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#ifdef DSP_CPP
//counter_rate = number of samples per counter event
//all rates are evenly divisible by counter_range (0x7800, 30720, or 2048 * 5 * 3)
//note that rate[0] is a special case, which never triggers
const uint16 DSP::counter_rate[32] = {
0, 2048, 1536,
1280, 1024, 768,
640, 512, 384,
320, 256, 192,
160, 128, 96,
80, 64, 48,
40, 32, 24,
20, 16, 12,
10, 8, 6,
5, 4, 3,
2,
1,
};
//counter_offset = counter offset from zero
//counters do not appear to be aligned at zero for all rates
const uint16 DSP::counter_offset[32] = {
0, 0, 1040,
536, 0, 1040,
536, 0, 1040,
536, 0, 1040,
536, 0, 1040,
536, 0, 1040,
536, 0, 1040,
536, 0, 1040,
536, 0, 1040,
536, 0, 1040,
0,
0,
};
inline void DSP::counter_tick() {
state.counter--;
if(state.counter < 0) state.counter = counter_range - 1;
}
//return true if counter event should trigger
inline bool DSP::counter_poll(unsigned rate) {
if(rate == 0) return false;
return (((unsigned)state.counter + counter_offset[rate]) % counter_rate[rate]) == 0;
}
#endif
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