lab 3mikro p updated

FACULTY OF ELECTRICAL ENGINEERING

UNIVERSITI TEKNOLOGI MARA

________________________________________________________________

MICROPROCESSOR SYSTEMS LABORATORY

(ECE365)

EXPERIMENT 3

ARITHMETIC AND LOGIC INSTRUCTIONS

1.0 OBJECTIVES

i) To understand the 68HC12 instructions of performing arithmetic and logic operations.

ii) To determine the contents inside the CPU registers and memory.

iii) To write a proper programming for arithmetic and logic instructions.

iv) To understand the functions of CCR.

2.0 LIST OF REQUIREMENTS

2.1 Equipments

1. Personal Computer

2. Software J2RE

3. Software MiniIDE

4. Software HC12SIM

5. Power supply

2.2 Depth understanding of :

1. Lab 1 Addressing Modes

2. Lab 2 Data Transfer and Manipulation Instructions

3. Topic on Arithmetic and Logic Instructions

3.0 THEORY

Arithmetic instructions in 68HC12 perform mathematical operations such as addition,

subtraction, multiplication and division whilst Logic and Bit Instructions perform Boolean

logical operations such and gate, or gate, ex-or gate etc. Table 3.0a and Table 3.0b depict a

summary of addition and subtraction instructions and summary of multiply and division

instruction correspondingly.

Arithmetic operations that require two operands will need one of the operands to be in

accumulator and the result of the operation is written back into accumulator. In order to know

what each instruction do, understanding of addressing modes is required. Knowing the

addressing mode of an instruction will tell us where data is stored, how it is accessed and

processed and finally where the result of the operation is kept.

After an arithmetic operation is finished, the result will be stored in accumulator and

some of the status flags will also be affected. The status flags are: S-Stop Disable, X-X

Interrupt Mask, H- Half-Carry (from bit 3), N-Negative, Z-Zero, V-Overflow and

C-Carry/Borrow. These status flags will be stored in the Z80 CPU, in a register called the

Condition Code Register (CCR). Most arithmetic instructions will affect the status flags.

Common logic instructions include logic gate, bit test, shift and rotate is summarized

in table 3.0c, Table 3.0d and Table 3.0e respectively. All the logic instructions will affect the

status flags accordingly. When dealing with input and output port pins, we often need to

change the values of a few bits. For these types of applications, Boolean logic instructions

come in handy.Usually, one would use the AND instruction to clear one or a few bits and use

the OR instruction to set one or a few bits. The exclusive OR instruction can be used to toggle

(change from 0 to 1 and from 1 to 0) one or a few bits.

The 68HC12 provides instructions for performing unsigned 8-bit by 8-bit and both

signed and unsigned 16-bit by 16-bit multiplications. Since the 68HC12 is a 16-bit

microcontroller, we expect that it will be used to perform complicated operations in many

sophisticated applications. Performing 32-bit by 32-bit multiplication will be one of them.

Since there is no 32-bit by 32-bit multiplication instructions, we will have to break a

32-bit number into two 16-bit halves and use the 16-bit by 16-bit multiply instruction to

synthesize the operation. Assume M and N are the multiplicand and the multiplier,

respectively. These two numbers can be broken down as follows:

M = MHML

N = NHNL

where, MH and NH are the upper 16 bits and ML and NL are the lower 16 bits of M and N,

respectively. Four 16-bit by 16-bit multiplications are performed, and then their partial

products are added together as shown in Figure 3.0.

Figure 3.0 Unsigned 32-bit by 32-bit multiplication

The procedure is as follows:

Step 1

Allocate eight bytes to hold the product. Assume these eight bytes are located at P, P+1, …,

and P+7.

Step 2

Generate the partial product MLNL (in Y:D) and save it at locations P+4 ~ P+7.

Step 3

Generate the partial product MHNH (in Y:D) and save it at locations P ~ P+3.

Step 4

Generate the partial product MHNL (in Y:D) and add it to memory locations P+2 ~ P+5. The

C flag may be set to 1 after this addition.

