(. 8.8) , . , , , .
.
, , ( ) " ".
-
- -. . 8.8.
(), , .
- , /. .
in aa, out aa, aa . , / 100 . , / .
- , , 0. /, .
, , , .
, . .
, :
□ ;
□ ;
□ ;
□ ,
, . 8.2.
8.2.
| 0,1,2 | |||
| 0, 1,2, 3 | |||
| 0, 1,2,3,4,5,6 | |||
| 0, 1 |
.
.
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CR SR, CR , SR .
CR , , SR , . SR , ( ). CR CR .
, CR , 1, CR , 0. CR , .
(. 8.9) , ASCII- (. American Standard Code for Information Interchange .) .
, 50 , (. 8.10).
- :
□ DR ( 0) ;
□ CR ( 1) , :
;
I ;
S .
□ SR ( 2) , :
Err ;
Rd .
DR , ASCII- , 0 . DR .
CR .
, , . = , . .
I, , . . 1 = 0 .
S = 1 . . , . S , , S .
, , I, . (, I = 1), .
, (. . 8.10). Rd ( . ready) SR. Err ( . error) 51 - . 51 - .
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Rd DR, Err . , ; 00h, .
. CR 1 .
:
□ xxxl0l ( );
□ 102 Err SR;
□ 103 S CR;
□ 104 S CR.
1 nn, 4- 5- CR :
(. 8.11) , . , ASCII-, . :
□ 128 ( );
□ 8 16 ;
□ - :
DR ( 0) ;
CR ( 1) ;
SR ( 2) ;
AR ( 3) .
AR DR . DR DR , AR.
CR 4- 5- :
- ; = 0 AR DR ;
- ; = 1 AR 1 DR .
, CR ( 11) nn, 4- 5- CR (8.1).
, CR, 1:
□ xxxl0l ( ), ( 032), 000 AR Err ;
□ 102 Err.
SR ( ) Err. , 127, AR, 127. Err (. 8.12).
(. 8.13) , :
, (); D;
□ CTR;
□ FT.
( 1, 3, 5 Tl, T2, ). . CLK 1 . , .
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CTR ( 2, 4, 6) :
□ ( 5) ;
□ EI ( 4) ;
□ I/D ( 3) (/), I/D = , I/D =1 ;
□ k ( [1:2]) ( 1 99).
SR, 0. (5, 4 3 Tl, T2, ) 1 . , , 99 999 0, 0 99 999.
(. 8.14) , 0 , CTR, 001000. , , , , , 01.
CTR . SR 1 , :
- 100 ( );
- xxxl0l FT1; 2 FT2; 103 FT3.
, , :
□ FR ( 0) ():
□ LR ( 1) ().
30. FR , LR- . LR .
. , . , , , 09.
, , , .
. . , .
, , , ( ) .
, , , .
100109. , 0 100, 2 102. 100109 .
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( ), . :
1. .
2. , ([3:5]) PC ( ), [1:2] , (I, OV, S, Z). , 1=1, OV = 0, S = 1, Z = 1, [1:2] 1110 = 10112.
3. 0 I.
4. , , PC, .
, , , , . iret, PC ( ret), , .
, , . - I . 1 = 0 . I . , ei ( . enable interrupt).
, 1 , . iret , . . 1 = 1, , .
, ei. , , .
, I - ,
- .
, , , (. CR CTR . 8.9, 8.13), 0. , . (, ) . call, , iret, , ( 0, . . call , 000).
, . . , int ( {0, 1,..., 9}), . , int , , .
, int , I .
