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Simtel MSDOS 1992 September
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PASLIB01.DOC
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1986-05-22
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A. Introduction
The following is the documentation for the subprogram
library PASLIB01.INC which is now placed in the public
domain.
CAVEAT: much of this library is IBM and PC DOS specific.
It has been tested on both an IBM PC-1 and an IBM PC/AT with
monochrome, CGA, EGA, and Hercules boards but there are no
guarantees for any other machines.
Any comments or suggestions will be appreciated.
Robert B. Wooster
(203) 227-5588
(212) 310-5222
CIS: 72415,1602
Version 1 released 22 May 1986
B. Global Declarations
1. Constants
a) IsColor
a boolean set by InitMonitor depending upon whether the
machines switches are set for monochrome or color.
Also used in SwapMonitors, q.v.
b) MaxRow, MaxCol should be self-evident
c) Video attributes:
LO_V: low video, HI_V high (or normal) video,
RE_V: reverse video
d) Special key scan codes
for the use of these constants see the functions ugetc
and NextField
1) cursor control keys
SK_HM: Home SK_UP: up SK_PU: PgUp
SK_LE: left SK_RI: right
SK_EN: End SK_DN: down SK_PD: PgDn
SK_IN: Ins SK_DE: Del
2) function keys
SK_F1 to SK_F0
3) the Esc key : E_S_C
2. Types
a) chrset
b) string80: used as standard string type in most of the
routines
c) bigstring: for use when string80 isn't enough
d) regtype: fairly standard register declaration for use in
DOS function calls
e) datetype: a standard date type to handle dates from 1/2/60
to 12/31/2050
f) timetype: a standard type for handling times
g) scrntype & scrnptr: used in SaveScrn and RestoreScrn
3. Variables
a) EquipFlag: the location of the equipment flag set by POST on
IBM PCs
b) MonoScrn & ColorScrn: the addresses of the monochrome and CGA
screens
c) KeyStat: the key status byte used by the keyboard routines
d) SavedScrn: used by SaveScrn & RestoreScrn, q.v.
e) SplKey: a flag used by the keyboard input routines, q.v.
f) sdt: the current date according to the machine's clock;
initialized in InitSys
g) out: used by WhereOut, q.v.
h) To_LST: see WhereOut
i) EscFlag: see ugetc
C. Hardware control functions
1. InitMonitor procedure
a) function: sets IsColor flag according to the switch
setting at EquipFlag
b) syntax: InitMonitor;
c) returns: nothing
d) side effects: sets IsColor flag
e) notes: EquipFlag is set during boot according to the
hardware switch settings. In a two monitor
system this means that the monochrome monitor
will come up. EquipFlag can, however, be
reset by some external programs such as Bob
Starr's UTIL.EXE.
2. SwapMonitors procedure
a) function: this is to allow two monitor systems to move
back and forth between the monochrome and
color monitors.
b) Syntax: SwapMonitors;
c) returns: nothing
d) side effects: resets EquipFlag, and IsColor to their
opposite monitor settings
e) notes: if you return to the Turbo editor after
switching monitors an odd number of times,
the results can be unpredictable, i.e. your
machine will more or less hang.
3. SaveScrn procedure
a) function: saves current screen
b) syntax: SaveScrn
c) returns: nothing
d) side effects: moves screen contents to savedscrn
e) notes: used with restorescrn
f) calls: nothing
4. RestoreScrn procedure
a) function: restores saved screen
b) syntax: RestoreScrn
c) returns: nothing
d) side effects: moves saved screen to current screen
e) notes: used with savescrn
f) calls: nothing
5. InitSystem procedure
a) function: initialize system to standard
setup
b) syntax: InitSystem;
c) returns: nothing
d) side effects: IsColor flag and sdt are set and the standard
window configuration (Sec. G) is initialized
e) notes: See TEMPLATE.PAS for an example of its use
f) calls: InitMonitor, InitWindows, SysDate
D. Low-level Screen I/O
1. ugetc character function
a) function: get a character from the keyboard without
echo but with several side effects
b) syntax c := ugetc;
c) returns the character typed
d) side effects
1) if Control-C is typed the program halts
2) if a special key, i.e. a function or cursor control key, is
typed, a null character is returned and the global variable
SplKey is set to that key's scan code
e) notes: this is the workhorse of the input functions
discussed in section D
2. putc procedure
a) function: put a character on the screen with a
specified attribute at the current cursor
position
b) syntax putc(c,b) where c is a character and b is an
attribute byte.
