Added a drum synthesis object to Audio library

Removed debug code, updated comments

Adding CPP/H implementation files, plus example sketch and update to
HTML file.

faster int32_t substract_32_then_divide (mixed c + assembly)

Optimize CPU Usage

Bugfix for passthrough

use AUDIO_SAMPLE_RATE_EXACT

use AUDIO_SAMPLE_RATE_EXACT

absolute worst case 2 : new variant 2 cycles faster
best case i've found: 30 cycles faster
all my tests showed identical results to the existing function

time to sleep....

did not work because of missing return - for num_channels<=1, "left channel" was still running..
(1  means pass trough)

In my testsketch with 2 x Chorus with n_chrous=4 & #define CHORUS_DELAY_LENGTH (24*AUDIO_BLOCK_SAMPLES),
Cpu-usage decreases from 13.8% to 9.8%

Access Q-bit from c

You mentioned in synth_dc.h "// if only C language provided a way to test Q status bit...."
Here it is :) . That return (out & 0x8000000)>>27; translates to only one more instruction : ubfx    r0, r0, #27, #1 , i decided to use the c -variant because it is better to readable.

I added a function to clear that bit ( clr_q_psr() ), too. Unfortunately, three instructions are needed (read-modify-write)

(PlatformIO) Use tagged source code from repo