BizHawk/waterbox/picodrive/pico/32x/pwm.c

338 lines
7.8 KiB
C

/*
* PicoDrive
* (C) notaz, 2009,2010,2013
*
* This work is licensed under the terms of MAME license.
* See COPYING file in the top-level directory.
*/
#include "../pico_int.h"
static int pwm_cycles;
static int pwm_mult;
static int pwm_ptr;
static int pwm_irq_reload;
static int pwm_doing_fifo;
static int pwm_silent;
void p32x_pwm_ctl_changed(void)
{
int control = Pico32x.regs[0x30 / 2];
int cycles = Pico32x.regs[0x32 / 2];
cycles = (cycles - 1) & 0x0fff;
pwm_cycles = cycles;
// supposedly we should stop FIFO when xMd is 0,
// but mars test disagrees
pwm_mult = 0;
if ((control & 0x0f) != 0)
pwm_mult = 0x10000 / cycles;
pwm_irq_reload = (control & 0x0f00) >> 8;
pwm_irq_reload = ((pwm_irq_reload - 1) & 0x0f) + 1;
if (Pico32x.pwm_irq_cnt == 0)
Pico32x.pwm_irq_cnt = pwm_irq_reload;
}
static void do_pwm_irq(SH2 *sh2, unsigned int m68k_cycles)
{
p32x_trigger_irq(sh2, m68k_cycles, P32XI_PWM);
if (Pico32x.regs[0x30 / 2] & P32XP_RTP) {
p32x_event_schedule(m68k_cycles, P32X_EVENT_PWM, pwm_cycles / 3 + 1);
// note: might recurse
p32x_dreq1_trigger();
}
}
static int convert_sample(unsigned int v)
{
if (v == 0)
return 0;
if (v > pwm_cycles)
v = pwm_cycles;
return ((int)v - pwm_cycles / 2) * pwm_mult;
}
#define consume_fifo(sh2, m68k_cycles) { \
int cycles_diff = ((m68k_cycles) * 3) - Pico32x.pwm_cycle_p; \
if (cycles_diff >= pwm_cycles) \
consume_fifo_do(sh2, m68k_cycles, cycles_diff); \
}
static void consume_fifo_do(SH2 *sh2, unsigned int m68k_cycles,
int sh2_cycles_diff)
{
struct Pico32xMem *mem = Pico32xMem;
unsigned short *fifo_l = mem->pwm_fifo[0];
unsigned short *fifo_r = mem->pwm_fifo[1];
int sum = 0;
if (pwm_cycles == 0 || pwm_doing_fifo)
return;
elprintf(EL_PWM, "pwm: %u: consume %d/%d, %d,%d ptr %d",
m68k_cycles, sh2_cycles_diff, sh2_cycles_diff / pwm_cycles,
Pico32x.pwm_p[0], Pico32x.pwm_p[1], pwm_ptr);
// this is for recursion from dreq1 writes
pwm_doing_fifo = 1;
for (; sh2_cycles_diff >= pwm_cycles; sh2_cycles_diff -= pwm_cycles)
{
if (Pico32x.pwm_p[0] > 0) {
fifo_l[0] = fifo_l[1];
fifo_l[1] = fifo_l[2];
fifo_l[2] = fifo_l[3];
Pico32x.pwm_p[0]--;
mem->pwm_current[0] = convert_sample(fifo_l[0]);
sum += mem->pwm_current[0];
}
if (Pico32x.pwm_p[1] > 0) {
fifo_r[0] = fifo_r[1];
fifo_r[1] = fifo_r[2];
fifo_r[2] = fifo_r[3];
Pico32x.pwm_p[1]--;
mem->pwm_current[1] = convert_sample(fifo_r[0]);
sum += mem->pwm_current[1];
}
mem->pwm[pwm_ptr * 2 ] = mem->pwm_current[0];
mem->pwm[pwm_ptr * 2 + 1] = mem->pwm_current[1];
pwm_ptr = (pwm_ptr + 1) & (PWM_BUFF_LEN - 1);
if (--Pico32x.pwm_irq_cnt == 0) {
Pico32x.pwm_irq_cnt = pwm_irq_reload;
do_pwm_irq(sh2, m68k_cycles);
}
}
Pico32x.pwm_cycle_p = m68k_cycles * 3 - sh2_cycles_diff;
pwm_doing_fifo = 0;
if (sum != 0)
pwm_silent = 0;
}
static int p32x_pwm_schedule_(SH2 *sh2, unsigned int m68k_now)
{
unsigned int sh2_now = m68k_now * 3;
int cycles_diff_sh2;
if (pwm_cycles == 0)
return 0;
cycles_diff_sh2 = sh2_now - Pico32x.pwm_cycle_p;
if (cycles_diff_sh2 >= pwm_cycles)
consume_fifo_do(sh2, m68k_now, cycles_diff_sh2);
if (!((Pico32x.sh2irq_mask[0] | Pico32x.sh2irq_mask[1]) & 1))
return 0; // masked by everyone
cycles_diff_sh2 = sh2_now - Pico32x.pwm_cycle_p;
return (Pico32x.pwm_irq_cnt * pwm_cycles
- cycles_diff_sh2) / 3 + 1;
}
void p32x_pwm_schedule(unsigned int m68k_now)
{
int after = p32x_pwm_schedule_(NULL, m68k_now);
if (after != 0)
p32x_event_schedule(m68k_now, P32X_EVENT_PWM, after);
}
void p32x_pwm_schedule_sh2(SH2 *sh2)
{
int after = p32x_pwm_schedule_(sh2, sh2_cycles_done_m68k(sh2));