Step 5

Add the C flag to memory location P+1 using the ADCA (or ADCB) instruction. This

addition may also set the C flag to 1. So, again, add the C flag to memory location P.

Step 6

Generate the partial product MLNH (in Y:D) and add it to memory locations P+2 ~ P+5. The

carry flag may be set to 1. So add the C flag to memory location P+1 and then add it to

memory location P.

Table 3.0a

Table 3.0b

Table 3.0c

Table 3.0d

Table 3.0e

4.0 PROCEDURE 1 Multiprecision Addition

1. Program in Figure 4.0 is the instruction sequence to add two 4-byte numbers that are stored

at $800~$803 and $804~$807, and store the sum at $910~$913. Write this program in

MiniIDE with comments, translate to the list file and machine file.

Figure 4.0

2. Load the machine file to the HC12SIM, set PC to $0800, clear all the registers and CCR,

and then use step execution to observe the contents of the CPU registers include CCR and

memory. Refer to Appendix 12.0.

3. Write a discussion regarding to this procedure.

Solution:

PROGRAMMING:

1: =00000800 ORG $0800

2:

3: 0800 FC 0802 LDD $0802 ;place the lowest two bytes of the first operand in D

4: 0803 F3 0806 ADDD $0806 ;add the lowest two bytes

5: 0806 7C 0912 STD $0912 ;save the sum of the lowest two bytes

6:

7: 0809 B6 0801 LDAA $0801 ;place the second-to-most-significant byte of the

first operand in A

8: 080C B9 0805 ; ADCA $0805 add the second-to-most-significant byte of the

second operand and carry to A

9: 080F 7A 0911 STAA $0911 ;save the sum of the second-to-most-significant bytes

10:

11: 0812 B6 0800 LDAA $0800 ;place the most-significant byte of the first

operand in A

12: 0815 B9 0804 ADCA $0804 ;add the most significant byte of the second

operand and carry to A

13: 0818 7A 0910 STAA $0910 ;save the sum of the most-significant bytes

14:

15: END

Discussion :

The programming that we used in this procedure is about multiprecision addition. It is the

instruction sequence to add two 4-byte numbers that are stored at $800~$803 and $804~$807,

and store the sum at $910~$913. We use instruction such as STAA, LDAA and ADCA.

ADCA $0805 for example add the second-to-most-significant byte of the second operand and

carry to A.

5.0 PROCEDURE 2 Multiprecision Subtraction

1. Program in Figure 5.0 is the instruction sequence to subtract the hex numbers stored at

$804~$807 from the hex number stored at $800~$803, and save the difference at

$900~$903. Write this program in MiniIDE with comments, translate to the list file and

machine file.

Figure 5.0





Solution:

PROGRAMMING:

1: =00000800 org $800 ;starting address of the program

2: 0800 FC 0802 ldd $802 ;place the lowest two bytes of the minuend in

D

3: 0803 B3 0806 subd $806 ;subtarct the lowest two bytes of the

subtrahend from D

4: 0806 7C 0902 std $902 ;save the lowest two bytes of the difference

5: 0809 B6 0801 ldaa $801 ;put the second-to-most-significant byte of the

minuend in A

6: 080C B2 0805 sbca $805 ;subtract the second-to-most-significant byte

of the subtrahend and the borrow from A

7: 080F 7A 0901 staa $901 ;save the second-to-most-significant byte of

the difference

8: 0812 B2 0804 sbca $804 ;subtract the most significant byte of the

subtrahend and the borrow from A

9: 0815 7A 0900 STAA $900 ;save the most-significant byte of the

difference

10: END

Discussion:

This procedure is about make an instruction in subtracting hex number. Multiprecision

subtraction like procedure 1 also added. We used multiprecision subtraction, the instruction

sequence to subtract the hex numbers stored at $804~$807 from the hex number stored at

$800~$803, and save the difference at $900~$903. Examples such as sbca $805 instruction

which is to subtract the second-to-most-significant byte and later staa $901 used to save the

file.

