Q15 Library

mikroPascal PRO for ARM includes a library for operating and working with Q15 fractional number format.

Library Routines

Q15_Abs

Prototype

function Q15_Abs(input : integer) : word;
Description

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

Function returns Q15 output number.

Q15_Add

Prototype

function Q15_Add(x : integer; y : integer; var z : integer) : 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

function Q15_Sub(x : integer; y : integer; var z : integer) : 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
  • in1: First Q15 number, ranging from -32768 to 32767.
  • in2: Second Q15 number, ranging from -32768 to 32767.
  • out: Q15 output number.
Returns
  • 1 - if the result exceeds [-2147483648, 2147483647] limits.
  • 0 - otherwise.

Q15_Itof

Prototype

function Q15_Itof(x : integer) : 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 resulting floating point number.

Q15_Ftoi

Prototype

function Q15_Ftoi(f : real) : integer;
Description

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

Input number scope should be in the range of [-1.00000, 0.99996].

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

Function returns resulting Q15 fractional format number.

Q15_Itoa

Prototype

procedure Q15_Itoa(x : integer; var s : 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

function Q15_Atoi(var s : string; var x : integer) : word;
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: sn.ddddddddddddddd

  • s - sign; '-' negative, space - positive.
  • n - integer part; 0 or 1.
  • d - decimal part; 0..9 (ending zeros are not displayed).
Parameters
  • s: pointer to the input ASCII string.
  • x: 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

function Q15_Cos(x : integer) : 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 17748 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 17748 to 32767.

Q15_Sin

Prototype

function Q15_Sin(x : integer) : 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 -27580 to 27578.

Q15_Tan

Prototype

function Q15_Tan(x : integer) : 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 -25733 to 25738.
Returns

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

Q15_Asin

Prototype

function Q15_Asin(x : integer) : 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 -27568 to 27578.
Returns

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

Q15_Atan

Prototype

function Q15_Atan(x : integer) : 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 -25532 to 25509.
Parameters
  • x: input number in the Q15 format number, ranging from -32768 to 32767.
Returns

Function returns value in the Q15 format, ranging from -25532 to 25509.

Q15_Acos

Prototype

function Q15_Acos(x : integer) : 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 2887 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 2887 to 32767.

Q15_Log

Prototype

function Q15_Log(x : integer) : 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 -32748 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 -32748 to 0.