/***************************************************************************

	pc_vga.h

	PC standard VGA adaptor

***************************************************************************/

#ifndef PC_VGA_H
#define PC_VGA_H

#include "osdepend.h"
#include "pc_video.h"

MACHINE_DRIVER_EXTERN( pcvideo_vga );
MACHINE_DRIVER_EXTERN( pcvideo_pc1640 );

struct pc_vga_interface
{
	/* VGA memory mapper */
	int vga_memory_bank;
	void (*map_vga_memory)(offs_t begin, offs_t end, read8_handler rh, write8_handler wh);

	/* VGA dipswitch (???) */
	read8_handler read_dipswitch;

	/* where the ports go */
	int port_addressspace;
	offs_t port_offset;
};

struct pc_svga_interface
{
	size_t vram_size;
	int seq_regcount;
	int gc_regcount;
	int crtc_regcount;
	pc_video_update_proc (*choosevideomode)(const UINT8 *sequencer, const UINT8 *crtc, const UINT8 *gc, int *width, int *height);
};

void pc_vga_init(const struct pc_vga_interface *vga_intf, const struct pc_svga_interface *svga_intf);
void pc_vga_reset(void);
void *pc_vga_memory(void);
size_t pc_vga_memory_size(void);

READ8_HANDLER( ega_port_03c0_r );
READ8_HANDLER( ega_port_03d0_r );

READ8_HANDLER( paradise_ega_03c0_r );

READ8_HANDLER( vga_port_03b0_r );
READ8_HANDLER( vga_port_03c0_r );
READ8_HANDLER( vga_port_03d0_r );

WRITE8_HANDLER( vga_port_03b0_w );
WRITE8_HANDLER( vga_port_03c0_w );
WRITE8_HANDLER( vga_port_03d0_w );

/*
  pega notes (paradise)
  build in amstrad pc1640

  ROM_LOAD("40100", 0xc0000, 0x8000, CRC(d2d1f1ae))

  4 additional dipswitches
  seems to have emulation modes at register level
  (mda/hgc lines bit 8 not identical to ega/vga)

  standard ega/vga dipswitches
  00000000	320x200
  00000001	640x200 hanging
  00000010	640x200 hanging
  00000011	640x200 hanging

  00000100	640x350 hanging
  00000101	640x350 hanging EGA mono
  00000110	320x200
  00000111	640x200

  00001000	640x200
  00001001	640x200
  00001010	720x350 partial visible
  00001011	720x350 partial visible

  00001100	320x200
  00001101	320x200
  00001110	320x200
  00001111	320x200

*/

/*
  oak vga (oti 037 chip)
  (below bios patch needed for running)

  ROM_LOAD("oakvga.bin", 0xc0000, 0x8000, CRC(318c5f43))
*/
#if 0
        int i; 
        UINT8 *memory=memory_region(REGION_CPU1)+0xc0000;
        UINT8 chksum;

		/* oak vga */
        /* plausibility check of retrace signals goes wrong */
        memory[0x00f5]=memory[0x00f6]=memory[0x00f7]=0x90;
        memory[0x00f8]=memory[0x00f9]=memory[0x00fa]=0x90;
        for (chksum=0, i=0;i<0x7fff;i++) {
                chksum+=memory[i];
        }
        memory[i]=0x100-chksum;
#endif

#endif /* PC_VGA_H */

