Embedded Software and Motor Control Libraries for PXR40xx

Function GFLIB_Atan_F16
{
}
// input ratio = 0x7FFFFFFF => 1
f32Input = FRAC32 (1);
// output angle should be 0x1FFFBD7F = 0.249999 => pi/4
f32Angle = GFLIB_Atan_F32 (f32Input, GFLIB_ATAN_DEFAULT_F32);
// output angle should be 0x1FFFBD7F = 0.249999 => pi/4
f32Angle = GFLIB_Atan (f32Input, GFLIB_ATAN_DEFAULT_F32, Define F32);
// ##############################################################
// Available only if 32-bit fractional implementation selected
// as default
// ##############################################################
// output angle should be 0x1FFFBD7F = 0.249999 => pi/4
f32Angle = GFLIB_Atan (f32Input);
4.32 Function GFLIB_Atan_F16
This function implements Minimax polynomial approximation of arctangent function.
4.32.1 Declaration
tFrac16 GFLIB_Atan_F16(tFrac16 f16In, const GFLIB_ATAN_T_F16 *const pParam);
4.32.2 Arguments
Table 4-40. GFLIB_Atan_F16 arguments
Type Name Direction Description
tFrac16 f16In input Input argument is a 16-bit number between [-1, 1).
const
GFLIB_ATAN_T_F16
*const
4.32.3 Return
pParam input Pointer to an array of minimax approximation coefficients.
The function returns the atan of the input argument as a fixed point 16-bit number that
contains the angle in radians between [- π/4, π/4), normalized between [-0.25, 0.25).
Embedded Software and Motor Control Libraries for PXR40xx, Rev. 1.0
238 Freescale Semiconductor, Inc.