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LD A
When (T) = 0, (A) ← (M)
Op e r a t io n :
F u n c t io n :
When T = 0, this instruction transfers the contents of M to A.
When T = 1, this instruction transfers the contents of M to
(M(X)). The contents of A remain unchanged, but status flags
are changed.
M(X) represents the contents of memory where is indicated by
X.
St a t u s fla g :
N :
V :
T :
B :
I :
D :
Z :
C :
Addressing mode
∆LDA∆#$nn
Immediate
∆LDA∆$zz
Zero page
∆LDA∆$zz,X
Zero page X
∆LDA∆$hhll
Absolute
∆LDA∆$hhll,X
Absolute X
∆LDA∆$hhll,Y
Absolute Y
∆LDA∆($zz,X)
(Indirect X)
∆LDA∆($zz),Y
(Indirect Y)
Note: When T = 1, add 2 to the cycle number.
L
D A
OA
CCUMULATOR WITH MEMORY
(T) = 1, (M(X)) ← (M)
N is 1 when bit 7 is 1 after the operation; otherwise N is
0.
No change
No change
No change
No change
No change
Z is 1 when the operation result is 0; otherwise Z is 0.
No change
Statement
Machine codes
Byte number
A9
, nn
16
16
A5
, zz
16
16
B5
, zz
16
16
AD
, ll
, hh
16
16
16
BD
, ll
, hh
16
16
16
B9
, ll
, hh
16
16
16
A1
, zz
16
16
B1
, zz
16
16
LD A
Cycle number
2
2
2
3
2
4
3
4
3
5
3
5
2
6
2
6
67
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