d@alice.UUCP (07/22/87)
Here's a public thank you to everyone who replied, and a summary
to the net of what I found out.
WHERE TO FIND THE TIME
----------------------
(all numbers in hex unless otherwise noted)
There is a location in memory that most DOS's increment every
55 milliseconds. It is at segment 40, address 6C. In BASIC, you'd
read it like this:
def seg=&h40
tick=peek(&h6c)
You can also use the built-in clock in a few different ways. Most
Microsoft-based BASICS provide the handy INP(port) function. Using
this table:
71 tenths of a second
72 unit seconds
73 10s of seconds
74 unit minutes
75 10s of minutes
76 unit hours
77 10s of hours
78 unit days
79 10s of days
7a day of week (1-7)
7b unit months
7c 10s of months
7d leap year
7e (stop/start - for out, not inp)
7f year
you can use the INP function to read in anything you want. Note that
what is returned is usually in the top eight bits of a sixteen bit
word, so you may have to convert to what you want by going
(foo\256) mod 128.
You could also use the INT86 call in QuickBASIC, and stick a hex 2c
in the first eight bits of the A register while doing an interrupt 21 hex.
DIM clockin%(7),clockout%(7)
clockin%(0) = &h2c00 ' stick hex 2c into the first eight bits
' of what will be passed into the A register
CALL INT86(&h21,varptr(clockin%(0)),varptr(clockout%(0)))
You get the goodies back in clockout%(), with generally two piece of
information per byte. To extract the high part of the word,
(foo\256) mod 128 works
To extract the low part, foo mod 128 works.
(See page 148-149 in the QuickBASIC manual.)
Thanks to everyone who replied.
And why did I go through all this trouble? So I could get my time
down to tenths of a second instead of seconds. Note that while my AT&T
manuals claim accuracy down to hundredths of a second, the hundredths
always come back in multiples of 10.
--
# Daniel Rosenberg / AT&T Bell Labs / Murray Hill / New Jersey
# These opinions are necessarily mine, not my employer's.
# UUCP: {ihnp4 || research || allegra}!alice!d HORN: 201/582-3059 (work)
# INTERNET: d%alice%btl@csnet-relay or d@alice.att.com --More--