Description
Answer the questions below according to the lab specification. Write
your answers directly in this text file and submit it to complete the
lab.
PROBLEM 1: Number conversions
=============================
A
~
Fill in the following table of equivalences. Filling in the table
from top to bottom is advantageous as earlier rows can sometimes be
used to infer lower values. Feel free to make use of any ASCII table
or the table.c program provided in the week 3 lecture code pack.
Dec Hex Oct Binary Char
—————————————–
9 0x09 11 0000 1001 TAB
10 \n (newline)
0x20 SPACE
0011 0010
65 0x41 101 0100 0001 A
66
0x4F 117 O
80 P
91 133 0101 1011 [
97 0x61 141
172 0111 1010 z
145 0x91 221 none
160 1010 0000 none
180 0xB4 264 none
255 none
B
~
Fill in the bits, hex, and decimal values for the given examples. The
first example is completed for you. Assume all of these are 32 bit
unsigned integers.
,—-
| COMPLETED
| Binary: 0000 0000 0000 0000 0001 1000 1110 1001
| 0 0 0 0 1 8 E 9
| Hex : 0018E9
| Decimal: 6377
|
|
| NUMBER 1
| Binary: 0000 0000 0010 1111 0011 1010 1000 1101
| ?
| Hex : ??
| Decimal: ??
|
|
| NUMBER 2
| Binary: ??
| 7 F 8 3 5 A 0 B
| Hex : 7F835A0B
| Decimal: ??
`—-
PROBLEM 2: Signed Integer Conversions
=====================================
A
~
Apply the steps involved in converting the following positive binary
number to it’s two’s complement negation in 8-bit signed
format. Recall the steps are
– Subtract 1
– Invert the bits
,—-
| 0111 1100 = 0x7C = 124 (decimal)
`—-
The result is the two’s complement representation of -124.
Reverse the process by
– Invert the bits
– Add one
to show that the original bits are gotten back.
B
~
Complete the following table of equivalences assuming 8-bit
twos-complement signed integers. The rightmost column is the inverse
of the binary representation: flip 1’s to 0’s, and vice versa.
Dec Hex Binary Inverse
———————————-
+5 0x05 0000 0101 1111 1010
-5 1111 1011
+32 0x20
-32 0xE0 0001 1111
+127 0x7F
-127 0x81
-128 1000 0000
+2
-2 0xFE
+1 0x01 0000 0001
-1 1111 1111
0
PROBLEM 3: Converting Strings to Numbers
========================================
Inspect the program in the lab pack called `convert.c’. Compile and
run it using
,—-
| > gcc convert.c
| > ./a.out
`—-
Describe briefly what kind of conversion is being done by the
`convert()’ function given.
– A. What kind of data is input?
– B. What result is produced by the function?
– C. How is a success versus an error reported?
– D. Why is this kind of conversion needed?
– E. What built-in C function (useful for the assignment) does this
conversion function use and how is its calling convention different
from convert()?
