mirror of
https://github.com/RaySollium99/picodrive.git
synced 2025-09-05 15:27:46 -04:00
282 lines
6.4 KiB
C
282 lines
6.4 KiB
C
/*
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* PicoDrive
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* (C) notaz, 2009,2010,2013
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*
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* This work is licensed under the terms of MAME license.
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* See COPYING file in the top-level directory.
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*/
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#include "../pico_int.h"
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static int pwm_cycles;
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static int pwm_mult;
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static int pwm_ptr;
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static int timer_cycles[2];
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static int timer_tick_cycles[2];
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// timers. This includes PWM timer in 32x and internal SH2 timers
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void p32x_timers_recalc(void)
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{
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int cycles = Pico32x.regs[0x32 / 2];
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int tmp, i;
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cycles = (cycles - 1) & 0x0fff;
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pwm_cycles = cycles;
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pwm_mult = 0x10000 / cycles;
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// SH2 timer step
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for (i = 0; i < 2; i++) {
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tmp = PREG8(Pico32xMem->sh2_peri_regs[i], 0x80) & 7;
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// Sclk cycles per timer tick
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if (tmp)
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cycles = 0x20 << tmp;
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else
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cycles = 2;
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timer_tick_cycles[i] = cycles;
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elprintf(EL_32X, "WDT cycles[%d] = %d", i, cycles);
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}
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}
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#define consume_fifo(cycles) { \
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int cycles_diff = (cycles) - Pico32x.pwm_cycle_p; \
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if (cycles_diff >= pwm_cycles) \
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consume_fifo_do((cycles), cycles_diff); \
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}
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static void consume_fifo_do(unsigned int cycles, int cycles_diff)
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{
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if (pwm_cycles == 0)
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return;
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elprintf(EL_PWM, "pwm: %u: consume %d/%d, %d,%d ptr %d",
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cycles, cycles_diff, cycles_diff / pwm_cycles,
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Pico32x.pwm_p[0], Pico32x.pwm_p[1], pwm_ptr);
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if (cycles_diff > pwm_cycles * 9) {
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// silence/skip
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Pico32x.pwm_cycle_p = cycles;
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Pico32x.pwm_p[0] = Pico32x.pwm_p[1] = 0;
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return;
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}
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for (; cycles_diff >= pwm_cycles; cycles_diff -= pwm_cycles) {
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struct Pico32xMem *mem = Pico32xMem;
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short *fifo_l = mem->pwm_fifo[0];
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short *fifo_r = mem->pwm_fifo[1];
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if (Pico32x.pwm_p[0] > 0) {
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fifo_l[0] = fifo_l[1];
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fifo_l[1] = fifo_l[2];
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fifo_l[2] = fifo_l[3];
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Pico32x.pwm_p[0]--;
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}
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if (Pico32x.pwm_p[1] > 0) {
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fifo_r[0] = fifo_r[1];
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fifo_r[1] = fifo_r[2];
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fifo_r[2] = fifo_r[3];
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Pico32x.pwm_p[1]--;
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}
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mem->pwm[pwm_ptr * 2 ] = fifo_l[0];
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mem->pwm[pwm_ptr * 2 + 1] = fifo_r[0];
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pwm_ptr = (pwm_ptr + 1) & (PWM_BUFF_LEN - 1);
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}
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Pico32x.pwm_cycle_p = cycles - cycles_diff;
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}
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void p32x_timers_do(unsigned int m68k_now, unsigned int m68k_slice)
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{
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unsigned int cycles = m68k_slice * 3;
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int cnt, i;
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consume_fifo(m68k_now * 3);
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// WDT timers
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for (i = 0; i < 2; i++) {
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void *pregs = Pico32xMem->sh2_peri_regs[i];
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if (PREG8(pregs, 0x80) & 0x20) { // TME
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timer_cycles[i] += cycles;
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cnt = PREG8(pregs, 0x81);
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while (timer_cycles[i] >= timer_tick_cycles[i]) {
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timer_cycles[i] -= timer_tick_cycles[i];
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cnt++;
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}
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if (cnt >= 0x100) {
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int level = PREG8(pregs, 0xe3) >> 4;
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int vector = PREG8(pregs, 0xe4) & 0x7f;
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elprintf(EL_32X, "%csh2 WDT irq (%d, %d)",
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i ? 's' : 'm', level, vector);
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sh2_internal_irq(&sh2s[i], level, vector);
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cnt &= 0xff;
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}
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PREG8(pregs, 0x81) = cnt;
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}
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}
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}
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static int p32x_pwm_schedule_(void)
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{
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int tm;
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if (Pico32x.emu_flags & P32XF_PWM_PEND)
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return 0; // already scheduled
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if (Pico32x.sh2irqs & P32XI_PWM)
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return 0; // previous not acked
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if (!((Pico32x.sh2irq_mask[0] | Pico32x.sh2irq_mask[1]) & 1))
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return 0; // masked by everyone
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Pico32x.emu_flags |= P32XF_PWM_PEND;
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tm = (Pico32x.regs[0x30 / 2] & 0x0f00) >> 8;
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tm = ((tm - 1) & 0x0f) + 1;
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return pwm_cycles * tm / 3;
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}
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void p32x_pwm_schedule(unsigned int now)
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{
