Oakland CPM Archive/oakcpm.iso/cpm/calculat/hp11.lbr/HP11.DZC/HP11.DOC

Text File | 1989-07-20 | 16KB | 410 lines

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                               H P

              A Programmer's Integer RPN Calculator

                  Version 1.1    July 20, 1989

                       Copyright (c) 1989
                               by
                           Terry Hazen
                      21460 Bear Creek Road
                       Los Gatos, CA 95030

                 Voice.......... [phone]
                 Saratoga RBBS.. [phone]
                 Zee-Machine.... [phone]


  HP11 and its documentation may not be circulated in any
  incomplete or modified form without written permission of the
  author.  Any commercial use of HP11 where the user receives
  revenue by duplicating or distributing HP11 by itself or in
  conjunction with any hardware or software product is expressly
  prohibited unless authorized in writing by the author.  All
  rights reserved.

=================================================================


Introduction
------------

HP11.COM is a simple and very useful programmer's integer
calculator modeled after a Hewlett-Packard calculator with RPN
notation.  It is an extensive upgrade of Eric Meyer's HP10 and
was rewritten and enhanced to reduce code size, to increase the
number of memory storage registers, to add stack roll and last-x
functions, and to improve the user interface and input error
trapping.

If you are not familiar with RPN notation, you should review the
file RPN.DOC for more information on RPN.  RPN.DOC also has more
detail on how HP11 uses its stack during stack and numeric
operations.

HP11 can operate in any of four display modes:  hexadecimal,
decimal, binary, and character, making it very useful for quickly
converting integer numbers from one base to another.  It can do
integer addition, subtraction, multiplication, division,
exponentiation and bitwise logical AND and OR operations.  It has
a 4 level stack and 6 memory storage registers.

All HP11 internal storage and arithmetic is unsigned 16 bit.
Thus 65537 becomes 00001, -1 becomes 65535, and so on.
Multiplication and exponentiation overflow and division by 0 will
generate errors.  In binary and character modes, the display
shows only the lowest 8 bits of 16, so 8-bit overflow does not
usually cause an error.


HP11 CP/M 2.2 RSX version
-------------------------

The utility HPRSX.COM will install a version of HP11.COM into
memory as a CP/M 2.2 resident system extension (RSX).  The RSX
remains resident in memory and can be called from the command
line or from within other programs.  The RSX version of HP11
operates just like HP11.COM.  See the file HPRSX.DOC for more
information on the HP11 RSX.


Running HP11
------------

When you invoke HP11, it will display its single operating line
and wait for your input:

  A0>hp11
  HP 1.1 - T.Hazen 7/89           H>     0000

The 'H>' indicates hexadecimal display mode (the default display
mode), and '0000' is the four digit hex calculator display of
register X, which is the register always displayed.  The HP11
stack and memory are initialized to zero when HP11 is first
loaded from disk.


Exiting HP11
------------

Use control-C (^C) to exit HP11.  If you operate under ZCPR3, you
may use the ZCPR3 'GO' command after exiting HP11 and before any
other command is executed and it will return you to HP11 exactly
where you left off.


Changing Display Modes
----------------------

To change the display mode, use the escape key (<ESC>) followed
by the first letter of the desired mode.  Either upper or lower
case letters may be used to select the mode.  The display
indicates which mode is currently being used, and the number in
the X register will be displayed in the current mode.  You may
translate numbers from one base to another by simply changing
display modes.


Hex Display Mode:
     To select the hex display mode, enter <ESC>H.  In hex mode,
     numbers display as four hex digits from 0000-FFFF.

Decimal Display Mode:
     To select the decimal display mode, enter <ESC>D.  In
     decimal mode, numbers display as five decimal digits from
     00000-65535.

Binary Display Mode:
     To select the binary display mode, enter <ESC>B.  In binary
     mode, the least significant byte of the number displays as 8
     binary digits, 00000000-11111111.

Character Display Mode:
     To select the character display mode, enter <ESC>C.  In
     character mode, the least significant 7 bits of the number
     display as an ASCII character.  Control characters are
     indicated by a '^' prefix.  For example, 03H will display as
     '^C' and DEL (7FH), will display as '^?'.

     All non-command characters can be directly entered as data
     in the character display mode.  Characters that have command
     functions such as 'L', '/', '=', ^C, <RET> (^M), etc, can be
     entered as data in the character mode by prefixing them with
     the <ESC> character.  See the section on Entering Special
     Characters for more information.


