I'm new with assembly language (8086 Program) and I am trying to create a program that display a greeting depending on system date and time. Like if the system date is December 25 then the program will print "Merry Christmas" or if January 1 then it's "Happy New Year". If it just a regular day / no holiday then just print a "Good day". On system time, probably display a "Good Evening" or "Good Morning".
So far, I learned how to get and display the system time and date. Now, I am wondering how can I apply conditionals (if-else) on it.
Assuming you've asked the date from DOS using function 2Bh, the day will be in DL and the month in DH. Checking for Christmas day is simply writing cmp dx, 0C19h.
Get inspired by next example:
mov si, Xmas
cmp dx, 0C19h ; 25 dec
je GoPrint
mov si, NewY
cmp dx, 0101h ; 01 jan
je GoPrint
...
GoPrint:
mov dx, si
mov ah, 09h ; DOS.PrintString
int 21h
...
Xmas: db 'Merry ...', 13, 10, '$'
NewY: db 'Happy ...', 13, 10, '$'
For 'Good day' vs 'Good evening', you can apply similar code to the time (hours) in the CH register that you get from invoking the DOS function 2Ch.
Related
I've been using the %local directive in NASM to define local variables and thus avoid typing [ebp - 8], [ebp - 24] etc. all the time.
However, I noticed that a local variable defined in one function between the preprocessor context %push and %pop is still available in the rest of the code, which may result in unexpected parsing errors.
Here, I've written a minimal example demonstrating the problem:
struc Rect
.left resd 1
.top resd 1
.width resd 1
.height resd 1
endstruc
%define RECT(x) g_rect + Rect. %+ x
segment .bss
g_rect resd 4
segment .text
; ================================================
function1:
%push
%stacksize flat
%assign %$localsize 0
%local width:dword ; defines local var "width"
push ebp
mov ebp, esp
sub esp, 4
pusha
; ...
popa
leave
ret
%pop
; ================================================
function2:
push ebp
mov ebp, esp
pusha
; ...
mov eax, RECT(height) ; OK
mov ebx, RECT(width) ; Parse error
; ...
popa
leave
ret
The exact error is:
nasm -f elf -d ELF_TYPE -g test.asm
test.asm:42: error: comma, colon, decorator or end of line expected after operand
Obviously, it happens because width is getting substituted with something else, and if I remove the local param definition, the problem goes away.
As you can see, the variable width is still available after the %pop. This doesn't look very local to me! I'd expect NASM to undefine width when the %pop is executed.
Is there a way to use %local but avoid these leaking macros? At the moment they act as a simple %define statement which is confusing.
Here's my code. I am unable to read the dates from the input, it keeps giving me incorrect format, I tried changing a few times to mmddyy10. mmddyy8. and others but it still does not read them in correctly.
data master_patients;
infile datalines;
input account_number name $8-16 address $17-34 date MMDDYYYY10. gender $1.
insurance_code $49-51 updated_date mmddyyyy10.;
datalines;
620135 Smith 234 Aspen St. 12-21-1975 m CBC 02-16-1998
645722 Miyamoto 65 3rd Ave. 04-03-1936 f MCR 05-30-1999
645739 Jensvold 505 Glendale Ave. 06-15-1960 f HLT 09-23-1993
874329 Kazoyan 76-C La Vista . . MCD 01-15-2003
;
proc print data=master_patients;
run;
Could you please point out where I am going wrong? Thanks for any help.
I recommend a specific informat, rather than anydtdte though it helps you get started. It will ensure that your data is correct.
data master_patients;
infile datalines;
informat date updated_date mmddyy10.;
format date updated_date date9.;
input account_number name $ 8-16 address $ 17-34 date gender $1.
insurance_code $ 49-51 updated_date;
datalines;
620135 Smith 234 Aspen St. 12-21-1975 m CBC 02-16-1998
645722 Miyamoto 65 3rd Ave. 04-03-1936 f MCR 05-30-1999
645739 Jensvold 505 Glendale Ave. 06-15-1960 f HLT 09-23-1993
874329 Kazoyan 76-C La Vista . . MCD 01-15-2003
;
run;
There are two main problems. First the informat name does not have 4 Y's in it. Just 2. Second you don't have the column pointer in the right place when you are trying to read 10 characters as a date so that you are getting a blank and then the first 9 characters of the date. SAS cannot represents dates in the second or third century AD. Try MDY(12,21,197) and see what happens.
data master_patients;
infile datalines firstobs=2;
input account_number name $8-16 address $17-34 #36 date MMDDYY10.
gender $1. insurance_code $49-51 #53 updated_date mmddyy10.
