/***************************************************************************
JPM IMPACT with Video hardware
****************************************************************************/
#include "emu.h"
#include "cpu/tms34010/tms34010.h"
#include "includes/jpmimpct.h"
/*************************************
*
* Brooktree Bt477 RAMDAC
*
*************************************/
/*
* 0 0 0 Address register (RAM write mode)
* 0 0 1 Color palette RAMs
* 0 1 0 Pixel read mask register
* 0 1 1 Address register (RAM read mode)
* 1 0 0 Address register (overlay write mode)
* 1 1 1 Address register (overlay read mode)
* 1 0 1 Overlay register
* 1 1 0 Command register
*/
WRITE16_HANDLER( jpmimpct_bt477_w )
{
jpmimpct_state *state = space->machine().driver_data<jpmimpct_state>();
UINT8 val = data & 0xff;
switch (offset)
{
case 0x0:
{
state->m_bt477.address = val;
state->m_bt477.addr_cnt = 0;
break;
}
case 0x1:
{
UINT8 *addr_cnt = &state->m_bt477.addr_cnt;
rgb_t *color = &state->m_bt477.color;
color[*addr_cnt] = val;
if (++*addr_cnt == 3)
{
palette_set_color(space->machine(), state->m_bt477.address, MAKE_RGB(color[0], color[1], color[2]));
*addr_cnt = 0;
/* Address register increments */
state->m_bt477.address++;
}
break;
}
case 0x2:
{
state->m_bt477.pixmask = val;
break;
}
case 0x6:
{
state->m_bt477.command = val;
break;
}
default:
{
popmessage("Bt477: Unhandled write access (offset:%x, data:%x)", offset, val);
}
}
}
READ16_HANDLER( jpmimpct_bt477_r )
{
popmessage("Bt477: Unhandled read access (offset:%x)", offset);
return 0;
}
/*************************************
*
* VRAM shift register callbacks
*
*************************************/
void jpmimpct_to_shiftreg(address_space *space, UINT32 address, UINT16 *shiftreg)
{
jpmimpct_state *state = space->machine().driver_data<jpmimpct_state>();
memcpy(shiftreg, &state->m_vram[TOWORD(address)], 512 * sizeof(UINT16));
}
void jpmimpct_from_shiftreg(address_space *space, UINT32 address, UINT16 *shiftreg)
{
jpmimpct_state *state = space->machine().driver_data<jpmimpct_state>();
memcpy(&state->m_vram[TOWORD(address)], shiftreg, 512 * sizeof(UINT16));
}
/*************************************
*
* Main video refresh
*
*************************************/
void jpmimpct_scanline_update(screen_device &screen, bitmap_t *bitmap, int scanline, const tms34010_display_params *params)
{
jpmimpct_state *state = screen.machine().driver_data<jpmimpct_state>();
UINT16 *vram = &state->m_vram[(params->rowaddr << 8) & 0x3ff00];
UINT32 *dest = BITMAP_ADDR32(bitmap, scanline, 0);
int coladdr = params->coladdr;
int x;
for (x = params->heblnk; x < params->hsblnk; x += 2)
{
UINT16 pixels = vram[coladdr++ & 0xff];
dest[x + 0] = screen.machine().pens[pixels & 0xff];
dest[x + 1] = screen.machine().pens[pixels >> 8];
}
}
/*************************************
*
* Video emulation start
*
*************************************/
VIDEO_START( jpmimpct )
{
jpmimpct_state *state = machine.driver_data<jpmimpct_state>();
memset(&state->m_bt477, 0, sizeof(state->m_bt477));
state_save_register_global(machine, state->m_bt477.address);
state_save_register_global(machine, state->m_bt477.addr_cnt);
state_save_register_global(machine, state->m_bt477.pixmask);
state_save_register_global(machine, state->m_bt477.command);
state_save_register_global(machine, state->m_bt477.color);
}