PIC Microcontoller Basic Math Methods

Try the http://www.piclist.com code generator by Nikolai Golovchenko for Multiplication and Division by a constant.

• Add

• Subtract

• Increment / Decrement

• Two's complement / Negate

• Multiply

• Divide / Modulo

• Scale

• Square

• Square Root

• Powers

• Vector Math

• Floating Point

• Bit-fiddling

See:

• 32-bit signed integer math routines. add, subtract, multiply, divide, round, sqrt, bin2dec, dec2bin. By Peter Hemsley. +
• 32-bit signed integer stack based math routines: add, subtract, multiple, divide by Alan Cashin
• 32-bit integer math routines: add, subtract by Brian Beard as adapted from AN526
• Roger Froud's 16 and 32 bit maths function macros for PIC18F458
• Peter Harrison's 16/32/48 bit math library for the PIC18F4520
• PIC Microcontoller Comparison Math Methods to compare values after a math operation.
• Microchip instruction set summary
• 32 bit add, 32 bit subtract, 32 bit multiply, 32 bit divide: 32 bit signed integer math routines and math tutorial. Add32 Subtract32 Multiply32 Divide32. In PIC16f876 assembly languages. by Fr. Thomas McGahee. Emphasizes readability over speed.
• Fixed Point Math

See also:

• http://avtanski.net/projects/math/ Multibyte Arithmetic Assembly Library for PIC Microcontrollers+
• http://www.sxlist.com/techref/expeval2.asp An interesting expression evaluator.+
• http://www.markworld.com/microtools.html excellent math (Generate 8 or 16 bit PIC code to evaluate an infix expression. Analyze an IEEE floating point number) and servos
• http://www.microchip.com Math Library Application Notes AN575 Floating Point and AN617 Fixed Point
• ftp://ftp.epemag.wimborne.co.uk/pub/PICS/PICtricks/Floating_Point/Floating Point.zip Floating point library and format conversion tools +
• http://ndsl226.dnvr.uswest.net/cgi-bin/tl.exe/AERC/Poscalc/ SIN, COS, SQRT, etc., routines

Archive:

• List post "Complete working 32 bit floating point math library forPIC18x needed" +
• PICList Thread "Rounding"

Questions:

• +

• How do I work with numbers bigger than 255?! They didn't teach me that at my university!
   
  Use more than one byte.
   
• ~NOSPAM~jiri.antos-Remove- at merret.cz asks: " I look for OR function. I have PIC16F628. Thank you for help"

  James Newton answers: Look at the math and logic section of the instruction set for AND, OR (called IOR), XOR, ADD, SUBtract, etc..
   

• ~NOSPAM~jjc-Remove- at ingenieria.uaemex.mx, jose_juanct@yahoo.com asks: " I need code or to turn a number of floating point of 24/32 bits, to an integer number with decimals"

  James Newton answers: See: http://www.piclist.com/techref/microchip/math/radix/index.htm for base conversion routines.

Comments:

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