Felisp
84436a5ae0
http://my.svgalib.org/svgalib/svgalib-1.9.25.tar.gz http://my.svgalib.org/svgalib/
219 lines
6.8 KiB
C
219 lines
6.8 KiB
C
/*
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This file assumes 132 column textmode :-).
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This program tries to fix problems with extended textmodes on some cards. The problem is that for 132x43 textmode, some
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BIOSes set the vertical display end register to 349 (350), instead of 343 (344 = 3 * 8 scanlines). Because in Linux textmode
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video memory is usually filled with old text that has already scrolled away (this includes the area below the 43rd textmode
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line, which changes when the console scrolls), the top half of a constantly changing irrelevant text line is visible
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at the bottom of the screen, which is very annoying.
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This program sets the VGA Vertical Display End register to the proper value.
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The problem is at least present in the BIOS of most Cirrus Logic 542x based cards, and some WD90C03x based cards.
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You can also change the number scanlines and number of lines per character of 132x43 textmode to improve readability.
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VGA CRTC 0x12 bits 0-7 Vertical Display End Register bits 0-7
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VGA CRTC 0x07 bit 1 Vertical Display End Register bit 8
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Cirrus 542x BIOS v1.10 132x43: 0x15d (349) (this is the wrong value that the BIOS sets)
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Correct value for 132x43: 0x157 (343)
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Correct value for 132x44: 0x15f (351)
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VGA CRTC 0x09 bits 0-4 Number of scanlines in a textmode font character.
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VGA MiscOut bits 6-7 Indicates number of scanlines: 1 = 400, 2 = 350, 3 = 480.
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VGA CRTC 0x06 bits 0-7 Vertical Total register bits 0-7 (should be #scanlines - 2)
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Bit 8 is in VGA CRTC 0x07, bit 0
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Bit 9 is in VGA CRTC 0x07, bit 5
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VGA CRTC 0x10 bits 0-7 Vertical Retrace Start
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Bit 8 is in VGA CRTC 0x07, bit 2
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Bit 9 is in VGA CRTC 0x07, bit 7
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VGA CRTC 0x11 bits 0-3 Vertical Retrace End (last 4 bits)
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VGA CRTC 0x15 bits 0-7 Vertical Blank Start
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Bit 8 is in VGA CRTC 0x07 bit 3
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*/
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/* Comment this out if setting graphics modes is undesirable. You can load proper fonts with restorefont. */
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#define FIX_FONT
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#include <stdlib.h>
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#include <stdio.h>
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#include <string.h>
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#include <unistd.h>
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#include <vga.h>
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#include "sys/io.h" /* For port I/O macros. */
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#define OUTB(a,d) outb(d,a)
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static void fixfont (int);
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int
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main (int argc, char *argv[])
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{
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int vgaIOBase;
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unsigned char val;
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int lines;
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vga_disabledriverreport ();
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vga_setchipset (VGA);
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vga_init ();
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if (argc == 1)
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{
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printf ("Fiddle with 132x43 textmode VGA registers.\n");
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printf ("Syntax: fix132x43 option (one at a time).\n");
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printf (" -f Fix problem of annoying changing line of text at bottom of screen.\n");
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printf (" -v Switch to 9 line characters (400 line frame, 70 Hz).\n");
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#ifdef INCLUDE_480LINEMODE
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printf (" -w Switch to 11 line characters (480 line frame, 60 Hz).\n");
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#endif
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printf (" -r Switch to 8 line characters again (350 line frame, 70 Hz).\n");
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printf ("LINES environment variable is used to detect 43 or 44 line console.\n");
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return 0;
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}
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if (argv[1][0] != '-')
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{
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printf ("Must specify -f, -v or -r.\n");
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return 1;
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}
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if (argv[1][1] != 'f' && argv[1][1] != 'v' && argv[1][1] != 'w' && argv[1][1] != 'r')
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{
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printf ("Must specify -f, -v, or -r.\n");
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return 1;
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}
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lines = atoi (getenv ("LINES"));
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printf ("Lines: %d\n", lines);
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/* Deprotect CRT registers 0-7. */
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vgaIOBase = (inb (0x3cc) & 0x01) ? 0x3D0 : 0x3B0;
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OUTB (vgaIOBase + 4, 0x11);
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val = inb (vgaIOBase + 5);
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OUTB (vgaIOBase + 5, val & 0x7f);
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if (argv[1][1] == 'f')
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{
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/* Fix stupid bottom line. */
