Mercurial > repos > blastem
changeset 1775:a9fc826c6a9d mame_interp
Make refresh delay emulation play nice with Musashi
| author | Michael Pavone <pavone@retrodev.com> |
|---|---|
| date | Wed, 13 Mar 2019 18:57:11 -0700 |
| parents | ddcd59a6122e |
| children | d5118d6f9c75 |
| files | genesis.c |
| diffstat | 1 files changed, 21 insertions(+), 15 deletions(-) [+] |
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--- a/genesis.c Tue Mar 12 22:05:40 2019 -0700 +++ b/genesis.c Wed Mar 13 18:57:11 2019 -0700 @@ -348,7 +348,7 @@ static uint32_t last_frame_num; //My refresh emulation isn't currently good enough and causes more problems than it solves -//#define REFRESH_EMULATION +#define REFRESH_EMULATION #ifdef REFRESH_EMULATION #define REFRESH_INTERVAL 128 #define REFRESH_DELAY 2 @@ -366,12 +366,14 @@ vdp_context * v_context = gen->vdp; z80_context * z_context = gen->z80; #ifdef REFRESH_EMULATION - //lame estimation of refresh cycle delay - refresh_counter += context->current_cycle - last_sync_cycle; - if (!gen->bus_busy) { - context->current_cycle += REFRESH_DELAY * MCLKS_PER_68K * (refresh_counter / (MCLKS_PER_68K * REFRESH_INTERVAL)); + if (context->current_cycle != last_sync_cycle) { + //lame estimation of refresh cycle delay + refresh_counter += context->current_cycle - last_sync_cycle; + if (!gen->bus_busy) { + context->current_cycle += REFRESH_DELAY * MCLKS_PER_68K * (refresh_counter / (MCLKS_PER_68K * REFRESH_INTERVAL)); + } + refresh_counter = refresh_counter % (MCLKS_PER_68K * REFRESH_INTERVAL); } - refresh_counter = refresh_counter % (MCLKS_PER_68K * REFRESH_INTERVAL); #endif uint32_t mclks = context->current_cycle; @@ -492,10 +494,12 @@ //printf("vdp_port write: %X, value: %X, cycle: %d\n", vdp_port, value, context->current_cycle); #ifdef REFRESH_EMULATION //do refresh check here so we can avoid adding a penalty for a refresh that happens during a VDP access - refresh_counter += context->current_cycle - 4*MCLKS_PER_68K - last_sync_cycle; - context->current_cycle += REFRESH_DELAY * MCLKS_PER_68K * (refresh_counter / (MCLKS_PER_68K * REFRESH_INTERVAL)); - refresh_counter = refresh_counter % (MCLKS_PER_68K * REFRESH_INTERVAL); - last_sync_cycle = context->current_cycle; + if (context->current_cycle - 4*MCLKS_PER_68K > last_sync_cycle) { + refresh_counter += context->current_cycle - 4*MCLKS_PER_68K - last_sync_cycle; + context->current_cycle += REFRESH_DELAY * MCLKS_PER_68K * (refresh_counter / (MCLKS_PER_68K * REFRESH_INTERVAL)); + refresh_counter = refresh_counter % (MCLKS_PER_68K * REFRESH_INTERVAL); + last_sync_cycle = context->current_cycle; + } #endif sync_components(context, 0); genesis_context * gen = context->system; @@ -630,11 +634,13 @@ vdp_port &= 0x1F; uint16_t value; #ifdef REFRESH_EMULATION - //do refresh check here so we can avoid adding a penalty for a refresh that happens during a VDP access - refresh_counter += context->current_cycle - 4*MCLKS_PER_68K - last_sync_cycle; - context->current_cycle += REFRESH_DELAY * MCLKS_PER_68K * (refresh_counter / (MCLKS_PER_68K * REFRESH_INTERVAL)); - refresh_counter = refresh_counter % (MCLKS_PER_68K * REFRESH_INTERVAL); - last_sync_cycle = context->current_cycle; + if (context->current_cycle - 4*MCLKS_PER_68K > last_sync_cycle) { + //do refresh check here so we can avoid adding a penalty for a refresh that happens during a VDP access + refresh_counter += context->current_cycle - 4*MCLKS_PER_68K - last_sync_cycle; + context->current_cycle += REFRESH_DELAY * MCLKS_PER_68K * (refresh_counter / (MCLKS_PER_68K * REFRESH_INTERVAL)); + refresh_counter = refresh_counter % (MCLKS_PER_68K * REFRESH_INTERVAL); + last_sync_cycle = context->current_cycle; + } #endif sync_components(context, 0); genesis_context *gen = context->system;