Central Processor Unit (CPU)
Table 4-1. Instruction Set Summary
Effect on
CCR
Source
Form
Operation
Description
V H I N Z C
A ← (A)–1 or M ← (M)–1 or X ← (X)–1
PC ← (PC) + 3 + rel ? (result) ≠ 0
PC ← (PC) + 2 + rel ? (result) ≠ 0
PC ← (PC) + 2 + rel ? (result) ≠ 0
PC ← (PC) + 3 + rel ? (result) ≠ 0
PC ← (PC) + 2 + rel ? (result) ≠ 0
PC ← (PC) + 4 + rel ? (result) ≠ 0
5
3
3
5
4
6
DBNZ opr,rel
DBNZA rel
DBNZX rel
DBNZ opr,X,rel
DBNZ X,rel
DBNZ opr,SP,rel
DIR
INH
– INH
IX1
IX
SP1
3B
4B
5B
6B
7B
dd rr
rr
rr
ff rr
rr
Decrement and Branch if Not Zero
–
–
–
–
–
9E6B ff rr
DEC opr
DECA
DECX
DEC opr,X
DEC ,X
DEC opr,SP
M ← (M) – 1
A ← (A) – 1
X ← (X) – 1
M ← (M) – 1
M ← (M) – 1
M ← (M) – 1
DIR
INH
INH
IX1
IX
3A
4A
5A
6A
7A
dd
ff
4
1
1
4
3
5
Decrement
Divide
o
–
–
–
–
o
o
o
–
SP1
9E6A ff
A ← (H:A)/(X)
H ← Remainder
DIV
–
–
o INH
52
7
EOR #opr
EOR opr
EOR opr
EOR opr,X
EOR opr,X
EOR ,X
EOR opr,SP
EOR opr,SP
IMM
DIR
EXT
IX2
IX1
IX
SP1
SP2
A8
B8
C8
D8
E8
F8
ii
2
3
4
4
3
2
4
5
dd
hh ll
ee ff
ff
Exclusive OR M with A
A ← (A ⊕ M)
0
–
–
–
–
o
o
o
o
–
9EE8 ff
9ED8 ee ff
INC opr
INCA
INCX
INC opr,X
INC ,X
INC opr,SP
M ← (M) + 1
A ← (A) + 1
X ← (X) + 1
M ← (M) + 1
M ← (M) + 1
M ← (M) + 1
DIR
INH
INH
IX1
IX
3C
4C
5C
6C
7C
dd
ff
4
1
1
4
3
5
Increment
o
–
SP1
9E6C ff
JMP opr
JMP opr
JMP opr,X
JMP opr,X
JMP ,X
DIR
EXT
– IX2
IX1
BC
CC
DC
EC
FC
dd
2
3
4
3
2
hh ll
ee ff
ff
Jump
PC ← Jump Address
–
–
–
–
–
–
–
–
–
–
IX
JSR opr
JSR opr
JSR opr,X
JSR opr,X
JSR ,X
DIR
EXT
– IX2
IX1
BD
CD
DD
ED
FD
dd
4
5
6
5
4
PC ← (PC) + n (n = 1, 2, or 3)
Push (PCL); SP ← (SP) – 1
Push (PCH); SP ← (SP) – 1
PC ← Unconditional Address
hh ll
ee ff
ff
Jump to Subroutine
IX
LDA #opr
LDA opr
LDA opr
LDA opr,X
LDA opr,X
LDA ,X
LDA opr,SP
LDA opr,SP
IMM
DIR
EXT
IX2
IX1
IX
SP1
SP2
A6
B6
C6
D6
E6
F6
ii
2
3
4
4
3
2
4
5
dd
hh ll
ee ff
ff
Load A from M
A ← (M)
0
0
–
–
–
–
o
o
o
o
–
9EE6 ff
9ED6 ee ff
LDHX #opr
LDHX opr
IMM
–
45
55
ii jj
dd
3
4
Load H:X from M
H:X ← (M:M + 1)
DIR
MC68HC908AP Family Data Sheet, Rev. 4
64
Freescale Semiconductor
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