/*
       Osbourne Modem I/O Routines
       These routines are the Osbourne
       versions of the routines needed
       to make TELNET work.
       To make TELNET work with the Osb 1
       make the obvious modifications to
       telnet.c and recompile.

       by:     Dan Sunday
               7473 Broken Staff
               Columbia, MD 21044

               (301)-730-6838

       date:   4-23-82

       Note:   by suitably resetting the
               io byte assignments in this
               package, I and Dave Richardson
               have successfully used the
               modio.c routines to get TELNET
               working on the TRS-80 Model 2
               using Pickles & Trout
*/
#include "a:osbdscio.h"


/*
       Routine to return true if input is present
       at the modem port.
*/

miready()
{
       char c;
       char *iob,sviob;

       iob = 3;
       sviob = *iob;   /* save io byte */
       *iob = 1;       /* console:= serial port */
       c = bios(2);    /* get console status */
       *iob = sviob;   /* restore io byte */
       return c;       /* return input status */
}


/*
       Routine to return true if modem is ready
       to output a byte.
*/

moready()
{
       char c;
       char *iob,sviob;

       iob = 3;
       sviob = *iob;   /* save io byte */
       *iob = 0x40;    /* list device:= serial port */
       c = bios(16);   /* get list device status */
       *iob = sviob;   /* restore io byte */
       return c;       /* return output status */
}

/*
       Get a byte from the modem:
*/

mgetch()
{
       char c;
       char *iob,sviob;        /* I/O Byte */
       unsigned n;     /* time-out counter */

       for (n=20000; !miready() && n; n--)
          if (kbabort())
               return ABORT;   /* Abort Input */
       if (!n) return TIMOUT;  /* Read Time Out */

       iob = 3;
       sviob = *iob;   /* save io byte */
       *iob = 1;       /* console:= serial port */
       c = bios(3,0);  /* get input char */
       *iob = sviob;   /* restore io byte */
       return c;       /* return input */
}


/*
       Output a byte to the modem:
*/


mputch(c)
char c;
{
       char *iob,sviob;

       while (!moready())
           if (kbabort())
               return ABORT;   /* Abort Output */

       iob = 3;
       sviob = *iob;   /* save io byte */
       *iob = 0x40;    /* list:= serial port */
       bios(5,c);      /* output char */
       *iob = sviob;   /* restore io byte */
       return OK;      /* A-OK */
}


mputs(s)
char *s;
{
       while (*s)
               mputch(*s++);
}
/*-----------------------------------------*/
/*
       Return true if keyboard hit and SPECIAL
       typed:
*/

kbabort()
{
       if (kbready() && getch() == SPECIAL)
               return ABORT;
       return OK;
}



kbready()
{
       return bios(2);
}



/*
       Get a character from the keyboard:
       (Uses a direct BIOS instead of going through
       the BDOS. By naming this the same as the library
       version of "getchar", we insure that THIS version
       is used by things like "gets" instead of the library
       version.)
*/

getchar()
{
       char c;
       c = getch();
       if (c == '\r') c = '\n';
       putchar(c);
       return c;
}


getch()
{
       return bios(3);
}


/*
       Write a character to the console.
*/

putchar(c)
char c;
{
       if (c == '\n') putch2('\r');
       putch2(c);
}

putch2(c)
char c;
{
       bios(4,c);
}