CMSC 311- Computer Organization

Fall 1995 - Assignment #5

Due (at the beginning of class) Tuesday, October 23

1. Represent the following floating-point numbers using a 16 bit normalized mantissa and 8 bit exponent:
1. 128.0
2. 46.5
3. 0.2
4. 17.21875
2. From Mano problem 4-3.
3. From Mano problem 4-6.
4. We have talked about buses for parallel transfer between registers. For this problem, you will design a bus for serial transfer between registers. The bus should be capable of transferring (shifting) bits between any two registers. The register from which the bit is coming is called the source register, the register to which the bit goes is called the destination register. A transfer causes the bit at the serial output of the source register to be shifted into the serial inputs of both the source and destination registers. The bit at the serial output of the destination register is lost. For example, if the source register contains 0011 and the destination contains 1010 before the transfer, after the transfer they will contain 1001 (source) and 1101 (destination). (This assumes a shift to the right.)

You have four shift registers (R 0, R 1, R 2, R 3) to interconnect with the bus. Each register has a serial input I s, a serial output Z s, and a shift control input S.. When S = 1 and the clock pulses, the data in the register is shifted. When S=0 and the clock pulses, nothing happens.

The bus system you design should have select inputs to determine the source register and destination register of the transfer. (How many select inputs are needed?) Design the serial bus and show a block diagram including all components and interconnections.

5. From Mano, problem 4-15.
6. From Mano, problem 4-23.