ssGetDataTypeFixedExponent

Return exponent of slope of registered data type

Syntax

extern int ssGetDataTypeFixedExponent (SimStruct *S, DTypeId
                                       dataTypeId)

Arguments

S

SimStruct representing an S-function block.

dataTypeId

Data type ID of the registered data type for which you want to know the exponent.

Description

Fixed-point numbers can be represented as

real-world value = (slope × integer) + bias,

where the slope can be expressed as

slope = fractional slope × 2^exponent.

This function returns the exponent of a registered fixed-point data type:

• For power-of-two scaling, the exponent is the negative of the fraction length.

• If the data type has trivial scaling, including for data types single and double, the exponent is 0.

• If the registered data type is ScaledDouble, the exponent returned is that of the nonoverridden data type.

This function errors out when ssGetDataTypeIsFxpFltApiCompat returns FALSE.

Requirements

• To use this function, you must include fixedpoint.h and fixedpoint.c. For more information, see Structure of the S-Function.

• To build an S-function that utilizes this function, you must compile it using the mex function with -lfixedpoint argument. For more information, see Create MEX Files.

Languages

C

TLC Functions

FixPt_DataTypeFixedExponent