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int after = p32x_pwm_schedule_();
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if (after != 0)
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p32x_event_schedule(now, P32X_EVENT_PWM, after);
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}
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void p32x_pwm_schedule_sh2(SH2 *sh2)
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{
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int after = p32x_pwm_schedule_();
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if (after != 0)
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p32x_event_schedule_sh2(sh2, P32X_EVENT_PWM, after);
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}
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unsigned int p32x_pwm_read16(unsigned int a, unsigned int cycles)
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{
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unsigned int d = 0;
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consume_fifo(cycles);
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a &= 0x0e;
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switch (a) {
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case 0: // control
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case 2: // cycle
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d = Pico32x.regs[(0x30 + a) / 2];
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break;
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case 4: // L ch
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if (Pico32x.pwm_p[0] == 3)
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d |= P32XP_FULL;
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else if (Pico32x.pwm_p[0] == 0)
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d |= P32XP_EMPTY;
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break;
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case 6: // R ch
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case 8: // MONO
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if (Pico32x.pwm_p[1] == 3)
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d |= P32XP_FULL;
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else if (Pico32x.pwm_p[1] == 0)
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d |= P32XP_EMPTY;
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break;
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}
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elprintf(EL_PWM, "pwm: read %02x %04x (p %d %d), c %u",
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a, d, Pico32x.pwm_p[0], Pico32x.pwm_p[1], cycles);
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return d;
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}
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void p32x_pwm_write16(unsigned int a, unsigned int d, unsigned int cycles)
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{
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consume_fifo(cycles);
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a &= 0x0e;
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if (a == 0) { // control
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// supposedly we should stop FIFO when xMd is 0,
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// but mars test disagrees
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Pico32x.regs[0x30 / 2] = d;
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}
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else if (a == 2) { // cycle
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Pico32x.regs[0x32 / 2] = d & 0x0fff;
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p32x_timers_recalc();
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Pico32x.pwm_irq_sample_cnt = 0; // resets?
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}
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else if (a <= 8) {
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d = (d - 1) & 0x0fff;
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if (d > pwm_cycles)
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d = pwm_cycles;
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d = (d - pwm_cycles / 2) * pwm_mult;
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if (a == 4 || a == 8) { // L ch or MONO
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short *fifo = Pico32xMem->pwm_fifo[0];
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if (Pico32x.pwm_p[0] < 3)
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Pico32x.pwm_p[0]++;
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else {
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fifo[1] = fifo[2];
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fifo[2] = fifo[3];
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}
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fifo[Pico32x.pwm_p[0]] = d;
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}
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if (a == 6 || a == 8) { // R ch or MONO
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short *fifo = Pico32xMem->pwm_fifo[1];
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if (Pico32x.pwm_p[1] < 3)
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Pico32x.pwm_p[1]++;
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else {
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fifo[1] = fifo[2];
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fifo[2] = fifo[3];
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}
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fifo[Pico32x.pwm_p[1]] = d;
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}
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}
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}
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void p32x_pwm_update(int *buf32, int length, int stereo)
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{
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short *pwmb;
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int step;
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int p = 0;
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int xmd;
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xmd = Pico32x.regs[0x30 / 2] & 0x0f;
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if ((xmd != 0x05 && xmd != 0x0a) || pwm_ptr <= 16)
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goto out;
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step = (pwm_ptr << 16) / length; // FIXME: division..
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pwmb = Pico32xMem->pwm;
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if (stereo)
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{
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if (xmd == 0x0a) {
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// channel swap
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while (length-- > 0) {
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*buf32++ += pwmb[1];
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*buf32++ += pwmb[0];
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p += step;
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pwmb += (p >> 16) * 2;
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p &= 0xffff;
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}
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}
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else {
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while (length-- > 0) {
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*buf32++ += pwmb[0];
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*buf32++ += pwmb[1];
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p += step;
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pwmb += (p >> 16) * 2;
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p &= 0xffff;
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}
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}
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}
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else
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{
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while (length-- > 0) {
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*buf32++ += pwmb[0];
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p += step;
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pwmb += (p >> 16) * 2;
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p &= 0xffff;
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}
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}
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elprintf(EL_PWM, "pwm_update: pwm_ptr %d, len %d, step %04x, done %d",
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pwm_ptr, length, step, (pwmb - Pico32xMem->pwm) / 2);
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out:
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pwm_ptr = 0;
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}
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// vim:shiftwidth=2:ts=2:expandtab
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