diff options
Diffstat (limited to 'genesis.c')
| -rw-r--r-- | genesis.c | 28 |
1 files changed, 17 insertions, 11 deletions
@@ -148,6 +148,10 @@ uint32_t last_sync_cycle; uint32_t refresh_counter; #endif +#include <limits.h> +#define ADJUST_BUFFER (8*MCLKS_LINE*313) +#define MAX_NO_ADJUST (UINT_MAX-ADJUST_BUFFER) + m68k_context * sync_components(m68k_context * context, uint32_t address) { genesis_context * gen = context->system; @@ -176,17 +180,19 @@ m68k_context * sync_components(m68k_context * context, uint32_t address) exit(0); } } - - vdp_adjust_cycles(v_context, mclks); - io_adjust_cycles(gen->io.ports, context->current_cycle, mclks); - io_adjust_cycles(gen->io.ports+1, context->current_cycle, mclks); - io_adjust_cycles(gen->io.ports+2, context->current_cycle, mclks); - context->current_cycle -= mclks; - z80_adjust_cycles(z_context, mclks); - gen->ym->current_cycle -= mclks; - gen->psg->cycles -= mclks; - if (gen->ym->write_cycle != CYCLE_NEVER) { - gen->ym->write_cycle = gen->ym->write_cycle >= mclks ? gen->ym->write_cycle - mclks : 0; + if (context->current_cycle > MAX_NO_ADJUST) { + uint32_t deduction = mclks - ADJUST_BUFFER; + vdp_adjust_cycles(v_context, deduction); + io_adjust_cycles(gen->io.ports, context->current_cycle, deduction); + io_adjust_cycles(gen->io.ports+1, context->current_cycle, deduction); + io_adjust_cycles(gen->io.ports+2, context->current_cycle, deduction); + context->current_cycle -= deduction; + z80_adjust_cycles(z_context, deduction); + gen->ym->current_cycle -= deduction; + gen->psg->cycles -= deduction; + if (gen->ym->write_cycle != CYCLE_NEVER) { + gen->ym->write_cycle = gen->ym->write_cycle >= deduction ? gen->ym->write_cycle - deduction : 0; + } } } gen->frame_end = vdp_cycles_to_frame_end(v_context); |