Clarify what mod_inv_5 is

This commit is contained in:
Victor Zverovich 2022-12-04 08:36:03 -08:00
parent 62ceb181b1
commit 1a854b4aa5

View File

@ -1040,7 +1040,8 @@ template <> struct cache_accessor<double> {
{0xfcf62c1dee382c42, 0x46729e03dd9ed7b6},
{0x9e19db92b4e31ba9, 0x6c07a2c26a8346d2},
{0xc5a05277621be293, 0xc7098b7305241886},
{0xf70867153aa2db38, 0xb8cbee4fc66d1ea8}
{ 0xf70867153aa2db38,
0xb8cbee4fc66d1ea8 }
#else
{0xff77b1fcbebcdc4f, 0x25e8e89c13bb0f7b},
{0xce5d73ff402d98e3, 0xfb0a3d212dc81290},
@ -1180,6 +1181,8 @@ bool is_left_endpoint_integer_shorter_interval(int exponent) noexcept {
// Remove trailing zeros from n and return the number of zeros removed (float)
FMT_INLINE int remove_trailing_zeros(uint32_t& n) noexcept {
FMT_ASSERT(n != 0, "");
// Modular inverse of 5 (mod 2^32): (mod_inv_5 * 5) mod 2^32 = 1.
// See https://github.com/fmtlib/fmt/issues/3163 for more details.
const uint32_t mod_inv_5 = 0xcccccccd;
const uint32_t mod_inv_25 = mod_inv_5 * mod_inv_5;
@ -1195,7 +1198,6 @@ FMT_INLINE int remove_trailing_zeros(uint32_t& n) noexcept {
n = q;
s |= 1;
}
return s;
}