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15 2009 ., 2
2007-2008 , , . 2015 , .
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Ó .., .. , 2010
. . , , 60- , 2- .
10. , 8- . : " 9 , , , , , - , ".
2. XVII Explication de lArithmétique Binaire. 0 1, . 1854 An investigation of the laws of thougt (" "), , . . 1937 , . . 1937 Model K, . 1938 Bell Labs . , 8 1940, . American Mathematical Society 11 1940 . . ( , ( ENIAC) ( ), .
1
1. - :
) (BCD);
|
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) (ASCII).
2. A WORD (16- ).
3. A B 1.
4. A B 2.
5. A B 3.
6. Y Z R S 1.
7. V W R S 2.
8. T Q R S 3.
.. 35 B ( ).
.1 ( A B) .2 ( R S) 1.
1.1. -
- , ( ):
(K), (UNPACK) .
, .
, 8421 ( ).
ASCII (American Standard Code for Interchang Information), . , 0011.
BCD- ( BCD- Binary Coded Decimal).
: =395.
a)
0000 0011 | 1001 0101 | |
9 5 |
) ASCII- ( ). 0011.
0011.0011 0011.1001 0011.0101
3 9 5
1.2.
.
. A = 250
1.2.1. A :
(250)10 = (11111010)2.
, () . , (15- ), .
: (250)10 = (FA)16.
.
1.2.2. ( ) . ( ).
[ A ] = 1.000 0000 1111 1010 ,
[ A ] = 1.111 1111 0000 0101 ,
+ 1
[ A ] = 1.111 1111 0000 0110 .
. , ( ) , , () . . :
|
|
:
1.3.
, :
,
sign A (0 , 1 ),
,
S ,
.
:
1. S =2 ( ) S =16 ( ). 2 , 16 . .
2. .
, ( ).
3. , , . , ( )
= + d,
, d .
2 :
1) ().
2) , 1.
, .
, 1; , VAX 2 ( , ); , ( IEEE-754) 3. IEEE (Institute of Electrical and Electronics Engineers) ( ) . , , .
IEEE: IEEE Standard for Binary Floating-Point Arithmetic (IEEE . 2008 IEEE ANSI/IEEE Std 754- 2008 (ANSI: American National Standards Institute ).
4. (32 ), (64 ) (128 ). (32 ) .
1.4.
1
. , 1 16, . , . . , . , . , .
|
|
, .
, .
( ) ( 1 64), , .
1.4.1. 1 =250.
A :
A: XA = PA + 64 = (66)10 = (1000010)2.
, , ( 64),
. . A 1 :
. ,
(1E8,5)16 = (0,1E85)16 ´ 163
.
1.4.2. 1 B = 0,0025. . , .
() , .
B = (0,0025)10 = (0,00A3D70A3)16.
, (3)16 = (0011)2, , (A)16, .
, , (8)16, .
B , , (2):
B = (0,00A3D70A)16 = (0,A3D70A)16 ´ 162.
B: XB = PB + 64 = 2 + 64 = 62 = (0111110)2.
, , : , ( 64)
000010 ,
111110 ,
0111110 .
B 1 :
1.5.
2
2 , S = 2. . (), .
( ) , 2 128 ( 1 2 8 ).
, 2 , , , ( ). , 2 ( ).
1.5.1. A:
A:
A 2
1.5.2. B 8 , , (8).
|
|
B:
B 2 :
B 1 2 . 1. ( 8), 2 .
, (0,1A90BC7)16 1
2 -
2 , 1. , , , , , 1 .
1.6.
3
3 2. :
1) 127 ( 2 128);
2) , .. ( 2 ).
1.6.1. A:
:
XA = PA + 127 = 134 = (10000110)2.
A 3
, :
) 1 2 3 ;
) 2 3 ( );
) 3 2 ( 2).
1.6.2. :
:
XB = PB + 127 = 118 = (01110110)2.
: , :
0001001 ,
1110110 ,
01110110 .
B 3 :
1.7. 1
R = C318FC00, S = 3E600000
1.6.1. Y R 1:
, Y ( ).
Y :
PY = XY 64 = 3.
Y :
Y = (0,18FC)16 ´ 163.
Y () . Y , , . :
Y = (18F,C)16.
Y :
Y = (1 ´ 162 + 8 ´ 161 + 15 ´ 160 + 12 ´ 161) =
= (256 + 128 +15 + 0,75) = 399,75.
1.7.2. Z S :
Z:
PZ = XZ 64 = 62 64 = 2.
Z:
Z = (0,6)16 ´ 162 = (0,006)16 = 6/163 = 6/212 = 3/211 =
= (3/2) ´ (1/210) = (3/2) ´ (1/1024) 1,5 ´ 10-3.
