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comparison blastem.c @ 997:560da2e455c2

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YOUR EMULATOR SUX is dead. Needs logic analyzer testing to check exact delay though.
author Michael Pavone <pavone@retrodev.com>
date Sat, 30 Apr 2016 10:47:29 -0700
parents 784bc1e45e80
children 8d032a368dd5
comparison
equal deleted inserted replaced
996:784bc1e45e80 997:560da2e455c2
364 364
365 while (vdp_data_port_write(v_context, value) < 0) { 365 while (vdp_data_port_write(v_context, value) < 0) {
366 while(v_context->flags & FLAG_DMA_RUN) { 366 while(v_context->flags & FLAG_DMA_RUN) {
367 vdp_run_dma_done(v_context, gen->frame_end); 367 vdp_run_dma_done(v_context, gen->frame_end);
368 if (v_context->cycles >= gen->frame_end) { 368 if (v_context->cycles >= gen->frame_end) {
369 context->current_cycle = v_context->cycles; 369 uint32_t cycle_diff = v_context->cycles - context->current_cycle;
370 uint32_t m68k_cycle_diff = (cycle_diff / MCLKS_PER_68K) * MCLKS_PER_68K;
371 if (m68k_cycle_diff < cycle_diff) {
372 m68k_cycle_diff += MCLKS_PER_68K;
373 }
374 context->current_cycle += m68k_cycle_diff;
370 gen->bus_busy = 1; 375 gen->bus_busy = 1;
371 sync_components(context, 0); 376 sync_components(context, 0);
372 gen->bus_busy = 0; 377 gen->bus_busy = 0;
373 } 378 }
374 } 379 }
379 if (blocked) { 384 if (blocked) {
380 while (blocked) { 385 while (blocked) {
381 while(v_context->flags & FLAG_DMA_RUN) { 386 while(v_context->flags & FLAG_DMA_RUN) {
382 vdp_run_dma_done(v_context, gen->frame_end); 387 vdp_run_dma_done(v_context, gen->frame_end);
383 if (v_context->cycles >= gen->frame_end) { 388 if (v_context->cycles >= gen->frame_end) {
384 context->current_cycle = v_context->cycles; 389 uint32_t cycle_diff = v_context->cycles - context->current_cycle;
390 uint32_t m68k_cycle_diff = (cycle_diff / MCLKS_PER_68K) * MCLKS_PER_68K;
391 if (m68k_cycle_diff < cycle_diff) {
392 m68k_cycle_diff += MCLKS_PER_68K;
393 }
394 context->current_cycle += m68k_cycle_diff;
385 gen->bus_busy = 1; 395 gen->bus_busy = 1;
386 sync_components(context, 0); 396 sync_components(context, 0);
387 gen->bus_busy = 0; 397 gen->bus_busy = 0;
388 } 398 }
399 if (!(v_context->flags & FLAG_DMA_RUN)) {
400 //two more slots of delay are needed to kill sufficient sprite capacity in Overdrive
401 //TODO: Measure exact value with logic analyzer
402 vdp_run_context(v_context, v_context->cycles + 1);
403 vdp_run_context(v_context, v_context->cycles + 1);
404 }
389 } 405 }
406
390 if (blocked < 0) { 407 if (blocked < 0) {
391 blocked = vdp_control_port_write(v_context, value); 408 blocked = vdp_control_port_write(v_context, value);
392 } else { 409 } else {
393 blocked = 0; 410 blocked = 0;
394 } 411 }
401 } else { 418 } else {
402 fatal_error("Illegal write to HV Counter port %X\n", vdp_port); 419 fatal_error("Illegal write to HV Counter port %X\n", vdp_port);
403 } 420 }
404 if (v_context->cycles != before_cycle) { 421 if (v_context->cycles != before_cycle) {
405 //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); 422 //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);
406 context->current_cycle = v_context->cycles; 423 uint32_t cycle_diff = v_context->cycles - context->current_cycle;
424 uint32_t m68k_cycle_diff = (cycle_diff / MCLKS_PER_68K) * MCLKS_PER_68K;
425 if (m68k_cycle_diff < cycle_diff) {
426 m68k_cycle_diff += MCLKS_PER_68K;
427 }
428 context->current_cycle += m68k_cycle_diff;
407 #ifdef REFRESH_EMULATION 429 #ifdef REFRESH_EMULATION
408 last_sync_cycle = context->current_cycle; 430 last_sync_cycle = context->current_cycle;
409 #endif 431 #endif
410 //Lock the Z80 out of the bus until the VDP access is complete 432 //Lock the Z80 out of the bus until the VDP access is complete
411 gen->bus_busy = 1; 433 gen->bus_busy = 1;