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archimds: finally correct audio frequency setting [R. Belmont]

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Please promote this to master for 0.181!
This commit is contained in:
arbee 2016-12-27 00:54:39 -05:00
parent 54cbd67a42
commit df3f863230
1 changed files with 16 additions and 9 deletions
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25
src/mame/machine/archimds.cpp
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@ -1037,7 +1037,19 @@ WRITE32_MEMBER(archimedes_state::archimedes_vidc_w)
vidc_dynamic_res_change();
}
else if(reg == 0xe0)
else if (reg == 0xc0)
{
m_vidc_regs[reg] = val&0xffff;
if (m_audio_dma_on)
{
double sndhz = 1000000.0f/(((m_vidc_regs[0xc0]&0xff)+2));
sndhz /= 8.0f;
m_snd_timer->adjust(attotime::zero, 0, attotime::from_hz(sndhz));
//printf("VIDC: sound freq to %d, sndhz = %f\n", (val & 0xff)-2, sndhz);
}
}
else if (reg == 0xe0)
{
m_vidc_bpp_mode = ((val & 0x0c) >> 2);
m_vidc_interlace = ((val & 0x40) >> 6);
@ -1120,15 +1132,10 @@ WRITE32_MEMBER(archimedes_state::archimedes_memc_w)
{
//printf("MEMC: Starting audio DMA at %d uSec, buffer from %x to %x\n", ((m_vidc_regs[0xc0]&0xff)-2)*8, m_vidc_sndstart, m_vidc_sndend);
#if 0 // more correct to manuals, but breaks ertictac/poizone
m_snd_timer->adjust(attotime::zero, 0, attotime::from_usec(((m_vidc_regs[0xc0]&0xff)-2)*8));
#else // original formula, definitely wrong in at least some cases
double sndhz;
/* FIXME: is the frequency correct? */
sndhz = (250000.0 / 2) / (double)((m_vidc_regs[0xc0]&0xff)+2);
double sndhz = 1000000.0f/(((m_vidc_regs[0xc0]&0xff)+2));
sndhz /= 8.0f;
m_snd_timer->adjust(attotime::zero, 0, attotime::from_hz(sndhz));
#endif
//printf("MEMC: audio DMA start, sound freq %d, sndhz = %f\n", (m_vidc_regs[0xc0] & 0xff)-2, sndhz);
m_vidc_sndcur = m_vidc_sndstart;
m_vidc_sndendcur = m_vidc_sndend;