com32/lib/sys/rawcon_read.c

   1 /* ----------------------------------------------------------------------- *
   2  *
   3  *   Copyright 2004 H. Peter Anvin - All Rights Reserved
   4  *
   5  *   Permission is hereby granted, free of charge, to any person
   6  *   obtaining a copy of this software and associated documentation
   7  *   files (the "Software"), to deal in the Software without
   8  *   restriction, including without limitation the rights to use,
   9  *   copy, modify, merge, publish, distribute, sublicense, and/or
  10  *   sell copies of the Software, and to permit persons to whom
  11  *   the Software is furnished to do so, subject to the following
  12  *   conditions:
  13  *
  14  *   The above copyright notice and this permission notice shall
  15  *   be included in all copies or substantial portions of the Software.
  16  *
  17  *   THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
  18  *   EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES
  19  *   OF MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
  20  *   NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT
  21  *   HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY,
  22  *   WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
  23  *   FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR
  24  *   OTHER DEALINGS IN THE SOFTWARE.
  25  *
  26  * ----------------------------------------------------------------------- */
  27
  28 /*
  29  * rawcon_read.c
  30  *
  31  * Character-oriented reading from the console without echo;
  32  * this is a NONBLOCKING device.
  33  */
  34
  35 #include <errno.h>
  36 #include <string.h>
  37 #include <com32.h>
  38 #include <minmax.h>
  39 #include <sys/times.h>
  40 #include "file.h"
  41
  42 /* Global, since it's used by stdcon_read */
  43 ssize_t __rawcon_read(struct file_info *fp, void *buf, size_t count)
  44 {
  45   com32sys_t ireg, oreg;
  46   char *bufp = buf;
  47   size_t n = 0;
  48   clock_t start;
  49
  50   (void)fp;
  51
  52   memset(&ireg, 0, sizeof ireg);
  53
  54   start = times(NULL);
  55
  56   while ( n < count ) {
  57     /* Poll */
  58     ireg.eax.b[1] = 0x0B;
  59     __intcall(0x21, &ireg, &oreg);
  60     if ( !oreg.eax.b[0] )
  61       break;
  62
  63     /* We have data, go get it */
  64     ireg.eax.b[1]  = 0x08;
  65     __intcall(0x21, &ireg, &oreg);
  66     *bufp++ = oreg.eax.b[0];
  67     n++;
  68   }
  69
  70   return n;
  71 }
  72
  73 const struct input_dev dev_rawcon_r = {
  74   .dev_magic  = __DEV_MAGIC,
  75   .flags      = __DEV_TTY | __DEV_INPUT,
  76   .fileflags  = O_RDONLY,
  77   .read       = __rawcon_read,
  78   .close      = NULL,
  79   .open       = NULL,
  80 };