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author Derrick Renaud <derrickr@mamedev.org>2008-08-28 20:58:05 +0000
committer Derrick Renaud <derrickr@mamedev.org>2008-08-28 20:58:05 +0000
commitae10d3987a3b966661a54d9659a687364fa302d8 (patch)
treeeac883e2d1b530ba63cd400004f9f774230772d7 /src/emu
parente5fbac92cf0ca948fb4a0a553d83390358c21bc6 (diff)
Optimized DISCRETE_RCINTEGRATE and DISCRETE_555_ASTABLE.
Diffstat (limited to 'src/emu')
-rw-r--r--src/emu/sound/disc_dev.c74
-rw-r--r--src/emu/sound/disc_flt.c81
-rw-r--r--src/emu/sound/discrete.h1
3 files changed, 105 insertions, 51 deletions
diff --git a/src/emu/sound/disc_dev.c b/src/emu/sound/disc_dev.c
index 9764bede8b5..3528a384a35 100644
--- a/src/emu/sound/disc_dev.c
+++ b/src/emu/sound/disc_dev.c
@@ -38,6 +38,12 @@ struct dsd_555_astbl_context
double v_out_high; /* Logic 1 voltage level */
double v_charge;
double *v_charge_node; /* point to output of node */
+ int has_rc_nodes;
+ double exp_bleed;
+ double exp_charge;
+ double exp_discharge;
+ double t_rc_charge;
+ double t_rc_discharge;
};
struct dsd_555_mstbl_context
@@ -127,6 +133,12 @@ struct dsd_ls624_context
#define DSD_555_ASTBL__C (*(node->input[3]))
#define DSD_555_ASTBL__CTRLV (*(node->input[4]))
+/* charge/discharge constants */
+#define DSD_555_ASTBL_T_RC_BLEED (DEFAULT_555_CAP_BLEED * DSD_555_ASTBL__C)
+/* Use quick charge if specified. */
+#define DSD_555_ASTBL_T_RC_CHARGE ((DSD_555_ASTBL__R1 + ((info->options & DISC_555_ASTABLE_HAS_FAST_CHARGE_DIODE) ? 0 : DSD_555_ASTBL__R2)) * DSD_555_ASTBL__C)
+#define DSD_555_ASTBL_T_RC_DISCHARGE (DSD_555_ASTBL__R2 * DSD_555_ASTBL__C)
+
static void dsd_555_astbl_step(node_description *node)
{
const discrete_555_desc *info = node->custom;
@@ -139,7 +151,8 @@ static void dsd_555_astbl_step(node_description *node)
double t_rc = 0; /* RC time constant */
double v_cap = context->cap_voltage; /* Current voltage on capacitor, before dt */
double v_cap_next = 0; /* Voltage on capacitor, after dt */
- double v_charge;
+ double v_charge, exponent;
+ int update_exponent, update_t_rc;
if(DSD_555_ASTBL__RESET)
{
@@ -217,6 +230,8 @@ static void dsd_555_astbl_step(node_description *node)
else
{
/* Keep looping until all toggling in time sample is used up. */
+ update_t_rc = context->has_rc_nodes;
+ update_exponent = update_t_rc;
do
{
if (context->flip_flop)
@@ -225,16 +240,28 @@ static void dsd_555_astbl_step(node_description *node)
{
/* Oscillation disabled because there is no longer any charge resistor. */
/* Bleed the cap due to circuit losses. */
- t_rc = DEFAULT_555_CAP_BLEED * DSD_555_ASTBL__C;
- v_cap_next = v_cap - (v_cap * (1.0 - exp(-(dt / t_rc ))));
+ if (update_exponent)
+ {
+ t_rc = DSD_555_ASTBL_T_RC_BLEED;
