Subversion Repositories planix.SVN

#include "u.h"
#include "../port/lib.h"
#include "mem.h"
#include "dat.h"
#include "fns.h"
#include "io.h"
#include "../port/error.h"

#define Image   IMAGE
#include <draw.h>
#include <memdraw.h>
#include <cursor.h>
#include "screen.h"

static Lock vgaxlock;                   /* access to index registers */

int
vgaxi(long port, uchar index)
{
        uchar data;

        ilock(&vgaxlock);
        switch(port){

        case Seqx:
        case Crtx:
        case Grx:
                outb(port, index);
                data = inb(port+1);
                break;

        case Attrx:
                /*
                 * Allow processor access to the colour
                 * palette registers. Writes to Attrx must
                 * be preceded by a read from Status1 to
                 * initialise the register to point to the
                 * index register and not the data register.
                 * Processor access is allowed by turning
                 * off bit 0x20.
                 */
                inb(Status1);
                if(index < 0x10){
                        outb(Attrx, index);
                        data = inb(Attrx+1);
                        inb(Status1);
                        outb(Attrx, 0x20|index);
                }
                else{
                        outb(Attrx, 0x20|index);
                        data = inb(Attrx+1);
                }
                break;

        default:
                iunlock(&vgaxlock);
                return -1;
        }
        iunlock(&vgaxlock);

        return data & 0xFF;
}

int
vgaxo(long port, uchar index, uchar data)
{
        ilock(&vgaxlock);
        switch(port){

        case Seqx:
        case Crtx:
        case Grx:
                /*
                 * We could use an outport here, but some chips
                 * (e.g. 86C928) have trouble with that for some
                 * registers.
                 */
                outb(port, index);
                outb(port+1, data);
                break;

        case Attrx:
                inb(Status1);
                if(index < 0x10){
                        outb(Attrx, index);
                        outb(Attrx, data);
                        inb(Status1);
                        outb(Attrx, 0x20|index);
                }
                else{
                        outb(Attrx, 0x20|index);
                        outb(Attrx, data);
                }
                break;

        default:
                iunlock(&vgaxlock);
                return -1;
        }
        iunlock(&vgaxlock);

        return 0;
}