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acorn_vidc.cpp: generate u255 law sound table on device start [Olivier Galibert, Angelo Salese]

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This commit is contained in:
angelosa 2019-09-21 12:41:14 +02:00
parent bb68b228c5
commit 3517c6fcb4
4 changed files with 27 additions and 45 deletions
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58
src/devices/machine/acorn_vidc.cpp
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@ -158,6 +158,23 @@ void acorn_vidc10_device::device_start()
m_video_timer = timer_alloc(TIMER_VIDEO);
m_sound_timer = timer_alloc(TIMER_SOUND);
// generate u255 law lookup table
// cfr. page 48 of the VIDC20 manual, page 33 of the VIDC manual
// TODO: manual mentions a format difference between VIDC10 revisions
for (int rawval = 0; rawval < 256; rawval++)
{
uint8_t chord = rawval >> 5;
uint8_t point = (rawval & 0x1e) >> 1;
bool sign = rawval & 1;
int16_t result = ((16+point)<<chord)-16;
if (sign)
result = -result;
m_ulaw_lookup[rawval] = result*8;
}
save_pointer(NAME(m_ulaw_lookup), 256);
}
@ -385,47 +402,8 @@ WRITE32_MEMBER( acorn_vidc10_device::sound_frequency_w )
void acorn_vidc10_device::write_dac(uint8_t channel, uint8_t data)
{
uint8_t ulaw_comp;
int16_t res;
static constexpr int16_t mulawTable[256] =
{
-32124,-31100,-30076,-29052,-28028,-27004,-25980,-24956,
-23932,-22908,-21884,-20860,-19836,-18812,-17788,-16764,
-15996,-15484,-14972,-14460,-13948,-13436,-12924,-12412,
-11900,-11388,-10876,-10364, -9852, -9340, -8828, -8316,
-7932, -7676, -7420, -7164, -6908, -6652, -6396, -6140,
-5884, -5628, -5372, -5116, -4860, -4604, -4348, -4092,
-3900, -3772, -3644, -3516, -3388, -3260, -3132, -3004,
-2876, -2748, -2620, -2492, -2364, -2236, -2108, -1980,
-1884, -1820, -1756, -1692, -1628, -1564, -1500, -1436,
-1372, -1308, -1244, -1180, -1116, -1052, -988, -924,
-876, -844, -812, -780, -748, -716, -684, -652,
-620, -588, -556, -524, -492, -460, -428, -396,
-372, -356, -340, -324, -308, -292, -276, -260,
-244, -228, -212, -196, -180, -164, -148, -132,
-120, -112, -104, -96, -88, -80, -72, -64,
-56, -48, -40, -32, -24, -16, -8, -1,
32124, 31100, 30076, 29052, 28028, 27004, 25980, 24956,
23932, 22908, 21884, 20860, 19836, 18812, 17788, 16764,
15996, 15484, 14972, 14460, 13948, 13436, 12924, 12412,
11900, 11388, 10876, 10364, 9852, 9340, 8828, 8316,
7932, 7676, 7420, 7164, 6908, 6652, 6396, 6140,
5884, 5628, 5372, 5116, 4860, 4604, 4348, 4092,
3900, 3772, 3644, 3516, 3388, 3260, 3132, 3004,
2876, 2748, 2620, 2492, 2364, 2236, 2108, 1980,
1884, 1820, 1756, 1692, 1628, 1564, 1500, 1436,
1372, 1308, 1244, 1180, 1116, 1052, 988, 924,
876, 844, 812, 780, 748, 716, 684, 652,
620, 588, 556, 524, 492, 460, 428, 396,
372, 356, 340, 324, 308, 292, 276, 260,
244, 228, 212, 196, 180, 164, 148, 132,
120, 112, 104, 96, 88, 80, 72, 64,
56, 48, 40, 32, 24, 16, 8, 0
};
uint8_t ulaw_temp = data ^ 0xff;
ulaw_comp = (ulaw_temp>>1) | ((ulaw_temp&1)<<7);
res = mulawTable[ulaw_comp];
res = m_ulaw_lookup[data];
m_dac[channel & 7]->write(res);
}

1
src/devices/machine/acorn_vidc.h
View File

@ -116,6 +116,7 @@ private:
u8 m_stereo_image[8];
const float m_sound_input_gain = 0.05;
const int m_sound_max_channels = 8;
int16_t m_ulaw_lookup[256];
void refresh_sound_frequency();
inline void refresh_stereo_image(uint8_t channel);
};

4
src/mame/drivers/riscpc.cpp
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@ -1009,7 +1009,7 @@ void riscpc_state::a7000p(machine_config &config)
void riscpc_state::sarpc(machine_config &config)
{
/* Basic machine hardware */
ARM7(config, m_maincpu, 202000000); // StrongARM
SA1110(config, m_maincpu, 202000000); // StrongARM
m_maincpu->set_addrmap(AS_PROGRAM, &riscpc_state::riscpc_map);
base_config(config);
}
@ -1017,7 +1017,7 @@ void riscpc_state::sarpc(machine_config &config)
void riscpc_state::sarpc_j233(machine_config &config)
{
/* Basic machine hardware */
ARM7(config, m_maincpu, 233000000); // StrongARM
SA1110(config, m_maincpu, 233000000); // StrongARM
m_maincpu->set_addrmap(AS_PROGRAM, &riscpc_state::riscpc_map);
base_config(config);
}

9
src/mame/machine/archimds.cpp
View File

@ -882,19 +882,22 @@ WRITE32_MEMBER(archimedes_state::archimedes_memc_w)
break;
case 4: /* sound start */
//logerror("MEMC: SNDSTART %08x\n",data);
archimedes_clear_irq_b(ARCHIMEDES_IRQB_SOUND_EMPTY);
m_vidc_sndstart = 0x2000000 | ((data>>2)&0x7fff)*16;
//printf("MEMC: SNDSTART %08x\n",m_vidc_sndstart);
break;
case 5: /* sound end */
//logerror("MEMC: SNDEND %08x\n",data);
// end buffer is actually +16 bytes wrt sound start
// TODO: it actually don't apply for ertictac and poizone?
m_vidc_sndend = 0x2000000 | (((data>>2)+1)&0x7fff)*16;
//printf("MEMC: SNDEND %08x\n",m_vidc_sndend);
break;
case 6:
m_vidc_sndcur = 0;
//printf("MEMC: SNDPTR\n");
m_vidc_sndcur = m_vidc_sndstart;
m_vidc_sndendcur = m_vidc_sndend;
archimedes_request_irq_b(ARCHIMEDES_IRQB_SOUND_EMPTY);
break;