X-Git-Url: http://git.mutantstargoat.com/user/nuclear/?p=3sys;a=blobdiff_plain;f=sys1%2Fkern%2Fsrc%2Fvga.c;fp=sys1%2Fkern%2Fsrc%2Fvga.c;h=29672990a36528127b8ccdd949ee82e4e040599d;hp=0000000000000000000000000000000000000000;hb=d49aa763f9b7c4ae66cf80f0cbfc3456789fc0ac;hpb=3e2e8a9156d288d230bbcd722bc91c4b3e4b21e1

diff --git a/sys1/kern/src/vga.c b/sys1/kern/src/vga.c
new file mode 100644
index 0000000..2967299
--- /dev/null
+++ b/sys1/kern/src/vga.c
@@ -0,0 +1,56 @@
+#include <string.h>
+#include "vga.h"
+#include "asmutil.h"
+
+#define CRTC_ADDR_PORT	0x3d4
+#define CRTC_DATA_PORT	0x3d5
+
+/* CRTC registers */
+#define CRTC_START_H	0x0c
+#define CRTC_START_L	0x0d
+#define CRTC_CURPOS_H	0x0e
+#define CRTC_CURPOS_L	0x0f
+
+static void crtc_write(int reg, unsigned char val);
+
+static uint16_t attr = 0x0700;
+static int yoffs;
+
+void vga_setcolor(int fg, int bg)
+{
+	attr = ((bg & 7) << 12) | ((fg & 0xf) << 8);
+}
+
+void vga_setcursor(int x, int y)
+{
+	int loc = (y + yoffs) * 80 + x;
+	crtc_write(CRTC_CURPOS_H, loc >> 8);
+	crtc_write(CRTC_CURPOS_L, loc);
+}
+
+void vga_setstart(int start)
+{
+	yoffs = start;
+	crtc_write(CRTC_START_H, start >> 8);
+	crtc_write(CRTC_START_L, start);
+}
+
+void vga_reset(void)
+{
+	vga_setcolor(VGA_WHITE, VGA_BLACK);
+	vga_setstart(0);
+	vga_setcursor(0, 0);
+	memset((void*)0xb8000, 0, 80 * 25 * 2);
+}
+
+void vga_drawchar(int x, int y, int c)
+{
+	uint16_t *ptr = (uint16_t*)0xb8000 + (y + yoffs) * 80 + x;
+	*ptr = (c & 0xff) | attr;
+}
+
+static void crtc_write(int reg, unsigned char val)
+{
+	outp(CRTC_ADDR_PORT, reg);
+	outp(CRTC_DATA_PORT, val);
+}