mirror of
https://github.com/RaySollium99/picodrive.git
synced 2025-09-05 15:27:46 -04:00
32x: improve pwm accuracy
This commit is contained in:
notaz
parent
e7b3ad1bda
commit
a7f82a776a
4 changed files with 131 additions and 63 deletions
171
pico/32x/pwm.c
171
pico/32x/pwm.c
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@ -1,20 +1,16 @@
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/*
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* PicoDrive
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* (C) notaz, 2009,2010
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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_cycle_counter;
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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 pwm_smp_cnt;
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static int pwm_smp_expect;
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static int timer_cycles[2];
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static int timer_tick_cycles[2];
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@ -25,10 +21,6 @@ void p32x_timers_recalc(void)
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int tmp, i;
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cycles = (cycles - 1) & 0x0fff;
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if (cycles < 500) {
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elprintf(EL_32X|EL_PWM|EL_ANOMALY, "pwm: low cycle value: %d", cycles + 1);
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cycles = 500;
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}
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pwm_cycles = cycles;
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pwm_mult = 0x10000 / cycles;
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@ -45,23 +37,59 @@ void p32x_timers_recalc(void)
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}
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}
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// PWM irq for every tm samples
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void p32x_timers_do(unsigned int cycles)
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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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cycles *= 3;
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// since we run things in async fashion, allow pwm to lag behind
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// but don't allow our "queue" to be infinite
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cnt = pwm_smp_expect - pwm_smp_cnt;
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if (cnt <= 0 || cnt * pwm_cycles < OSC_NTSC/7*3 / 60 / 2) {
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pwm_cycle_counter += cycles;
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while (pwm_cycle_counter > pwm_cycles) {
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pwm_cycle_counter -= pwm_cycles;
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pwm_smp_expect++;
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}
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}
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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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@ -117,61 +145,80 @@ void p32x_pwm_schedule_sh2(SH2 *sh2)
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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)
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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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int diff;
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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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return Pico32x.regs[(0x30 + a) / 2];
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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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diff = pwm_smp_cnt - pwm_smp_expect;
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elprintf(EL_PWM, "pwm: read status: ptr %d/%d %d",
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pwm_smp_cnt, pwm_smp_expect, diff);
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if (diff > 3)
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if (Pico32x.pwm_p[1] == 3)
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d |= P32XP_FULL;
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else if (diff < 0)
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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)
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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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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 &= 0x0fff;
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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 < 6) // L ch
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Pico32xMem->pwm[pwm_ptr * 2] = d;
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else if (a == 6) // R ch
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Pico32xMem->pwm[pwm_ptr * 2 + 1] = d;
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else // MONO
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Pico32xMem->pwm[pwm_ptr * 2] = Pico32xMem->pwm[pwm_ptr * 2 + 1] = d;
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if (a >= 6) { // R or MONO
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pwm_smp_cnt++;
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pwm_ptr = (pwm_ptr + 1) & (PWM_BUFF_LEN - 1);
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elprintf(EL_PWM, "pwm: smp_cnt %d, ptr %d, smp %x",
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pwm_smp_cnt, pwm_ptr, d);
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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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@ -181,22 +228,37 @@ void p32x_pwm_update(int *buf32, int length, int stereo)
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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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if (pwm_ptr <= 16) // at least some samples..
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return;
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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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while (length-- > 0) {
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*buf32++ += pwmb[0];
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*buf32++ += pwmb[1];
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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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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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@ -213,6 +275,7 @@ void p32x_pwm_update(int *buf32, int length, int stereo)
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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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