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Approximation of refresh wait states
author Michael Pavone <pavone@retrodev.com>
date Mon, 16 Nov 2015 21:57:17 -0800
parents e3f5ec336432
children 90d54ccf9557
comparison
equal deleted inserted replaced
888:bc127fa1f800 889:2d1122123fe9
228 ym_run(gen->ym, target); 228 ym_run(gen->ym, target);
229 229
230 //printf("Target: %d, YM bufferpos: %d, PSG bufferpos: %d\n", target, gen->ym->buffer_pos, gen->psg->buffer_pos * 2); 230 //printf("Target: %d, YM bufferpos: %d, PSG bufferpos: %d\n", target, gen->ym->buffer_pos, gen->psg->buffer_pos * 2);
231 } 231 }
232 232
233 #define REFRESH_INTERVAL 130
234 #define REFRESH_DELAY 2
233 uint32_t last_frame_num; 235 uint32_t last_frame_num;
236 uint32_t last_sync_cycle;
237 uint32_t refresh_counter;
234 m68k_context * sync_components(m68k_context * context, uint32_t address) 238 m68k_context * sync_components(m68k_context * context, uint32_t address)
235 { 239 {
236 genesis_context * gen = context->system; 240 genesis_context * gen = context->system;
237 vdp_context * v_context = gen->vdp; 241 vdp_context * v_context = gen->vdp;
238 z80_context * z_context = gen->z80; 242 z80_context * z_context = gen->z80;
243 //lame estimation of refresh cycle delay
244 refresh_counter += context->current_cycle - last_sync_cycle;
245 context->current_cycle += REFRESH_DELAY * MCLKS_PER_68K * (refresh_counter / (MCLKS_PER_68K * REFRESH_INTERVAL));
246 refresh_counter = refresh_counter % (MCLKS_PER_68K * REFRESH_INTERVAL);
247
239 uint32_t mclks = context->current_cycle; 248 uint32_t mclks = context->current_cycle;
240 sync_z80(z_context, mclks); 249 sync_z80(z_context, mclks);
241 sync_sound(gen, mclks); 250 sync_sound(gen, mclks);
242 vdp_run_context(v_context, mclks); 251 vdp_run_context(v_context, mclks);
243 if (v_context->frame != last_frame_num) { 252 if (v_context->frame != last_frame_num) {
293 puts("Saved state to savestate.gst"); 302 puts("Saved state to savestate.gst");
294 } else if(save_state) { 303 } else if(save_state) {
295 context->sync_cycle = context->current_cycle + 1; 304 context->sync_cycle = context->current_cycle + 1;
296 } 305 }
297 } 306 }
307 last_sync_cycle = context->current_cycle;
298 return context; 308 return context;
299 } 309 }
300 310
301 m68k_context * vdp_port_write(uint32_t vdp_port, m68k_context * context, uint16_t value) 311 m68k_context * vdp_port_write(uint32_t vdp_port, m68k_context * context, uint16_t value)
302 { 312 {
352 } else { 362 } else {
353 fatal_error("Illegal write to HV Counter port %X\n", vdp_port); 363 fatal_error("Illegal write to HV Counter port %X\n", vdp_port);
354 } 364 }
355 if (v_context->cycles != before_cycle) { 365 if (v_context->cycles != before_cycle) {
356 //printf("68K paused for %d (%d) cycles at cycle %d (%d) for write\n", v_context->cycles - context->current_cycle, v_context->cycles - before_cycle, context->current_cycle, before_cycle); 366 //printf("68K paused for %d (%d) cycles at cycle %d (%d) for write\n", v_context->cycles - context->current_cycle, v_context->cycles - before_cycle, context->current_cycle, before_cycle);
357 context->current_cycle = v_context->cycles; 367 last_sync_cycle = context->current_cycle = v_context->cycles;
358 //Lock the Z80 out of the bus until the VDP access is complete 368 //Lock the Z80 out of the bus until the VDP access is complete
359 gen->bus_busy = 1; 369 gen->bus_busy = 1;
360 sync_z80(gen->z80, v_context->cycles); 370 sync_z80(gen->z80, v_context->cycles);
361 gen->bus_busy = 0; 371 gen->bus_busy = 0;
362 } 372 }
425 } else { 435 } else {
426 value = vdp_test_port_read(v_context); 436 value = vdp_test_port_read(v_context);
427 } 437 }
428 if (v_context->cycles != before_cycle) { 438 if (v_context->cycles != before_cycle) {
429 //printf("68K paused for %d (%d) cycles at cycle %d (%d) for read\n", v_context->cycles - context->current_cycle, v_context->cycles - before_cycle, context->current_cycle, before_cycle); 439 //printf("68K paused for %d (%d) cycles at cycle %d (%d) for read\n", v_context->cycles - context->current_cycle, v_context->cycles - before_cycle, context->current_cycle, before_cycle);
430 context->current_cycle = v_context->cycles; 440 last_sync_cycle = context->current_cycle = v_context->cycles;
431 //Lock the Z80 out of the bus until the VDP access is complete 441 //Lock the Z80 out of the bus until the VDP access is complete
432 genesis_context *gen = context->system; 442 genesis_context *gen = context->system;
433 gen->bus_busy = 1; 443 gen->bus_busy = 1;
434 sync_z80(gen->z80, v_context->cycles); 444 sync_z80(gen->z80, v_context->cycles);
435 gen->bus_busy = 0; 445 gen->bus_busy = 0;