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istrebiteli: a bit of guesswork (nw)

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This commit is contained in:
MetalliC 2016-10-03 17:57:17 +03:00
parent 8be20c8cbf
commit fb89088f3f
1 changed files with 15 additions and 15 deletions
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30
src/mame/drivers/istrebiteli.cpp
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@ -46,7 +46,6 @@ private:
int m_rom_cnt; int m_rom_cnt;
int m_rom_incr; int m_rom_incr;
int m_sample_num; int m_sample_num;
int m_temp_vol;
bool m_cnt_reset; bool m_cnt_reset;
bool m_rom_out_en; bool m_rom_out_en;
UINT8 m_prev_data; UINT8 m_prev_data;
@ -66,7 +65,6 @@ istrebiteli_sound_device::istrebiteli_sound_device(const machine_config &mconfig
m_rom_cnt(0), m_rom_cnt(0),
m_rom_incr(0), m_rom_incr(0),
m_sample_num(0), m_sample_num(0),
m_temp_vol(0),
m_cnt_reset(true), m_cnt_reset(true),
m_rom_out_en(false), m_rom_out_en(false),
m_prev_data(0) m_prev_data(0)
@ -87,7 +85,13 @@ void istrebiteli_sound_device::sound_stream_update(sound_stream &stream, stream_
{ {
int smpl = 0; int smpl = 0;
if (m_rom_out_en) if (m_rom_out_en)
smpl = ((m_rom[m_rom_cnt] >> m_sample_num) & 1) * 4000; smpl = (m_rom[m_rom_cnt] >> m_sample_num) & 1;
// below is huge guess
if ((m_prev_data & 0x40) == 0) // b6 noice enable ?
smpl &= rand() & 1;
smpl *= (m_prev_data & 0x80) ? 1000 : 4000; // b7 volume ?
*sample++ = smpl; *sample++ = smpl;
m_rom_cnt = (m_rom_cnt + m_rom_incr) & 0x1ff; m_rom_cnt = (m_rom_cnt + m_rom_incr) & 0x1ff;
} }
@ -95,23 +99,19 @@ void istrebiteli_sound_device::sound_stream_update(sound_stream &stream, stream_
void istrebiteli_sound_device::sound_w(UINT8 data) void istrebiteli_sound_device::sound_w(UINT8 data)
{ {
// if (m_prev_data != data) m_cnt_reset = (data & 2) ? true : false;
// printf("sound %02X rescnt %d sample %d outen %d vol %d\n", data, (data >> 1) & 1, (data >> 2) & 7, (data >> 5) & 1, (data >> 6) & 3);
m_cnt_reset = ((data >> 1) & 1) ? true : false;
m_sample_num = (data >> 2) & 7; m_sample_num = (data >> 2) & 7;
m_rom_out_en = ((data >> 5) & 1) ? false : true; m_rom_out_en = (data & 0x20) ? false : true;
if (m_cnt_reset) { if (m_cnt_reset)
{
m_rom_cnt = 0; m_rom_cnt = 0;
m_rom_incr = 0; m_rom_incr = 0;
m_temp_vol = 0; }
} else else
m_rom_incr = 1; m_rom_incr = 1;
// if (m_prev_data != data)
if (((data >> 6) & 1) && ((m_prev_data >> 6) & 1) == 0) // printf("sound %02X rescnt %d sample %d outen %d b6 %d b7 %d\n", data, (data >> 1) & 1, (data >> 2) & 7, (data >> 5) & 1, (data >> 6) & 1, (data >> 7) & 1);
m_temp_vol = (m_temp_vol + 1) & 3;
m_prev_data = data; m_prev_data = data;
} }