. . , PSW ( ).
. , . . 21. () , () .
21. 51
48 51 .
. 48 51 .
: ( ). , .
, , .
. , 48, 51. MOVX
@Ri 256 .
, 16 , (DPRT). MOVX @DPTR 65 536 .
24 , , , / . 48 , .
DD ADDC 48, . ADDC SUBB, , 48, . 51 ( 48) / , 16- - .
M U L.
M U L
- B;
- AB ( A, B);
- (C) "0";
- (OV) - "0", , "1", .
, .
MUL AB | (A): (B):= (A) * (B) (C):= 0 (AB) > 255 (OV):= 1 (OV):= 0 (P):= 0\1 |
|
|
:
; (A) = 50H, (B) = 0A0H
: MUL AB
; (B): (A) Ü 3200H
; (C) Ü 0, (OV) Ü 0, (P) Ü 1
D I V.
D I V
- () B ();
- () , - B;
- (C) "0";
- (OV) "1", B , - "0";
, .
, .
DIV AB | (B) = 0 (OV):= 1 (OV):= 0 (TMP):= (A) / (B) (B):= (A) (B) (A):= (TMP) (C):= 0 (P):= 0\1 |
:
; (A) = 0FBH, (B) = 12H
: DIV AB
; (A) Ü 0DH (B) Ü11H, 0FBH=0DH*12H+11H
; (C) Ü 0, (OV) Ü 0, (P) Ü 0