61
EOR
EOR
E
XCLUSIVE
OR
MEMORY WITH ACCUMULATOR
Op e r a t io n :
F u n c t io n :
St a t u s fla g :
When (T) = 0, (A)
←
(A)
∀
(M)
(T) = 1, (M(X))
←
(M(X))
∀
(M)
When T = 0, this instruction transfers the contents of the M
and A to the ALU which performs a bit-wise Exclusive OR, and
stores the result in A.
When T = 1, the contents of M(X) and M are transferred to the
ALU, which performs a bit-wise Exclusive OR and stores the
results in M(X). The contents of A remain unchanged, but sta-
tus flags are changed.
M(X) represents the contents of memory where is indicated by
X.
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
N :
V :
T :
B :
I :
D :
Z :
C :
Addressing mode
Immediate
Zero page
Zero page X
Absolute
Absolute X
Absolute Y
(Indirect X)
(Indirect Y)
Machine codes
49
16
, nn
16
45
16
, zz
16
55
16
, zz
16
4D
16
, ll
16
, hh
16
5D
16
, ll
16
, hh
16
59
16
, ll
16
, hh
16
41
16
, zz
16
51
16
, zz
16
Cycle number
2
3
4
4
5
5
6
6
Byte number
2
2
2
3
3
3
2
2
Note: When T=1, add 3 to the cycle number.
Statement
∆
EOR
∆
#$nn
∆
EOR
∆
$zz
∆
EOR
∆
$zz,X
∆
EOR
∆
$hhll
∆
EOR
∆
$hhll,X
∆
EOR
∆
$hhll,Y
∆
EOR
∆
($zz,X)
∆
EOR
∆
($zz),Y
