ref: 21336d544ae90e20070fd7c8be67f3f2c9ccbe38
dir: /os/pc/vgabt485.c/
#include "u.h"
#include "../port/lib.h"
#include "mem.h"
#include "dat.h"
#include "fns.h"
#include "../port/error.h"
#define Image IMAGE
#include <draw.h>
#include <memdraw.h>
#include <cursor.h>
#include "screen.h"
/*
* Hardware graphics cursor support for
* Brooktree Bt485 Monolithic True-Color RAMDAC.
* Assumes hooked up to an S3 86C928.
*
* BUGS:
* 64x64x2 cursor always used;
* no support for interlaced mode.
*/
enum {
AddrW = 0x00, /* Address register; palette/cursor RAM write */
Palette = 0x01, /* 6/8-bit color palette data */
Pmask = 0x02, /* Pixel mask register */
AddrR = 0x03, /* Address register; palette/cursor RAM read */
ColorW = 0x04, /* Address register; cursor/overscan color write */
Color = 0x05, /* Cursor/overscan color data */
Cmd0 = 0x06, /* Command register 0 */
ColorR = 0x07, /* Address register; cursor/overscan color read */
Cmd1 = 0x08, /* Command register 1 */
Cmd2 = 0x09, /* Command register 2 */
Status = 0x0A, /* Status */
Cmd3 = 0x1A, /* Command register 3 */
Cram = 0x0B, /* Cursor RAM array data */
Cxlr = 0x0C, /* Cursor x-low register */
Cxhr = 0x0D, /* Cursor x-high register */
Cylr = 0x0E, /* Cursor y-low register */
Cyhr = 0x0F, /* Cursor y-high register */
Nreg = 0x10,
};
/*
* Lower 2-bits of indirect DAC register
* addressing.
*/
static ushort dacxreg[4] = {
PaddrW, Pdata, Pixmask, PaddrR
};
static uchar
bt485io(uchar reg)
{
uchar crt55, cr0;
crt55 = vgaxi(Crtx, 0x55) & 0xFC;
if((reg & 0x0F) == Status){
/*
* 1,2: Set indirect addressing for Status or
* Cmd3 - set bit7 of Cr0.
*/
vgaxo(Crtx, 0x55, crt55|((Cmd0>>2) & 0x03));
cr0 = vgai(dacxreg[Cmd0 & 0x03])|0x80;
vgao(dacxreg[Cmd0 & 0x03], cr0);
/*
* 3,4: Set the index into the Write register,
* index == 0x00 for Status, 0x01 for Cmd3.
*/
vgaxo(Crtx, 0x55, crt55|((AddrW>>2) & 0x03));
vgao(dacxreg[AddrW & 0x03], (reg == Status) ? 0x00: 0x01);
/*
* 5,6: Get the contents of the appropriate
* register at 0x0A.
*/
}
return crt55;
}
static uchar
bt485i(uchar reg)
{
uchar crt55, r;
crt55 = bt485io(reg);
vgaxo(Crtx, 0x55, crt55|((reg>>2) & 0x03));
r = vgai(dacxreg[reg & 0x03]);
vgaxo(Crtx, 0x55, crt55);
return r;
}
static void
bt485o(uchar reg, uchar data)
{
uchar crt55;
crt55 = bt485io(reg);
vgaxo(Crtx, 0x55, crt55|((reg>>2) & 0x03));
vgao(dacxreg[reg & 0x03], data);
vgaxo(Crtx, 0x55, crt55);
}
static void
bt485disable(VGAscr*)
{
uchar r;
/*
* Disable
* cursor mode 3;
* cursor control enable for Bt485 DAC;
* the hardware cursor external operation mode.
*/
r = bt485i(Cmd2) & ~0x03;
bt485o(Cmd2, r);
r = vgaxi(Crtx, 0x45) & ~0x20;
vgaxo(Crtx, 0x45, r);
r = vgaxi(Crtx, 0x55) & ~0x20;
vgaxo(Crtx, 0x55, r);
}
static void
bt485enable(VGAscr*)
{
uchar r;
/*
* Turn cursor off.
*/
r = bt485i(Cmd2) & 0xFC;
bt485o(Cmd2, r);
/*
* Overscan colour,
* cursor colour 1 (white),
* cursor colour 2, 3 (black).
*/
bt485o(ColorW, 0x00);
bt485o(Color, Pwhite); bt485o(Color, Pwhite); bt485o(Color, Pwhite);
bt485o(Color, Pwhite); bt485o(Color, Pwhite); bt485o(Color, Pwhite);
bt485o(Color, Pblack); bt485o(Color, Pblack); bt485o(Color, Pblack);
bt485o(Color, Pblack); bt485o(Color, Pblack); bt485o(Color, Pblack);
/*
* Finally, enable
* the hardware cursor external operation mode;
* cursor control enable for Bt485 DAC.
* The #9GXE cards seem to need the 86C928 Bt485 support
* enabled in order to work at all in enhanced mode.
*/
r = vgaxi(Crtx, 0x55)|0x20;
vgaxo(Crtx, 0x55, r);
r = vgaxi(Crtx, 0x45)|0x20;
vgaxo(Crtx, 0x45, r);
}
static void
bt485load(VGAscr* scr, Cursor* curs)
{
uchar r;
int x, y;
/*
* Turn cursor off;
* put cursor into 64x64x2 mode and clear MSBs of address;
* clear LSBs of address;
*/
r = bt485i(Cmd2) & 0xFC;
bt485o(Cmd2, r);
r = (bt485i(Cmd3) & 0xFC)|0x04;
bt485o(Cmd3, r);
bt485o(AddrW, 0x00);
/*
* Now load the cursor RAM array, both planes.
* The cursor is 16x16, the array 64x64; put
* the cursor in the top left. The 0,0 cursor
* point is bottom-right, so positioning will
* have to take that into account.
*/
for(y = 0; y < 64; y++){
for(x = 0; x < 64/8; x++){
if(x < 16/8 && y < 16)
bt485o(Cram, curs->clr[x+y*2]);
else
bt485o(Cram, 0x00);
}
}
for(y = 0; y < 64; y++){
for(x = 0; x < 64/8; x++){
if(x < 16/8 && y < 16)
bt485o(Cram, curs->set[x+y*2]);
else
bt485o(Cram, 0x00);
}
}
/*
* Initialise the cursor hot-point
* and enable the cursor.
*/
scr->offset.x = 64+curs->offset.x;
scr->offset.y = 64+curs->offset.y;
r = (bt485i(Cmd2) & 0xFC)|0x01;
bt485o(Cmd2, r);
}
static int
bt485move(VGAscr* scr, Point p)
{
int x, y;
x = p.x+scr->offset.x;
y = p.y+scr->offset.y;
bt485o(Cxlr, x & 0xFF);
bt485o(Cxhr, (x>>8) & 0x0F);
bt485o(Cylr, y & 0xFF);
bt485o(Cyhr, (y>>8) & 0x0F);
return 0;
}
VGAcur vgabt485cur = {
"bt485hwgc",
bt485enable,
bt485disable,
bt485load,
bt485move,
};