On Sat Sep 2, 2023 at 3:02 AM AEST, Richard Henderson wrote:
> On 9/1/23 04:51, Cédric Le Goater wrote:
> > Adding more reviewers since this patch is modifying a common service.
> >
> > Thanks,
> >
> > C.
> >
> >
> > On 8/8/23 06:19, Nicholas Piggin wrote:
> >> This will be used for converting time intervals in different base units
> >> to host units, for the purpose of scheduling timers to emulate target
> >> timers. Timers typically must not fire before their requested expiry
> >> time but may fire some time afterward, so rounding up is the right way
> >> to implement these.
> >>
> >> Signed-off-by: Nicholas Piggin <npig...@gmail.com>
> >> ---
> >> include/qemu/host-utils.h | 21 ++++++++++++++++++++-
> >> 1 file changed, 20 insertions(+), 1 deletion(-)
> >>
> >> diff --git a/include/qemu/host-utils.h b/include/qemu/host-utils.h
> >> index 011618373e..e2a50a567f 100644
> >> --- a/include/qemu/host-utils.h
> >> +++ b/include/qemu/host-utils.h
> >> @@ -56,6 +56,11 @@ static inline uint64_t muldiv64(uint64_t a, uint32_t b,
> >> uint32_t c)
> >> return (__int128_t)a * b / c;
> >> }
> >> +static inline uint64_t muldiv64_round_up(uint64_t a, uint32_t b, uint32_t
> >> c)
> >> +{
> >> + return ((__int128_t)a * b + c - 1) / c;
> >> +}
> >> +
> >> static inline uint64_t divu128(uint64_t *plow, uint64_t *phigh,
> >> uint64_t divisor)
> >> {
> >> @@ -83,7 +88,8 @@ void mulu64(uint64_t *plow, uint64_t *phigh, uint64_t a,
> >> uint64_t b);
> >> uint64_t divu128(uint64_t *plow, uint64_t *phigh, uint64_t divisor);
> >> int64_t divs128(uint64_t *plow, int64_t *phigh, int64_t divisor);
> >> -static inline uint64_t muldiv64(uint64_t a, uint32_t b, uint32_t c)
> >> +static inline uint64_t __muldiv64(uint64_t a, uint32_t b, uint32_t c,
> >> + bool round_up)
>
> Perhaps better avoiding the reserved name: muldiv64_internal?
Thanks, that would be okay. Or could be muldiv64_rounding?
>
> Otherwise,
> Reviewed-by: Richard Henderson <richard.hender...@linaro.org>
>
>
> r~
>
>
> >> {
> >> union {
> >> uint64_t ll;
> >> @@ -99,12 +105,25 @@ static inline uint64_t muldiv64(uint64_t a, uint32_t
> >> b, uint32_t c)
> >> u.ll = a;
> >> rl = (uint64_t)u.l.low * (uint64_t)b;
> >> + if (round_up) {
> >> + rl += c - 1;
> >> + }
> >> rh = (uint64_t)u.l.high * (uint64_t)b;
> >> rh += (rl >> 32);
> >> res.l.high = rh / c;
> >> res.l.low = (((rh % c) << 32) + (rl & 0xffffffff)) / c;
> >> return res.ll;
> >> }
> >> +
> >> +static inline uint64_t muldiv64(uint64_t a, uint32_t b, uint32_t c)
> >> +{
> >> + return __muldiv64(a, b, c, false);
> >> +}
> >> +
> >> +static inline uint64_t muldiv64_round_up(uint64_t a, uint32_t b, uint32_t
> >> c)
> >> +{
> >> + return __muldiv64(a, b, c, true);
> >> +}
> >> #endif
> >> /**
> >
> >
