Similar to the bitops_ctz change just made.
Signed-off-by: Richard Henderson <r...@twiddle.net>
---
include/qemu/bitops.h | 44 +++++++++++++++-----------------------------
target-i386/topology.h | 2 +-
util/bitops.c | 2 +-
3 files changed, 17 insertions(+), 31 deletions(-)
diff --git a/include/qemu/bitops.h b/include/qemu/bitops.h
index 8b88791..07ada63 100644
--- a/include/qemu/bitops.h
+++ b/include/qemu/bitops.h
@@ -50,41 +50,27 @@ static unsigned long bitops_ctzl(unsigned long word)
}
/**
- * bitops_fls - find last (most-significant) set bit in a long word
+ * bitops_clzl - find last (most-significant) set bit in a long word
* @word: the word to search
*
* Undefined if no set bit exists, so code should check against 0 first.
*/
-static inline unsigned long bitops_flsl(unsigned long word)
+static inline unsigned long bitops_clzl(unsigned long word)
{
- int num = BITS_PER_LONG - 1;
-
-#if LONG_MAX > 0x7FFFFFFF
- if (!(word & (~0ul << 32))) {
- num -= 32;
- word <<= 32;
- }
+ /* Both this function and the gcc builtin are undefined at 0, whereas
+ the host-utils functions return word-size at 0. Thus we prefer the
+ gcc builtin as the closer match. */
+#if QEMU_GNUC_PREREQ(3, 4)
+ return __builtin_clzl(word);
+#else
+ if (sizeof(long) == 4) {
+ return clz32(word);
+ } else if (sizeof(long) == 8) {
+ return clz64(word);
+ } else {
+ abort();
+ }
#endif
- if (!(word & (~0ul << (BITS_PER_LONG-16)))) {
- num -= 16;
- word <<= 16;
- }
- if (!(word & (~0ul << (BITS_PER_LONG-8)))) {
- num -= 8;
- word <<= 8;
- }
- if (!(word & (~0ul << (BITS_PER_LONG-4)))) {
- num -= 4;
- word <<= 4;
- }
- if (!(word & (~0ul << (BITS_PER_LONG-2)))) {
- num -= 2;
-
- word <<= 2;
- }
- if (!(word & (~0ul << (BITS_PER_LONG-1))))
- num -= 1;
- return num;
}
/**
diff --git a/target-i386/topology.h b/target-i386/topology.h
index 24ed525..96a559e 100644
--- a/target-i386/topology.h
+++ b/target-i386/topology.h
@@ -55,7 +55,7 @@ static unsigned apicid_bitwidth_for_count(unsigned count)
if (count == 1) {
return 0;
}
- return bitops_flsl(count - 1) + 1;
+ return bitops_clzl(count - 1) + 1;
}
/* Bit width of the SMT_ID (thread ID) field on the APIC ID
diff --git a/util/bitops.c b/util/bitops.c
index 7b853cf..4f4fa95 100644
--- a/util/bitops.c
+++ b/util/bitops.c
@@ -133,7 +133,7 @@ unsigned long find_last_bit(const unsigned long *addr,
unsigned long size)
tmp = addr[--words];
if (tmp) {
found:
- return words * BITS_PER_LONG + bitops_flsl(tmp);
+ return words * BITS_PER_LONG + bitops_clzl(tmp);
}
}
--
1.8.1
