CZ1101, Basic Computer Architecture and Assembly Programming

Tutorial 1, Week 4, 4-8 August, 1997

You should do the problems before going to the tutorial classes. For this set you need not hand in the solutions. Tutorial hours are for asking questions and clarifying points of the tutorial problems. The number in parentheses ( ) refers to the question number in the textbook, ``Computer Organization & Design'', Patterson and Hennessy. The first problem comes from the textbook page 42-43. The rest problems are my own concoction.

(1.1-1.13) Find the word or phase from the list below that best matches the description in the following questions. Use the letters to the left of words in the answer. Each answer should be used not more than once. It would be easier if you have read Chapter 1.
```
a  abstraction                   n  DRAM (dynamic random access memory)
b  assembler                     o  implementation 
c  binary number                 p  instruction
d  bit                           q  instruction set architecture
e  cache                         r  integrated circuit
f  CPU (central processor unit)  s  memory
g  chip                          t  operating system
h  compiler                      u  processor
i  computer family               v  semiconductor
j  control                       w  supercomputer
k  datapath                      x  transistor
l  defect                        y  VLSI (very large scale integrated circuit)
m  die                           z  yield
```
(1.1) Specific abstraction that the hardware provides the low-level software.
(1.2) Active part of the computer, following the instructions of the programs to the letter: It adds numbers, tests numbers, and so on.
(1.3) Another name for processor.
(1.4) Approach to the design of hardware or software; the system consists of hierarchical layers, with each lower layer hiding details from the above.
(1.5) Base 2 number.
(1.6) Binary digit.
(1.7) Collection of implementations of the same instruction set architecture; they are available at the same time and vary in price and performance.
(1.8) Component of the processor that performs arithmetic operation.
(1.9) Component of the processor that tells the datapath, memory, and I/O devices what to do according to the instructions of the program.
(1.10) Hardware that obeys the instruction set architecture abstraction.
(1.11) High performance machine, costing more than $1 million.
(1.12) Individual command to a computer.
(1.13) Integrated circuit commonly used to construct main memory.
How would a compiler translate the following C statement into MIPS instructions? Assuming that all the variables are integers and are in registers $2, $3, $4, $5, $6, for f, p, r, a, b, respectively.
```
   f = - p*r +  (a/b)*a*a  - b;
```

Let assume that all registers and memory have value 0 before the program starts. Stepping through the execution of the program, indicate changes in registers or memory, if any, after each instruction.

main:
   li  $3, 1
   li  $2, 0x10000000
   li  $4, 1
   sw  $4, 0($2)
   li  $4, 2
   sw  $4, 4($2)
   li  $4, 3
   sw  $4, 8($2)
   lw  $5, 0($2)
   add $5, $5, $3
   sw  $5, 12($2)
   lw  $5, 4($2)
   add $5, $5, $3
   sw  $5, 16($2)
   lw  $5, 8($2)
   add $5, $5, $3
   sw  $5, 20($2)
   j $31

What is the binary encoding of the instruction sequence:
```
   lw  $5, 0($2)
   add $5, $5, $3
   sw  $5, 12($2)
```
You need to refer to Figure 3.6, page 107 of the textbook.