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Better emulation of the YM-2612 busy flag
author Mike Pavone <pavone@retrodev.com>
date Thu, 13 Feb 2014 00:55:01 -0800
parents 666210adf87b
children 55b550fe8891
comparison
equal deleted inserted replaced
534:c641006da28e 535:aaa77e351c24
19 #else 19 #else
20 #define dfprintf 20 #define dfprintf
21 #define dfopen(var, fname, mode) 21 #define dfopen(var, fname, mode)
22 #endif 22 #endif
23 23
24 #define BUSY_CYCLES 17 24 #define BUSY_CYCLES_ADDRESS 17
25 #define BUSY_CYCLES_DATA_LOW 83
26 #define BUSY_CYCLES_DATA_HIGH 47
25 #define OP_UPDATE_PERIOD 144 27 #define OP_UPDATE_PERIOD 144
26 28
27 enum { 29 enum {
28 REG_LFO = 0x22, 30 REG_LFO = 0x22,
29 REG_TIMERA_HIGH = 0x24, 31 REG_TIMERA_HIGH = 0x24,
503 render_wait_ym(context); 505 render_wait_ym(context);
504 } 506 }
505 } 507 }
506 } 508 }
507 } 509 }
508 if (context->current_cycle >= context->write_cycle + (BUSY_CYCLES * context->clock_inc / 6)) { 510 if (context->current_cycle >= context->write_cycle + (context->busy_cycles * context->clock_inc / 6)) {
509 context->status &= 0x7F; 511 context->status &= 0x7F;
510 context->write_cycle = CYCLE_NEVER; 512 context->write_cycle = CYCLE_NEVER;
511 } 513 }
512 //printf("Done running YM2612 at cycle %d\n", context->current_cycle, to_cycle); 514 //printf("Done running YM2612 at cycle %d\n", context->current_cycle, to_cycle);
513 } 515 }
515 void ym_address_write_part1(ym2612_context * context, uint8_t address) 517 void ym_address_write_part1(ym2612_context * context, uint8_t address)
516 { 518 {
517 //printf("address_write_part1: %X\n", address); 519 //printf("address_write_part1: %X\n", address);
518 context->selected_reg = address; 520 context->selected_reg = address;
519 context->selected_part = 0; 521 context->selected_part = 0;
522 context->write_cycle = context->current_cycle;
523 context->busy_cycles = BUSY_CYCLES_ADDRESS;
520 } 524 }
521 525
522 void ym_address_write_part2(ym2612_context * context, uint8_t address) 526 void ym_address_write_part2(ym2612_context * context, uint8_t address)
523 { 527 {
524 //printf("address_write_part2: %X\n", address); 528 //printf("address_write_part2: %X\n", address);
525 context->selected_reg = address; 529 context->selected_reg = address;
526 context->selected_part = 1; 530 context->selected_part = 1;
531 context->write_cycle = context->current_cycle;
532 context->busy_cycles = BUSY_CYCLES_ADDRESS;
527 } 533 }
528 534
529 uint8_t fnum_to_keycode[] = { 535 uint8_t fnum_to_keycode[] = {
530 //F11 = 0 536 //F11 = 0
531 0,0,0,0,0,0,0,1, 537 0,0,0,0,0,0,0,1,
800 } 806 }
801 } 807 }
802 } 808 }
803 809
804 context->write_cycle = context->current_cycle; 810 context->write_cycle = context->current_cycle;
811 context->busy_cycles = context->selected_reg < 0xA0 ? BUSY_CYCLES_DATA_LOW : BUSY_CYCLES_DATA_HIGH;
805 context->status |= 0x80; 812 context->status |= 0x80;
806 } 813 }
807 814
808 uint8_t ym_read_status(ym2612_context * context) 815 uint8_t ym_read_status(ym2612_context * context)
809 { 816 {