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From: tsp@killer.UUCP
Newsgroups: comp.os.minix
Subject: Clock setting program for AST Six Pack
Message-ID: <771@killer.UUCP>
Date: Mon, 13-Apr-87 15:34:56 EST
Article-I.D.: killer.771
Posted: Mon Apr 13 15:34:56 1987
Date-Received: Sun, 19-Apr-87 03:16:02 EST
Organization: The Unix(tm) Connection, Dallas, Texas
Lines: 272
Keywords: /etc/rc, clock, AST



Attached is a clock setting program for an AST Six Pack card.  I use this
in /etc/rc as:

  /etc/astclock
  /usr/bin/echo -n "Current time is: "
  /usr/bin/date

No makefile is included, just: cc -o astclock astclock.c port_io.s


Known bugs:  I couldn't seem to get the ten-year count from the AST 
clock chip.  Instead, I just add a constant DECADE to the years value.
If anyone knows how to read the ten-year count, please make the changes
and post the diffs.


Tom Poindexter			April 13, 1987



---------cut here---------------------------------------------------------
echo x - astclock.c
gres '^X' '' > astclock.c << '/'
X/* astclock.c  - set MINIX's system clock from an AST Six Pack board */
X/* should be run in /etc/rc as /etc/astclock                         */
X/* date values to seconds calculation borrowed from date.c           */
X/* port_in() & port_out() in port_io.s were grafted from klib88.s    */
X/* author:  Tom Poindexter, April 9, 1987                            */
X/* I hereby place this software in the public domain                 */
X
X#include "stdio.h"
X
Xint days_per_month[] =
X  { 31, 28, 31, 30, 31, 30, 31, 31, 30, 31, 30, 31 };
X
Xstruct tm {
X  int year, month, day, hour, min, sec;
X};
X
X/* define the current decade */
X#define DECADE          80
X
X/* ports for the ast clock; first is the index, next is the data */
X
X#define AST_IDX_REG     0x02c0
X#define AST_VAL_REG     0x02c1
X
X/* registers on the ast clock; data returned in lowest 4 bits */
X
X#define SEC_1s          0
X#define SEC_10s         1
X#define MIN_1s          2
X#define MIN_10s         3
X#define HR_1s           4
X#define HR_10s          5
X#define DAY_1s          7
X#define DAY_10s         8
X#define MON_1s          9
X#define MON_10s         10
X#define YR_1s           11
X#define YR_10s          12
X#define CLK_MODE        13
X#define CLK_ENABLE      0x0c
X
X#define LOW_4           0x000f
X
X#define TRIES           10
X
X
X
X/******************************************************************/
X
Xmain()
X{
X  struct tm tm1;
X  struct tm tm2;
X  int  i;
X  long t;
X  long calc_sec();
X  int stime();		/* stime() sets the date in minix */
X
X  /* try several times to read the clock */
X
X  for (i = 0; i < TRIES; i++) {
X
X    read_clk(&tm1);			/* read the clock twice */
X    read_clk(&tm2);
X    
X    if (tm1.year  == tm2.year  &&	/* and compare the results */
X        tm1.month == tm2.month &&
X        tm1.day   == tm2.day   &&
X        tm1.hour  == tm2.hour  &&
X        tm1.min   == tm2.min   &&
X        tm1.sec   == tm2.sec) {
X
X      t = calc_sec(&tm1);      		/* calculate the seconds */
X
X      if (stime(&t) == -1) {		/* and set the time */
X        die("astclock: can't set stime(), are you super user?\n");
X      }
X
X      exit(0);                  /* normal termination */
X
X    }
X
X  }
X
X  /* too many errors in reading the ast clock chip, give up */
X
X  die("astclock: can't get a consistent time from the ast clock");
X
X}
X/* end of main */
X
X
X/* calculate seconds since epoch; this code borrowed from `date.c' */
X
Xlong calc_sec(tp)
Xstruct tm *tp;
X{
X  int i = 0;
X  long ct;
X  long s_p_min;
X  long s_p_hour;
X  long s_p_day;
X  long s_p_year;
X
X  /* first, calculate seconds per known intervals */
X  s_p_min  = 60;
X  s_p_hour = 60  * s_p_min;