+ exponent = 1.0 - exp(-(dt / t_rc));
+ }
+ else
+ exponent = context->exp_bleed;
+ v_cap_next = v_cap - (v_cap * exponent);
dt = 0;
}
else
{
/* Charging */
- /* Use quick charge if specified. */
- t_rc = (DSD_555_ASTBL__R1 + ((info->options & DISC_555_ASTABLE_HAS_FAST_CHARGE_DIODE) ? 0 : DSD_555_ASTBL__R2)) * DSD_555_ASTBL__C;
- v_cap_next = v_cap + ((v_charge - v_cap) * (1.0 - exp(-(dt / t_rc ))));
+ if (update_t_rc)
+ t_rc = DSD_555_ASTBL_T_RC_CHARGE;
+ else
+ t_rc = context->t_rc_charge;
+ if (update_exponent)
+ exponent = 1.0 - exp(-(dt / t_rc ));
+ else
+ exponent = context->exp_charge;
+ v_cap_next = v_cap + ((v_charge - v_cap) * exponent);
dt = 0;
/* has it charged past upper limit? */
@@ -246,6 +273,7 @@ static void dsd_555_astbl_step(node_description *node)
v_cap = context->threshold;
context->flip_flop = 0;
count_f++;
+ update_exponent = 1;
}
}
}
@@ -254,8 +282,15 @@ static void dsd_555_astbl_step(node_description *node)
/* Discharging */
if(DSD_555_ASTBL__R2 != 0)
{
- t_rc = DSD_555_ASTBL__R2 * DSD_555_ASTBL__C;
- v_cap_next = v_cap - (v_cap * (1 - exp(-(dt / t_rc ))));
+ if (update_t_rc)
+ t_rc = DSD_555_ASTBL_T_RC_DISCHARGE;
+ else
+ t_rc = context->t_rc_discharge;
+ if (update_exponent)
+ exponent = 1.0 - exp(-(dt / t_rc ));
+ else
+ exponent = context->exp_discharge;
+ v_cap_next = v_cap - (v_cap * exponent);
dt = 0;
}
else
@@ -268,12 +303,12 @@ static void dsd_555_astbl_step(node_description *node)
if (v_cap_next <= context->trigger)
{
/* calculate the overshoot time */
- if (dt == 0)
- dt = t_rc * log(1.0 / (1.0 - ((context->trigger - v_cap_next) / v_cap)));
+ dt = t_rc * log(1.0 / (1.0 - ((context->trigger - v_cap_next) / v_cap)));
x_time = dt;
v_cap = context->trigger;
context->flip_flop = 1;
count_r++;
+ update_exponent = 1;
}
}
} while(dt);
@@ -324,6 +359,9 @@ static void dsd_555_astbl_reset(node_description *node)
struct dsd_555_astbl_context *context = node->context;
node_description *v_charge_node;
+ double neg_dt = 0.0 - discrete_current_context->sample_time;
+ double t_rc;
+
context->use_ctrlv = (node->input_is_node >> 4) & 1;
context->output_type = info->options & DISC_555_OUT_MASK;
@@ -355,6 +393,22 @@ static void dsd_555_astbl_reset(node_description *node)
context->trigger = info->v_pos / 3.0;
}
+ /* optimization if none of the values are nodes */
+ context->has_rc_nodes = 0;
+ if (node->input_is_node & 0x0e)
+ context->has_rc_nodes = 1;
+ else
+ {
+ t_rc = DSD_555_ASTBL_T_RC_BLEED;
+ context->exp_bleed = 1.0 - exp(neg_dt / t_rc);
+ t_rc = DSD_555_ASTBL_T_RC_CHARGE;
+ context->exp_charge = 1.0 - exp(neg_dt / t_rc);
+ context->t_rc_charge = t_rc;
+ t_rc = DSD_555_ASTBL_T_RC_DISCHARGE;
+ context->exp_discharge = 1.0 - exp(neg_dt / t_rc);
+ context->t_rc_discharge = t_rc;
