Commit 7bdcecb7 authored by Richard Henderson's avatar Richard Henderson
Browse files

qemu/host-utils.h: Reduce the operation count in the fallback ctpop 



Reviewed-by: default avatarAlex Bennée <alex.bennee@linaro.org>
Signed-off-by: default avatarRichard Henderson <rth@twiddle.net>
parent 4885c3c4

include/qemu/host-utils.h

+11 −14
Original line number Diff line number Diff line
@@ -327,7 +327,7 @@ static inline int ctpop8(uint8_t val) 
#else

    val = (val & 0x55) + ((val >> 1) & 0x55);

    val = (val & 0x33) + ((val >> 2) & 0x33);

    val = (val & 0x0f) + ((val >> 4) & 0x0f);

    val = (val + (val >> 4)) & 0x0f;



    return val;

#endif
@@ -344,8 +344,8 @@ static inline int ctpop16(uint16_t val) 
#else

    val = (val & 0x5555) + ((val >> 1) & 0x5555);

    val = (val & 0x3333) + ((val >> 2) & 0x3333);

    val = (val & 0x0f0f) + ((val >> 4) & 0x0f0f);

    val = (val & 0x00ff) + ((val >> 8) & 0x00ff);

    val = (val + (val >> 4)) & 0x0f0f;

    val = (val + (val >> 8)) & 0x00ff;



    return val;

#endif
@@ -362,9 +362,8 @@ static inline int ctpop32(uint32_t val) 
#else

    val = (val & 0x55555555) + ((val >> 1) & 0x55555555);

    val = (val & 0x33333333) + ((val >> 2) & 0x33333333);

    val = (val & 0x0f0f0f0f) + ((val >>  4) & 0x0f0f0f0f);

    val = (val & 0x00ff00ff) + ((val >>  8) & 0x00ff00ff);

    val = (val & 0x0000ffff) + ((val >> 16) & 0x0000ffff);

    val = (val + (val >> 4)) & 0x0f0f0f0f;

    val = (val * 0x01010101) >> 24;



    return val;

#endif
@@ -381,10 +380,8 @@ static inline int ctpop64(uint64_t val) 
#else

    val = (val & 0x5555555555555555ULL) + ((val >> 1) & 0x5555555555555555ULL);

    val = (val & 0x3333333333333333ULL) + ((val >> 2) & 0x3333333333333333ULL);

    val = (val & 0x0f0f0f0f0f0f0f0fULL) + ((val >>  4) & 0x0f0f0f0f0f0f0f0fULL);

    val = (val & 0x00ff00ff00ff00ffULL) + ((val >>  8) & 0x00ff00ff00ff00ffULL);

    val = (val & 0x0000ffff0000ffffULL) + ((val >> 16) & 0x0000ffff0000ffffULL);

    val = (val & 0x00000000ffffffffULL) + ((val >> 32) & 0x00000000ffffffffULL);

    val = (val + (val >> 4)) & 0x0f0f0f0f0f0f0f0fULL;

    val = (val * 0x0101010101010101ULL) >> 56;



    return val;

#endif