Invention Grant
- Patent Title: Binary coded decimal addition
- Patent Title (中): 二进制编码十进制加法
-
Application No.: US11861748Application Date: 2007-09-26
-
Publication No.: US07991819B2Publication Date: 2011-08-02
- Inventor: Neelamekakannan Alagarsamy , Kulanthaivelu Veluchamy Balamurugan
- Applicant: Neelamekakannan Alagarsamy , Kulanthaivelu Veluchamy Balamurugan
- Applicant Address: US NY Armonk
- Assignee: International Business Machines Corporation
- Current Assignee: International Business Machines Corporation
- Current Assignee Address: US NY Armonk
- Agent Anthony V S England; William Steinberg
- Main IPC: G06F7/50
- IPC: G06F7/50

Abstract:
The binary coded decimal (BCD) adder circuit adds two BCD encoded operands, with an input carry bit, and produces a BCD encoded sum. The adder has three stages. The first stage receives two BCD encoded operands as inputs, groups the inputs into contiguous blocks of 4-bits each, computes an intermediate sum vector and carry vector without considering the input carry bit, and also computes propagation and generate functions for each 4-bit group. The second stage is a carry look ahead circuit which computes all carries from the input carry, and the propagate and generate functions of the 4-bit groups from the first stage. The third stage adjusts the intermediate sum vector with pre-correction factors which depend upon the input carry and the carries generated from the second stage and the carry vectors from the first stage.
Public/Granted literature
- US20080016140A1 Binary Coded Decimal Addition Public/Granted day:2008-01-17
Information query