From: kub <derkub@gmail.com>
Date: Fri, 22 Oct 2021 23:09:04 +0000 (+0200)
Subject: sound, remove hysteresis (lessens distortion, increases frequency limit)
X-Git-Tag: v2.00~453
X-Git-Url: https://notaz.gp2x.de/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=027940e108276282f0f32f66c6477f6e43536a43;p=picodrive.git

sound, remove hysteresis (lessens distortion, increases frequency limit)
---

diff --git a/pico/sms.c b/pico/sms.c
index 2aa8838c..4e20a9b7 100644
--- a/pico/sms.c
+++ b/pico/sms.c
@@ -225,7 +225,7 @@ static void z80_sms_out(unsigned short a, unsigned char d)
 
       case 0x40:
       case 0x41:
-        PsndDoPSG(z80_cyclesDone());
+        PsndDoPSG(Pico.m.scanline*228 + 228-z80_cyclesLeft);
         SN76496Write(d);
         break;
 
diff --git a/pico/sound/sound.c b/pico/sound/sound.c
index 602f2907..56bbadc9 100644
--- a/pico/sound/sound.c
+++ b/pico/sound/sound.c
@@ -130,10 +130,6 @@ PICO_INTERNAL void PsndDoDAC(int cyc_to)
   // number of samples to fill in buffer (Q20)
   len = (cyc_to * Pico.snd.clkl_mult) - Pico.snd.dac_pos;
 
-  // don't do this too often (about once every 2 scanlines)
-  if (len <= PicoIn.sndRate << 3) // Q16, (PicoIn.sndRate << 16) >> 13
-    return;
-
   // update position and calculate buffer offset and length
   pos = (Pico.snd.dac_pos+0x80000) >> 20;
   Pico.snd.dac_pos += len;
@@ -173,10 +169,6 @@ PICO_INTERNAL void PsndDoPSG(int cyc_to)
   // number of samples to fill in buffer (Q20)
   len = (cyc_to * Pico.snd.clkl_mult) - Pico.snd.psg_pos;
 
-  // don't do this too often (about once every 2 scanlines)
-  if (len <= PicoIn.sndRate << 3) // Q16, (PicoIn.sndRate << 16) >> 13
-    return;
-
   // update position and calculate buffer offset and length
   pos = (Pico.snd.psg_pos+0x80000) >> 20;
   Pico.snd.psg_pos += len;
@@ -204,10 +196,6 @@ PICO_INTERNAL void PsndDoYM2413(int cyc_to)
   // number of samples to fill in buffer (Q20)
   len = (cyc_to * Pico.snd.clkl_mult) - Pico.snd.ym2413_pos;
 
-  // don't do this too often (about once every 2 scanlines)
-  if (len <= PicoIn.sndRate << 3) // Q16, (PicoIn.sndRate << 16) >> 13
-    return;
-
   // update position and calculate buffer offset and length
   pos = (Pico.snd.ym2413_pos+0x80000) >> 20;
   Pico.snd.ym2413_pos += len;
@@ -245,13 +233,9 @@ PICO_INTERNAL void PsndDoFM(int cyc_to)
   int pos, len;
   int stereo = 0;
 
-  // Q16, number of samples since last call
+  // Q20, number of samples since last call
   len = (cyc_to * Pico.snd.clkl_mult) - Pico.snd.fm_pos;
 
-  // don't do this too often (about once every 2 scanlines)
-  if (len <= PicoIn.sndRate << 3) // Q16, (PicoIn.sndRate << 16) >> 13
-    return;
-
   // update position and calculate buffer offset and length
   pos = (Pico.snd.fm_pos+0x80000) >> 20;
   Pico.snd.fm_pos += len;
@@ -351,7 +335,7 @@ static int PsndRender(int offset, int length)
     return length;
   }
 
-  // Fill up DAC output in case of missing samples (Q16 rounding errors)
+  // Fill up DAC output in case of missing samples (Q rounding errors)
   if (length-daclen > 0) {
     short *dacbuf = PicoIn.sndOut + (daclen << stereo);
     Pico.snd.dac_pos += (length-daclen) << 20;