cff531af |
1 | /* |
2 | * PicoDrive |
3 | * (C) notaz, 2009,2010 |
4 | * |
5 | * This work is licensed under the terms of MAME license. |
6 | * See COPYING file in the top-level directory. |
7 | */ |
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8 | #include "../pico_int.h" |
9 | |
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10 | static int pwm_cycle_counter; |
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11 | static int pwm_cycles; |
12 | static int pwm_mult; |
13 | static int pwm_ptr; |
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14 | |
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15 | static int pwm_smp_cnt; |
16 | static int pwm_smp_expect; |
17 | |
18 | static int timer_cycles[2]; |
19 | static int timer_tick_cycles[2]; |
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20 | |
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21 | // timers. This includes PWM timer in 32x and internal SH2 timers |
22 | void p32x_timers_recalc(void) |
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23 | { |
24 | int cycles = Pico32x.regs[0x32 / 2]; |
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25 | int tmp, i; |
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26 | |
27 | cycles = (cycles - 1) & 0x0fff; |
28 | if (cycles < 500) { |
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29 | elprintf(EL_32X|EL_PWM|EL_ANOMALY, "pwm: low cycle value: %d", cycles + 1); |
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30 | cycles = 500; |
31 | } |
32 | pwm_cycles = cycles; |
33 | pwm_mult = 0x10000 / cycles; |
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34 | |
35 | // SH2 timer step |
36 | for (i = 0; i < 2; i++) { |
37 | tmp = PREG8(Pico32xMem->sh2_peri_regs[i], 0x80) & 7; |
38 | // Sclk cycles per timer tick |
39 | if (tmp) |
40 | cycles = 0x20 << tmp; |
41 | else |
42 | cycles = 2; |
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43 | timer_tick_cycles[i] = cycles; |
44 | elprintf(EL_32X, "WDT cycles[%d] = %d", i, cycles); |
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45 | } |
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46 | } |
47 | |
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48 | // PWM irq for every tm samples |
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49 | void p32x_timers_do(unsigned int cycles) |
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50 | { |
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51 | int cnt, i; |
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52 | |
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53 | cycles *= 3; |
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54 | |
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55 | pwm_cycle_counter += cycles; |
56 | while (pwm_cycle_counter > pwm_cycles) { |
57 | pwm_cycle_counter -= pwm_cycles; |
58 | pwm_smp_expect++; |
59 | } |
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60 | |
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61 | // WDT timers |
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62 | for (i = 0; i < 2; i++) { |
63 | void *pregs = Pico32xMem->sh2_peri_regs[i]; |
64 | if (PREG8(pregs, 0x80) & 0x20) { // TME |
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65 | timer_cycles[i] += cycles; |
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66 | cnt = PREG8(pregs, 0x81); |
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67 | while (timer_cycles[i] >= timer_tick_cycles[i]) { |
68 | timer_cycles[i] -= timer_tick_cycles[i]; |
69 | cnt++; |
70 | } |
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71 | if (cnt >= 0x100) { |
72 | int level = PREG8(pregs, 0xe3) >> 4; |
73 | int vector = PREG8(pregs, 0xe4) & 0x7f; |
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74 | elprintf(EL_32X, "%csh2 WDT irq (%d, %d)", |
75 | i ? 's' : 'm', level, vector); |
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76 | sh2_internal_irq(&sh2s[i], level, vector); |
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77 | cnt &= 0xff; |
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78 | } |
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79 | PREG8(pregs, 0x81) = cnt; |