X  s_p_day  = 24  * s_p_hour;
X  s_p_year = 365 * s_p_day;
X
X  /* calculate seconds from epoch until the start of this year */
X  tp->year -= 70;			/* deal with years since 1970   */
X  ct = tp->year * s_p_year;		/* seconds per year since epoch */
X  ct += ((tp->year + 1) / 4) * s_p_day;	/* add in the leap years and    */
X  if (((tp->year + 2) % 4) == 0) {	/* check if this year is a leap */
X	days_per_month[1]++;		/* and make feb one more day    */
X  }
X
X  /* calculate seconds from january until the start of this month */
X  tp->month--;
X  while (i < tp->month) {
X	ct += days_per_month[i++] * s_p_day;
X  }
X   
X  /* calculate seconds of the days this month */
X  ct += --tp->day * s_p_day;
X
X  /* calculate seconds of the hour this day */
X  ct += tp->hour * s_p_hour;
X
X  /* calculate seconds of the minutes this hour */
X  ct += tp->min * s_p_min;
X 
X  /* and finally add in the seconds so far this minute */
X  ct += tp->sec;
X
X  return (ct);
X }
X
X
X/* read the ast clock and fill values into a tm structure */
X
Xread_clk(tp)
Xstruct tm *tp;
X{
X  
X/*  can't seem to get the 10 year count from the clock chip - the
X    following should work, but YR_10s always returns 0
X  tp->year  = (rd_ast_clk(YR_10s) * 10) + rd_ast_clk(YR_1s);
X*/
X
X  tp->year  = DECADE + rd_ast_clk(YR_1s);
X  tp->month = (rd_ast_clk(MON_10s) * 10) + rd_ast_clk(MON_1s);
X  tp->day   = (rd_ast_clk(DAY_10s) * 10) + rd_ast_clk(DAY_1s);
X  tp->hour  = (rd_ast_clk(HR_10s)  * 10) + rd_ast_clk(HR_1s);
X  tp->min   = (rd_ast_clk(MIN_10s) * 10) + rd_ast_clk(MIN_1s);
X  tp->sec   = (rd_ast_clk(SEC_10s) * 10) + rd_ast_clk(SEC_1s);
X
X}
X/* end of read_clk */
X
X
X/* rd_ast_clk() - read a register from the ricoh rp5c15 clock chip */
X
Xint rd_ast_clk(reg)
Xint reg;
X{
X  int val;
X
X  port_out(AST_IDX_REG, CLK_MODE);	/* index on the clock mode reg */
X  port_out(AST_VAL_REG, CLK_ENABLE);	/* make sure timers are enabled */
X  port_out(AST_IDX_REG, reg);		/* index on the register desired */
X  port_in (AST_VAL_REG, &val);		/* and get the value of the reg */
X 
X  return (val & LOW_4);			/* make sure lower 4 bits only */
X  
X}
X/* end of rd_ast_clk */
X
X
X/* die() - print a message on stderr and exit with false code */
X
Xdie(msg)
Xchar *msg;
X{
X  fprintf(stderr,msg);
X  fflush(stderr);
X  _cleanup();
X  exit(1);
X
X}
X/* end of die */
X
X
X/* end of astclock.c */
/
echo x - port_io.s
gres '^X' '' > port_io.s << '/'
X| this file was grafted from klib88.s 
X
X.globl _port_out, _port_in
X
X
X
X|*===========================================================================*
X|*				port_out				     *
X|*===========================================================================*
X| port_out(port, value) writes 'value' on the I/O port 'port'.
X
X_port_out:
X	push bx			| save bx
X	mov bx,sp		| index off bx
X	push ax			| save ax
X	push dx			| save dx
X	mov dx,4(bx)		| dx = port
X	mov ax,6(bx)		| ax = value
X	out			| output 1 byte
X	pop dx			| restore dx
X	pop ax			| restore ax
X	pop bx			| restore bx
X	ret			| return to caller
X
X
X|*===========================================================================*
X|*				port_in					     *
X|*===========================================================================*
X| port_in(port, &value) reads from port 'port' and puts the result in 'value'.
X_port_in:
X	push bx			| save bx
X	mov bx,sp		| index off bx
X	push ax			| save ax
X	push dx			| save dx
X	mov dx,4(bx)		| dx = port
X	in			| input 1 byte
X	xorb ah,ah		| clear ah
X	mov bx,6(bx)		| fetch address where byte is to go
X	mov (bx),ax		| return byte to caller in param
X	pop dx			| restore dx
X	pop ax			| restore ax
X	pop bx			| restore bx
X	ret			| return to caller
X
X
/

Tom Poindexter
..!ihnp4!killer!tsp