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ZSM: optimize: skip PWM write on non-pulse, change delay flush logic

This commit is contained in:
MooingLemur 2023-08-15 00:16:33 -07:00
parent f328e33bbc
commit fd2c17e4f9
1 changed files with 18 additions and 2 deletions
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20
src/engine/zsm.cpp
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@ -133,6 +133,14 @@ void DivZSM::writePSG(unsigned char a, unsigned char v) {
} else if (a>=64) {
return writePCM(a-64,v);
}
if (optimize) {
if ((a&3)==3 && v>64) {
// Pulse width on non-pulse waves is nonsense and wasteful
// No need to preserve state here because the next write that
// selects pulse will also set the pulse width in this register
v=v&0xc0;
}
}
if (psgState[psg_PREV][a]==v) {
if (psgState[psg_NEW][a]!=v) {
// NEW value is being reset to the same as PREV value
@ -148,7 +156,7 @@ void DivZSM::writePSG(unsigned char a, unsigned char v) {
}
psgState[psg_NEW][a]=v;
// mark channel as used in the psgMask if volume is set>0.
if ((a%4==2) && (v&0x3f)) psgMask|=(1<<(a>>2));
if ((a&3)==2 && (v&0x3f)) psgMask|=(1<<(a>>2));
}
void DivZSM::writePCM(unsigned char a, unsigned char v) {
@ -278,7 +286,7 @@ SafeWriter* DivZSM::finish() {
void DivZSM::flushWrites() {
logD("ZSM: flushWrites.... numwrites=%d ticks=%d ymwrites=%d pcmMeta=%d pcmCache=%d pcmData=%d syncCache=%d",numWrites,ticks,ymwrites.size(),pcmMeta.size(),pcmCache.size(),pcmData.size(),syncCache.size());
if (numWrites==0) return;
flushTicks(); // only flush ticks if there are writes pending.
bool hasFlushed=false;
for (unsigned char i=0; i<64; i++) {
if (psgState[psg_NEW][i]==psgState[psg_PREV][i]) continue;
// if optimize=true, suppress writes to PSG voices that are not audible (volume=0 or R+L=0)
@ -287,11 +295,19 @@ void DivZSM::flushWrites() {
if (optimize && (i&3)!=2 && (psgState[psg_NEW][(i&0x3c)+2]&0x3f)==0) continue; // vol
if (optimize && (i&3)!=2 && (psgState[psg_NEW][(i&0x3c)+2]&0xc0)==0) continue; // R+L
psgState[psg_PREV][i]=psgState[psg_NEW][i];
if (!hasFlushed) {
flushTicks();
hasFlushed=true;
}
w->writeC(i);
w->writeC(psgState[psg_NEW][i]);
}
int n=0; // n=completed YM writes. used to determine when to write the CMD byte...
for (DivRegWrite& write: ymwrites) {
if (!hasFlushed) {
flushTicks();
hasFlushed=true;
}
if (n%ZSM_YM_MAX_WRITES==0) {
if (ymwrites.size()-n>ZSM_YM_MAX_WRITES) {
w->writeC((unsigned char)(ZSM_YM_CMD+ZSM_YM_MAX_WRITES));