mirror of
https://github.com/RaySollium99/picodrive.git
synced 2025-09-05 07:17:45 -04:00
301 lines
6.9 KiB
C
301 lines
6.9 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 pwm_irq_reload;
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void p32x_pwm_ctl_changed(void)
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{
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int control = Pico32x.regs[0x30 / 2];
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int cycles = Pico32x.regs[0x32 / 2];
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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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pwm_irq_reload = (control & 0x0f00) >> 8;
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pwm_irq_reload = ((pwm_irq_reload - 1) & 0x0f) + 1;
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if (Pico32x.pwm_irq_cnt == 0)
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Pico32x.pwm_irq_cnt = pwm_irq_reload;
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}
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static void do_pwm_irq(SH2 *sh2, unsigned int m68k_cycles)
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{
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Pico32x.sh2irqs |= P32XI_PWM;
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p32x_update_irls(sh2, m68k_cycles);
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if (Pico32x.regs[0x30 / 2] & P32XP_RTP) {
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p32x_event_schedule(m68k_cycles, P32X_EVENT_PWM, pwm_cycles / 3 + 1);
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// note: might recurse
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p32x_dreq1_trigger();
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}
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}
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#define consume_fifo(sh2, m68k_cycles) { \
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int cycles_diff = ((m68k_cycles) * 3) - Pico32x.pwm_cycle_p; \
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if (cycles_diff >= pwm_cycles) \
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consume_fifo_do(sh2, m68k_cycles, cycles_diff); \
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}
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static void consume_fifo_do(SH2 *sh2, unsigned int m68k_cycles,
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int sh2_cycles_diff)
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{
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int do_irq = 0;
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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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m68k_cycles, sh2_cycles_diff, sh2_cycles_diff / pwm_cycles,
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Pico32x.pwm_p[0], Pico32x.pwm_p[1], pwm_ptr);
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if (sh2_cycles_diff >= pwm_cycles * 17) {
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// silence/skip
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Pico32x.pwm_cycle_p = m68k_cycles * 3;
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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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while (sh2_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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sh2_cycles_diff -= pwm_cycles;
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if (--Pico32x.pwm_irq_cnt == 0) {
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Pico32x.pwm_irq_cnt = pwm_irq_reload;
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// irq also does dreq1, so call it after cycle update
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do_irq = 1;
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break;
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}
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}
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Pico32x.pwm_cycle_p = m68k_cycles * 3 - sh2_cycles_diff;
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if (do_irq)
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do_pwm_irq(sh2, m68k_cycles);
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}
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static int p32x_pwm_schedule_(SH2 *sh2, unsigned int m68k_now)
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{
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unsigned int sh2_now = m68k_now * 3;
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int cycles_diff_sh2;
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if (pwm_cycles == 0)
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return 0;
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cycles_diff_sh2 = sh2_now - Pico32x.pwm_cycle_p;
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if (cycles_diff_sh2 >= pwm_cycles)
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consume_fifo_do(sh2, m68k_now, cycles_diff_sh2);
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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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cycles_diff_sh2 = sh2_now - Pico32x.pwm_cycle_p;
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return (Pico32x.pwm_irq_cnt * pwm_cycles
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- cycles_diff_sh2) / 3 + 1;
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}
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void p32x_pwm_schedule(unsigned int m68k_now)
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{
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int after = p32x_pwm_schedule_(NULL, m68k_now);
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if (after != 0)
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p32x_event_schedule(m68k_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_(sh2, sh2_cycles_done_m68k(sh2));
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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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void p32x_pwm_irq_event(unsigned int m68k_now)
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{
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p32x_pwm_schedule(m68k_now);
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}
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unsigned int p32x_pwm_read16(unsigned int a, SH2 *sh2,
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unsigned int m68k_cycles)
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{
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unsigned int d = 0;
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consume_fifo(sh2, m68k_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: %u: r16 %02x %04x (p %d %d)",
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m68k_cycles, a, d, Pico32x.pwm_p[0], Pico32x.pwm_p[1]);
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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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SH2 *sh2, unsigned int m68k_cycles)
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{
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elprintf(EL_PWM, "pwm: %u: w16 %02x %04x (p %d %d)",
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m68k_cycles, a & 0x0e, d, Pico32x.pwm_p[0], Pico32x.pwm_p[1]);
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consume_fifo(sh2, m68k_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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p32x_pwm_ctl_changed();
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Pico32x.pwm_irq_cnt = pwm_irq_reload; // ?
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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_pwm_ctl_changed();
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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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void p32x_pwm_state_loaded(void)
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{
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int cycles_diff_sh2;
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p32x_pwm_ctl_changed();
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// for old savestates
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cycles_diff_sh2 = SekCycleCntT * 3 - Pico32x.pwm_cycle_p;
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if (cycles_diff_sh2 >= pwm_cycles || cycles_diff_sh2 < 0) {
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Pico32x.pwm_irq_cnt = pwm_irq_reload;
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Pico32x.pwm_cycle_p = SekCycleCntT * 3;
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p32x_pwm_schedule(SekCycleCntT);
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}
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}
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// vim:shiftwidth=2:ts=2:expandtab
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