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Correct oscillator frequency used in the gameblaster. Thanks OPLx, Great Hierophant and NewRisingSun. Reported on VOGONS: 38350.

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Imported-from: https://svn.code.sf.net/p/dosbox/code-0/dosbox/trunk@4010
This commit is contained in:
Peter Veenstra 2017-05-02 14:14:46 +00:00
parent d6e983b08d
commit 1c786cccde
1 changed files with 7 additions and 5 deletions
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12
src/hardware/gameblaster.cpp
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@ -32,6 +32,8 @@
#define RIGHT 0x01
#define CMS_BUFFER_SIZE 128
#define CMS_RATE 22050
/*#define MASTER_CLOCK 14318180/2 */
#define MASTER_CLOCK 7159090
typedef Bit8u UINT8;
@ -205,9 +207,9 @@ static void saa1099_update(int chip, INT16 **buffer, int length)
{
switch (saa->noise_params[ch])
{
case 0: saa->noise[ch].freq = 31250.0 * 2; break;
case 1: saa->noise[ch].freq = 15625.0 * 2; break;
case 2: saa->noise[ch].freq = 7812.5 * 2; break;
case 0: saa->noise[ch].freq = MASTER_CLOCK/256 * 2; break;
case 1: saa->noise[ch].freq = MASTER_CLOCK/512 * 2; break;
case 2: saa->noise[ch].freq = MASTER_CLOCK/1024 * 2; break;
case 3: saa->noise[ch].freq = saa->channels[ch * 3].freq; break;
}
}
@ -221,7 +223,7 @@ static void saa1099_update(int chip, INT16 **buffer, int length)
for (ch = 0; ch < 6; ch++)
{
if (saa->channels[ch].freq == 0.0)
saa->channels[ch].freq = (double)((2 * 15625) << saa->channels[ch].octave) /
saa->channels[ch].freq = (double)((2 * MASTER_CLOCK/512) << saa->channels[ch].octave) /
(511.0 - (double)saa->channels[ch].frequency);
/* check the actual position in the square wave */
@ -229,7 +231,7 @@ static void saa1099_update(int chip, INT16 **buffer, int length)
while (saa->channels[ch].counter < 0)
{
/* calculate new frequency now after the half wave is updated */
saa->channels[ch].freq = (double)((2 * 15625) << saa->channels[ch].octave) /
saa->channels[ch].freq = (double)((2 * MASTER_CLOCK/512) << saa->channels[ch].octave) /
(511.0 - (double)saa->channels[ch].frequency);
saa->channels[ch].counter += sample_rate;