The HP11 Stack
--------------

The structure of HP11's 4 level stack is shown below:

               T -> 0000      Stack register 4
               Z -> 0000      Stack register 3
               Y -> 0000      Stack register 2
               --------------------------------------------
               X -> 0000      Stack register 1 <- Displayed

HP11 always displays the contents of the X register and all
values entered are entered into the X register.  When a number is
entered into the X register, the previous contents of the X
register are automatically moved up to the Y register, the
previous contents of the Y register are moved up to the Z
register, etc.  See the section on Stack Operations for more
information on how HP11's operations use the stack.


Entering Numbers
----------------

Invoke HP11 and try entering the following sequence of keys:

               ^X  <ESC>D  1 <RET>  2  +  4  *

You have cleared the stack, selected the decimal mode, entered
the decimal numbers '1' and '2', added them, entered '4' and
multiplied 4 times the previous result.  The display should show
'00012', which is (1+2)*4.

Your <ENTER> or <RET> key corresponds to the HP <ENTER> key.  It
is used to separate two numbers as they are being entered one
after the other or to copy the number in the displayed X register
into the Y register.  You normally key in a string of digits,
then press <RET> to enter the number in the displayed X register.
You do not need to use <RET> after every number entry, however,
as the use of the function keys also automatically terminates
digit entry.

Depending on the current display mode, a maximum number of digits
can be entered into the display, after which the leading digits
will begin to be discarded.  HP11 accepts a maximum of four
digits in the hex display mode, five digits in the decimal
display mode, eight digits in the binary display mode and one
digit in the character display mode.  The console bell will ring
if you enter a character that is not acceptable in the current
display mode.


Correcting Entries
------------------

The backspace key (^H) works like the left arrow '<--' key on an
HP calculator.  It has two functions.  During digit entry, it
will delete the last digit typed.  Otherwise it will clear the X
register and leave the stack lift disabled.


Entering Special Characters
---------------------------

The <ESC> key may be used as a prefix in the character display
mode to allow you to enter as a digit those characters that would
otherwise be interpreted by HP11 as calculator functions:

                       +-*^/&|~=lLsSrR<>.,

as well as the control characters ^X, ^C and <RET> (^M).

To enter the character 's', for example, enter '<ESC>s' instead
of 's', since entering 's' initiates a store to a memory
register.


Numeric Functions
-----------------

HP11's integer numeric functions and the keys to invoke them are:

     +    Addition, Y+X
     -    Subtraction, Y-X
     *    Multiplication, Y*X
     ^    Exponentiation, Y^X  (Y to the Xth power)
     /    Integer quotient, INT(Y/X)
               - Remainder, X*(Y/X-INT(Y/X)) -> Register R
     &    Bitwise AND, X&Y
     |    Bitwise OR, X|Y
     ~    Negation [2's complement], ~X

Negation affects only the X register.  The other operations use
the numbers in the first two registers X and Y as operands, and
display the result in the X register, dropping the stack.

When an integer division is performed, you are often interested
in both the quotient and the remainder.  To obtain both values
with HP10, the operations had to be performed separately.  With
HP11, the remainder is saved in the special reserved memory
register R during the division operation.  Memory register R is
accessed just like any of the regular memory registers 0-5.  It
may also be used to store numbers, but any contents will be
overwritten by the remainder during integer division operations.

The console bell will ring if an undefined key is pressed as an
operator.  It will also ring and the current multiplication (*),
division (/) or exponentiation (^) function will not operate if
16-bit overflow occurs or if division by 0 is attempted.  The
stack is left unchanged.  Use the backspace key to delete the
offending operand if you wish to try again.


Stack Operations
----------------

See the file RPN.DOC for more detail on how HP11's functions
affect the stack registers.

Entering a Number:
     <RET> lifts the stack, copying the number in register X
     into register Y.  The number being entered is then placed in
     register X.  Stack lift is disabled.

Clearing the Stack:
     You can clear the entire stack with Control-X (^X) at any
     time.  Memory and Last-X registers are not affected.

Exchanging X and Y:
     You can exchange the contents of the two lowest stack
     registers X and Y with the '=' function (X<>Y).  No other
     registers are affected.  This function is useful when you
     need to reverse the order of operands before performing a
     function sensitive to operand order such as subtraction,
     divison or exponentiation.

Last-X:
     When a numeric function is executed, a copy of the last
     value in the X register before the function is executed is
     saved in the Last-X register.  That value can be restored to
     the X register using the 'L' (or 'l') key.  The stack is
     lifted, moving the current contents of the X register to the
     Y register, etc, unless stack lift has been disabled by the
     <RET> or backspace key.  The value in the Last-X register is
     not affected.  The Last-X function saves you from having to
     reenter numbers you wish to use again and can assist you in
     error recovery.


