diff options
Diffstat (limited to 'src/emu/sound/flt_rc.c')
-rw-r--r-- | src/emu/sound/flt_rc.c | 145 |
1 files changed, 59 insertions, 86 deletions
diff --git a/src/emu/sound/flt_rc.c b/src/emu/sound/flt_rc.c index f4c059b9811..7d026a65253 100644 --- a/src/emu/sound/flt_rc.c +++ b/src/emu/sound/flt_rc.c @@ -1,38 +1,65 @@ #include "emu.h" #include "flt_rc.h" -struct filter_rc_state + +const flt_rc_config flt_rc_ac_default = {FLT_RC_AC, 10000, 0, 0, CAP_U(1)}; + + +// device type definition +const device_type FILTER_RC = &device_creator<filter_rc_device>; + + +//************************************************************************** +// LIVE DEVICE +//************************************************************************** + +//------------------------------------------------- +// qsound_device - constructor +//------------------------------------------------- + +filter_rc_device::filter_rc_device(const machine_config &mconfig, const char *tag, device_t *owner, UINT32 clock) + : device_t(mconfig, FILTER_RC, "RC Filter", tag, owner, clock), + device_sound_interface(mconfig, *this), + m_stream(NULL), + m_k(0), + m_memory(0), + m_type(0) { - device_t *device; - sound_stream * stream; - int k; - int memory; - int type; -}; - -INLINE filter_rc_state *get_safe_token(device_t *device) +} + + +//------------------------------------------------- +// device_start - device-specific startup +//------------------------------------------------- + +void filter_rc_device::device_start() { - assert(device != NULL); - assert(device->type() == FILTER_RC); - return (filter_rc_state *)downcast<filter_rc_device *>(device)->token(); + const flt_rc_config *conf = (const flt_rc_config *)static_config(); + + m_stream = stream_alloc(1, 1, machine().sample_rate()); + if (conf) + set_RC_info(conf->type, conf->R1, conf->R2, conf->R3, conf->C); + else + set_RC_info(FLT_RC_LOWPASS, 1, 1, 1, 0); } -const flt_rc_config flt_rc_ac_default = {FLT_RC_AC, 10000, 0, 0, CAP_U(1)}; +//------------------------------------------------- +// sound_stream_update - handle a stream update +//------------------------------------------------- -static STREAM_UPDATE( filter_rc_update ) +void filter_rc_device::sound_stream_update(sound_stream &stream, stream_sample_t **inputs, stream_sample_t **outputs, int samples) { stream_sample_t *src = inputs[0]; stream_sample_t *dst = outputs[0]; - filter_rc_state *info = (filter_rc_state *)param; - int memory = info->memory; + int memory = m_memory; - switch (info->type) + switch (m_type) { case FLT_RC_LOWPASS: while (samples--) { - memory += ((*src++ - memory) * info->k) / 0x10000; + memory += ((*src++ - memory) * m_k) / 0x10000; *dst++ = memory; } break; @@ -41,26 +68,27 @@ static STREAM_UPDATE( filter_rc_update ) while (samples--) { *dst++ = *src - memory; - memory += ((*src++ - memory) * info->k) / 0x10000; + memory += ((*src++ - memory) * m_k) / 0x10000; } break; } - info->memory = memory; + m_memory = memory; } -static void set_RC_info(filter_rc_state *info, int type, double R1, double R2, double R3, double C) + +void filter_rc_device::set_RC_info(int type, double R1, double R2, double R3, double C) { double Req; - info->type = type; + m_type = type; - switch (info->type) + switch (m_type) { case FLT_RC_LOWPASS: if (C == 0.0) { /* filter disabled */ - info->k = 0x10000; + m_k = 0x10000; return; } Req = (R1 * (R2 + R3)) / (R1 + R2 + R3); @@ -70,80 +98,25 @@ static void set_RC_info(filter_rc_state *info, int type, double R1, double R2, d if (C == 0.0) { /* filter disabled */ - info->k = 0x0; - info->memory = 0x0; + m_k = 0x0; + m_memory = 0x0; return; } Req = R1; break; default: - fatalerror("filter_rc_setRC: Wrong filter type %d\n", info->type); + fatalerror("filter_rc_setRC: Wrong filter type %d\n", m_type); } /* Cut Frequency = 1/(2*Pi*Req*C) */ /* k = (1-(EXP(-TIMEDELTA/RC))) */ - info->k = 0x10000 - 0x10000 * (exp(-1 / (Req * C) / info->device->machine().sample_rate())); -} - - -static DEVICE_START( filter_rc ) -{ - filter_rc_state *info = get_safe_token(device); - const flt_rc_config *conf = (const flt_rc_config *)device->static_config(); - - info->device = device; - info->stream = device->machine().sound().stream_alloc(*device, 1, 1, device->machine().sample_rate(), info, filter_rc_update); - if (conf) - set_RC_info(info, conf->type, conf->R1, conf->R2, conf->R3, conf->C); - else - set_RC_info(info, FLT_RC_LOWPASS, 1, 1, 1, 0); -} - - -void filter_rc_set_RC(device_t *device, int type, double R1, double R2, double R3, double C) -{ - filter_rc_state *info = get_safe_token(device); - - info->stream->update(); - - set_RC_info(info, type, R1, R2, R3, C); - -} - -const device_type FILTER_RC = &device_creator<filter_rc_device>; - -filter_rc_device::filter_rc_device(const machine_config &mconfig, const char *tag, device_t *owner, UINT32 clock) - : device_t(mconfig, FILTER_RC, "RC Filter", tag, owner, clock), - device_sound_interface(mconfig, *this) -{ - m_token = global_alloc_clear(filter_rc_state); + m_k = 0x10000 - 0x10000 * (exp(-1 / (Req * C) / machine().sample_rate())); } -//------------------------------------------------- -// device_config_complete - perform any -// operations now that the configuration is -// complete -//------------------------------------------------- -void filter_rc_device::device_config_complete() +void filter_rc_device::filter_rc_set_RC(int type, double R1, double R2, double R3, double C) { + m_stream->update(); + set_RC_info(type, R1, R2, R3, C); } -//------------------------------------------------- -// device_start - device-specific startup -//------------------------------------------------- - -void filter_rc_device::device_start() -{ - DEVICE_START_NAME( filter_rc )(this); -} - -//------------------------------------------------- -// sound_stream_update - handle a stream update -//------------------------------------------------- - -void filter_rc_device::sound_stream_update(sound_stream &stream, stream_sample_t **inputs, stream_sample_t **outputs, int samples) -{ - // should never get here - fatalerror("sound_stream_update called; not applicable to legacy sound devices\n"); -} |