: 2-10 10 -3.
1.8. 2
1.8.1. V 2 :
V:
PV = XV 128 = 134 128 = 6.
V :
, 1.
V 6 :
V = (100110,00111111)2.
V :
) :
(100110)2
= 25 + 22 + 21 = 32 + 4 + 2 = 38;
) :
:
(0,00111111)2 = 2-3 + 2-4 + 2-5 + 2-6 + 2-7 + 2-8 =
= 1/8 + 1/16 + 1/32 + 1/64 + 1/128 + 1/256 = 63/256 0,246;
:
(0,00111111)2 = (111111)2 ´ 2-8 = 63 ´ (1/256) 0,246;
:
(0,0011111)2 = (0,01)2 (0,00000001)2 = 1/4 1/256
0,25 0,004 = 0,246.
V:
V 38,246.
1.8.2. W :
W:
PW = XW 128 = 124 128 = 4.
W :
W = (0,111)2 ´ 24.
W :
W = (0,0000111)2.
W:
W = (0,0000111)2 = (111)2 ´ 27 = 7 / 128 0,0547.
1.9. 3
1.9.1. 3 , V 2 (. 1.8.1).
:
PT = XT 127 = 134 127 = 7.
:
:
) :
(10011000)2 = 27 + 24 + 23 = 128 + 16 + 8 = 152.
) :
(0,111111)2 = 1 (0,000001)2 = 1 1 / 64 0,984.
T:
152,984.
V, , ( ).
1.9.2. Q 3 , 2 (.1.8.2.).
Q:
PQ = XQ 127 = 124 127 = 3.
Q:
Q = (1,11)2 ´ 2-3 = (0,00111)2 = (111)2 ´ 2-5 = 7 / 32 0,219.
2
.
1. (4 ).
:
) , .
) . .
) . .
) .
2. , , . , . , .1.
3. , , , ( , ) . , , .1 .
. , . . . .
, (, ). , . :
CF Carry Flag ( ). . CF (CF =0) (CF =1) () , .
.
PF Parity Flag (). , . ().
AF uxiliary Carry Flag ( ). . ASCII- .
ZF Zero Flag ( ). , - .
SF Sign Flag ( ). ( ) , .
OF Overflow Flag ( ). , . , . . () , , ( ).
. 3 1.
ai i 1- , bi i 2- , pi-1 (i -1)- i , Si i - , pi i (i +1)- | ai | bi | pi-1 | si | pi |
, . :
, :
- : -128 =- 27 ≤ ≤ 27 1=127
1.0000000 | 0.1111111 |
- : 0 ≤ ≤ 28 1 = 255
2.1. = 57, = 49
6 0 | 6 0 | ||||
- | - | ||||
6 0 | 6 0 |
1) >0, >0
A = 0.0 1 1 1 0 0 1 57 57
= + 0.0 1 1 0 0 0 1 + 49 + 49
= 0.1 1 0 1 0 1 0 106 106
:
F = 0 - ( );
SF = 0 - ( );
ZF = 0 - ( );
AF = 0 - ( );
PF = 1 - ( );
OF = 0 - ( ).
2 ) A <0, B >0
A = 1.1 0 0 0 1 1 1 57 199
= + 0.0 1 1 0 0 0 1 + 49 + 49
= 1.1 1 1 1 0 0 0 248
= 1.0 0 0 1 0 0 0 8
F = 0; SF = 1; ZF = 0; AF = 0; PF = 0; OF = 0.
3) >0, <0
A = 0.0 1 1 1 0 0 1 57 57
= + 1.1 0 0 1 1 1 1 + 49 + 207
= 0.0 0 0 1 0 0 0 8 8?
CF=1; SF=0; ZF=0; AF=1; PF=0; OF=0.
. 256 (8+256 = 264 = =57+207).
4) <0, <0
A = 1.1 0 0 0 1 1 1 57 199
=+ 1.1 0 0 1 1 1 1 + 49 + 207
= 1.0 0 1 0 1 1 0 150?
= 1.1 1 0 1 0 1 0 106
CF=1; SF=1; ZF=0; AF=1; PF=1; OF=0.
. 256 (150+256 = = 406 = 199+207).
2.2. :
+ > 128, 128 < ≤ 127.
= 57 (), = 96 ()
+ | - | ||||
6 0 | 6 0 |
.
1) > 0, > 0
= 0.0 1 1 1 0 0 1 57 57
= + 0.1 1 0 0 0 0 0 + 96 + 96
= 1.0 0 1 1 0 0 1 153
= 1.1 1 0 0 1 1 1 -103?
CF = 0; SF = 1; ZF = 0; AF = 0; PF = 1; OF = 1.
.
:
- . , .
- . , , .
