Download Logic, Arithmetic, Data Test and Control Instructions of MC68HC11

ECE 447: Lecture 12
Logic, Arithmetic,
Data Test and Control
Instructions of MC68HC11
ECE 447: Groups of Instructions (1)
1. Data handling instructions
a. Move instructions
(e.g., load, store, exchange)
b. Alter data instructions
(e.g., clear, increment, decrement)
c. Edit instructions
(e.g., shift, rotate)
2. Logic instructions
(e.g., and, or, xor)
3. Arithmetic instructions
(e.g., add, subtract, multiply, divide, negate)
ECE 447: Groups of Instructions (2)
4. Data test instructions
(e.g. compare, test, bit test)
5. Control instructions
(e.g., jump, branch)
6. Condition code instructions
(e.g., set carry, clear overflow flag)
7. Stack operations
(e.g. push, pull)
ECE 447: Groups of Instructions (3)
8. Subroutine-related instructions
(e.g. jump to subroutine, return from subroutine)
9. Interrupt-related instructions
(e.g. software interrupt, return from interrupt,
wait for interrupt)
10. Miscellaneous instructions
(e.g. no operation, stop)
ECE 447: Move Instructions (1)
1. memory  register
LDA[A, B]
M
LD[D, X, Y, S] M
N Z V C
IMM, DIR, EXT, IND
0 –
2. register  memory
STA[A, B]
M
ST[D, X, Y, S] M
DIR, EXT, IND
0 –
3. register  register
TAB, TBA
4. memory  memory
INH
0 –
ECE 447: Move Instructions (2)
N Z V C
1. register  register
XGD[X, Y]
INH
– – – –
ECE 447: Alter Data Instructions (1)
NZVC
1. 0  register
CLR[A, B]
INH
01 00
EXT, IND
01 00
2. 0  memory
CLR
M
ECE 447: Alter Data Instructions (2)
NZVC
3. increment X++
INC[A, B]
INC M
IN[X, Y]
INH
EXT, IND
INH
4. decrement X-DEC[A, B]
DEC M
DE[X, Y]
INH
EXT, IND
INH
–
–
––
–
–
––
ECE 447: Logic Instructions (1)
Acc & M  Acc
1. AND
AND[A, B]
2. OR
M
IMM, DIR, EXT, IND
0–
IMM, DIR, EXT, IND
0–
IMM, DIR, EXT, IND
0–
Acc | M  Acc
ORA[A, B]
3. XOR
NZVC
M
Acc  M  Acc
EOR[A, B]
M
ECE 447: Logic Instructions (2)
3. complement
XX
COM[A, B]
COM
M
4. bit set
NZVC
INH
EXT, IND
01
DIR, IND
0–
DIR, IND
0–
M | mask  M
BSET M, mask
5. bit clear M & mask  M
BCLR M, mask
ECE 447: Arithmetic Instructions (1)
1. addition
ADD[A, B, D]
ADC[A, B]
Acc + M [+ C]  Acc
M
M
IMM, DIR, EXT, IND
2. subtraction Acc – M [-C]  Acc
SUB[A, B, D]
SBC[A, B]
M
M
IMM, DIR, EXT, IND
NZVC
ECE 447: Arithmetic Instructions (2)
3. negation
-X
INH
EXT, IND
NEG[A, B]
NEG
M
4. addition
Reg + B  Reg
ABA
AB [X, Y]
INH
5. subtraction A – B  A
SBA
INH
– – – –
ECE 447: Signed vs. Unsigned
B = b7 b6 b5 b4 b3 b2 b1 b0
Unsigned number
weights
128 64 32 16
8
4
2
1
B = b7 b 6 b 5 b 4 b 3 b 2 b 1 b 0
7
B = b020 + b121 + b222 + b323 + b424 + b525 + b626 + b727 =

