PIC Microcontoller Math Library Methods

• Basic Math: Add, subtract, multipy, divide, negate, square, square root, etc... and stack based version
• Conversions (Base: decimal to binary, binary to ASCII hex, etc., Units)
• Comparison: if(A<B)then...else...endif, do...while(A<B)
• Range check: if((Lo < x) and (x < Hi))then ... else ... endif.
• Min / Max / Limit / Saturate / Absolute Value
• Bit operations (CRC, Parity, Setting bit number X, etc...)
• Filtering / DSP
• Scott Dattalo Tweaking a PIC for sin, arcsine, arctan, sqrt, log, parity, bcd,ArcTan (including Fractional Division), scale
• Eric Smith Implementing the Sine function on the PIC.
• Powers: x^y, 2^x, log2(x), etc., (using fixed-point math).
• Random
• Table lookups

Math@ SX specific math@,

See also:

• avtanskispam at gmail.com refers to

  http://avtanski.net/projects/math Hello, I have set up an online generator for multi-bite math code (addition, subtraction, multiplication, division, logical operations) that might be useful for somebody: http://avtanski.net/projects/math In the form you enter operand size (how many bytes each number consists of), select what subroutines you need, press a button and get your code. Regards, - Alex

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• ftp://ftp.epemag.wimborne.co.uk/pub/PICS/PICtricks/ Misc. PIC routines, some good, some not so good.
• PICmicro Code Snippets and Macros by Myke Predko has some short and useful PIC routines.
• http://picfloat.sourceforge.net PICFLOAT is a open source floating point library for midrange PIC processors from Microchip+
• Salvador Eduardo Tropea of Instituto Nacional de Tecnologia Industrial refers to

  http://mifit.utic.com.ar/ Mifit (Micro fitter) searches the best approximation to a set of data points using simple equations (rects and quadratics), and computes the maximum absolute and relative errors for the adjusted interval, the whole data set, or a specified range. It can generate the assembly code to implement it (currently only for Microchip's PIC family of microcontrollers). Currently only Linux is supported.

• Edi Permadi of President University Says:

  The AES-128 could be efffectively implemented on PICmicros processor. I was coding that cipher on PIC16F84 and PIC16F877 and of course PIC16F877 results better throughput. If you wish to see my code, i may freely download it on links below.

  Source Codes: v1.0 v1.1 v1.2 v1.3 v1.4
  Now, PIC16F877 could run AES-128 faster than previous version. v1.5.7

  If you wish to see my PICmicros cryptographic codes, you may see it on
  http://cryptonutter.googlecode.com

  the articles of those codes are available on
  http://edipermadi.wordpress.com

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• http://www.microchip.com/1010/suppdoc/appnote/category/pic16/931/index.htm AN 526 Math functions
• http://www.microchip.com/1010/suppdoc/appnote/category/library/index.htm#17 Math libraries
• Dontronics BASIC Stamp clone pages. A collection of ready-to-use assembly language routines based on the instruction set of the BASIC Stamp ® single-board computer by Scott Edwards Electronics. Includes useful schematics.
  • http://www.dontronics.com/convert.html for MicroChip code
  • http://www.dontronics.com/see.html for Parallax code ParaPic is better now and these are being re-converted with the latest version and updated versions of the routines added by James Newton of piclist.com. Watch this space.

Comments:

• I very much appreciate your site. I am just learning about microcontrollers, and this is certainly a panacea for one like me. Your site is extremely informative, well-organized, and lean.
  
  A++
  
  Allasso+
• http://www.microchip.com/10/appnote/category/library/ Go to Microchip for source code for (PIC assembly language) math libraries. The app notes explain several collections of routines: fixed-point math, floating-point math, and IEEE 754 Compliant Floating Point Routines.

Questions:

• Lee Kok Zhi asks: " Im using PIC16F877. How can I do 16-bits square root with it? I realize that all the square root routine available at here is only for 17Cxx or 18cxx."
• grahamspam at london-electronics.com asks:

  Hi
  
  Using PIC16F877 - I have an input value of up to 65535 (from an A/D convereter) and want to scale it by a variable factor to give an answer from 0.0001 up to 99999, with 1 in 65535 resolution. (The value will be displayed on a 5 digit 7 segment display, with + or - sign)
  
  I'm struggling.. any bright folk have a suggestion?
  
  Thanks in advance,
  
  Graham

  James Newton replies: So 0 will be .0001? and 65535 will be 99999? First, convert to integer: Multiply your beginning and ending output by 10000. 0.0001 * 10000 = 1. 99999 * 10000 = 999,990,000. Now, subtract the starting value from the ending value to find the output range. 999,990,000 - 1 = 999989999. Now for any input value, you will multiply it by 999989999/65535 = 15258.869291218432898451209277485 and then add 1. You will display the first 5 digits of this answer, then a period, then the last 4 digits.

  For example, if the input is 0, the answer will be 0 * 15258.869291218432898451209277485 + 1 = 1. Please note that this is actually 000,000,001 which will be displayed as 00000.0001. If the input is 65535, the answer will be 65535 * 15258.869291218432898451209277485 + 1 = 999990000 which will be displayed as 99999.0000

  Now, I have no idea how the heck you are going to get that kind of precision out of a PIC. The best I can show you is the input * 15258.9 + 1. with that, the top end is 99999.2012. The code to do the multiplication is at
  http://www.piclist.com/cgi-bin/constdivmul.exe?Acc=ACC&Bits=16&endian=little&Const=15258.9&ConstErr=0&Temp=TEMP&cpu=pic16

  Increment the result by one:
  http://www.piclist.com/techref/microchip/math/incdec/32bitwz.htm

  Convert to decimal ASCII:
  http://www.piclist.com/techref/microchip/math/radix/b2bp-32b10d.htm +

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• louispam at g2a.net asks:

  louis frias asks: Hi every one I am looking for 48 bit x 48 bit "signed integer divide" I see in the your math libraries 48/24 bit code but not 48/48. If there is non ...Is there any one willing to write/modify any existing signed integer divides such as the 32/32 signed divide given in the microchip math library Handbook ??????????????? Please email to me loui@g2a.net at your earliest convenience Louis Frias
   

• shenyeepangspam at hotmail.com asks: " I have a series of 1 and 0, how can I apply quarter wave symmetry to mirror this series? eg. 010001110111111 (quarter)" +
  See Bit Math Method Reverse bit order in a byte
   
• Hernan J Freschi asks: " How do I use numbers bigger than 255? I mean, I have a 32-bit pentium processor, which counts over 4,294,967,296..."
• hjfspam at hjf.com.ar asks: " How do I work with numbers bigger than 255?! They didn't teach me that at my university!"
  Use a second register. The first does 0 to 255, if the second is 0, but it represents 256 to 511 if the second register is 1 and so on. The result is 256 times 256 different possible values or 65536 total values. This can continue with three or more registers untill you reach a point where all the memory locations are used or you have a big enough number range.

Archive:

• List post "Complete working 32 bit floating point math library forPIC18x needed" +
• PICList post "Hacker's Delight" +
• PICList post "x^y routine implementation" +

Code:

• Henry Santana shares a parity generator in PIC16F872 assembly language

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