-
Review the conversion from one base to another in text as well as two's complement.
ASCII (American Standard Code for Information Interchange)
|
Dec
|
Hex
|
Sym
|
Dec
|
Hex
|
Sym
|
Dec
|
Hex
|
Sym
|
Dec
|
Hex
|
Sym
|
|
0
|
0
|
NUL
|
32
|
20
|
|
64
|
40
|
@
|
96
|
60
|
`
|
|
1
|
1
|
SOH
|
33
|
21
|
!
|
65
|
41
|
A
|
97
|
61
|
a
|
|
2
|
2
|
STX
|
34
|
22
|
"
|
66
|
42
|
B
|
98
|
62
|
b
|
|
3
|
3
|
ETX
|
35
|
23
|
#
|
67
|
43
|
C
|
99
|
63
|
c
|
|
4
|
4
|
EOT
|
36
|
24
|
$
|
68
|
44
|
D
|
100
|
64
|
d
|
|
5
|
5
|
ENQ
|
37
|
25
|
%
|
69
|
45
|
E
|
101
|
65
|
e
|
|
6
|
6
|
ACK
|
38
|
26
|
&
|
70
|
46
|
F
|
102
|
66
|
f
|
|
7
|
7
|
BEL
|
39
|
27
|
'
|
71
|
47
|
G
|
103
|
67
|
g
|
|
8
|
8
|
BS
|
40
|
28
|
(
|
72
|
48
|
H
|
104
|
68
|
h
|
|
9
|
9
|
TAB
|
41
|
29
|
)
|
73
|
49
|
I
|
105
|
69
|
i
|
|
10
|
A
|
LF
|
42
|
2A
|
*
|
74
|
4A
|
J
|
106
|
6A
|
j
|
|
11
|
B
|
VT
|
43
|
2B
|
+
|
75
|
4B
|
K
|
107
|
6B
|
k
|
|
12
|
C
|
FF
|
44
|
2C
|
,
|
76
|
4C
|
L
|
108
|
6C
|
l
|
|
13
|
D
|
CR
|
45
|
2D
|
-
|
77
|
4D
|
M
|
109
|
6D
|
m
|
|
14
|
E
|
SO
|
46
|
2E
|
.
|
78
|
4E
|
N
|
110
|
6E
|
n
|
|
15
|
F
|
SI
|
47
|
2F
|
/
|
79
|
4F
|
O
|
111
|
6F
|
o
|
ASCII (American Standard Code for Information Interchange)
|
Dec
|
Hex
|
Sym
|
Dec
|
Hex
|
Sym
|
Dec
|
Hex
|
Sym
|
Dec
|
Hex
|
Sym
|
|
16
|
10
|
DLE
|
48
|
30
|
0
|
80
|
50
|
P
|
112
|
70
|
p
|
|
17
|
11
|
DC1
|
49
|
31
|
1
|
81
|
51
|
Q
|
113
|
71
|
q
|
|
18
|
12
|
DC2
|
50
|
32
|
2
|
82
|
52
|
R
|
114
|
72
|
r
|
|
19
|
13
|
DC3
|
51
|
33
|
3
|
83
|
53
|
S
|
115
|
73
|
s
|
|
20
|
14
|
DC4
|
52
|
34
|
4
|
84
|
54
|
T
|
116
|
74
|
t
|
|
21
|
15
|
NAK
|
53
|
35
|
5
|
85
|
55
|
U
|
117
|
75
|
u
|
|
22
|
16
|
SYN
|
54
|
36
|
6
|
86
|
56
|
V
|
118
|
76
|
v
|
|
23
|
17
|
ETB
|
55
|
37
|
7
|
87
|
57
|
W
|
119
|
77
|
w
|
|
24
|
18
|
CAN
|
56
|
38
|
8
|
88
|
58
|
X
|
120
|
78
|
x
|
|
25
|
19
|
EM
|
57
|
39
|
9
|
89
|
59
|
Y
|
121
|
79
|
y
|
|
26
|
1A
|
SUB
|
58
|
3A
|
:
|
90
|
5A
|
Z
|
122
|
7A
|
z
|
|
27
|
1B
|
ESC
|
59
|
3B
|
;
|
91
|
5B
|
[
|
123
|
7B
|
{
|
|
28
|
1C
|
FS
|
60
|
3C
|
<
|
92
|
5C
|
\
|
124
|
7C
|
|
|
|
29
|
1D
|
GS
|
61
|
3D
|
=
|
93
|
5D
|
]
|
125
|
7D
|
}
|
|
30
|
1E
|
RS
|
62
|
3E
|
>
|
94
|
5E
|
^
|
126
|
7E
|
~
|
|
31
|
1F
|
US
|
63
|
3F
|
?
|
95
|
5F
|
_
|
127
|
7F
|
|
-
ASCII: Stored using an assembler directive db:
-
Word-sized (
dw
) and doubleword-sized data (
dd
):
-
Little endian: Least significant byte is always stored in the lowest-numbered memory location.
-
For single percision, the sign bit + 8-bit exponent + 24-bit mantissa = 33 bits !
-
The mantissa has a hidden 1 bit in the leftmost position that allows it to be stored as a 23-bit value.
-
The mantissa is first normalized to be >= 1 and < 2, e.g., 12 in binary is 1100, normalized is 1.1 X 23.
-
The exponent is also biased by adding 127 (single) or 1023 (double), e.g. the 3 in the previous example is stored as 127 + 3 = 130 (82H).
-
There are two exceptions:
-
The number 0.0 is stored as all zeros.
-
The number infinity is stored as all ones in the exponent and all zeros in the mantissa. (The sign bit is used to indicate + or - infinity.)
-
Directive is
dd
for single,
dq
for double and
dt
for 10 bytes:
