Floating-Point IP Cores User Guide

ID 683750
Date 5/05/2023
Public
Document Table of Contents

7.7. ALTFP_EXP Parameters

Table 44.  ALTFP_EXP IP Core Parameters
Parameter Name Type Required Description
WIDTH_EXP Integer Yes Specifies the precision of the exponent. If this parameter is not specified, the default is 8. The bias of the exponent is always set to 2 (WIDTH_EXP -1) -1, that is, 127 for the single-precision format and 1023 for the double-precision format. The value of the WIDTH_EXP parameter must be 8 for the single-precision format, 11 for the double-precision format, and a minimum of 11 for the single-extended precision format. The value of the WIDTH_EXP parameter must be less than the value of the WIDTH_MAN parameter, and the sum of the WIDTH_EXP and WIDTH_MAN parameters must be less than 64.
WIDTH_MAN Integer Yes Specifies the value of the mantissa. If this parameter is not specified, the default is 23. When the WIDTH_EXP parameter is 8 and the floating-point format is single-precision, the WIDTH_MAN parameter value must be 23. Otherwise, the value of the WIDTH_MAN parameter must be a minimum of 31. The value of the WIDTH_MAN parameter must be greater than the value of the WIDTH_EXP parameter. The sum of the WIDTH_EXP and WIDTH_MAN parameters must be less than 64.
PIPELINE Integer Yes Specifies the amount of latency, expressed in clock cycles, used in the ALTFP_EXP IP core. Acceptable pipeline values are 17, 22, and 25 cycles of latency. Create the ALTFP_EXP IP core with the MegaWizard Plug-In Manager to calculate the value for this parameter.
ROUNDING String Yes Specifies the rounding mode. The default value is TO_NEAREST. Other rounding modes are not supported.