c) returns nothing
d) side effects none, but note that the cursor is not moved
e) notes: uses direct screen addressing
3. aputc procedure
a) function: put a character c on the screen with
attribute b at column x and row y
b) syntax aputc(c,b,x,y)
c) returns nothing
d) side effects none, but note that the cursor is not moved
e) notes: uses direct screen addressing
E. Data I/O
1. GetUC character function
a) function: get an upper case character from the
keyboard if it is in OKSet, otherwise ring
bell until a character in OKSet is typed
b) syntax c := GetUC(default, OKSet)
c) returns an upper case character
d) side effects same as ugetc
e) notes: useful for menu selections
f) calls: ugetc
2. PutString procedure
a) function: put a string on the CRT at the indicated
position
b) syntax PutString(s,x,y)
c) returns nothing
d) side effects none
e) notes: writes a string80 but $V- parameter permits
sending any string
3. GetString procedure
a) function: get a string from the keyboard
b) syntax: GetString(s1,len,x,y,s2)
where s1 is the string returned as a
side effect
len is the maximum length of the string
x,y are the screen coordinates
s2 is the default string or ''
c) returns: nothing
d) side effects: If a string has been typed it is returned in
s1. If no string typed before a special
function key or <Enter> is typed s2 is
returned as s1. If a special function key is
pressed the global variables are set.
e) notes: The function terminates after len characters
have been entered.
<Esc> clears an unfinished entry and lets you
start over
f) calls: ugetc, PutString
4. PutInteger procedure
a) function: put an integer on the screen at x,y
b) syntax: PutInteger(i,x,y,len)
c) returns: nothing
d) side effects: none
e) notes:
f) calls: PutString
5. GetInteger procedure
a) function: get an integer from the keyboard
b) syntax: GetInteger(i1,x,y,len,min,max,i2)
where i1 is the integer returned
x,y are the screen coordinates
len is the maximum length
min is the minimum acceptable value
max is the maximum acceptable value
i2 is the default value
c) returns: nothing
d) side effects: the entered value in i2 plus the same other
side effects as GetString
e) notes: the NumLock is set upon entering this
function and released upon exit
f) calls: GetString, PutInteger
6. Format string function
a) function: format a number with parentheses and commas
b) syntax: s := Format(r,i,j)
c) returns: s as a string of length i representing a
number to j decimal places with imbedded
commas and parens if negative.
d) side effects: none
e) notes: use for pretty-printing output
f) calls:
7. PutNumber procedure
a) function: put a real number on CRT at x,y with length i
and j decimal places
b) syntax: PutNumber(r,i,j,x,y)
c) returns: nothing
d) side effects: none
e) notes: results are unpredictable if number has more
than i digits
f) calls: nothing
8. GetNumber procedure
a) function: get a real number from the keyboard
b) syntax: GetInteger(r1,x,y,i,j,min,max,r2)
where r1 is the integer returned
x,y are the screen coordinates
i is the maximum length
j is the # of decimals
min is the minimum acceptable value
max is the maximum acceptable value
r2 is the default value
c) returns: nothing
d) side effects: the entered value in r1 plus the same other
side effects as GetString
e) notes: the NumLock is set upon entering this
function and released upon exit
f) calls: GetString, PutNumber
9. PutDate procedure
a) function: put a date on the CRT in the form mm/dd/yy
b) syntax: PutDate(date,x,y);
c) returns: nothing
d) side effects: none
e) notes:
f) calls:
10. GetDate procedure
a) function: get a legal date form the keyboard
b) syntax: GetDate(date1,x,y,date2)
where: date1 is the date returned
x,y are the screen coordinates
date2 is the default date
c) returns: nothing
d) side effects: date entered in date1
e) notes: NumLock is set upon entering this procedure
and cleared upon exit.
