Commit: a9a1e51cee3a6fb560fc7128d96a12e6e08f50db Parent: 86c1d7e50957d620c6b2b73a5c9c564913ca5cb6 Author: Randy Palamar Date: Mon, 8 Jul 2024 09:01:42 -0600 hadamard: don't rely on compiler lifting the test out of the loop Diffstat:
| M | shaders/hadamard.glsl | | | 18 | +++++++----------- |
1 file changed, 7 insertions(+), 11 deletions(-)
diff --git a/shaders/hadamard.glsl b/shaders/hadamard.glsl @@ -41,20 +41,16 @@ void main() uint ridx = rfoff / 2; uint ridx_delta = rstride / 2; + /* NOTE: rf_data is i16 so each access grabs two time samples at time. + * We need to shift arithmetically (maintaining the sign) to get the + * desired element. If the time sample is even we take the upper half + * and if its odd we take the lower half. */ + int lfs = (int(time_sample) & 1) * int(16); + /* NOTE: Compute N-D dot product */ int sum = 0; for (int i = 0; i < u_rf_data_dim.z; i++) { - int data = rf_data[ridx]; - - /* NOTE: rf_data is i16 so each access grabs two time samples at time. - * We need to shift and mask to get the desired element. If the time sample - * is even we take the upper half and if its odd we take the lower half. - * Hopefully shader compiler is smart enough to lift this out of the loop. */ - if ((int(time_sample) & 1) == 1) - data = data >> 16; - else - data = (data << 16) >> 16; - + int data = (rf_data[ridx] << lfs) >> 16; sum += hadamard[hoff + i] * data; ridx += ridx_delta; }