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author | Paolo Bonzini <pbonzini@redhat.com> | 2013-01-21 17:09:39 +0100 |
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committer | Kevin Wolf <kwolf@redhat.com> | 2013-01-25 18:18:32 +0100 |
commit | 4c37ef022381e777251d7084591978a4dc622efe (patch) | |
tree | 321ffddba6c78e884be819f9b8200695a6238b71 | |
parent | 11c29918be32be5b00f367c7da9724a5cddbbb0f (diff) | |
download | hqemu-4c37ef022381e777251d7084591978a4dc622efe.zip hqemu-4c37ef022381e777251d7084591978a4dc622efe.tar.gz |
host-utils: add ffsl
We can provide fast versions based on the other functions defined
by host-utils.h. Some care is required on glibc, which provides
ffsl already.
Reviewed-by: Eric Blake <eblake@redhat.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
-rw-r--r-- | include/qemu/host-utils.h | 26 |
1 files changed, 26 insertions, 0 deletions
diff --git a/include/qemu/host-utils.h b/include/qemu/host-utils.h index 81c9a75..2a32be4 100644 --- a/include/qemu/host-utils.h +++ b/include/qemu/host-utils.h @@ -26,6 +26,7 @@ #define HOST_UTILS_H 1 #include "qemu/compiler.h" /* QEMU_GNUC_PREREQ */ +#include <string.h> /* ffsl */ #if defined(__x86_64__) #define __HAVE_FAST_MULU64__ @@ -237,4 +238,29 @@ static inline int ctpop64(uint64_t val) #endif } +/* glibc does not provide an inline version of ffsl, so always define + * ours. We need to give it a different name, however. + */ +#ifdef __GLIBC__ +#define ffsl qemu_ffsl +#endif +static inline int ffsl(long val) +{ + if (!val) { + return 0; + } + +#if QEMU_GNUC_PREREQ(3, 4) + return __builtin_ctzl(val) + 1; +#else + if (sizeof(long) == 4) { + return ctz32(val) + 1; + } else if (sizeof(long) == 8) { + return ctz64(val) + 1; + } else { + abort(); + } +#endif +} + #endif |