REQUEST: REPORT
ID: N8CUED
P-NAME: ALU_SQRT
Fab-ID: 57002 / 67
P-P:
REPORT:

Shipping and packaging -

All chips arrived in good condition without damage.

Functionality -

All 5 chips were partially functional due to a design defect.

After running our test vectors we discovered that the Load, And,
Or, Not, and Adder functions worked correctly, but the square root
failed due to a clock wiring error in the design.  

Timing -

The chip ran with a maximum clock frequency between 6.8MHz and 17MHz.  Test
equipment limitations prevented us from determining the maximum clock
frequency more precisely.

Purpose -

Our chip is an 8-bit, accumulator based, ALU with square root.  It uses a
6.2 fixed point operand format with three bit opcodes.  It supports the
following operations: ADD, AND, OR, NOT, LOAD, SQRT, and NOOP.  The adder
was implemented using a single cycle ripple-carry adder.  The square root
requires 12 cycles and operates on the principle of trying to iteratively
find the largest number that is still smaller than the input when squared.

More details on our design can be found at
www.owlnet.rice.edu/~waterman/vlsi.

Todd Waterman     waterman@rice.edu
Indra Datta       kashent@rice.edu
Abhinav Dubey     dubey@rice.edu