ANY character may be used as a delimiter
If no year is given the current year is
assumed
Dates must be between 1/1/1960 and
12/31/2059, the appropriate century is
assumed.
f) calls: GetString
11. Heading procedure
a) function: put a string on the heading line
b) syntax: Heading(string)
c) returns: nothing
d) side effects: prints a message centered on line 1
e) notes: see above
f) calls: MainWdo, aputc
12. Wait procedure
a) function: wait for any key to be pressed
b) syntax: Wait;
c) returns: nothing
d) side effects: none
e) notes: prints "Press any key to continue" on the
message line and waits for it. An
improvement over REPEAT UNTIL KeyPressed
because it throws away the key that was
pressed.
f) calls: HelpWdo, MainWdo
13. ShowHelp procedure
a) function: Display a message on the message
line
b) syntax: ShowHelp(string)
c) returns: nothing
d) side effects: none
e) notes: Use for explanatory messages
f) calls: HelpWdo, MAinWdo
14. Prompt character function
a) function: a variation on the UCSD standard prompt such
as "C)ompile, E)dit, F)ile, R)un ?"
b) syntax: c := Prompt(string, default);
c) returns: character c
d) side effects: none
e) notes: any capitalized character in string is a
valid response.
f) calls: HelpWdo, MainWdo, GetUC
F. Date Manipulation
1. Jul integer function
a) function: calculate pseudo-Julian number from date
b) syntax: i := Jul(date)
c) returns: returns pseudo-Julian as an integer
d) side effects: none
e) notes: the algorithm first calculates the true
Julian number as a real and then subtracts
the Julian number for 1/1/60. This insures
that the number will be an integer over the
range of datetype. Based on a FORTRAN
one-liner fount in the HP-41 user library.
f) calls: None.
2. JtoD procedure
a) function: convert a pseudo-Julian number to a datetype
b) syntax: JtoD(i, date);
c) returns: nothing
d) side effects: returns date as a side effect
e) notes: See Jul; this just reverses the process
f) calls: none
3. J30 integer function
a) function: Does the equivalent of Jul except following
a 30-day month convention.
b) syntax: i := J30(date)
c) returns: a 30-day equivalent pseudo-Julian number
d) side effects: none
e) notes: See Jul.
f) calls: nothing
4. LegalDate procedure
a) function: checks to see if a date is a legal
date, i.e., not June 31, and if it
is, fixes it
b) syntax: LegalDate(date);
c) returns: nothing
d) side effects: if date is corrected, the corrected date
is returned, else the original date is
returned
e) notes: can be used for some input checking
f) calls: nothing
5. mmdd string function
a) function: converts a date to a string of the
form "mm/dd"
b) syntax: s := mmdd(date);
c) returns: string of date in the form "mm/dd"
d) side effects: none
e) notes: useful for printing dates
f) calls: nothing
6. mmddyy string function
a) function: converts a date to a string of the
form "mm/dd/yy"
b) syntax: s := mmddyy(date);
c) returns: string of date in the form "mm/dd/yy"
d) side effects: none
e) notes: useful for printing dates
f) calls: nothing
7. DayofWeek integer function
a) function: find the day of the week from a date
b) syntax: i := DayOfWeek(date);
c) returns: an integer with 0 representing Monday and 6
representing Sunday
d) side effects: none
e) notes: used by NextBDay
f) calls: Jul
8. NextBDay procedure
a) function: find the next weekday after a date
b) syntax: NextBDay(date1,date2)
c) returns: nothing
d) side effects: date2 is the next business or week day after
date1
e) notes: used for some investment calculations
f) calls: DayofWeek, JtoD, jul
9. AddMonths procedure
a) function: add n months to a date
b) syntax: AddMonths(date1,n,date2)
c) returns: nothing
d) side effects: date2 is n months from date1
e) notes: very useful for bond calculations but
admittedly a little kludgey
f) calls: nothing
10. DayCount integer function
a) function: return days between two dates
b) syntax: i := DayCount(date1, date2)
c) returns: number of days between two dates
d) side effects: none
e) notes: I was doing this so often in programs I
decided to make it a function. The order of
the dates is irrelevant; the absolute value
of the dates is returned.
