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Improved video DMA operations (4 usecs is another thing)

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This commit is contained in:
Angelo Salese 2010-08-25 00:50:44 +00:00
parent 4f344bf3eb
commit 2bb61f771c
1 changed files with 15 additions and 12 deletions
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27
src/mame/machine/archimds.c
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@ -111,27 +111,26 @@ static TIMER_CALLBACK( vidc_vblank )
timer_adjust_oneshot(vbl_timer, machine->primary_screen->time_until_pos(vidc_regs[0xb4]), 0);
}
/* at about every ~4/4 USEC do a DMA transfer byte */
/* video DMA */
/* TODO: what type of DMA this is, burst or cycle steal? Docs doesn't explain it (4 usec is the DRAM refresh). */
static TIMER_CALLBACK( vidc_video_tick )
{
address_space *space = cputag_get_address_space(machine, "maincpu", ADDRESS_SPACE_PROGRAM);
static UINT8 *vram = memory_region(machine,"vram");
UINT32 size;
vram[vidc_vidcur] = (space->read_byte(vidc_vidstart+vidc_vidcur+vidc_vidinit));
size = vidc_vidend-vidc_vidstart;
vidc_vidcur++;
for(vidc_vidcur = 0;vidc_vidcur < size;vidc_vidcur++)
vram[vidc_vidcur] = (space->read_byte(vidc_vidstart+vidc_vidcur+vidc_vidinit));
if(video_dma_on)
{
if (vidc_vidcur >= vidc_vidend-vidc_vidstart)
vidc_vidcur = 0;
timer_adjust_oneshot(vid_timer, ATTOTIME_IN_USEC(1), 0);
}
timer_adjust_oneshot(vid_timer, space->machine->primary_screen->time_until_pos(vidc_regs[0xb4]), 0);
else
timer_adjust_oneshot(vid_timer, attotime_never, 0);
}
/* audio DMA */
static TIMER_CALLBACK( vidc_audio_tick )
{
address_space *space = cputag_get_address_space(machine, "maincpu", ADDRESS_SPACE_PROGRAM);
@ -384,7 +383,7 @@ static READ32_HANDLER( ioc_ctrl_r )
case CONTROL:
{
UINT8 i2c_data;
static UINT8 flyback;
static UINT8 flyback; //internal name for vblank here
int vert_pos;
vert_pos = space->machine->primary_screen->vpos();
@ -799,6 +798,7 @@ WRITE32_HANDLER(archimedes_vidc_w)
(vidc_regs[VIDC_VBER] >= vidc_regs[VIDC_VBSR]))
{
rectangle visarea;
attoseconds_t refresh;
visarea.min_x = 0;
visarea.min_y = 0;
@ -810,7 +810,10 @@ WRITE32_HANDLER(archimedes_vidc_w)
visarea.max_x, visarea.max_y,
vidc_regs[VIDC_HDER]-vidc_regs[VIDC_HDSR],vidc_regs[VIDC_VDER]-vidc_regs[VIDC_VDSR]+1);
space->machine->primary_screen->configure(vidc_regs[VIDC_HCR], vidc_regs[VIDC_VCR], visarea, space->machine->primary_screen->frame_period().attoseconds);
/* FIXME: pixel clock */
refresh = HZ_TO_ATTOSECONDS(16000000) * vidc_regs[VIDC_HCR] * vidc_regs[VIDC_VCR];
space->machine->primary_screen->configure(vidc_regs[VIDC_HCR], vidc_regs[VIDC_VCR], visarea, refresh);
}
}
@ -881,7 +884,7 @@ WRITE32_HANDLER(archimedes_memc_w)
if ((data>>10)&1)
{
vidc_vidcur = 0;
timer_adjust_oneshot(vid_timer, ATTOTIME_IN_USEC(1), 0);
timer_adjust_oneshot(vid_timer, space->machine->primary_screen->time_until_pos(vidc_regs[0xb4]), 0);
}
if ((data>>11)&1)