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/******************************************************************************
PeT mess@utanet.at 2000,2001
******************************************************************************/
#include "emu.h"
#include "includes/lynx.h"
/* accordingly to atari's reference manual
there were no stereo lynx produced (the manual knows only production until mid 1991)
the howard/developement board might have stereo support
the revised lynx 2 hardware might have stereo support at least at the stereo jacks
some games support stereo
*/
/*
AUDIO_A EQU $FD20
AUDIO_B EQU $FD28
AUDIO_C EQU $FD30
AUDIO_D EQU $FD38
VOLUME_CNTRL EQU 0
FEEDBACK_ENABLE EQU 1 ; enables 11/10/5..0
OUTPUT_VALUE EQU 2
SHIFTER_L EQU 3
AUD_BAKUP EQU 4
AUD_CNTRL1 EQU 5
AUD_COUNT EQU 6
AUD_CNTRL2 EQU 7
; AUD_CNTRL1
FEEDBACK_7 EQU %10000000
AUD_RESETDONE EQU %01000000
AUD_INTEGRATE EQU %00100000
AUD_RELOAD EQU %00010000
AUD_CNTEN EQU %00001000
AUD_LINK EQU %00000111
; link timers (0->2->4 / 1->3->5->7->Aud0->Aud1->Aud2->Aud3->1
AUD_64us EQU %00000110
AUD_32us EQU %00000101
AUD_16us EQU %00000100
AUD_8us EQU %00000011
AUD_4us EQU %00000010
AUD_2us EQU %00000001
AUD_1us EQU %00000000
; AUD_CNTRL2 (read only)
; B7..B4 ; shifter bits 11..8
; B3 ; who knows
; B2 ; last clock state (0->1 causes count)
; B1 ; borrow in (1 causes count)
; B0 ; borrow out (count EQU 0 and borrow in)
ATTEN_A EQU $FD40
ATTEN_B EQU $FD41
ATTEN_C EQU $FD42
ATTEN_D EQU $FD43
; B7..B4 attenuation left ear (0 silent ..15/16 volume)
; B3..B0 " right ear
MPAN EQU $FD44
; B7..B4 left ear
; B3..B0 right ear
; B7/B3 EQU Audio D
; a 1 enables attenuation for channel and side
MSTEREO EQU $FD50 ; a 1 disables audio connection
AUD_D_LEFT EQU %10000000
AUD_C_LEFT EQU %01000000
AUD_B_LEFT EQU %00100000
AUD_A_LEFT EQU %00010000
AUD_D_RIGHT EQU %00001000
AUD_C_RIGHT EQU %00000100
AUD_B_RIGHT EQU %00000010
AUD_A_RIGHT EQU %00000001
*/
#define LYNX_AUDIO_CHANNELS 4
typedef struct {
struct {
INT8 volume;
UINT8 feedback;
INT8 output;
UINT8 shifter;
UINT8 bakup;
UINT8 control1;
UINT8 counter;
UINT8 control2;
} reg;
UINT8 attenuation;
UINT16 mask; // 12-bit
UINT16 shifter; // 12-bit
float ticks;
int count;
} LYNX_AUDIO;
typedef struct _lynx_sound_state lynx_sound_state;
struct _lynx_sound_state
{
sound_stream *mixer_channel;
float usec_per_sample;
int *shift_mask;
int *shift_xor;
UINT8 attenuation_enable;
UINT8 master_enable;
LYNX_AUDIO audio[4];
};
INLINE lynx_sound_state *get_safe_token(device_t *device)
{
assert(device != NULL);
assert(device->type() == LYNX || device->type() == LYNX2);
return (lynx_sound_state *)downcast<lynx_sound_device *>(device)->token();
}
static void lynx_audio_reset_channel(LYNX_AUDIO *This)
{
This->reg.volume = 0;
This->reg.feedback = 0;
This->reg.output = 0;
This->reg.shifter = 0;
This->reg.bakup = 0;
This->reg.control1 = 0;
This->reg.counter = 0;