2) < 0, < 0
= 1.1 0 0 0 1 1 1 -57 199
= + 1.0 1 0 0 0 0 0 + -96 + 160
= 0.1 1 0 0 1 1 1 +103? 103?
CF = 1; SF = 0; ZF = 0; AF = 0; PF = 0; OF = 1.
(. ), .
2.3. ( = 49), + = 128, , - . = 79.
+ | - | ||||
6 0 | 6 0 |
1) > 0, B > 0
= 0. 1 0 0 1 1 1 1 79 79
= + 0. 0 1 1 0 0 0 1 + 49 + 49
= 1. 0 0 0 0 0 0 0 -128? 128
CF = 0; SF = 1; ZF = 0; AF = 1; PF = 0; OF = 1.
(. ).
2) A < 0, B < 0
= 1. 0 1 1 0 0 0 1 - 79 177
= + 1.1 0 0 1 1 1 1 + - 49 + 207
= 1. 0 0 0 0 0 0 0 -128 128?
CF = 1; SF = 1; ZF = 0; AF = 1; PF = 0; OF = 0.
, .
3
.
, 2, , 2 3 .
.3 1.
, .
:
ai , bi , zi-1 i - (i -1)- , r i i - , zi (i +1)- i- . 3.1. = 67, = 51 | ai | bi | zi-1 | ri | zi |
= (67)10 = (1000011)2
= (51)10 = (110011)2
1) > 0, B > 0
= _ 0.1 0 0 0 0 1 1 _ 67 _ 67
= 0.0 1 1 0 0 1 15151
= 0.0 0 1 0 0 0 0 16 16
CF = 0; SF = 0; ZF = 0; AF = 0; PF = 0; OF = 0.
2) < 0, > 0
= _ 1.0 1 1 1 1 0 1 _- 67 _189
= 0.0 1 1 0 0 1 1+5151
= 1.0 0 0 1 0 1 0 138
= 1.1 1 1 0 1 1 0 - 118
CF = 0; SF = 1; ZF = 0; AF = 0; PF = 0; OF = 0.
3) > 0, B < 0
= _ 0. 1 0 0 0 0 1 1 _ 67 _ 67
= 1. 1 0 0 1 1 0 1- 51205
= 0. 1 1 1 0 1 1 0 118 118?
CF = 1; SF = 0; ZF = 0; AF = 1; PF = 0; OF = 0.
.
4) < 0, B < 0
= _ 1.0 1 1 1 1 0 1 _ - 67 _ 189
= 1 .1 0 0 1 1 0 1- 51205
= 1.1 1 1 0 0 0 0 240?
= 1.0 0 1 0 0 0 0 -16
CF = 1; SF = 1; ZF = 0; AF = 0; PF = 1; OF = 0.
.
3.2. :
+ > 128, 128 < < 127
= 67 (), = 64 ()
1) < 0, > 0
= _ 1.0 1 1 1 1 0 1 _ - 67 _ 189
= 0.1 0 0 0 0 0 06464
= 0.1 1 1 1 1 0 1 125? 125
CF = 0; SF = 0; ZF = 0; AF = 0; PF = 1; OF = 1.
, :
- ;
- ( , ).
2) > 0, < 0
= _ 0.1 0 0 0 0 1 1 _ 67 _ 67
= 1 .1 0 0 0 0 0 0 - 64192
= 1.0 0 0 0 0 1 1 131?
= 1.1 1 1 1 1 0 1 -125?
CF = 1; SF = 1; ZF = 0; AF = 0; PF = 0; OF = 1.
, - .
3.3. ( = 51), + = 128, , . = 77.
1) > 0, B < 0
=_ 0.1 0 0 1 1 0 1 _ 77 _ 77
= 1.1 0 0 1 1 0 1- 51205
= 1.0 0 0 0 0 0 0 128?
= 1.0 0 0 0 0 0 0 - 128?
CF = 1; SF = 1; ZF = 0; AF = 0; PF = 0; OF = 1.
; - .
2) < 0, B > 0
_ 1.0 1 1 0 0 1 1 _ -77 _ 179
0 .0 1 1 0 0 1 15151
1.0 0 0 0 0 0 0 128
1.0 0 0 0 0 0 0 - 128
CF = 0; SF = 1; ZF = 0; AF = 0; PF = 0; OF = 0.
.
4
1. ( ) A B , . , () . (16 : 15 ). .
2. , .1, A B , . .
.4 1.
. . , . , , .. , . , . , , , , .. , .
, . : ) ; ) . , . , .
( ), .. .
1. A = 15, B = 13.
( 4 ) ( 9 ). , . , , .
:
[+ A ] = 0.1111; [ A ] = 1.0001;
[+ B ] = 0.1101; [ B ]