6.0 PROCEDURE 3 Simple Multiplication and Division

1. Program in Figure 6.0 is instruction sequence to multiply the unsigned 16-bit number

stored at memory locations $800~$801 by the 16-bit unsigned number stored at memory

locations $802~$803, and store the product at memory locations $900~$903 and next

instructions are to divide the unsigned 16-bit number stored at accumulator D by the 16-bit

unsigned number stored at index register X, and store the quotient and remainder at

$904~$905 and $906~$909, respectively. Write this program in MiniIDE with comments,

translate to the list file and machine file.

Figure 6.0




3. Write a discussion regarding to this procedure

Solution:

PROGRAMMING:

1: =00000800 org $800

2: ;unsigned 16bit multiply with 16bit

3: 0800 FC 0800 ldd $800 ;d <= ($800) = $FC08

4: 0803 FD 0802 ldy $802 ;y <= ($802) = $00FD

5: 0806 13 emul ;y x d

6: 0807 7D 0900 sty $900 ; ($900) <= Y

7: 080A 7C 0902 std $902 ; ($902) <= D

8: ;unsigned 16bit divide by 16bit

9: 080D CC 80E8 ldd #33000 ;d <= 33k (decimal)

10: 0810 CE 07D0 ldx #2000 ;x <= 2k (decimal)

11: 0813 1810 idiv ;($906 & $907) <= quotient of d/x

12: 0815 7D 0908 sty $908 ;($908 & $909) <= remainder of d/x

13: end

Discussion :

In this procedure, the instruction sequence is about to multiply the unsigned 16-bit number.

We used it to multiply the unsigned 16-bit number located at memory locations $800~$801

by the 16-bit unsigned number stored at memory locations $802~$803, and store the product

at memory locations $900~$903. The next instructions are to divide the unsigned 16-bit

number stored at accumulator D by the 16-bit unsigned number stored at index register X, and

store the quotient and remainder at $904~$905 and $906~$909. We used the emul and idiv

instruction, an specific instuction to multiply in divide in btween 16-bit number.

7.0 PROCEDURE 4 Extended Bits of Multiplication

1. Program in Figure 7.0 is instruction sequence to multiply the 32-bit unsigned integersstored at M~M+3 and N~N+3, respectively and store the product at memory locationsP~P+7.Write this program in MiniIDE with comments, translate to the list file andmachine file.

org $800

M: dc.l $13281250 ; holds the multiplicand

N: dc.l $321F1030 ; holds the multiplier

P: rmb 8 ; reserved to hold the product

org $900

ldd M+2 ; place ML in D

ldy N+2 ; place NL in Y

emul ; compute MLNL

sty P+4 ; save the upper 16 bits of the partial product MLNL

std P+6 ; save the lower 16 bits of the partial product MLNL

ldd M ; place MH in D

ldy N ; place NH in Y

emul ; compute MHNH

sty P ; save the upper 16 bits of the partial product MHNH

std P+2 ; save the lower 16 bits of the partial product MHNH

ldd M ; place MH in D

ldy N+2 ; place NL in Y

emul ; compute MHNL

; the following seven instructions add MHNL to memory locations P+2~P+5

addd P+4 ; add the lower half of MHNL to P+4~P+5

std P+4 ;

tfr y,d ; transfer Y to D

adcb P+3

stab P+3

adca P+2

staa P+2

; the following six instructions propagate carry to the most significant byte

ldaa P+1

adca #0 ; add C flag to location P+1

staa P+1 ;

ldaa P

adca #0 ; add C flag to location P

staa P

; the following three instructions compute MLNH

ldd M+2 ; place ML in D

ldy N ; place NH in Y

emul ; compute MLNH

; the following seven instructions add MLNH to memory locations P+2~P+5

addd P+4 ; add the lower half of MLNH to P+4~P+5

std P+4 ;

tfr y,d ; transfer Y to D

adcb P+3

stab P+3

adca P+2

staa P+2

; the following six instructions propagate carry to the most significant byte

ldaa P+1

adca #0 ; add C flag to location P+1

staa P+1

ldaa P

adca #0 ; add C flag to location P

staa P

end

Figure 7.0

2. Load the machine file to the HC12SIM (B32 Single Chip Mode), set PC to $900, clear all

the registers and CCR, and then use Go execution to observe the executions of overall

instructions affected to the contents of the memory. Refer to Appendix 12.0.


