diff options
Diffstat (limited to 'os/pc/vgabt485.c')
| -rw-r--r-- | os/pc/vgabt485.c | 245 |
1 files changed, 245 insertions, 0 deletions
diff --git a/os/pc/vgabt485.c b/os/pc/vgabt485.c new file mode 100644 index 00000000..1c155e6d --- /dev/null +++ b/os/pc/vgabt485.c @@ -0,0 +1,245 @@ +#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, +}; |