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/***************************************************************************
Atari vector hardware
***************************************************************************/
#include "driver.h"
#include "atari_vg.h"
#define EAROM_SIZE 0x40
static int earom_offset;
static int earom_data;
static char earom[EAROM_SIZE];
READ8_HANDLER( atari_vg_earom_r )
{
logerror("read earom: %02x(%02x):%02x\n", earom_offset, offset, earom_data);
return (earom_data);
}
WRITE8_HANDLER( atari_vg_earom_w )
{
logerror("write earom: %02x:%02x\n", offset, data);
earom_offset = offset;
earom_data = data;
}
/* 0,8 and 14 get written to this location, too.
* Don't know what they do exactly
*/
WRITE8_HANDLER( atari_vg_earom_ctrl_w )
{
logerror("earom ctrl: %02x:%02x\n",offset, data);
/*
0x01 = clock
0x02 = set data latch? - writes only (not always)
0x04 = write mode? - writes only
0x08 = set addr latch?
*/
if (data & 0x01)
earom_data = earom[earom_offset];
if ((data & 0x0c) == 0x0c)
{
earom[earom_offset]=earom_data;
logerror(" written %02x:%02x\n", earom_offset, earom_data);
}
}
NVRAM_HANDLER( atari_vg )
{
if (read_or_write)
mame_fwrite(file,earom,EAROM_SIZE);
else if (file)
mame_fread(file,earom,EAROM_SIZE);
else
memset(earom,0,EAROM_SIZE);
}
void atari_vg_register_states(void)
{
state_save_register_global(earom_offset);
state_save_register_global(earom_data);
}
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