This->reg.control2 = 0;
This->attenuation = 0;
This->mask = 0;
This->shifter = 0;
This->ticks = 0;
This->count = 0;
}
void lynx_audio_count_down(device_t *device, int nr)
{
lynx_sound_state *state = get_safe_token(device);
LYNX_AUDIO *This=state->audio+nr;
if (This->reg.control1&8 && (This->reg.control1&7)!=7) return;
if (nr==0) state->mixer_channel->update();
//if ((This->reg.control1&0x0f)==0x0f) //count down if linking enabled and count enabled
This->count--;
}
static void lynx_audio_shift(device_t *device, LYNX_AUDIO *channel)
{
lynx_sound_state *state = get_safe_token(device);
INT16 out_temp;
UINT8 channel_number = (UINT8)(channel - state->audio);
//channel->shifter = ((channel->shifter<<1)&0xffe) | (state->shift_xor[ channel->shifter & channel->mask ]&1);
// alternative method (functionally the same as above)
UINT8 xor_out=0;
for(int bit=0;bit<12;bit++)
{
if((channel->mask>>bit)&1) xor_out ^= (channel->shifter>>bit)&1;
}
channel->shifter = ((channel->shifter<<1)&0xffe) | (xor_out ^ 1); // output of xor is inverted
if (channel->reg.control1&0x20) // integrate mode enabled
{
if (channel->shifter&1)
{
out_temp = channel->reg.output + channel->reg.volume;
}
else
{
out_temp = channel->reg.output - channel->reg.volume;
}
// clipping
if(out_temp > 127) out_temp = 127;
if(out_temp < -128) out_temp = -128;
channel->reg.output = (INT16)out_temp;
}
switch (channel_number)
{
case 0: lynx_audio_count_down(device, 1); break;
case 1: lynx_audio_count_down(device, 2); break;
case 2: lynx_audio_count_down(device, 3); break;
case 3: lynx_timer_count_down(device->machine(), 1); break;
default: logerror("Invalid channel number %d\n", channel_number); break;
}
}
static void lynx_audio_execute(device_t *device, LYNX_AUDIO *channel)
{
lynx_sound_state *state = get_safe_token(device);
if (channel->reg.control1&8) // count enable
{
channel->ticks+=state->usec_per_sample;
if ((channel->reg.control1&7)==7) // link
{
if (channel->count<0) // counter finished
{
//channel->count+=channel->reg.counter; // reload (wrong?)
if (channel->reg.control1&0x10)
channel->count = channel->reg.bakup;
lynx_audio_shift(device, channel);
}
}
else
{
int t=1<<(channel->reg.control1&7); // microseconds per count
for (;;)
{
for (;(channel->ticks >= t) && (channel->count >= 0); channel->ticks-=t) // at least one sampled worth of time left, timer not expired
{
channel->count--;
}
if (channel->ticks<t) break;
if (channel->count<0)
{
lynx_audio_shift(device, channel);
if (channel->reg.control1&0x10)
channel->count = channel->reg.bakup;
else
break;
}
}
}
if (!(channel->reg.control1&0x20)) // normal mode
{
channel->reg.output = (channel->shifter & 1) ? channel->reg.volume : -channel->reg.volume;
}
}
else
{
channel->ticks=0;
channel->count=0;
}
}
UINT8 lynx_audio_read(device_t *device, int offset)
{
lynx_sound_state *state = get_safe_token(device);
UINT8 value=0;
