RGBCube/serenity
1
Fork 0
mirror of https://github.com/RGBCube/serenity synced 2025-07-26 17:47:44 +00:00
Code Issues Activity Actions

AK+Everywhere: Add sincos and use it in some places

Browse source 
Calculating sin and cos at once is quite a bit cheaper than calculating
them individually.
x87 has even a dedicated instruction for it: `fsincos`.
This commit is contained in:
Hendiadyoin1 2022-02-03 12:48:17 +01:00 • committed by Andreas Kling
parent 47fe911196
commit cd21e03225
6 changed files with 30 additions and 10 deletions
Download patch file Download diff file Expand all files Collapse all files

5
Userland/Libraries/LibDSP/FFT.h
View file

@ -28,11 +28,12 @@ constexpr void fft(Span<Complex<double>> sample_data, bool invert = false)
for (int len = 2; len <= n; len <<= 1) {
double ang = 2 * AK::Pi<double> / len * (invert ? -1 : 1);
Complex<double> wlen(AK::cos(ang), AK::sin(ang));
Complex<double> wlen = Complex<double>::from_polar(1., ang);
for (int i = 0; i < n; i += len) {
Complex<double> w = { 1., 0. };
for (int j = 0; j < len / 2; j++) {
Complex<double> u = sample_data[i + j], v = sample_data[i + j + len / 2] * w;
Complex<double> u = sample_data[i + j];
Complex<double> v = sample_data[i + j + len / 2] * w;
sample_data[i + j] = u + v;
sample_data[i + j + len / 2] = u - v;
w *= wlen;