f) calls: Jul
11. DatesEqual boolean function
a) function: test for the equality of two dates
b) syntax: Boolean := DatesEqual(date1, date2);
c) returns: TRUE if date1 equals Date2, false otherwise
d) side effects: none
e) notes: why can't Pascal test for equality of
records?
f) calls: nothing
12. NullDate procedure
a) function: sets a date to 1/1/60
b) syntax: NullDate(date)
c) returns: nothing
d) side effects: date is set to 1/1/60, which may be used as a
null
e) notes: used to test if a date record is initialized;
may also be used to force no default in
GetDate
f) calls: nothing
G. Window Support
My standard display uses the first line as a header and
the last line as a message line. The active window then
becomes rows 2 through 24. Both the header and the message
line are in reverse video. The procedures InitWindows,
MainWdo, and HelpWdo manage this
1. InitWindows procedure
a) function: set up standard windows
b) syntax: InitWindows
c) returns: nothing
d) side effects: CRT lines 1 and 25 are set to reverse video
and the active window is set to 1,2;80,24
e) notes: see above
f) calls: MainWdo, aputc
2. MainWdo procedure
a) function: set the active window to 1,2;80,24
b) syntax: MainWdo
c) returns: nothing
d) side effects: sets the active window to 1,2;80,24
e) notes: see above
f) calls: nothing
3. HelpWdo procedure
a) function: set the active window to the message
line
b) syntax: HelpWdo
c) returns: nothing
d) side effects: sets the active window to 1,1;80,25
e) notes: sets the cursor at 1,25
f) calls: nothing
4. UseWdo procedure
a) function: creates a window for i/o
b) syntax: UseWdo(x,y,col,row,string);
c) returns: nothing
d) side effects: see notes
e) notes: creates a window with the upper left corner
at x,y, col wide and row high. If possible,
draws a box around the window. String is
inserted in the row above the window. The
window is cleared.
f) calls: aputc
5. CloseWdo procedure
a) function: restores MainWdo after a call to UseWdo
b) syntax: CloseWdo;
c) returns: nothing
d) side effects: none
e) notes: used to cancel effect of UseWdo. It does
not, however, clear the screen. To do that
use the window save and restore functions.
f) calls: MainWdo
H. System Services
1. SysDate procedure
a) function: gets the date from the system clock
b) syntax: SysDate(date);
c) returns: nothing
d) side effects: date is initialized to whatever date the
computer's clock says it is
e) notes:
f) calls:
2. SysTime procedure
a) function: gets the time from the system
clock
b) syntax: SysTime(time)
c) returns: nothing
d) side effects: time is initialized to whatever time the
computer's clock says it is
e) notes:
f) calls:
3. TimeStamp string function
a) function: returns a string with the current date and
time
b) syntax: s := TimeStamp
c) returns: s initialized to a string of the form
"mm/dd/yy hh:mm am"
d) side effects: none
e) notes: useful for including in a write statement.
The value returned is based on the computer's
clock.
f) calls: SysTime, SysDate,TimeStamp
I. Miscellaneous
1. MakeBox
a) function: draws a box using reverse video on the
CRT
b) syntax: DrawBox(x1,y1,x2,y2)
c) returns: nothing
d) side effects: none
e) notes: draws a box from x1,y1 to x2,y2
f) calls: aputc
2. WhereOut
a) function: permits user to select between CRT and
printer output.
b) syntax: WhereOut
c) returns: nothing
d) side effects: opens "out" as either LST: or CON: depending
on user response
e) notes: file out should be closed when finished.
f) calls: HelpWdo, MainWdo
3. Page
a) function: if printer selected as output sends a form
feed as per standard procedure, does a Wait
if CRT selected.
b) syntax: Page;
c) returns: nothing
d) side effects: form feed or wait
e) notes: Tests To_LST flag
f) calls: wait
