Method and apparatus for dynamic partitionable saturating adder/subtractor

A method to manufacture an apparatus that performs an arithmetic operation on two N-nary operands, comprising:

• providing arithmetic logic that performs an arithmetic operation on one or more bits of a 1-of-P first operand and one or more bits of a 1-of-Q second operand to generate an intermediate result, wherein each said operand comprises one or more blocks comprising one or more bits;
• providing a 1-of-R partition size input that receives a 1-of-R partition size indicator whose value defines the boundaries of one or more partitions, wherein each said partition comprises one or more of said operand blocks;
• providing a partition detection logic that generates a block-level HPG indicator for each said block, wherein said partition detection logic overrides the value of said block-level HPG indicator with a “Halt” value when said block comprises the most significant said block of said partition;
• coupling said partition detection logic to said partition size input;
• providing an HPG logic that generates a final HPG indicator for said intermediate result;
• coupling said HPG logic to said partition detection logic;
• providing a sum logic that generates a 1-of-T arithmetic result by incrementing the value of said intermediate result if said final HPG indicator indicates that a carry has propagated into said intermediate result;
• coupling said sum logic to said HPG logic and to said arithmetic logic;
• providing a saturation logic that overrides the value of said arithmetic result with a constant overflow saturation value when an overflow has occurred, sand that overrides the value of said arithmetic result with a constant underflow saturation value when an underflow has occurred;
• and
• coupling said saturation logic to said sum logic.

A system that performs an arithmetic operation on two N-nary operands, comprising:

• arithmetic logic that performs an arithmetic operation on one or more bits of a 1-of-P first operand and one or more bits of a 1-of-Q second operand to generate an intermediate result, wherein each said operand comprises one or more blocks comprising one or more bits;
• a 1-of-R partition size input that receives a 1-of-R partition indicator whose value defines the boundaries of one or more partitions, wherein each said partition comprises one or more of said operand blocks;
• a partition detection logic, coupled to said partition size input, that generates a block-level HPG indicator for each said block, wherein said partition detection logic overrides the value of said block-level HPG indicator with a “Halt” value when said block comprises the most significant said block of said partition;
• an HPG logic, coupled to said partition detection logic, that generates a final HPG indicator for said intermediate result;
• a sum logic, coupled to said HPG logic and to said arithmetic logic, that generates a 1-of-T arithmetic result by incrementing the value of said intermediate result if said final HPG indicator indicates that a carry has propagated into said intermediate result;
• and
• a saturation logic, coupled to said sum logic, that overrides the value of said arithmetic result with a constant overflow saturation value when an overflow has occurred, said saturation logic overrides the value of said arithmetic result with a constant underflow saturation value when an underflow has occurred.

A method to perform an arithmetic operation on two N-nary operands, comprising:

• performing an arithmetic operation with arithmetic logic on one or more bits of a 1-of-P first operand and one or more bits of a 1-of-Q second operand to generate an intermediate result, each said operand comprises one or more blocks comprising one or more bits;
• receiving a 1-of-R partition indicator with a 1-of-R partition size input whose value defines the boundaries of one or more partitions, each said partition comprises one or more of said operand blocks;
• generating a block-level HPG indicator with a partition detection logic for each said block, said partition detection logic overrides the value of said block-level HPG indicator with a “Halt” value when said block comprises the most significant said block of said partition, said partition detection logic is coupled to said partition size input;
• generating a final HPG indicator for said intermediate result with an HPG logic, said HPG logic is coupled to said partition detection logic;
• generating a 1-of-T arithmetic result with a sum logic by incrementing the value of said intermediate result if said final HPG indicator indicates that a carry has propagated into said intermediate result, said sum logic is coupled to said HPG logic and to said arithmetic logic;
• and
• overriding the value of said arithmetic result with a constant overflow saturation value when an overflow has occurred and overriding the value of said arithmetic result with a constant underflow saturation value when an underflow has occurred using a saturation logic that is coupled to said sum logic.