Pipelined divider and dividing method with small lookup table
A pipelined divider with a small lookup table is disclosed. The pipelined divider can greatly reduce the size of a lookup table with a low cost to overcome the problems involved in the conventional pipelined divider requiring a large lookup table due to its iterative operation type. The pipelined divider has a delay time of 3 cycles in a single precision, and can reduce a chip size by about ⅓ in comparison to the existing pipelined divider.
1. A pipelined divider, comprising:
a lookup table for storing internal parameters and a value of 1/Y h 2 obtained from a divisor Y;
a first multiplier for operating a divisor A by multiplying the value of 1/Y h 2 by a value of Y h −Y 1 obtained from the divisor Y;
second and third multipliers for operating values of AX and AY by multiplying the divisor A by a dividend X and the divisor Y in parallel, respectively; and
a fourth multiplier for operating a quotient Q by multiplying the value of AX by a bit inverted 2−AY, wherein the Y h is a value of an upper bit of the divisor Y, and wherein the Y 1 is a value obtained by subtracting the Y h from the divisor Y.
2. The pipelined divider as claimed in claim 1 , wherein the internal parameters include a bit number specifying a precision (m), an address bit number (p) of the lookup table, a bit-width of the lookup table (q), an entry number of the lookup table, and a ROM size.
3. The pipelined divider as claimed in claim 1 , wherein the entry number of the lookup table is 2 p−1 , wherein p is the address bit number.
4. The pipelined divider as claimed in claim 1 , wherein 2−AY is obtained by performing a bit-inversion of AY calculated through the third multiplier.
5. The pipelined divider as claimed in claim 1 , wherein the divider is composed of one lookup table and four multipliers.
6. The pipelined divider as claimed in claim 1 , an area of the lookup table is in linear proportion to a byte unit.
7. The pipelined divider as claimed in claim 1 , wherein the first to fourth multipliers operate in one cycle, and the lookup table operates in two or three cycles.
8. The pipelined divider as claimed in claim 7 , wherein chip areas of the first to fourth multipliers are in linear proportion to a product of the bit numbers of a multiplier and a multiplicand.