if (after != 0)
p32x_event_schedule_sh2(sh2, P32X_EVENT_PWM, after);
}
void p32x_pwm_sync_to_sh2(SH2 *sh2)
{
int m68k_cycles = sh2_cycles_done_m68k(sh2);
consume_fifo(sh2, m68k_cycles);
}
void p32x_pwm_irq_event(unsigned int m68k_now)
{
p32x_pwm_schedule(m68k_now);
}
unsigned int p32x_pwm_read16(unsigned int a, SH2 *sh2,
unsigned int m68k_cycles)
{
unsigned int d = 0;
consume_fifo(sh2, m68k_cycles);
a &= 0x0e;
switch (a) {
case 0: // control
case 2: // cycle
d = Pico32x.regs[(0x30 + a) / 2];
break;
case 4: // L ch
if (Pico32x.pwm_p[0] == 3)
d |= P32XP_FULL;
else if (Pico32x.pwm_p[0] == 0)
d |= P32XP_EMPTY;
break;
case 6: // R ch
case 8: // MONO
if (Pico32x.pwm_p[1] == 3)
d |= P32XP_FULL;
else if (Pico32x.pwm_p[1] == 0)
d |= P32XP_EMPTY;
break;
}
elprintf(EL_PWM, "pwm: %u: r16 %02x %04x (p %d %d)",
m68k_cycles, a, d, Pico32x.pwm_p[0], Pico32x.pwm_p[1]);
return d;
}
void p32x_pwm_write16(unsigned int a, unsigned int d,
SH2 *sh2, unsigned int m68k_cycles)
{
elprintf(EL_PWM, "pwm: %u: w16 %02x %04x (p %d %d)",
m68k_cycles, a & 0x0e, d, Pico32x.pwm_p[0], Pico32x.pwm_p[1]);
consume_fifo(sh2, m68k_cycles);
a &= 0x0e;
if (a == 0) { // control
// avoiding pops..
if ((Pico32x.regs[0x30 / 2] & 0x0f) == 0)
Pico32xMem->pwm_fifo[0][0] = Pico32xMem->pwm_fifo[1][0] = 0;
Pico32x.regs[0x30 / 2] = d;
p32x_pwm_ctl_changed();
Pico32x.pwm_irq_cnt = pwm_irq_reload; // ?
}
else if (a == 2) { // cycle
Pico32x.regs[0x32 / 2] = d & 0x0fff;
p32x_pwm_ctl_changed();
}
else if (a <= 8) {
d = (d - 1) & 0x0fff;
if (a == 4 || a == 8) { // L ch or MONO
unsigned short *fifo = Pico32xMem->pwm_fifo[0];
if (Pico32x.pwm_p[0] < 3)
Pico32x.pwm_p[0]++;
else {
fifo[1] = fifo[2];
fifo[2] = fifo[3];
}
fifo[Pico32x.pwm_p[0]] = d;
}
if (a == 6 || a == 8) { // R ch or MONO
unsigned short *fifo = Pico32xMem->pwm_fifo[1];
if (Pico32x.pwm_p[1] < 3)
Pico32x.pwm_p[1]++;
else {
fifo[1] = fifo[2];
fifo[2] = fifo[3];
}
fifo[Pico32x.pwm_p[1]] = d;
}
}
}
void p32x_pwm_update(int *buf32, int length, int stereo)
{
short *pwmb;
int step;
int p = 0;
int xmd;
consume_fifo(NULL, SekCyclesDone());
xmd = Pico32x.regs[0x30 / 2] & 0x0f;
if (xmd == 0 || xmd == 0x06 || xmd == 0x09 || xmd == 0x0f)
goto out; // invalid?
if (pwm_silent)
return;
step = (pwm_ptr << 16) / length;
pwmb = Pico32xMem->pwm;
if (stereo)
{
if (xmd == 0x05) {
// normal
while (length-- > 0) {
*buf32++ += pwmb[0];
*buf32++ += pwmb[1];
p += step;
pwmb += (p >> 16) * 2;
p &= 0xffff;
}
}
else if (xmd == 0x0a) {
// channel swap
while (length-- > 0) {
*buf32++ += pwmb[1];
*buf32++ += pwmb[0];
p += step;
pwmb += (p >> 16) * 2;
p &= 0xffff;
}
}
else {
// mono - LMD, RMD specify dst
if (xmd & 0x06) // src is R
pwmb++;
if (xmd & 0x0c) // dst is R
buf32++;
while (length-- > 0) {
*buf32 += *pwmb;
p += step;
pwmb += (p >> 16) * 2;
p &= 0xffff;
buf32 += 2;
}
}
}
else
{
// mostly unused
while (length-- > 0) {
*buf32++ += pwmb[0];
p += step;
pwmb += (p >> 16) * 2;
p &= 0xffff;
}
}
elprintf(EL_PWM, "pwm_update: pwm_ptr %d, len %d, step %04x, done %d",
pwm_ptr, length, step, (pwmb - Pico32xMem->pwm) / 2);
out:
pwm_ptr = 0;
pwm_silent = Pico32xMem->pwm_current[0] == 0
&& Pico32xMem->pwm_current[1] == 0;
}
void p32x_pwm_state_loaded(void)
{
int cycles_diff_sh2;
p32x_pwm_ctl_changed();
// for old savestates
cycles_diff_sh2 = SekCycleCnt * 3 - Pico32x.pwm_cycle_p;
if (cycles_diff_sh2 >= pwm_cycles || cycles_diff_sh2 < 0) {
Pico32x.pwm_irq_cnt = pwm_irq_reload;
Pico32x.pwm_cycle_p = SekCycleCnt * 3;
p32x_pwm_schedule(SekCycleCnt);
}
}
// vim:shiftwidth=2:ts=2:expandtab