bi2i
i=0
Signed number
weights
-128 64 32 16
8
4
2
1
B = b7 b 6 b 5 b 4 b 3 b 2 b 1 b 0
6
B = b020 + b121 + b222 + b323 + b424 + b525 + b626 - b727 = - b727 +
 b2
i
i=0
i
ECE 447: 2’s Complement Representation
X>0
0
X<0
X
0
X+2k = X+1
-8 -7 -6 -5 -4 -3 -2 -1 0 1
k=4
2 3 4 5 6 7
0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15
ECE 447: Unsigned vs. Signed Addition
Programmer
Machine
128 64 32 16 8 4
weight
carry
Unsigned
mind
2 1
Signed
mind
1 1 1
0 0 0 1 0 0 1 1
1 0 0 0 0 1 0 1
1 0 0 1 1 0 0 0
X
+Y
=S
c8
x7 y7
x6 y6
x5 y5
x4 y4
FA
FA
FA
FA
s7
c7
s6
c6
s5
c5
s4
x3 y3
c4
FA
s3
x2 y2
c3
FA
s2
x1 y1
c2
FA
s1
x0 y0
c1
FA
s0
ECE447: Definitions of CCR flags (1)
Zero flag - Z
Z=1
0
zero result
if result = 0
otherwise
Negative flag- N
negative result
N = sign bit of the result
r7 - for 8-bit operands
r15 - for 16-bit operands
ECE447: Definitions of CCR flags (2)
Carry flag - C
C=1
if
0
out-of-range for unsigned numbers
result > MAX_UNSIGNED or
result < 0 (a borrow occurred)
otherwise
where MAX_UNSIGNED = 28-1 for 8-bit operands (registers A, B)
216-1 for 16-bit operands (register D)
Overflow flag - V
V=1
0
out-of-range for signed numbers
if
result > MAX_SIGNED or
result < MIN_SIGNED
otherwise
where MAX_SIGNED = 27-1 for 8-bit operands (registers A, B)
215-1 for 16-bit operands (register D)
MIN_SIGNED = -27 for 8-bit operands (registers A, B)
-215 for 16-bit operands (register D)
ECE 447: Overflow of Signed Numbers
Indication of overflow
Positive
+ Positive
= Negative
Negative
+ Negative
= Positive
Formulas
Overflow2’s complement = xk-1 yk-1 sk-1 + xk-1 yk-1 sk-1
ECE 447: Arithmetic Instructions (3)
1. unsigned multiplication
MUL
2. unsigned division
IDIV
AxB D
INH
– – –
D/IX  IX
D mod IX  D
INH
–
3. unsigned fractional division D < IX
16) D/ IX  IX
(scaled
by
2
FDIV
(scaled by 216) D mod IX  D
INH
4. decimal adjustment
DAA
NZVC
INH
0
–
?
ECE 447: Sign Extension
Extending the number of bits of a
signed number
X
Y
xk-1 xk-2 … x1 x0
yk’-1 yk’-2 … yk yk-1 yk-2 … y1 y0
two’s complement
xk-1 xk-1 xk-1 . . .xk-1 xk-2 … x1 x0
ECE 447: Data Test Instructions
NZVC
1. comparison
CMP[A, B]
CP[D, X, Y]
R-M
M
M
IMM, DIR, EXT, IND
2. comparison A – B
CBA
INH
3. test register
TST[A, B]
INH
00
ECE 447: Data Test Instructions
NZVC
4. test memory
TST
M
5. Bit test
Acc & M
BIT[A, B]
M
EXT, IND
00
IMM, DIR, EXT, IND
0 –
ECE 447: Branch Instructions (1)
NZVC
– – – –
after comparison register vs. memory
REL
unsigned numbers
BHI higher
BLO lower
>
<
signed numbers
BGT greater than >
BLT less than
<
BHS higher or same 
BLS lower or same 
BGE greater than or equal 
BLE less than or equal

BEQ equal
=
BNE not equal 
ECE 447: Brach Instructions (2)
after arithmetic operations (testing for overflow)
unsigned numbers
BCS
BCC
carry set
carry clear
signed numbers
BVS overflow set
BVC overflow clear
after testing register or memory
BPL plus
BMI minus
0
<0
unconditional
BRA always
BRN never
ECE 447: Bit test and branch instructions
1. Bit test and branch
BRCLR
M, mask label
2. Bit test and branch
BRSET
branch if
DIR, IND
branch if
M, mask label
(M & mask) == 0
– – – –
(M & mask) == 0
DIR, IND
– – – –