LYNX_AUDIO *channel=&state->audio[(offset>>3)&3];
state->mixer_channel->update();
if (offset < 0x40)
{
switch (offset&7) {
case 0:
value = channel->reg.volume;
break;
case 1:
value = channel->reg.feedback;
break;
case 2:
value = channel->reg.output;
break;
case 3:
// current shifter state (lower 8 bits)
value = channel->shifter&0xff;
break;
case 4:
value = channel->reg.bakup;
break;
case 5:
value = channel->reg.control1;
break;
case 6:
//current timer value
if (channel->count >=0)
value = channel->count;
else
value = 0;
break;
case 7:
// current shifter state (upper 4 bits), status bits
value = (channel->shifter>>4)&0xf0;
value |= channel->reg.control2&0x0f;
break;
}
}
else
{
switch (offset) // Lynx II stereo control registers
{
case 0x40: case 0x41: case 0x42: case 0x43:
value = state->audio[offset&3].attenuation;
break;
case 0x44:
value = state->attenuation_enable;
break;
case 0x50:
value = state->master_enable;
break;
}
}
return value;
}
void lynx_audio_write(device_t *device, int offset, UINT8 data)
{
lynx_sound_state *state = get_safe_token(device);
//logerror("audio write %.2x %.2x\n", offset, data);
LYNX_AUDIO *channel=&state->audio[(offset>>3)&3];
state->mixer_channel->update();
if (offset < 0x40)
{
switch (offset & 0x07) {
// Volume control (signed)
case 0:
channel->reg.volume = data;
//logerror("write to volume %d\n", data);
break;
// Shift register feedback enable bits 0-5, 11,10
case 1:
channel->reg.feedback = data;
channel->mask &= 0x80;
channel->mask |= (data & 0x3f) | ((data & 0xc0)<<4);
break;
// Output value
case 2:
channel->reg.output = data;
//logerror("write to output %d\n", data);
break;
// Lower 8 bits of shift register
case 3:
channel->shifter &= 0xf00;
channel->shifter |= data;
break;
// Audio timer backup value
case 4:
channel->reg.bakup = data;
break;
// Audio control bits
case 5:
channel->mask &= ~0x80;
channel->mask |= (data&0x80);
channel->reg.control1 = data;
break;
// Current count
case 6:
channel->count=data;
break;
// Upper 4 bits of shift register and audio status bits
case 7:
channel->shifter&=0xff;
channel->shifter|=(data&0xf0)<<4;
channel->reg.control2 = data;
break;
}
}
else
{
switch (offset) // Stereo Registers
{
case 0x40: case 0x41: case 0x42: case 0x43:
state->audio[offset&3].attenuation=data;
break;
case 0x44:
state->attenuation_enable=data;
break;
case 0x50:
state->master_enable=data;
break;
}
}
}
/************************************/
/* Sound handler update */
/************************************/
static STREAM_UPDATE( lynx_update )
{
lynx_sound_state *state = get_safe_token(device);
int i, channel;
//LYNX_AUDIO *channel;
int v;
stream_sample_t *buffer = outputs[0];
for (i = 0; i < samples; i++, buffer++)
{
*buffer = 0;
for (channel=0; channel<LYNX_AUDIO_CHANNELS; channel++)
{
lynx_audio_execute(device, &state->audio[channel]);
v=state->audio[channel].reg.output;
*buffer+=v*15; // where does the *15 come from?
