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From: | Cédric Le Goater |
Subject: | Re: [PATCH v2 05/19] host-utils: Add muldiv64_round_up |
Date: | Mon, 4 Sep 2023 15:30:57 +0200 |
User-agent: | Mozilla/5.0 (X11; Linux x86_64; rv:102.0) Gecko/20100101 Thunderbird/102.13.0 |
On 9/4/23 15:07, Nicholas Piggin wrote:
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 <npiggin@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.henderson@linaro.org>
oh, and I already sent the PR with the Rb of Richard ... :/ Sorry about that. Can we fix it later ? Or I will respin with the update. Someone really ought to take over PPC. Daniel and I are real busy on other subsystems. Volunteers ? Thanks, C.
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 /**
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