Solution

: =00000800 org $800

2: 0800 13281250 M: dc.l $13281250 ; holds the multiplicand

3: 0804 321F1030 N: dc.l $321F1030 ; holds the multiplier

4: 0808 +0008 P: rmb 8 ; reserved to hold the product

5:

6: =00000900 org $900

7: 0900 FC 0802 ldd M+2 ; place ML in D

8: 0903 FD 0806 ldy N+2 ; place NL in Y

9: 0906 13 emul ; compute MLNL

10: 0907 7D 080C sty P+4 ; save the upper 16 bits of the partial product

MLNL

11: 090A 7C 080E std P+6 ; save the lower 16 bits of the partial product

MLNL

12: 090D FC 0800 ldd M ; place MH in D

13: 0910 FD 0804 ldy N ; place NH in Y

14: 0913 13 emul ; compute MHNH

15: 0914 7D 0808 sty P ; save the upper 16 bits of the partial product

MHNH

16: 0917 7C 080A std P+2 ; save the lower 16 bits of the partial product

MHNH

17: 091A FC 0800 ldd M ; place MH in D

18: 091D FD 0806 ldy N+2 ; place NL in Y

19: 0920 13 emul ; compute MHNL

20: ; the following seven instructions add MHNL to memory locations

P+2~P+5

21: 0921 F3 080C addd P+4 ; add the lower half of MHNL to P+4~P+5

22: 0924 7C 080C std P+4 ;

23: 0927 B7 64 tfr y,d ; transfer Y to D

24: 0929 F9 080B adcb P+3

25: 092C 7B 080B stab P+3

26: 092F B9 080A adca P+2

27: 0932 7A 080A staa P+2

28: ; the following six instructions propagate carry to the most

significant byte

29: 0935 B6 0809 ldaa P+1

30: 0938 89 00 adca #0 ; add C flag to location P+1

31: 093A 7A 0809 staa P+1 ;

32: 093D B6 0808 ldaa P

33: 0940 89 00 adca #0 ; add C flag to location P

34: 0942 7A 0808 staa P

35: ; the following three instructions compute MLNH

36: 0945 FC 0802 ldd M+2 ; place ML in D

37: 0948 FD 0804 ldy N ; place NH in Y

38: 094B 13 emul ; compute MLNH

39: ; the following seven instructions add MLNH to memory locations

P+2~P+5

40: 094C F3 080C addd P+4 ; add the lower half of MLNH to P+4~P+5

41: 094F 7C 080C std P+4 ;

42: 0952 B7 64 tfr y,d ; transfer Y to D

43: 0954 F9 080B adcb P+3

44: 0957 7B 080B stab P+3

45: 095A B9 080A adca P+2

46: 095D 7A 080A staa P+2

47: ; the following six instructions propagate carry to the most

significant byte

48: 0960 B6 0809 ldaa P+1

49: 0963 89 00 adca #0 ; add C flag to location P+1

50: 0965 7A 0809 staa P+1

51: 0968 B6 0808 ldaa P

52: 096B 89 00 adca #0 ; add C flag to location P

53: 096D 7A 0808 staa P

54: end

Symbols:

m *00000800

n *00000804

p *00000808

Discussion

In this procedure, extended bits is involved. The is instruction sequence to multiply the 32-bit unsigned integers stored at M~M+3 and N~N+3, respectively and store the product at memory locations P~P+7. Extended bits is involved in this procedure. We use combination of instruction such as addd P+4 which to add lower half of MNHL. All the instuction in this procedure is more complicated than the other procedures.

