RCAL - A "ROLLING" CALCULATOR Copyright (C) 2018 Mateusz Viste http://rcal.sourceforge.net rcal is an interactive calculator that loosely mimics the behavior of "roller printing" calculators. It supports huge numbers, floating point and has extremely low hardware requirements. === REQUIREMENTS ============================================================= rcal is a 16-bit (real mode) DOS application. It needs DOS 3+, an 8086 CPU and around 100 KiB of available conventional RAM. === USAGE ==================================================================== Using rcal is as simple as launching the rcal executable and providing the operands and operators that need to be computed. Following operators are supported: '+' and '-' (add/subtract) '*' and '/' (multiply/divide) ^ - power % - percent Inputing a negative operand requires to press the 'S' key (S = change sign). Operator notes: 1. The percent operator acts in a perhaps peculiar way, since it actually does slightly more than just scaling a value down by 100. When it is preceded by an addition or subtraction, the percent operator will add or subtract the product of the previous operand. Example: Operation: "300 + 5%" will actually perform "300 + (300 * 5%)" 2. The power operator (^) supports only integer exponents. 3. Divisions are performed using a precision limited to 20 decimal places. === LIMITATIONS ============================================================== Values that can be input to rcal can have up to 10 integer digits and 6 fractional digits. The computation engine itself is able to handle much bigger numbers though: the entire result can be up to 56 digits long (longer intermediate results are possible, but won't be displayed). === LICENSE ================================================================== rcal is published under the MIT license, as printed below. Permission is hereby granted, free of charge, to any person obtaining a copy of this software and associated documentation files (the "Software"), to deal in the Software without restriction, including without limitation the rights to use, copy, modify, merge, publish, distribute, sublicense, and/or sell copies of the Software, and to permit persons to whom the Software is furnished to do so, subject to the following conditions: The above copyright notice and this permission notice shall be included in all copies or substantial portions of the Software. THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE. rcal relies on the APM (Arbitrary Precision Math) library v1.0, published by Lloyd Zusman in 1988. The APM library is falls under different licensing terms than rcal, since it is licensed under its own license, the APM GPL. Lloyd Zusman kindly provided his blessing to rcal using APM. The APM GPL is printed below. Arbitrary Precision Math Library General Public License (Written October 5, 1988) Copyright (C) 1988 Lloyd Zusman, Master Byte Software, Los Gatos, California. Everyone is permitted to copy and distribute verbatim copies of this license, but changing it is not allowed. You can also use this wording to make the terms for other programs. The wording of this license is based on that of the "GNU EMACS GENERAL PUBLIC LICENSE" by Richard Stallman, Copyright (C) 1985, 1987, 1988, version of February 11, 1988, but since some of the text has been changed, please be sure to READ THIS CAREFULLY! This general public license is intended to give everyone the right to share the Arbitrary Precision Math Library (hereinafter referred to as the "APM Library"). To make sure that you get the rights we want you to have, I need to make restrictions that forbid anyone to deny you these rights or to ask you to surrender the rights. Specifically, we want to make sure that you have the right to give away copies of the APM Library, that you receive source code or else can get it if you want it, that you can change the APM Library or use pieces of it in new programs, and that you know you can do these things. To make sure that everyone has such rights, we have to forbid you to deprive anyone else of these rights. For example, if you distribute copies of the APM Library, you must give the recipients all the rights that you have. You must make sure that they, too, receive or can get the source code. And you must tell them their rights. Also, for our own protection, we must make certain that everyone finds out that there is no warranty for the APM Library. If the APM Library is modified by someone else and passed on, we want its recipients to know that what they have is not what we distributed, so that any problems introduced by others will not reflect on our reputation. Therefore we (Lloyd Zusman and Master Byte Software) make the following terms which say what you must do to be allowed to distribute or change the APM Library. COPYING POLICIES 1. You may copy and distribute verbatim copies of the APM Library source code as you receive it, in any medium, provided that you conspicuously and appropriately publish on each copy a valid copyright notice "Copyright (C) 1988 Lloyd Zusman, Master Byte Software, Los Gatos, California" (or with whatever year is appropriate); keep intact the notices on all