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Merge remote-tracking branch 'upstream/esp32-millis-euclidean-decomposition' into integration

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J. Nick Koston
2026-03-02 00:16:16 -10:00
parent 7bed94aa38 1e3f7b3c90
commit 696c93ee43
1 changed files with 6 additions and 6 deletions
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esphome/core/helpers.h
+6 -6
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@@ -626,18 +626,18 @@ inline uint32_t fnv1a_hash(const std::string &str) { return fnv1a_hash(str.c_str
/// See: https://en.wikipedia.org/wiki/Euclidean_division
/// See: https://ridiculousfish.com/blog/posts/labor-of-division-episode-iii.html
template<typename ReturnT = uint32_t> inline constexpr ESPHOME_ALWAYS_INLINE ReturnT micros_to_millis(uint64_t us) {
constexpr uint32_t D = 125U;
constexpr uint32_t Q = static_cast<uint32_t>((1ULL << 32) / D); // 34359738
constexpr uint32_t R = static_cast<uint32_t>((1ULL << 32) % D); // 46
constexpr uint32_t d = 125U;
constexpr uint32_t q = static_cast<uint32_t>((1ULL << 32) / d); // 34359738
constexpr uint32_t r = static_cast<uint32_t>((1ULL << 32) % d); // 46
// 1000 = 8 * 125; divide-by-8 is a free shift
uint64_t x = us >> 3;
uint32_t lo = static_cast<uint32_t>(x);
uint32_t hi = static_cast<uint32_t>(x >> 32);
// Combine remainder term: hi * (2^32 % 125) + lo
uint32_t adj = hi * R + lo;
uint32_t adj = hi * r + lo;
// If adj overflowed, the true value is 2^32 + adj; apply the identity again
// static_cast<ReturnT>(hi) widens to 64-bit when ReturnT=uint64_t, preserving upper bits of hi*Q
return static_cast<ReturnT>(hi) * Q + (adj < lo ? (adj + R) / D + Q : adj / D);
// static_cast<ReturnT>(hi) widens to 64-bit when ReturnT=uint64_t, preserving upper bits of hi*q
return static_cast<ReturnT>(hi) * q + (adj < lo ? (adj + r) / d + q : adj / d);
}
/// Return a random 32-bit unsigned integer.