20060303

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,
+};