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Annotation of Gnu-Mach/i386/i386at/immc.c, revision 1.1.1.1

1.1       root        1: /* 
                      2:  * Copyright (c) 1995-1994 The University of Utah and
                      3:  * the Computer Systems Laboratory at the University of Utah (CSL).
                      4:  * All rights reserved.
                      5:  *
                      6:  * Permission to use, copy, modify and distribute this software is hereby
                      7:  * granted provided that (1) source code retains these copyright, permission,
                      8:  * and disclaimer notices, and (2) redistributions including binaries
                      9:  * reproduce the notices in supporting documentation, and (3) all advertising
                     10:  * materials mentioning features or use of this software display the following
                     11:  * acknowledgement: ``This product includes software developed by the
                     12:  * Computer Systems Laboratory at the University of Utah.''
                     13:  *
                     14:  * THE UNIVERSITY OF UTAH AND CSL ALLOW FREE USE OF THIS SOFTWARE IN ITS "AS
                     15:  * IS" CONDITION.  THE UNIVERSITY OF UTAH AND CSL DISCLAIM ANY LIABILITY OF
                     16:  * ANY KIND FOR ANY DAMAGES WHATSOEVER RESULTING FROM THE USE OF THIS SOFTWARE.
                     17:  *
                     18:  * CSL requests users of this software to return to [email protected] any
                     19:  * improvements that they make and grant CSL redistribution rights.
                     20:  *
                     21:  *      Author: Bryan Ford, University of Utah CSL
                     22:  */
                     23: 
                     24: #ifdef ENABLE_IMMEDIATE_CONSOLE
                     25: 
                     26: /* This is a special "feature" (read: kludge)
                     27:    intended for use only for kernel debugging.
                     28:    It enables an extremely simple console output mechanism
                     29:    that sends text straight to CGA/EGA/VGA video memory.
                     30:    It has the nice property of being functional right from the start,
                     31:    so it can be used to debug things that happen very early
                     32:    before any devices are initialized.  */
                     33: 
                     34: int immediate_console_enable = 1;
                     35: 
                     36: void
                     37: immc_cnputc(unsigned char c)
                     38: {
                     39:        static int ofs = -1;
                     40: 
                     41:        if (!immediate_console_enable)
                     42:                return;
                     43:        if (ofs < 0)
                     44:        {
                     45:                ofs = 0;
                     46:                immc_cnputc('\n');
                     47:        }
                     48:        else if (c == '\n')
                     49:        {
                     50:                bcopy(0xb8000+80*2, 0xb8000, 80*2*24);
                     51:                bzero(0xb8000+80*2*24, 80*2);
                     52:                ofs = 0;
                     53:        }
                     54:        else
                     55:        {
                     56:                volatile unsigned char *p;
                     57: 
                     58:                if (ofs >= 80)
                     59:                {
                     60:                        immc_cnputc('\r');
                     61:                        immc_cnputc('\n');
                     62:                }
                     63: 
                     64:                p = (void*)0xb8000 + 80*2*24 + ofs*2;
                     65:                p[0] = c;
                     66:                p[1] = 0x0f;
                     67:                ofs++;
                     68:        }
                     69: }
                     70: 
                     71: int immc_cnmaygetc(void)
                     72: {
                     73:        return -1;
                     74: }
                     75: 
                     76: #endif ENABLE_IMMEDIATE_CONSOLE
                     77: 

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