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clockdev.c
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C/C++ Source or Header
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1992-05-14
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6KB
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300 lines
/*
* A simple device driver for u:\dev\clock. Reading from this
* device produces a single line containing the current time, in the
* format:
* MM/DD/YY hh:mm:ss\r\n
* Writing to it will change the time to the given one.
*
* This program is written by Eric R. Smith and is hereby placed in
* the public domain.
*
* COMPILER NOTE: I've assumed that you're using a compiler (like gcc
* or Lattice) that preserves registers d2 and a2 across function calls.
* If your compiler uses these registers as scratch registers (e.g.
* MWC, Alcyon) then you'll have to provide assembly language wrapper
* functions that the kernel can call.
* This code also assumes that sizeof(int) == 2.
*
* for gcc: compile with gcc -mshort -O clockdev.c -o clockdev.prg
* for lcc: compile with -bn -b0 -r0 -v -w -t= clockdev.c -oclockdev.prg
*/
#ifdef __GNUC__
#include <minimal.h>
#endif
#include <osbind.h>
#include <basepage.h>
#include "mintbind.h"
#include "filesys.h"
#include "atarierr.h"
#ifdef LATTICE
#define BP _pbase
#else
#define BP _base
#endif
/* the name of the device we're installing */
char name[] = "U:\\DEV\\CLOCK";
/* kernel information */
struct kerinfo *kernel;
#define CCONWS (void)(*kernel->dos_tab[0x09])
#define RWABS (*kernel->bios_tab[4])
#define GETBPB (void *)(*kernel->bios_tab[7])
#define TGETTIME (*kernel->dos_tab[0x2c])
#define TGETDATE (*kernel->dos_tab[0x2a])
#define TSETTIME (*kernel->dos_tab[0x2d])
#define TSETDATE (*kernel->dos_tab[0x2b])
#define SPRINTF (*kernel->sprintf)
#define DEBUG (*kernel->debug)
#define ALERT (*kernel->alert)
#define TRACE (*kernel->trace)
#define FATAL (*kernel->fatal)
/* assumption: 16 bit integers */
#define word int
/* device driver information */
static long clock_open P_((FILEPTR *)),
clock_write P_((FILEPTR *, char *, long)),
clock_read P_((FILEPTR *, char *, long)),
clock_lseek P_((FILEPTR *, long, word)),
clock_ioctl P_((FILEPTR *, word, void *)),
clock_datime P_((FILEPTR *, word *, word)),
clock_close P_((FILEPTR *));
static long clock_select();
static void clock_unselect();
DEVDRV clock_device = {
clock_open, clock_write, clock_read, clock_lseek, clock_ioctl,
clock_datime, clock_close, clock_select, clock_unselect,
0, 0, 0
};
struct dev_descr devinfo = {
&clock_device, 0, 0, (struct tty *)0, 0L, 0L, 0L, 0L
};
#ifdef LATTICE
BASEPAGE *BP;
void
start(BASEPAGE *bp)
{
BP = bp;
main();
}
#endif
/*
* the main program just installs the device, and then does Ptermres
* to remain resident
*/
main()
{
kernel = (struct kerinfo *)Dcntl(DEV_INSTALL, name, &devinfo);
if (!kernel || ((long)kernel) == -32) {
Cconws("Unable to install clock device\r\n");
Pterm(1);
}
Ptermres(256L + BP->p_tlen + BP->p_dlen + BP->p_blen, 0);
}
/*
* here are the actual device driver functions
*/
/*
* utility functions:
* getclock(buf): get the current date and time and write it into
* the pointed to buffer in the format "MM/DD/YY hh:mm:ss\r\n"
*
* setclock(buf): set the current date and time from the ASCII
* string pointed to by buf, which must have the same format
* as that returned by getdate
*/
void
getclock(buf)
char *buf;
{
int DD, MM, YY, hh, ss, mm;
unsigned date, time;
date = TGETDATE();
time = TGETTIME();
DD = date & 31;
MM = (date >> 5) & 15;
YY = 80 + ( (date >> 9) & 127 ); if (YY > 99) YY -= 100;
ss = (time & 31) << 1;
mm = (time >> 5) & 63;
hh = (time >> 11) & 31;
SPRINTF(buf, "%02d/%02d/%02d %02d:%02d:%02d\r\n", MM, DD, YY,
hh, mm, ss);
}
static int
getint(buf)
char *buf;
{
int val = 0;
val = *buf++ - '0';
val = 10 * val + *buf - '0';
return val;
}
void
setclock(buf)
char *buf;
{
int DD, MM, YY, hh, mm, ss;
unsigned time, date;
MM = getint(buf); buf += 3;
if (MM < 1 || MM > 12) return;
DD = getint(buf); buf += 3;
if (DD < 1 || DD > 31) return;
YY = getint(buf); buf += 3;
if (YY < 80 || YY > 99) return;
hh = getint(buf); buf += 3;
if (hh < 0 || hh > 23) return;
mm = getint(buf); buf += 3;
if (mm < 0 || mm > 59) return;
ss = getint(buf);
if (ss < 0 || ss > 59) return;
time = (hh << 11) | (mm << 5) | (ss >> 1);
date = ((YY - 80) << 9) | (MM << 5) | DD;
TSETTIME(time);
TSETDATE(date);
}
#define NBYTES 19 /* strlen("DD/MM/YY hh:mm:ss\r\n") */
static long
clock_open(f)
FILEPTR *f;
{
return 0;
}
static long
clock_write(f, buf, bytes)
FILEPTR *f; char *buf; long bytes;
{
static char writebuf[NBYTES];
static int bufptr = 0;
long wrote = 0;
while (bytes-- > 0 && bufptr < NBYTES) {
/* ignore CR/LF at beginning of line */
if (bufptr == 0 && (*buf == '\r' || *buf == '\n'))
buf++;
else
writebuf[bufptr++] = *buf++;
wrote++;
}
/* do we have a complete date now? if so, set the clock */
if (bufptr == NBYTES) {
setclock(writebuf);
bufptr = 0;
}
return wrote;
}
static long
clock_read(f, buf, bytes)
FILEPTR *f; char *buf; long bytes;
{
/* SPRINTF will stuff one too many bytes in here (the \0) */
static char readbuf[NBYTES+1];
int where;
long total = 0;
getclock(readbuf);
while (f->pos < NBYTES) {
*buf++ = readbuf[f->pos++];
total++;
}
return total;
}
static long
clock_lseek(f, where, whence)
FILEPTR *f; long where; int whence;
{
long newplace;
switch(whence) {
case 0:
newplace = where;
break;
case 1:
newplace = f->pos + where;
break;
case 2:
newplace = (NBYTES-1) - where;
break;
}
if (newplace < 0 || newplace >= NBYTES)
return ERANGE;
f->pos = newplace;
return newplace;
}
static long
clock_ioctl(f, mode, buf)
FILEPTR *f; int mode; void *buf;
{
if (mode == FIONREAD || mode == FIONWRITE) {
*((long *)buf) = (NBYTES-1) - f->pos;
return 0;
}
else
return EINVFN;
}
static long
clock_datime(f, timeptr, rwflag)
FILEPTR *f;
word *timeptr;
int rwflag;
{
if (rwflag)
return EACCDN;
*timeptr++ = TGETTIME();
*timeptr = TGETDATE();
return 0;
}
static long
clock_close(f)
FILEPTR *f;
{
return 0;
}
static long
clock_select()
{
return 1; /* we're always ready for I/O */
}
static void
clock_unselect()
{
/* nothing for us to do here */
}