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comparison z80_to_x86.c @ 854:adeb6465ad53

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Improve timing of Z80 busack. Fixes a crash in Barkley: Shut Up and Jam. Also vastly improves the audio output of Stuck Somewhere in Time
author Michael Pavone <pavone@retrodev.com>
date Wed, 04 Nov 2015 19:14:39 -0800
parents 74e161fe7d39
children 252dfd29831d
comparison
equal deleted inserted replaced
853:2d474efb4629 854:adeb6465ad53
12 #include <stdlib.h> 12 #include <stdlib.h>
13 #include <stddef.h> 13 #include <stddef.h>
14 #include <string.h> 14 #include <string.h>
15 15
16 #define MODE_UNUSED (MODE_IMMED-1) 16 #define MODE_UNUSED (MODE_IMMED-1)
17 #define MAX_MCYCLE_LENGTH 6
17 18
18 //#define DO_DEBUG_PRINT 19 //#define DO_DEBUG_PRINT
19 20
20 #ifdef DO_DEBUG_PRINT 21 #ifdef DO_DEBUG_PRINT
21 #define dprintf printf 22 #define dprintf printf
2621 2622
2622 void z80_assert_busreq(z80_context * context, uint32_t cycle) 2623 void z80_assert_busreq(z80_context * context, uint32_t cycle)
2623 { 2624 {
2624 z80_run(context, cycle); 2625 z80_run(context, cycle);
2625 context->busreq = 1; 2626 context->busreq = 1;
2627 //this is an imperfect aproximation since most M-cycles take less tstates than the max
2628 //and a short 3-tstate m-cycle can take an unbounded number due to wait states
2629 if (context->current_cycle - cycle > MAX_MCYCLE_LENGTH * context->options->gen.clock_divider) {
2630 context->busack = 1;
2631 }
2626 } 2632 }
2627 2633
2628 void z80_clear_busreq(z80_context * context, uint32_t cycle) 2634 void z80_clear_busreq(z80_context * context, uint32_t cycle)
2629 { 2635 {
2630 z80_run(context, cycle); 2636 z80_run(context, cycle);