dos fixes and vga modex

[dosdemo] / src / dos / vga.c

diff --git a/src/dos/vga.c b/src/dos/vga.c
index c829684..376e72b 100644 (file)
--- a/src/dos/vga.c
+++ b/src/dos/vga.c
@@ -1,5 +1,10 @@
 #include "vga.h"
+#include "vgaregs.h"
 #include "cdpmi.h"
+#include "dosutil.h"
+
+static void crtc_write(int reg, unsigned char val);
+static unsigned char crtc_read(int reg);
 
 int vga_setmode(int mode)
 {
@@ -9,3 +14,57 @@ int vga_setmode(int mode)
        dpmi_int(0x10, &regs);
        return 0;
 }
+
+static unsigned short crtc_modex_regs[] = {
+       0x0d06, /* vertical total */
+       0x3e07, /* vcount overflow bit */
+       0x4109, /* double-scan */
+       0xea10, /* vsync start */
+       0xac11, /* vsync end & protect */
+       0xdf12, /* vertical visible */
+       0x0014, /* no dword mode */
+       0xe715, /* vblank start */
+       0x0616, /* vblank end */
+       0xe317, /* byte mode */
+       0
+};
+
+int vga_setmodex(void)
+{
+       int i;
+       unsigned char val;
+
+       vga_setmode(0x13);
+
+       /* disable chain-4 (C4=0, O/E=1 (sequential), EM=1 (extmem), A/G=0 (gfx) */
+       outpw(VGA_SC_ADDR_PORT, VGA_SC_MEMMODE_REG | 0x0600);
+       /* pull reset low */
+       outpw(VGA_SC_ADDR_PORT, VGA_SC_RESET_REG | 0x0100);
+       /* 25mhz dot clock, 60hz scan */
+       outp(VGA_MISC_PORT, VGA_MISC_480 | VGA_MISC_PG1 | VGA_MISC_CLK25 |
+                       VGA_MISC_CPUEN | VGA_MISC_COLOR);
+       /* return reset high */
+       outpw(VGA_SC_ADDR_PORT, VGA_SC_RESET_REG | 0x0300);
+
+       /* disable CRTC write-protect */
+       crtc_write(CRTC_VRETEND_REG, crtc_read(CRTC_VRETEND_REG) & ~CRTC_VRETEND_PR);
+       /* change CRTC registers */
+       for(i=0; crtc_modex_regs[i]; i++) {
+               outpw(VGA_CRTC_PORT, crtc_modex_regs[i]);
+       }
+
+       vga_planemask(0xf);
+       memset(VGA_FBADDR, 3, 320 * 240 / 4);
+       return 0;
+}
+
+static void crtc_write(int reg, unsigned char val)
+{
+       outpw(VGA_CRTC_ADDR_PORT, reg | ((unsigned int)val << 8));
+}
+
+static unsigned char crtc_read(int reg)
+{
+       outp(VGA_CRTC_ADDR_PORT, reg);
+       return inp(VGA_CRTC_DATA_PORT);
+}