files that refer to this License Agreement and to the absence of any warranty; and give any other recipients of the the APM Library program a copy of this License Agreement along with the program. You may charge a distribution fee for the physical act of transferring a copy. 2. You may modify your copy or copies of the APM Library source code or any portion of it, and copy and distribute such modifications under the terms of Paragraph 1 above, provided that you also do the following: a) cause the modified files to carry prominent notices stating that you changed the files and the date of any change; and b) cause the whole of any work that you distribute or publish, that in whole or in part contains or is a derivative of the APM Library or any part thereof, to be licensed to all third parties on terms identical to those contained in this License Agreement (except that you may choose to grant more extensive warranty protection to some or all third parties, at your option). c) You may charge a distribution fee for the physical act of transferring a copy, and you may at your option offer warranty protection in exchange for a fee. d) You may not charge a license fee for the whole of any work that you distribute or publish, that in whole or in part contains or is a derivative of the APM library or any part thereof, without the express written permission of Lloyd Zusman and Master Byte Software; whether this permission is granted for free or in return for goods services, royalties, or other compensation will be determined solely by Lloyd Zusman and Master Byte Software. Mere aggregation of another unrelated program with this program (or its derivative) on a volume of a storage or distribution medium does not bring the other program under the scope of these terms. 3. You may copy and distribute the APM Library (or a portion or derivative of it, under Paragraph 2) in object code or executable form under all the terms of Paragraphs 1 and 2 above provided that you also do one of the following: a) accompany it with the complete corresponding machine-readable source code, which must be distributed under the terms of Paragraphs 1 and 2 above; or, b) accompany it with a written offer, valid for at least three years, to give any third party free (except for a nominal shipping charge) a complete machine-readable copy of the corresponding source code, to be distributed under the terms of Paragraphs 1 and 2 above; or, c) accompany it with the information you received as to where the corresponding source code may be obtained. (This alternative is allowed only for noncommercial distribution and only if you received the program in object code or executable form alone.) For an executable file, complete source code means all the source code for all modules it contains; but, as a special exception, it need not include source code for modules which are standard libraries that accompany the operating system on which the executable file runs. 4. You may not copy, sublicense, distribute or transfer the APM Library except as expressly provided under this License Agreement. Any attempt otherwise to copy, sublicense, distribute or transfer the APM Library is void and your rights to use the APM Library under this License agreement shall be automatically terminated. However, parties who have received computer software programs from you with this License Agreement will not have their licenses terminated so long as such parties remain in full compliance. 5. If you wish to incorporate parts of the APM Library into other programs whose distribution conditions are different, write to Lloyd Zusman at Master Byte Software. We have not yet worked out a simple rule that can be stated here, but we will often permit this. We will be guided by the goals of (1) preserving the free status of all derivatives of our free software; of (2) promoting the sharing and reuse of software; and of (3) not allowing anyone to profit from the use of our software without us also having the opportunity to share in these profits. Your comments and suggestions about our licensing policies and our software are welcome! Please contact Lloyd Zusman, Master Byte Software, 127 Wilder Ave., Los Gatos, California 95030, or call (408) 395-5693. NO WARRANTY BECAUSE THE APM LIBRARY IS LICENSED FREE OF CHARGE, WE PROVIDE ABSOLUTELY NO WARRANTY, TO THE EXTENT PERMITTED BY APPLICABLE STATE LAW. 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IN NO EVENT UNLESS REQUIRED BY APPLICABLE LAW WILL MASTER BYTE SOFTWARE, LLOYD ZUSMAN, AND/OR ANY OTHER PARTY WHO MAY MODIFY AND REDISTRIBUTE THE APM LIBRARY AS PERMITTED ABOVE, BE LIABLE TO YOU FOR DAMAGES, INCLUDING ANY LOST PROFITS, LOST MONIES, OR OTHER SPECIAL, INCIDENTAL OR CONSEQUENTIAL DAMAGES ARISING OUT OF THE USE OR INABILITY TO USE (INCLUDING BUT NOT LIMITED TO LOSS OF DATA OR DATA BEING RENDERED INACCURATE OR LOSSES SUSTAINED BY THIRD PARTIES OR A FAILURE OF THE PROGRAM TO OPERATE WITH PROGRAMS NOT DISTRIBUTED BY MASTER BYTE SOFTWARE) THE PROGRAM, EVEN IF YOU HAVE BEEN ADVISED OF THE POSSIBILITY OF SUCH DAMAGES, OR FOR ANY CLAIM BY ANY OTHER PARTY. ==============================================================================