+ }
+
context->output_is_ac = info->options & DISC_555_OUT_AC;
/* Calculate DC shift needed to make squarewave waveform AC */
context->ac_shift = context->output_is_ac ? -context->v_out_high / 2.0 : 0;
diff --git a/src/emu/sound/disc_flt.c b/src/emu/sound/disc_flt.c
index 81def840584..37280859fdf 100644
--- a/src/emu/sound/disc_flt.c
+++ b/src/emu/sound/disc_flt.c
@@ -103,19 +103,17 @@ struct dst_rcfilter_sw_context
struct dst_rcintegrate_context
{
- int state;
- double t; /* time */
- double f; /* RCINTEGRATE */
- double R1; /* RCINTEGRATE */
- double R2; /* RCINTEGRATE */
- double R3; /* RCINTEGRATE */
- double C; /* RCINTEGRATE */
- double vCap; /* RCDISC_MOD */
- double vCE; /* RCINTEGRATE */
- double exponent0;
- double exponent1;
- double exp_exponent0;/* RCINTEGRATE */
- double exp_exponent1;/* RCINTEGRATE */
+ int type;
+ double gain_r1_r2;
+ double f; /* r2,r3 gain */
+ double vCap;
+ double vCE;
+ double exponent0;
+ double exponent1;
+ double exp_exponent0;
+ double exp_exponent1;
+ double c_exp0;
+ double c_exp1;
};
/************************************************************************
@@ -1186,40 +1184,40 @@ static void dst_rcintegrate_step(node_description *node)
struct dst_rcintegrate_context *context = node->context;
double diff, u, iQ, iQc, iC, RG, vE;
- double dt, vP;
+ double vP;
if(DST_RCINTEGRATE__ENABLE)
{
u = DST_RCINTEGRATE__IN1;
vP = DST_RCINTEGRATE__VP;
- dt = discrete_current_context->sample_time;
- if ( u-0.7 < context->vCap*context->R2/(context->R1+context->R2))
+
+ if ( u - 0.7 < context->vCap * context->gain_r1_r2)
{
/* discharge .... */
- diff = 0.0 - context->vCap;
- iC = 0.0 - context->C / context->exponent1 * diff * context->exp_exponent1; /* iC */
- diff = diff - (diff * context->exp_exponent1);
+ diff = 0.0 - context->vCap;
+ iC = 0.0 - context->c_exp1 * diff; /* iC */
+ diff -= diff * context->exp_exponent1;
context->vCap += diff;
iQ = 0;
- vE = context->vCap*context->R2/(context->R1+context->R2);
- RG = vE/(-iC);
+ vE = context->vCap * context->gain_r1_r2;
+ RG = vE / (-iC);
}
else
{
/* charging */
- diff = (vP - context->vCE) * context->f - context->vCap;
- iC = 0.0 - context->C / context->exponent0 * diff * context->exp_exponent0; /* iC */
- diff = diff - (diff * context->exp_exponent0);
+ diff = (vP - context->vCE) * context->f - context->vCap;
+ iC = 0.0 - context->c_exp0 * diff; /* iC */
+ diff -= diff * context->exp_exponent0;
context->vCap += diff;
- iQ = iC + (iC * context->R1 + context->vCap) / context->R2;
- RG = (vP - context->vCE)/iQ;
- vE = (RG - context->R3) / RG * (vP - context->vCE);
+ iQ = iC + (iC * DST_RCINTEGRATE__R1 + context->vCap) / DST_RCINTEGRATE__R2;
+ RG = (vP - context->vCE) / iQ;
