High PC speaker frequencies treated as constant level.

Improved timing for port 0x61 writes.

src/keyboard_amstrad.c

@@ -76,6 +76,9 @@ void keyboard_amstrad_write(uint16_t port, uint8_t val, void *priv)
                 keyboard_amstrad.pb = val;
                 ppi.pb = val;
 
+                timer_process();
+                timer_update_outstanding();
+
                 speaker_gated = val & 1;
                 speaker_enable = val & 2;
                 if (speaker_enable) 

src/keyboard_at.c

@@ -284,6 +284,10 @@ void keyboard_at_write(uint16_t port, uint8_t val, void *priv)
                
                 case 0x61:
                 ppi.pb = val;
+
+                timer_process();
+                timer_update_outstanding();
+
                 speaker_gated = val & 1;
                 speaker_enable = val & 2;
                 if (speaker_enable) 

src/keyboard_olim24.c

@@ -144,6 +144,9 @@ void keyboard_olim24_write(uint16_t port, uint8_t val, void *priv)
                 case 0x61:
                 ppi.pb = val;
                 
+                timer_process();
+                timer_update_outstanding();
+
                 speaker_gated = val & 1;
                 speaker_enable = val & 2;
                 if (speaker_enable) 

src/keyboard_pcjr.c

@@ -124,6 +124,10 @@ void keyboard_pcjr_write(uint16_t port, uint8_t val, void *priv)
                 
                 case 0x61:
                 keyboard_pcjr.pb = val;
+
+                timer_process();
+                timer_update_outstanding();
+
                 speaker_gated = val & 1;
                 speaker_enable = val & 2;
                 if (speaker_enable) 

src/keyboard_xt.c

@@ -76,6 +76,9 @@ void keyboard_xt_write(uint16_t port, uint8_t val, void *priv)
                 keyboard_xt.pb = val;
                 ppi.pb = val;
 
+                timer_process();
+                timer_update_outstanding();
+        
                 speaker_gated = val & 1;
                 speaker_enable = val & 2;
                 if (speaker_enable) 

src/sound_speaker.c

@@ -20,6 +20,8 @@ static void speaker_poll(void *p)
         {
                 if (!pit.m[2] || pit.m[2]==4)
                         speaker_buffer[speaker_pos] = speakval;
+                else if (pit.l[2] < 0x40)
+                        speaker_buffer[speaker_pos] = 0xa00;
                 else 
                         speaker_buffer[speaker_pos] = speakon ? 0x1400 : 0;
         }