}
}
}
static STREAM_UPDATE( lynx2_update )
{
lynx_sound_state *state = get_safe_token(device);
stream_sample_t *left=outputs[0], *right=outputs[1];
int i, j;
LYNX_AUDIO *channel;
int v;
for (i = 0; i < samples; i++, left++, right++)
{
*left = 0;
*right= 0;
for (channel=state->audio, j=0; j<ARRAY_LENGTH(state->audio); j++, channel++)
{
lynx_audio_execute(device, channel);
v=channel->reg.output;
if (!(state->master_enable&(0x10<<j)))
{
if (state->attenuation_enable&(0x10<<j)) {
*left+=v*(channel->attenuation>>4);
} else {
*left+=v*15;
}
}
if (!(state->master_enable&(1<<j)))
{
if (state->attenuation_enable&(1<<j)) {
*right+=v*(channel->attenuation&0xf);
} else {
*right+=v*15;
}
}
}
}
}
static void lynx_audio_init(device_t *device)
{
lynx_sound_state *state = get_safe_token(device);
int i;
state->shift_mask = auto_alloc_array(device->machine(), int, 512);
assert(state->shift_mask);
state->shift_xor = auto_alloc_array(device->machine(), int, 4096);
assert(state->shift_xor);
for (i=0; i<512; i++)
{
state->shift_mask[i]=0;
if (i&1) state->shift_mask[i]|=1;
if (i&2) state->shift_mask[i]|=2;
if (i&4) state->shift_mask[i]|=4;
if (i&8) state->shift_mask[i]|=8;
if (i&0x10) state->shift_mask[i]|=0x10;
if (i&0x20) state->shift_mask[i]|=0x20;
if (i&0x40) state->shift_mask[i]|=0x400;
if (i&0x80) state->shift_mask[i]|=0x800;
if (i&0x100) state->shift_mask[i]|=0x80;
}
for (i=0; i<4096; i++)
{
int j;
state->shift_xor[i]=1;
for (j=4096/2; j>0; j>>=1)
{
if (i & j)
state->shift_xor[i] ^= 1;
}
}
}
static DEVICE_RESET( lynx_sound )
{
lynx_sound_state *state = get_safe_token(device);
int i;
for (i=0; i<ARRAY_LENGTH(state->audio); i++)
{
lynx_audio_reset_channel(state->audio+i);
}
}
/************************************/
/* Sound handler start */
/************************************/
static DEVICE_START(lynx_sound)
{
lynx_sound_state *state = get_safe_token(device);
state->mixer_channel = device->machine().sound().stream_alloc(*device, 0, 1, device->machine().sample_rate(), 0, lynx_update);
state->usec_per_sample = 1000000 / device->machine().sample_rate();
lynx_audio_init(device);
}
static DEVICE_START(lynx2_sound)
{
lynx_sound_state *state = get_safe_token(device);
state->mixer_channel = device->machine().sound().stream_alloc(*device, 0, 2, device->machine().sample_rate(), 0, lynx2_update);
state->usec_per_sample = 1000000 / device->machine().sample_rate();
lynx_audio_init(device);
}
const device_type LYNX = &device_creator<lynx_sound_device>;
lynx_sound_device::lynx_sound_device(const machine_config &mconfig, const char *tag, device_t *owner, UINT32 clock)
: device_t(mconfig, LYNX, "Mikey", tag, owner, clock),
device_sound_interface(mconfig, *this)
{
m_token = global_alloc_array_clear(UINT8, sizeof(lynx_sound_state));
}
lynx_sound_device::lynx_sound_device(const machine_config &mconfig, device_type type, const char *name, const char *tag, device_t *owner, UINT32 clock)
: device_t(mconfig, type, name, tag, owner, clock),
device_sound_interface(mconfig, *this)
{
m_token = global_alloc_array_clear(UINT8, sizeof(lynx_sound_state));
}
//-------------------------------------------------
// device_config_complete - perform any
// operations now that the configuration is
// complete
//-------------------------------------------------
void lynx_sound_device::device_config_complete()
{
}
//-------------------------------------------------
// device_start - device-specific startup
//-------------------------------------------------
void lynx_sound_device::device_start()
{
DEVICE_START_NAME( lynx_sound )(this);
}
//-------------------------------------------------
// device_reset - device-specific reset
//-------------------------------------------------
void lynx_sound_device::device_reset()
{
DEVICE_RESET_NAME( lynx_sound )(this);
}
//-------------------------------------------------
// sound_stream_update - handle a stream update
//-------------------------------------------------
void lynx_sound_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");
}
const device_type LYNX2 = &device_creator<lynx2_sound_device>;
lynx2_sound_device::lynx2_sound_device(const machine_config &mconfig, const char *tag, device_t *owner, UINT32 clock)
: lynx_sound_device(mconfig, LYNX2, "Mikey (Lynx II)", tag, owner, clock)
{
}
void lynx2_sound_device::device_start()
{
DEVICE_START_NAME( lynx2_sound )(this);
}
//-------------------------------------------------
// sound_stream_update - handle a stream update
//-------------------------------------------------
void lynx2_sound_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");
}
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