Q15 Library
  mikroBasic PRO for dsPIC30/33 and PIC24 Libraries > DSP Libraries > 
  

Q15 Library

mikroBasic PRO for dsPIC30/33 and PIC24 includes a library for operating and working with Q15 fractional number format.

Library Routines

Q15_Abs

Prototype

sub function Q15_Abs(dim input as integer) as integer
Description

Function calculates absolute value of the Q15 fractional format number.
Parameters
  • x: Q15 input number, ranging from -32768 to 32767.
Returns

Function returns number in Q15 fractional format, ranging from 0 to 32767.

Q15_Add

Prototype

sub function Q15_Add(dim x as integer, dim y as integer, dim byref z as integer) as byte
Description

Function sums two Q15 format numbers.

If the result exceeds [-32768, 32767] limits, result will be maximal(minimal) number in Q15 format.
Parameters
  • x: First Q15 number, ranging from -32768 to 32767.
  • y: Second Q15 number, ranging from -32768 to 32767.
  • z: Q15 output number.
Returns
  • 1 - if the result exceeds [-32768, 32767] limits.
  • 0 - otherwise.

Q15_Sub

Prototype

sub function Q15_Sub(dim x as integer, dim y as integer, dim byref z as integer) as byte
Description

Function subtracts two Q15 format numbers.

If the result exceeds [-32768, 32767] limits, result will be maximal(minimal) number in Q15 format.
Parameters
  • x: First Q15 number, ranging from -32768 to 32767.
  • y: Second Q15 number, ranging from -32768 to 32767.
  • z: Q15 output number.
Returns
  • 1 - if the result exceeds [-32768, 32767] limits.
  • 0 - otherwise.

Q15_Itof

Prototype

sub function Q15_Itof(dim x as integer) as real
Description

Function converts number from the Q15 fractional number format to floating point number format.
Parameters
  • x: input Q15 number, ranging from -32768 to 32767.
Returns

Function returns number in single precision floating point format, ranging from -1 to 0.99997.

Q15_Ftoi

Prototype

sub function Q15_Ftoi(dim r as real) as integer
Description

Function converts number from the single precision floating point number format to Q15 fractional number format.

Input number scope should be in the range of [-1.00000, 0.99997].

If the floating point number is not in this range, the resulting number will be 0x7FFF (0x8000).
Parameters
  • x: floating format number to be converted.
Returns

Converted Q15 fractional fromat number in the range of -32768 to 32767.

Q15_Itoa

Prototype

sub procedure Q15_Itoa(dim x as integer, dim byref s as string)
Description

Function converts number from the Q15 fractional format to ASCII string.

Output ASCII string is in the following format : sn.ddddddddddddddd

  • s - sign; '-' negative, space - positive.
  • n - integer part; 0 or 1.
  • d - decimal part; 0..9 (ending zeros are not displayed).
Parameters
  • x: Q15 format number to be converted.
  • s: resulting ASCII string.
Returns

Nothing.

Q15_Atoi

Prototype

sub function Q15_Atoi(dim byref s as string, dim x as ^integer) as byte
Description

Function converts the input ASCII string s into a number in Q15 fractional point format.

Input ASCII string should be in the following format: _s_n.ddddddddddddddd_

  • _ - sign; '_' spaces or tabs (it is allowed any count od spaces or tabs).
  • s - sign; '-' negative, space - positive.
  • n - integer part; 0 or 1.
  • d - decimal part; 0..9, if there is more than 15 digits, only first 15 will be considered in calculation (ending zeros are not displayed).

Parser of input characters has following features :

  1. Spaces: leading, trailing and after sign are allowed.
  2. Zeroes: leading and trailing zeroes are allowed.
  3. Sign: positive number can have '+' sign or can be without sign.
  4. Special: accept omited digits before/after decimal point (.123 or -1.).
Parameters
  • s: pointer to the input ASCII string.
  • out: pointer to the resulting number in Q15 format.
Returns
  • 2 - If input string is in not in the appropriate format.
  • 1 - If overflow has been detected.
  • 0 - If no errors occured.

Q15_Cos

Prototype

sub function Q15_Cos(dim x as integer) as integer
Description

Function returns the cosine of x. The input number is in the Q15 format number and returns value in the Q15 format, ranging from 17705 to 32767.
Parameters
  • x: input number in the Q15 format number, ranging from -32768 to 32767
Returns

Function returns value in the Q15 format, ranging from 17705 to 32767.

Q15_Sin

Prototype

sub function Q15_Sin(dim x as integer) as integer
Description

Function returns the sine of x. The input number is in the Q15 format number and returns value in the Q15 format, ranging from -27580 to 27578.
Parameters
  • x: input number in the Q15 format number, ranging from -32768 to 32767.
Returns

Function returns value in the Q15 format, ranging from -27573 to 27573.

Q15_Tan

Prototype

sub function Q15_Tan(dim x as integer) as integer
Description

Function returns the tangent of x. The input number is in the Q15 format number and returns value in the Q15 format, ranging from -32768 to 32767.
Parameters
  • x: input number in the Q15 format number, ranging from -25763 to 25735.
Returns

Function returns value in the Q15 format, ranging from -32768 to 32767.

Q15_Asin

Prototype

sub function Q15_Asin(dim x as integer) as integer
Description

Function returns the arc sine of x. The input number is in the Q15 format number and returns value in the Q15 format, ranging from -32768 to 32767.
Parameters
  • x: input number in the Q15 format number, ranging from -27573 to 27573.
Returns

Function returns value in the Q15 format, ranging from -32768 to 32767.

Q15_Atan

Prototype

sub function Q15_Atan(dim x as integer) as integer
Description

Function returns the arc tangent of x. The input number is in the Q15 format number and returns value in the Q15 format, ranging from -25736 to 25735.
Parameters
  • x: input number in the Q15 format number, ranging from -32768 to 32767.
Returns

Function returns value in the Q15 format, ranging from -25736 to 25735.

Q15_Acos

Prototype

sub function Q15_Acos(dim x as integer) as integer
Description

Function returns the arc cosine of x. The input number is in the Q15 format number and returns value in the Q15 format, ranging from 256 to 32767.
Parameters
  • x: input number in the Q15 format number, ranging from 17705 to 32767.
Returns

Function returns value in the Q15 format, ranging from 256 to 32767.

Q15_Log

Prototype

sub function Q15_Log(dim x as integer) as integer
Description

Function returns the logarithm of x. The input number is in the Q15 format number and returns value in the Q15 format, ranging from -32767 to 0.
Parameters
  • x: input number in the Q15 format number, ranging from 3277 to 32767.
Returns

Function returns value in the Q15 format, ranging from -32767 to 0.
Copyright (c) 2002-2012 mikroElektronika. All rights reserved.
What do you think about this topic ? Send us feedback!
Want more examples and libraries? 
Find them on LibStock - A place for the code