You are expected to derive the requirement based test cases for a program

that displays the contents of memory locations, by using Cause Effect Graphing

technique. Here is the requirement specification for the program to be tested:

The SHOWMEM command is to observe the contents of memory locations from a

terminal window. The command syntax is provided below. Brackets denote optional

operands, and the various alternative values that can be provided for those optionaloperands. Uppercase letters signify operand keywords, while lowercase letters stand

for operand values $($which are to be replaced with actual values$).$ Underlined operands

indicate default values $($i$.$e$.,$ the value used when the operand is omitted$).$

The initial operand $($hexloc$1)$ determines the address of the first byte whose contents

are to be shown. This address can be one to six hexadecimal digits $(09,$ A$$F$)$ long. If

not specified, the address defaults to $0.$ The address must fall within the actual

memory range of the machine.

The second operand specifies the amount of memory to be displayed. If hexloc$2$ is

specified, it defines the address of the last byte in the range of locations to be

displayed. It may be one to six hexadecimal digits in length. The address must be

greater than or equal to the starting address $($hexloc$1).$ Also, hexloc$2$ must be within

the actual memory range of the machine. If END is specified, memory is displayed

up through the last actual byte in the machine. If bytecount is specified, it defines the

number of bytes of memory to be displayed $($starting with the location specified in

hexloc$1).$ The operand bytecount is a hexadecimal integer $($one to six digits$).$ The sum

of bytecount and hexloc$1$ must not exceed the actual memory size plus $1,$ and

bytecount must have a value of at least $1.$ When the second operand is omitted, it is

assumed to be $1$ by default.

When memory contents are displayed, the output format on the screen is one or

more lines of the format

xxxxxx $=$ byte$1$byte$2$ byte$3$ byte$4$

where xxxxxx is the hexadecimal address of byte$1.$ All output lines will always contain

four bytes, regardless of the value of hexloc$1$ or the amount of memory to be

displayed.

The error messages that can be produced are:

E$1$ is invalid command syntax.E$2$ memory requested is beyond actual memory limit$.$

E$3$ memory requested is a zero or negative range.

Some examples of the command usage are:

SHOWMEM displays the first byte in memory $($default starting address

of $0,$ default byte count of $1),$

SHOWMEM $88$F displays the byte at address $88$F$,$

SHOWMEM $88$F$-429$A displays the bytes in the address range $88$F$-429$A;

After analysis of the specification, following causes and effects have been identified:

Causes:

$1.$ First operand is present.

$2.$ The first operand contains only hexadecimal digits.

$3.$ The first operand contains one to six characters.

$4.$ The first operand is within the actual memory range of the machine.

$5.$ Second operand is END.

$6.$ Second operand is hexloc.

$7.$ Second operand is bytecount.

$8.$ Second operand is omitted.

$9.$ The hexloc$2$ operand contains only hexadecimal digits.

$10.$ The hexloc$2$ operand contains one to six characters.

$11.$ The hexloc$2$ operand is within the actual memory range of the machine.

$12.$ The hexloc$2$ operand is greater than or equal to the hexloc$1$ operand.

$13.$ The bytecount operand contains only hexadecimal digits.

$14.$ The bytecount operand contains one to six characters.

$15.$ bytecount $+$ hexloc$1<=$ memory size $+1.$

$16.$ bytecount $>=1.$

$17.$ Specified range is large enough to require multiple output lines.

Effects:

$61.$ Message E$1$ is displayed.

$62.$ Message E$2$ is displayed.

$63.$ Message E$3$ is displayed.

$64.$ Memory is displayed on one line.

$65.$ Memory is displayed on multiple lines.

$>>>>$ Convert the Cause Effect Graph you constructed in $($a$)$ above toa limited entry

decision table, by following the technique and rules we have seen during our lecture

$($Week$08).$