;
datalines;
----+----1----+----2----+----3----+----4----+----5----+----6----+
620135 Smith 234 Aspen St. 12-21-1975 m CBC 02-16-1998
645722 Miyamoto 65 3rd Ave. 04-03-1936 f MCR 05-30-1999
645739 Jensvold 505 Glendale Ave. 06-15-1960 f HLT 09-23-1993
874329 Kazoyan 76-C La Vista . . MCD 01-15-2003
;
proc print data=master_patients;
run;
For modified list input for this problem.Just add ":" between variable name and informat.
data master_patients;
infile datalines;
input account_number name $8-16 address $17-34 date : mmddyy10. gender $1.
insurance_code $49-51 updated_date : mmddyy10.;
datalines;
620135 Smith 234 Aspen St. 12-21-1975 m CBC 02-16-1998
645722 Miyamoto 65 3rd Ave. 04-03-1936 f MCR 05-30-1999
645739 Jensvold 505 Glendale Ave. 06-15-1960 f HLT 09-23-1993
874329 Kazoyan 76-C La Vista . . MCD 01-15-2003
;
proc print data=master_patients;
run;
Please note if you don't add ":" , just change mmddyy10. to anydtdte. , the data read into dataset may Not correct.
I have the next problem with gnuplot, when I print the time gnuplot
prints de time+30years.
This is a part of my data:
1411336800,1390,0,0,0,10,1411,0,10,0,0,0,0,0,1411
1411340400,1506,0,0,0,10,969,0,10,0,0,0,0,0,969
1411344000,1115,0,0,0,10,1108,0,10,0,0,0,0,0,1108
1411347600,719,0,0,0,10,712,0,10,0,0,0,0,0,712
A part of the script is:
set timefmt "%s"
stats "<tail -1 uur.txt " using 1:2 nooutput
tijd = strftime("%d %B %Y %H:%M", STATS_max_x)
print tijd
And then gnuplot prints: 21 September 2044 01:00. 44 ?
Has some one a clue?
I tried several formats but nothing helped.
Until version 4.6, internally gnuplot uses the 1. January 2000 as reference for its date and time functions (in version 5.0 the standard Unix timestamp is used).
You shouldn't have any problems with set timefmt "%s" if you plot the data. But when using strftime it makes a difference. Since you're using tail anyway, you can simply use
tijd = system('date -d #$(tail -1 uur.txt | cut -d, -f1) +"%d %B %Y %H:%M"')
print tijd
Please, does anybody know how to code string input in assembly language? I'm using int 21 to display and input characters.
You can use function 0Ah to read buffered input. Given a string buffer in ds:dx it reads a string of up to length 255. The buffer layout is:
Byte 0 String length (0-255)
Byte 1 Bytes read (0-255, filled by DOS on return)
Bytes 2-..Length+2 (The character string including newline as read by DOS).
An example of a small COM file that reads a string and then echos it back to the user:
org 0x100
start:
push cs
pop ds ; COM file, ds = cs
mov ah, 0x0A ; Function 0Ah Buffered input
mov dx, string_buf ; ds:dx points to string buffer
int 0x21
movzx si, byte [string_buf+1] ; get number of chars read
mov dx, string_buf + 2 ; start of actual string
add si, dx ; si points to string + number of chars read
mov byte [si], '$' ; Terminate string
mov ah, 0x09 ; Function 09h Print character string
int 0x21 ; ds:dx points to string
; Exit
mov ax, 0x4c00
int 0x21
string_buf:
db 255 ; size of buffer in characters
db 0 ; filled by DOS with actual size
times 255 db 0 ; actual string
Note that it will overwrite the input line (and it thus might not look the program is doing anything!)
Alternatively you can use function 01h and read the characters yourself in a loop. Something like this (note it will overflow later buffers if more than 255 characters are entered):
org 0x100
start:
push cs
pop ax
mov ds, ax
mov es, ax; make sure ds = es = cs
mov di, string ; es:di points to string
cld ; clear direction flag (so stosb incremements rather than decrements)
read_loop:
mov ah, 0x01 ; Function 01h Read character from stdin with echo
int 0x21
cmp al, 0x0D ; character is carriage return?
je read_done ; yes? exit the loop
stosb ; store the character at es:di and increment di
jmp read_loop ; loop again
read_done:
mov al, '$'
stosb ; 'Make sure the string is '$' terminated
mov dx, string ; ds:dx points to string
mov ah, 0x09 ; Function 09h Print character string
int 0x21
; Exit
mov ax, 0x4c00
int 0x21
string:
times 255 db 0 ; reserve room for 255 characters
A string is just a series of characters, so you can use your int 21 code inside of a loop to get a string, one character at a time. Create a label in the data segment to hold your string, and each time you read a character, copy it to that label (incrementing an offset each time so your characters get stored sequentially). Stop looping when a certain character is read (perhaps enter).
