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aica_xm: use timer underflow flag

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This commit is contained in:
Zack Buhman 2025-06-20 14:54:59 -05:00
parent 5acc19473f
commit 204f58c74a
1 changed files with 8 additions and 12 deletions
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20
example/aica/aica_xm.cpp
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@ -544,13 +544,6 @@ void main()
serial::character('\n');
}
sh7091.TMU.TSTR = 0; // stop all timers
sh7091.TMU.TOCR = tmu::tocr::tcoe::tclk_is_external_clock_or_input_capture;
sh7091.TMU.TCR0 = tmu::tcr0::tpsc::p_phi_256; // 256 / 50MHz = 5.12 μs ; underflows in ~1 hour
sh7091.TMU.TCOR0 = 0xffff'ffff;
sh7091.TMU.TCNT0 = 0xffff'ffff;
sh7091.TMU.TSTR = tmu::tstr::str0::counter_start;
wait(); aica_sound.common.dmea0_mrwinh = aica::dmea0_mrwinh::MRWINH(0b0001);
for (int i = 0; i < 64; i++) {
@ -604,17 +597,20 @@ void main()
printf("pattern %d\n", state.pattern_index);
int start = sh7091.TMU.TCNT0;
sh7091.TMU.TSTR = 0; // stop all timers
sh7091.TMU.TCOR0 = state.tick_rate / 2;
sh7091.TMU.TOCR = tmu::tocr::tcoe::tclk_is_external_clock_or_input_capture;
sh7091.TMU.TCR0 = tmu::tcr0::tpsc::p_phi_256; // 256 / 50MHz = 5.12 μs ; underflows in ~1 hour
sh7091.TMU.TCNT0 = 0;
sh7091.TMU.TSTR = tmu::tstr::str0::counter_start;
while (1) {
xm_pattern_header_t * pattern_header = xm.pattern_header[state.pattern_index];
int pattern_data_size = s16(&pattern_header->packed_pattern_data_size);
int end = sh7091.TMU.TCNT0;
while ((start - end) < (state.tick_rate / 2)) {
end = sh7091.TMU.TCNT0;
while ((sh7091.TMU.TCR0 & tmu::tcr0::UNF) == 0) {
}
start = sh7091.TMU.TCNT0;
sh7091.TMU.TCR0 = tmu::tcr0::tpsc::p_phi_256; // clear underflow
bool keyoff_tick = (state.tick + 1) % (state.ticks_per_line * 2) == 0;
bool note_tick = state.tick % (state.ticks_per_line * 2) == 0;