80 | } |
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81 | } |
82 | } |
83 | |
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84 | void p32x_pwm_schedule(unsigned int now) |
85 | { |
86 | int tm; |
87 | |
88 | if (Pico32x.emu_flags & P32XF_PWM_PEND) |
89 | return; // already scheduled |
90 | if (Pico32x.sh2irqs & P32XI_PWM) |
91 | return; // previous not acked |
92 | if (!((Pico32x.sh2irq_mask[0] | Pico32x.sh2irq_mask[1]) & 1)) |
93 | return; // masked by everyone |
94 | |
95 | tm = (Pico32x.regs[0x30 / 2] & 0x0f00) >> 8; |
96 | tm = ((tm - 1) & 0x0f) + 1; |
97 | p32x_event_schedule(P32X_EVENT_PWM, now, pwm_cycles * tm / 3); |
98 | Pico32x.emu_flags |= P32XF_PWM_PEND; |
99 | } |
100 | |
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101 | unsigned int p32x_pwm_read16(unsigned int a) |
102 | { |
103 | unsigned int d = 0; |
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104 | int diff; |
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105 | |
106 | a &= 0x0e; |
107 | switch (a) { |
108 | case 0: // control |
109 | case 2: // cycle |
110 | return Pico32x.regs[(0x30 + a) / 2]; |
111 | |
112 | case 4: // L ch |
113 | case 6: // R ch |
114 | case 8: // MONO |
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115 | diff = pwm_smp_cnt - pwm_smp_expect; |
116 | elprintf(EL_PWM, "pwm: read status: ptr %d/%d %d", |
117 | pwm_smp_cnt, pwm_smp_expect, diff); |
118 | if (diff > 3) |
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119 | d |= P32XP_FULL; |
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120 | else if (diff < 0) |
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121 | d |= P32XP_EMPTY; |
122 | break; |
123 | } |
124 | |
125 | return d; |
126 | } |
127 | |
128 | void p32x_pwm_write16(unsigned int a, unsigned int d) |
129 | { |
130 | a &= 0x0e; |
131 | if (a == 0) // control |
132 | Pico32x.regs[0x30 / 2] = d; |
133 | else if (a == 2) { // cycle |
134 | Pico32x.regs[0x32 / 2] = d & 0x0fff; |
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135 | p32x_timers_recalc(); |
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136 | Pico32x.pwm_irq_sample_cnt = 0; // resets? |
137 | } |
138 | else if (a <= 8) { |
139 | d &= 0x0fff; |
140 | if (d > pwm_cycles) |
141 | d = pwm_cycles; |
142 | d = (d - pwm_cycles / 2) * pwm_mult; |
143 | |
144 | if (a < 6) // L ch |
145 | Pico32xMem->pwm[pwm_ptr * 2] = d; |
146 | else if (a == 6) // R ch |
147 | Pico32xMem->pwm[pwm_ptr * 2 + 1] = d; |
148 | else // MONO |
149 | Pico32xMem->pwm[pwm_ptr * 2] = Pico32xMem->pwm[pwm_ptr * 2 + 1] = d; |
150 | |
151 | if (a >= 6) { // R or MONO |
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152 | pwm_smp_cnt++; |
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153 | pwm_ptr = (pwm_ptr + 1) & (PWM_BUFF_LEN - 1); |
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154 | elprintf(EL_PWM, "pwm: smp_cnt %d, ptr %d, smp %x", |
155 | pwm_smp_cnt, pwm_ptr, d); |
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156 | } |
157 | } |
158 | } |
159 | |
160 | void p32x_pwm_update(int *buf32, int length, int stereo) |
161 | { |
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162 | short *pwmb; |
163 | int step; |
164 | int p = 0; |
165 | |
166 | if (pwm_ptr <= 16) // at least some samples.. |
167 | return; |
168 | |
169 | step = (pwm_ptr << 16) / length; // FIXME: division.. |
170 | pwmb = Pico32xMem->pwm; |
171 | |
172 | if (stereo) |
173 | { |
174 | while (length-- > 0) { |
175 | *buf32++ += pwmb[0]; |
176 | *buf32++ += pwmb[1]; |
177 | |
178 | p += step; |
179 | pwmb += (p >> 16) * 2; |
180 | p &= 0xffff; |
181 | } |
182 | } |
183 | else |
184 | { |
185 | while (length-- > 0) { |
186 | *buf32++ += pwmb[0]; |
187 | |
188 | p += step; |
189 | pwmb += (p >> 16) * 2; |
190 | p &= 0xffff; |
191 | } |
192 | } |
193 | |
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194 | elprintf(EL_PWM, "pwm_update: pwm_ptr %d, len %d, step %04x, done %d", |
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195 | pwm_ptr, length, step, (pwmb - Pico32xMem->pwm) / 2); |
196 | |
197 | pwm_ptr = 0; |
198 | } |
199 | |
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200 | // vim:shiftwidth=2:ts=2:expandtab |