8.0 PROCEDURE 5 Boolean Logic and Shift

1. Program in Figure 8.0 is instruction sequence to perform Boolean logic and shift/rotate

operations. Write this program in MiniIDE with comments, translate to the list file and

machine file.

org $800

ldaa #89

ldab #$FE

anda $800

staa $850

orab $802

stab $851

eora $804

staa $852

nega

staa $853

comb

stab $854

asla

staa $855

asrb

stab $856

rola

staa $857

rorb

stab $859

end


and then use step execution to observe the contents of the CPU registers include CCR

and memory. Refer to Appendix 12.0.


Solution

1: =00000800 org $800

2: 0800 86 59 ldaa #89 ; load data and save into accumulator A

immediatelly

3: 0802 C6 FE ldab #$FE ;load data and store in accumulator B

4: 0804 B4 0800 anda $800 ;AND accumulator A with memory

5: 0807 7A 0850 staa $850 ;store data in A

6: 080A FA 0802 orab $802 ;logical OR accumulator B with memory

7: 080D 7B 0851 stab $851 ;store accumulator B to memory

8: 0810 B8 0804 eora $804 ; exclusive OR accumulator A with memory

9: 0813 7A 0852 staa $852 ;store accumulator A to memory

10: 0816 40 nega ;negate accumulator A


12: 081A 51 comb ;complement accumulator B

13: 081B 7B 0854 stab $854 ;store accumulator B to memory

14: 081E 48 asla ;arithmetic shift left accumulator A

15: 081F 7A 0855 staa $855 ;store accumulator A to memory

16: 0822 57 asrb ;arithmetic shift right accumulator B

17: 0823 7B 0856 stab $856 ;store accumulator B to memory

18: 0826 45 rola ;rotate accumulator A left through carrry


20: 082A 56 rorb ;rotate accumulator B through carry

21: 082B 7B 0859 stab $859 ;store accumulator B to memory

22: end

Discussion

This procedure is about using instruction sequence to perform Boolean logic and shift/rotate

operations. This programming used logic gate to do operation such as OR and EXOR gate.

New instruction such as eora, nega, comb, asla, asrb, rola and rorb are used. Instructon like

eora $804 is used to insert exclusive OR accumulator A with memory and rola is to rotate

accumulator A left through carrry.

9.0 QUESTIONS

Answer all the questions.

1. Write an instruction sequence to add the two 24-bit numbers stored at $800-$802 and

$803-$805, and save the sum at $900-$902.

Solution

ORG $0800

LDD $0801

ADD $0804

STD $0901

LDAA $0800

ADCA $0803

STAA $0900

END

2. Write an instruction sequence to subtract the 6-byte number stored at $800-$805 from

the 6-byte number stored at $806-$80B and save the sum at $900-$905.

Solution

ORG $0800

LDD $0804

SUBD $0804

STD $0904

SBCA $0803

STAA $0901

LDAA $0800

SBCA $0806

STAA $0900

END

3. Write a program to multiply two 3-byte numbers that are store at $800-$802 and $803-

$805, and save the product at $900-$905.

Solution

ORG $0800

LDD $0801

LDY $0803

EMUL

STY $0900

STD $0804

LDD #33000

LDX #2000

IDIV

STX $0906

STY $0908

END

4. Write a program to shift the 8-byte number located at $800-$807 to the left four places.

ORG $0800

LDD $0801

LDY $0803

ASLA

END

Result

Conclusion

-From this experiment,we manage to achieve the objectives stated. We slowly to understand

the 68HC12 instructions of performing arithmetic and logic operations by using the listed

instruction. We also learnt to determine the contents inside the CPU registers and memory.

We now know to write a proper programming for arithmetic and logic instructions and

understand the functions of CCR.

11.0 REFERENCES[1] S. F. Barret and D. J. Pack. (2005). Embedded Systems : Design and Application withthe 68HC12 and HCS12. Available:[2] M. G, "Experiment 2 Arithmetic and Logic Instruction," in KEC346, ed: FKE UiTM, Aug2006.[3] H.-W. Huang. (2009). Introduction to the 68HC12 Microcontroller.[4] D. T. Li, "EEL 4744C lecture 5 68HC12 Instruction Set," ed.[5] H.-W. Huang. (2009). 68HC12 Assembly Programming.