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OUTB (vgaIOBase + 4, 0x12);
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OUTB (vgaIOBase + 5, 0x57); /* Value for 43 lines (343). */
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}
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if (argv[1][1] == 'r')
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{
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/* Set 8 line characters, 350 line frame (344 used). */
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OUTB (vgaIOBase + 4, 0x09);
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val = inb (vgaIOBase + 5);
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OUTB (vgaIOBase + 5, (val & 0xe0) | 7); /* Set 8-line characters. */
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val = inb (0x3cc);
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OUTB (0x3c2, (val & 0x3f) | (2 << 6)); /* 350 scanlines. */
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OUTB (vgaIOBase + 4, 0x12); /* Vertical Display End */
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if (lines == 44)
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OUTB (vgaIOBase + 5, 0x60); /* Value for 44 lines (352). */
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else
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OUTB (vgaIOBase + 5, 0x57); /* Value for 43 lines (343). */
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OUTB (vgaIOBase + 4, 0x10); /* Retrace Start */
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OUTB (vgaIOBase + 5, 0x83); /* Value for 350 line frame. */
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OUTB (vgaIOBase + 4, 0x11); /* Retrace End */
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val = inb (vgaIOBase + 5);
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OUTB (vgaIOBase + 5, (val & 0xf0) | 0x05);
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OUTB (vgaIOBase + 4, 0x15); /* Vertical Blank Start */
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OUTB (vgaIOBase + 5, 0x63); /* Value for 350 line frame. */
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}
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if (argv[1][1] == 'v')
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{
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/* Set 9 line characters, 400 line frame (387 used). */
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OUTB (vgaIOBase + 4, 0x09);
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val = inb (vgaIOBase + 5);
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OUTB (vgaIOBase + 5, (val & 0xe0) | 8); /* Set 9-line characters. */
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val = inb (0x3cc);
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OUTB (0x3c2, (val & 0x3f) | (1 << 6)); /* 400 scanlines. */
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OUTB (vgaIOBase + 4, 0x12);
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if (lines == 44)
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OUTB (vgaIOBase + 5, 0x8b); /* End scanline is 44 * 9 - 1 = 395 */
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else
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OUTB (vgaIOBase + 5, 0x82); /* End scanline is 43 * 9 - 1 = 386 */
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OUTB (vgaIOBase + 4, 0x10); /* Retrace Start */
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OUTB (vgaIOBase + 5, 0x9c); /* Value for 400 line frame. */
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OUTB (vgaIOBase + 4, 0x11); /* Retrace End */
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val = inb (vgaIOBase + 5);
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OUTB (vgaIOBase + 5, (val & 0xf0) | 0x0e);
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OUTB (vgaIOBase + 4, 0x15); /* Vertical Blank Start */
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OUTB (vgaIOBase + 5, 0x95); /* Value for 400 line frame. */
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#ifdef FIX_FONT
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fixfont (9);
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#endif
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}
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#ifdef INCLUDE_480LINEMODE
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if (argv[1][1] == 'w')
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{
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/* Set 11 line characters, 480 line frame (473 used). */
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OUTB (vgaIOBase + 4, 0x09);
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val = inb (vgaIOBase + 5);
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OUTB (vgaIOBase + 5, (val & 0xe0) | 10); /* Set 11-line characters. */
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OUTB (0x3c2, 0xeb);
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OUTB (vgaIOBase + 4, 0x12);
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OUTB (vgaIOBase + 5, 0xd8); /* End scanline is 43 * 11 - 1 = 472 */
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OUTB (vgaIOBase + 4, 0x10); /* Retrace Start */
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OUTB (vgaIOBase + 5, 0xf4 /*0xea */ ); /* Value for 480 line frame. ?? */
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OUTB (vgaIOBase + 4, 0x11); /* Retrace End */
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val = inb (vgaIOBase + 5);
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OUTB (vgaIOBase + 5, (val & 0xf0) | 0x0c);
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OUTB (vgaIOBase + 4, 0x15); /* Vertical Blank Start */
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OUTB (vgaIOBase + 5, 0xf4 /*0xe7 */ ); /* Value for 480 line frame. */
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#ifdef FIX_FONT
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fixfont (11);
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#endif
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}
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#endif
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return 0;
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}
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/* Clear offsets 8-31 of each character bitmap (the BIOS usually leaves some trash here from the 16 line font that was loaded */
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/* prior to setting 132x43 (8 line font) textmode). */
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static void
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fixfont (int lines)
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{
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unsigned char font[8192];
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int i;
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vga_setmode (G640x480x16);
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vga_gettextfont (font);
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for (i = 0; i < 256; i++)
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memset (font + i * 32 + 8, 0, 32 - 8); /* Clear remaining part of character bitmap buffer. */
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vga_puttextfont (font);
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vga_setmode (TEXT);
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}
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