mem-pcxtat.c

//
// EGA / MDA Video read/write routines
//

#include "emu-mem-io.h"

#include "mem-io-pcxtat.h"
#include "rom-bios.h"

#include <stdio.h>


int vid_minx = 32767, vid_miny = 32767;
int vid_maxx = -1, vid_maxy = -1;
#define MIN(a,b)      ((a) < (b) ? (a) : (b))
#define MAX(a,b)      ((a) > (b) ? (a) : (b))

// return video RAM base address based on video mode
int vid_base (void)
	{
		return mem_stat [BDA_VIDEO_MODE] == 7? 0xB0000: 0xB8000;
	}

void update_dirty_region (int x, int y)
	{
	vid_minx = MIN(x, vid_minx);
	vid_miny = MIN(y, vid_miny);
	vid_maxx = MAX(vid_maxx, x);
	vid_maxy = MAX(vid_maxy, y);
	}

void reset_dirty_region ()
	{
	vid_minx = vid_miny = 32767;
	vid_maxx = vid_maxy = -1;
	}

// Memory and video access

byte_t mem_read_byte (addr_t a)
	{
	byte_t b = mem_read_byte_0 (a);

	/*
	if (a < 0x40)
		{
		printf ("\ninfo: reading byte %hhXh from %lXh\n", b, a);
		}
	*/

	return b;
	}


word_t mem_read_word (addr_t a)
	{
	word_t w = mem_read_word_0 (a);

	/*
	if (a < 0x40)
		{
		printf ("\ninfo: reading word %hXh from %lXh\n", w, a);
		}
	*/

	return w;
	}


void mem_write_byte (addr_t a, byte_t b, byte_t init)
	{
	// FIXME change VID_PAGE_SIZE to VID_SIZE when pages implemented
	if (a >= vid_base() && a < (vid_base() + VID_PAGE_SIZE))
		{
		byte_t * p = (byte_t *) mem_get_addr (a);
		*p = b;

		// calculate bounding rectangle
		a = (a - vid_base()) / 2;
		update_dirty_region(a % VID_COLS, a / VID_COLS);
		}

	/*
	else if (a < 0x40)
		{
		printf ("\ninfo: writing byte %hhXh into %lXh\n", b, a);
		mem_write_byte_0 (a, b, init);
		}
	*/

	else
		{
		// Main memory

		mem_write_byte_0 (a, b, init);
		}
	}

void mem_write_word (addr_t a, word_t w, byte_t init)
	{
	// FIXME change VID_PAGE_SIZE to VID_SIZE when pages implemented
	if (a >= vid_base() && a < (vid_base() + VID_PAGE_SIZE))
		{
		word_t * p = (word_t *) mem_get_addr (a);
		*p = w;

		// calculate bounding rectangle
		a = (a - vid_base()) / 2;
		update_dirty_region(a % VID_COLS, a / VID_COLS);
		}

	/*
	else if (a < 0x40)
		{
		printf ("\ninfo: writing word %hXh into %lXh\n", w, a);
		mem_write_word_0 (a, w, init);
		}
	*/

	else
		{
		// Main memory

		mem_write_word_0 (a, w, init);
		}
	}