An instruction is executed in round-for-reround mode wherein the permissible resultant value that is closest to and no greater in magnitude than the infinitely precise result is selected. If the selected value is not exact and the units digit of the selected value is either 0 or 5, then the digit is incremented by one and the selected value is delivered. In all other cases, the selected value is delivered.

A method includes receiving an unrounded mantissa value and a round bit associated with the unrounded mantissa value. The method also includes receiving a 2's complement signal that indicates whether the unrounded mantissa value results from a 1's complement operation. The method includes incrementing the unrounded mantissa value to provide an incremented value. The unrounded mantissa value is a non-incremented value. The method further includes providing one of the incremented value or non-incremented value as a rounded mantissa value responsive to the 2's complement signal.

A Physical Unclonable Function (PUF) based true random number generator (TRNG), a method for generating true random numbers, and an associated electronic device are provided. The PUF based TRNG may include a first obfuscation circuit, a cryptography circuit coupled to the first obfuscation circuit, and a second obfuscation circuit coupled to the cryptography circuit. The first obfuscation circuit obtains a first PUF value from a PUF pool of the electronic device, and performs a first obfuscation function on a preliminary seed based on the first PUF value to generate a final seed. The cryptography circuit utilizes the final seed as a key of a cryptography function to generate preliminary random numbers. The second obfuscation circuit obtains a second PUF value from the PUF pool, and performs a second obfuscation function on the preliminary random numbers based on the second PUF value to generate final random numbers.

A modular operation circuit includes a controller, a modular multiplier and a modular adder. The controller divides a first number into K segments. The modular multiplier performs modular multiplication operations and the modular adder performs modular addition operations to the K segments in (K−1) iterations for deriving a remainder of a division of the first number by a second number.

A Physical Unclonable Function (PUF) based true random number generator (TRNG), a method for generating true random numbers, and an associated electronic device are provided. The PUF based TRNG may include a first obfuscation circuit, a cryptography circuit coupled to the first obfuscation circuit, and a second obfuscation circuit coupled to the cryptography circuit. The first obfuscation circuit obtains a first PUF value from a PUF pool of the electronic device, and performs a first obfuscation function on a preliminary seed based on the first PUF value to generate a final seed. The cryptography circuit utilizes the final seed as a key of a cryptography function to generate preliminary random numbers. The second obfuscation circuit obtains a second PUF value from the PUF pool, and performs a second obfuscation function on the preliminary random numbers based on the second PUF value to generate final random numbers.

Techniques for operating on and calculating binary floating-point numbers using an enhanced floating-point number format are presented. The enhanced format can comprise a single sign bit, six bits for the exponent, and nine bits for the fraction. Using six bits for the exponent can provide an enhanced exponent range that facilitates desirably fast convergence of computing-intensive algorithms and low error rates for computing-intensive applications. The enhanced format can employ a specified definition for the lowest binade that enables the lowest binade to be used for zero and normal numbers; and a specified definition for the highest binade that enables it to be structured to have one data point used for a merged Not-a-Number (NaN)/infinity symbol and remaining data points used for finite numbers. The signs of zero and merged NaN/infinity can be “don't care” terms. The enhanced format employs only one rounding mode, which is for rounding toward nearest up.

A decimal floating-point instruction is executed in a round-for-reround mode. The decimal floating-point instruction is configured to perform a decimal floating-point operation on a decimal floating-point operand. The executing includes forming based on performing the decimal floating-point operation, an intermediate result having a high order portion and a low order portion. The high order portion has a least significant digit. A rounded-for-reround number is created from the intermediate result. The rounded-for-reround number includes the high order portion of the intermediate result and based on the least significant coefficient digit of the high order portion being a selected value and based on the low order portion having another selected value, the least significant digit of the rounded-for-reround number is incremented. The rounded-for-reround number is stored.

A modular operation circuit includes a controller, a modular multiplier and a modular adder. The controller divides a first number into K segments. The modular multiplier performs modular multiplication operations and the modular adder performs modular addition operations to the K segments in (K−1) iterations for deriving a remainder of a division of the first number by a second number.

An instruction is executed in round-for-reround mode wherein the permissible resultant value that is closest to and no greater in magnitude than the infinitely precise result is selected. If the selected value is not exact and the units digit of the selected value is either 0 or 5, then the digit is incremented by one and the selected value is delivered. In all other cases, the selected value is delivered.

A round-for-reround mode (preferably in a BID encoded Decimal format) of a floating point instruction prepares a result for later rounding to a variable number of digits by detecting that the least significant digit may be a 0, and if so changing it to 1 when the trailing digits are not all 0. A subsequent reround instruction is then able to round the result to any number of digits at least 2 fewer than the number of digits of the result. An optional embodiment saves a tag indicating the fact that the low order digit of the result is 0 or 5 if the trailing bits are non-zero in a tag field rather than modify the result. Another optional embodiment also saves a half-way-and-above indicator when the trailing digits represent a decimal with a most significant digit having a value of 5. An optional subsequent reround instruction is able to round the result to any number of digits fewer or equal to the number of digits of the result using the saved tags.