+ vE = (RG - DST_RCINTEGRATE__R3) / RG * (vP - context->vCE);
}
u = DST_RCINTEGRATE__IN1;
- if (u > 0.7+vE)
- vE = u-0.7;
+ if (u > 0.7 + vE)
+ vE = u - 0.7;
iQc = EM_IC(u - vE);
context->vCE = MIN(vP - 0.1, vP - RG * iQc);
@@ -1229,9 +1227,9 @@ static void dst_rcintegrate_step(node_description *node)
*/
context->vCE = MAX(context->vCE, 0.1 );
- context->vCE = 0.1 * context->vCE + 0.9 * (vP - vE - iQ * context->R3);
+ context->vCE = 0.1 * context->vCE + 0.9 * (vP - vE - iQ * DST_RCINTEGRATE__R3);
- switch (context->state)
+ switch (context->type)
{
case DISC_RC_INTEGRATE_TYPE1:
node->output[0] = context->vCap;
@@ -1240,7 +1238,7 @@ static void dst_rcintegrate_step(node_description *node)
node->output[0] = vE;
break;
case DISC_RC_INTEGRATE_TYPE3:
- node->output[0] = MAX(0, vP - iQ * context->R3);
+ node->output[0] = MAX(0, vP - iQ * DST_RCINTEGRATE__R3);
break;
}
}
@@ -1256,24 +1254,25 @@ static void dst_rcintegrate_reset(node_description *node)
double r;
double dt = discrete_current_context->sample_time;
- node->output[0]=0;
-
- context->state = DST_RCINTEGRATE__TYPE;
- context->R1 = DST_RCINTEGRATE__R1;
- context->R2 = DST_RCINTEGRATE__R2;
- context->R3 = DST_RCINTEGRATE__R3;
- context->C = DST_RCINTEGRATE__C;
+ context->type = DST_RCINTEGRATE__TYPE;
context->vCap = 0;
context->vCE = 0;
- r = context->R1 / context->R2 * context->R3 + context->R1 + context->R3;
+ /* pre-calculate fixed values */
+ context->gain_r1_r2 = RES_VOLTAGE_DIVIDER(DST_RCINTEGRATE__R1, DST_RCINTEGRATE__R2);
+
+ r = DST_RCINTEGRATE__R1 / DST_RCINTEGRATE__R2 * DST_RCINTEGRATE__R3 + DST_RCINTEGRATE__R1 + DST_RCINTEGRATE__R3;
- context->f = DST_RCINTEGRATE__R2/(DST_RCINTEGRATE__R2+DST_RCINTEGRATE__R3);
+ context->f = RES_VOLTAGE_DIVIDER(DST_RCINTEGRATE__R3, DST_RCINTEGRATE__R2);
context->exponent0 = -1.0 * r * context->f * DST_RCINTEGRATE__C;
context->exponent1 = -1.0 * (DST_RCINTEGRATE__R1 + DST_RCINTEGRATE__R2) * DST_RCINTEGRATE__C;
context->exp_exponent0 = exp(dt / context->exponent0);
context->exp_exponent1 = exp(dt / context->exponent1);
+ context->c_exp0 = DST_RCINTEGRATE__C / context->exponent0 * context->exp_exponent0;
+ context->c_exp1 = DST_RCINTEGRATE__C / context->exponent1 * context->exp_exponent1;
+
+ node->output[0] = 0;
}
diff --git a/src/emu/sound/discrete.h b/src/emu/sound/discrete.h
index e6a50e4b5b4..7df1941e85f 100644
--- a/src/emu/sound/discrete.h
+++ b/src/emu/sound/discrete.h
@@ -206,6 +206,7 @@
* DISCRETE_SQUAREWAVE2(NODE,ENAB,AMPL,T_OFF,T_ON,BIAS,TSHIFT)
* DISCRETE_TRIANGLEWAVE(NODE,ENAB,FREQ,AMP,BIAS,PHASE)
*
+ * DISCRETE_INVERTER_OSC(NODE,ENAB,MOD,RCHARGE,RP,C,R2,INFO)
* DISCRETE_OP_AMP_OSCILLATOR(NODE,ENAB,INFO)
* DISCRETE_OP_AMP_VCO1(NODE,ENAB,VMOD1,INFO)
* DISCRETE_OP_AMP_VCO2(NODE,ENAB,VMOD1,VMOD2,INFO)