Doing all this manually is tedious (think about how backspace will work) but you can do it. Alternatively, you can link against stdio, stdlib, etc. and call library functions to do much of the work for you.
How can I elegantly print the date in RFC822 format in Perl?
use POSIX qw(strftime);
print strftime("%a, %d %b %Y %H:%M:%S %z", localtime(time())) . "\n";
The DateTime suite gives you a number of different ways, e.g.:
use DateTime;
print DateTime->now()->strftime("%a, %d %b %Y %H:%M:%S %z");
use DateTime::Format::Mail;
print DateTime::Format::Mail->format_datetime( DateTime->now() );
print DateTime->now( formatter => DateTime::Format::Mail->new() );
Update: to give time for some particular timezone, add a time_zone argument
to now():
DateTime->now( time_zone => $ENV{'TZ'}, ... )
It can be done with strftime, but its %a (day) and %b (month) are expressed in the language of the current locale.
From man strftime:
%a The abbreviated weekday name according to the current locale.
%b The abbreviated month name according to the current locale.
The Date field in mail must use only these names (from rfc2822 DATE AND TIME SPECIFICATION):
day = "Mon" / "Tue" / "Wed" / "Thu" / "Fri" / "Sat" / "Sun"
month = "Jan" / "Feb" / "Mar" / "Apr" / "May" / "Jun" /
"Jul" / "Aug" / "Sep" / "Oct" / "Nov" / "Dec"
Therefore portable code should switch to the C locale:
use POSIX qw(strftime locale_h);
my $old_locale = setlocale(LC_TIME, "C");
my $date_rfc822 = strftime("%a, %d %b %Y %H:%M:%S %z", localtime(time()));
setlocale(LC_TIME, $old_locale);
print "$date_rfc822\n";
Just using POSIX::strftime() has issues that have already been pointed out in other answers and comments on them:
It will not work with MS-DOS aka Windows which produces strings like "W. Europe Standard Time" instead of "+0200" as required by RFC822 for the %z conversion specification.
It will print the abbreviated month and day names in the current locale instead of English, again required by RFC822.
Switching the locale to "POSIX" resp. "C" fixes the latter problem but is potentially expensive, even more for well-behaving code that later switches back to the previous locale.
But it's also not completely thread-safe. While temporarily switching locale will work without issues inside Perl interpreter threads, there are races when the Perl interpreter itself runs inside a kernel thread. This can be the case, when the Perl interpreter is embedded into a server (for example mod_perl running in a threaded Apache MPM).
The following version doesn't suffer from any such limitations because it doesn't use any locale dependent functions:
sub rfc822_local {
my ($epoch) = #_;
my #time = localtime $epoch;
use integer;
my $tz_offset = (Time::Local::timegm(#time) - $now) / 60;
my $tz = sprintf('%s%02u%02u',
$tz_offset < 0 ? '-' : '+',
$tz_offset / 60, $tz_offset % 60);
my #month_names = qw(Jan Feb Mar Apr May Jun
Jul Aug Sep Oct Nov Dec);
my #day_names = qw(Sun Mon Tue Wed Thu Fri Sat Sun);
return sprintf('%s, %02u %s %04u %02u:%02u:%02u %s',
$day_names[$time[6]], $time[3], $month_names[$time[4]],
$time[5] + 1900, $time[2], $time[1], $time[0], $tz);
}
But it should be noted that converting from seconds since the epoch to a broken down time and vice versa are quite complex and expensive operations, even more when not dealing with GMT/UTC but local time. The latter requires the inspection of zoneinfo data that contains the current and historical DST and time zone settings for the current time zone. It's also error-prone because these parameters are subject to political decisions that may be reverted in the future. Because of that, code relying on the zoneinfo data is brittle and may break, when the system is not regulary updated.
However, the purpose of RFC822 compliant date and time specifications is not to inform other servers about the timezone settings of "your" server but to give its notion of the current date and time in a timezone indepent manner. You can save a lot of CPU cycles (they can be measured in CO2 emission) on both the sending and receiving end by simply using UTC instead of localtime:
sub rfc822_gm {
my ($epoch) = #_;
my #time = gmtime $epoch;
my #month_names = qw(Jan Feb Mar Apr May Jun
Jul Aug Sep Oct Nov Dec);
my #day_names = qw(Sun Mon Tue Wed Thu Fri Sat Sun);
return sprintf('%s, %02u %s %04u %02u:%02u:%02u +0000',
$day_names[$time[6]], $time[3], $month_names[$time[4]],
$time[5] + 1900, $time[2], $time[1], $time[0]);
}
By hard-coding the timezone to +0000 you avoid all of the above mentioned problems, while still being perfectly standards compliant, leave alone faster. Go with that solution, when performance could be an issue for you. Go with the first solution, when your users complain about the software reporting the "wrong" timezone.