Stack Roll:
     You can roll the stack by using '>' (or the unshifted
     equivalent '.') to roll it up one level and '<' (or ',') to
     roll it down one level.  When the stack is rolled up, the
     contents of all stack registers are moved up one level and
     the value in the top stack register is moved down to the X
     register.  When the stack is rolled down, the contents of
     all stack registers are moved down one level and the value
     in the X register is moved up to the top stack register.  No
     stack values are lost as a result of stack roll operations.


Memory Storage Registers
------------------------

There are 6 memory storage registers numbered 0-5 that may be
used to store constants or intermediate values during
calculations, for recalled as needed later.  The contents of
memory registers are not affected by the clear stack (^X)
operation.  Either upper or lower case letters may be used to
specify memory register Store or Recall functions.

Storing a Number:
     The number in the X register may be stored in any of the
     memory registers using the command 'S' followed by the
     number of the desired memory register.  The previous
     contents of the memory register will be overwritten, but the
     number in the X register will not be affected.  For example,
     to store the number in register X in memory register 2,
     enter 'S2'.


Recalling a Number:
     Numbers may be recalled from a memory register to register X
     using the 'R' command followed by the number of the memory
     register.  The stack will be lifted, putting the previous
     contents of register X into register Y, but the number in
     the memory register will not be affected.  For example, to
     recall memory register 0 to register X, enter 'R0'.

Remainder Register:
     An additional memory register R is used by the division
     operation to store the remainder.  It may also be used to
     store and recall numbers, but any contents will be
     overwritten during a division operation.  The command 'RR'
     (Recall Remainder) after a division operation will store a
     copy of the remainder in register X and put the quotient in
     register Y.  An exchange (=) operation will swap them if
     desired.


Examples
--------

Try the following sample calculations.  Press the keys shown, and
see whether the answer you get matches the example and if you
understand the process.  In the sample problems, the 'h' suffix
indicates a hex number.

1)  Whatis(122+31)*8 ?
          KEYSTROKES:  <ESC>D122<RET>31+8*
          ANSWER:  D>    01224

2)   How many 128-byte records are there between addresses D000h
     and E100h?
          KEYSTROKES:    <ESC>H E100<RET> D000 - <ESC>D 128 /
          ANSWER:   D>    00034    (E100h-D000h)/128d

3)   What character results from 'w' AND 5Fh ?
          KEYSTROKES:  <ESC>Cw <ESC>H5F& <ESC>C
          ANSWER:  C>   W    ('w'&5Fh)

4)   Whatdoes-115looklikeinbinary?
          KEYSTROKES:  <ESC>D115~<ESC>B
          ANSWER:  B>10001101

5)  Whatis5tothe4thpower?
          KEYSTROKES:  <ESC>D5<RET>4^
          ANSWER:  D>    00625

6)   What is 6+7+8+9 ?
          KEYSTROKES:    6<RET> 7<RET> 8<RET> 9 + + +
          ANSWER:   H>     001E    (What is that in decimal?)

7)   What is 1+2+3+4+5+6+7 ?  (Why can't you do it exactly the
     same way as in example 6?)
          KEYSTROKES:    <ESC>D 1<RET> 2<RET> 3<RET> 4 + + +
                         5<RET> 6<RET> 7 + + +
          ANSWER:   D>    00028    (The stack has 4 levels)


Acknowledgements
----------------

HP11 is based on HP10, copyright (c) 1984 by Eric Meyers, and was
upgraded with his kind permission.  Eric's many contributions to
CP/M include the famous Video Display Editor (VDE), recently
upgraded to the amazing ZDE by Carson Wilson.

My original intention was to write a CP/M 2.2 RSX version of
HP10, following the conventions set by Bridger Mitchell, so that
I could access the calculator from within programs such as text
editors and patchers (Eric had already written the HP+ RSX for
CP/M 3.0).

Along the way, however, I got inspired by recent articles in The
Computer Journal by Hal Bower and Cameron Cotrill on ZSDOS and
Lee Hart on Programming for Performance as well as Bridger
Mitchell's columns on Advanced CP/M (including his columns on
relocation and CP/M 2.2 RSX's) and Jay Sage's ZCPR3 Corner
columns on the Z-System (including his column on PRL files).  So
I decided to extensively reorganize and rewrite HP using some of
the code size reduction and other programming techniques I was
learning.

The result was a new and smaller (less than 1200 bytes) utility
that has more functions and an improved user interface, including
better input error trapping.  Plus it makes a really great RSX!

Thanks to all of you for the inspiration and the shared
knowledge!

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