Embedded Software and Motor Control Libraries for PXR40xx

Function GFLIB_Lut2D_FLT
data, the pTable}, shall be defined by the parameter structure member pParam-
>pfltTable.
The offset amounts s32ShamOffset_{12} can be provided by the following formulas:
Equation GFLIB_Lut2D_Eq17
where n_1 and n_2 are the integers defining the length of the interpolating interval in the
range of 1, 2, ... 29.
This simple way to calculate the interpolating abscissa offsets is the consequence of
assuming that all interpolating interval lengths equal 2 -n1 and 2 -n2 .
It should be noted that the input abscissa values can be positive or negative. If they are
positive then the ordinate values are read as in the ordinary data array, that are at or after
the data pointer provided in the parameters structure pParam->pfltTable. However, if
they are negative, then the ordinate values are read from the memory, which is located
behind the pParam->pfltTable pointer.
Note
The function performs a bilinear interpolation.
CAUTION
The function does not check whether the input values are within
the range allowed by the interpolating data table pParam-
>pfltTable. If the computed interval index points to data outside
the provided data table then the interpolation will be computed
with invalid data.
4.72.5 Re-entrancy
The function is re-entrant.
4.72.6 Code Example
#include "gflib.h"
tFloat fltIn1;
tFloat fltIn2;
tFloat fltOut;
GFLIB_LUT2D_T_FLT trfltMyLut2D = GFLIB_LUT2D_DEFAULT_FLT;
Embedded Software and Motor Control Libraries for PXR40xx, Rev. 1.0
386 Freescale Semiconductor, Inc.