
+ * order in memory:
+ * 00 01 02 03 04 05 06 07 08 09 0a 0b 0c 0d 0e 0f
+ * 10 11 12 13 14 15 16 17 18 19 1a 1b 1c 1d 1e 1f
+ * 20 21 22 23 24 25 26 27 28 29 2a 2b 2c 2d 2e 2f
+ * 30 31 32 33 34 35 36 37 38 39 3a 3b 3c 3d 3e 3f
+ * after that follows the next long with bit numbers
+ * 40 41 42 43 44 45 46 47 48 49 4a 4b 4c 4d 4e 4f
+ * 50 51 52 53 54 55 56 57 58 59 5a 5b 5c 5d 5e 5f
+ * 60 61 62 63 64 65 66 67 68 69 6a 6b 6c 6d 6e 6f
+ * 70 71 72 73 74 75 76 77 78 79 7a 7b 7c 7d 7e 7f
+ * The reason for this bit ordering is the fact that
+ * the hardware sets bits in a bitmap starting at bit 0
+ * and we don't want to scan the bitmap from the 'wrong
+ * end'.
+ */
+static inline unsigned long find_first_bit_left(const unsigned long *addr,
+ unsigned long size)
+{
+ unsigned long bytes, bits;
+
+ if (!size)
+ return 0;
+ bytes = __ffs_word_loop(addr, size);
+ bits = __flo_word(bytes * 8, __load_ulong_be(addr, bytes));
+ return (bits < size) ? bits : size;
+}
+
+static inline int find_next_bit_left(const unsigned long *addr,
+ unsigned long size,
+ unsigned long offset)
+{
+ const unsigned long *p;
+ unsigned long bit, set;
+
+ if (offset >= size)
+ return size;
+ bit = offset & (__BITOPS_WORDSIZE - 1);
+ offset -= bit;
+ size -= offset;
+ p = addr + offset / __BITOPS_WORDSIZE;
+ if (bit) {
+ set = __flo_word(0, *p & (~0UL << bit));
+ if (set >= size)
+ return size + offset;
+ if (set < __BITOPS_WORDSIZE)
+ return set + offset;
+ offset += __BITOPS_WORDSIZE;
+ size -= __BITOPS_WORDSIZE;
+ p++;
+ }
+ return offset + find_first_bit_left(p, size);
+}
+
+#define for_each_set_bit_left(bit, addr, size) \
+ for ((bit) = find_first_bit_left((addr), (size)); \
+ (bit) < (size); \
+ (bit) = find_next_bit_left((addr), (size), (bit) + 1))
+
+/* same as for_each_set_bit() but use bit as value to start with */
+#define for_each_set_bit_left_cont(bit, addr, size) \
+ for ((bit) = find_next_bit_left((addr), (size), (bit)); \
+ (bit) < (size); \
+ (bit) = find_next_bit_left((addr), (size), (bit) + 1))
+
/**
* find_next_zero_bit - find the first zero bit in a memory region
* @addr: The address to base the search on
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