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AmigActive 10
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AACD 10.iso
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MAME
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machine
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atari_vg.c
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C/C++ Source or Header
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2000-04-23
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1KB
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65 lines
/***************************************************************************
machine.c
Functions to emulate general aspects of the machine (RAM, ROM, interrupts,
I/O ports)
***************************************************************************/
#include "driver.h"
#define EAROM_SIZE 0x40
static int earom_offset;
static int earom_data;
static char earom[EAROM_SIZE];
READ_HANDLER( atari_vg_earom_r )
{
logerror("read earom: %02x(%02x):%02x\n", earom_offset, offset, earom_data);
return (earom_data);
}
WRITE_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
*/
WRITE_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);
}
}
void atari_vg_earom_handler(void *file,int read_or_write)
{
if (read_or_write)
osd_fwrite(file,earom,EAROM_SIZE);
else
{
if (file)
osd_fread(file,earom,EAROM_SIZE);
else
memset(earom,0,EAROM_SIZE);
}
}