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olo_fix_from_real

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Status Information

VHDL Source: olo_fix_from_real
Bit-true Model: olo_fix_from_real

Description

This entity converts a real (floating-point) number to fixed-point format.

Real numbers are not used for synthesis normally. The olo_fix_from_real entity has the following use-case:

  • Create fixed-point representation of constants
    • Example: Calculation of the gravitational force
    • A real constant with the value 9.81 is defined (good readability)
    • For fixed-point calculations, the constant is converted to fixed-point representation using olo_fix_from_real
    • In this case the input is static, therefore the generic interface (Value_g) is used

Note that this entity does not contain any pipeline registers. Real (floating-point) values do no exist in synthesized netlists - so the conversion only is executed at compile-time or in simulations. Hence no registers are needed.

This entity does only allow to handle constant values. For the conversion of real values in simulation, use olo_fix_sim_from_real instead.

For details about the fixed-point number format used in Open Logic, refer to the fixed point principles.

Generics

Name Type Default Description
ResultFmt_g string - Format of the result
String representation of an en_cl_fix Format_t (e.g. "(0,1,15)")
Saturate_g string "SatWarn_s" Saturation mode
String representation of an en_cl_fix FixSaturate_t.
Value_g real 0.0 Generic to be used for compile-time static inputs.

Interfaces

Input Data

None

Output Data

Name In/Out Length Default Description
Out_Value out width(ResultFmt_g) N/A Output data

Detail

No detailed description required. All details that could be mentioned here are already covered by fixed point principles.