Sap 3 Architecture 6oq73

SAP 3 SAP3 instruction set includes all the SAP 2 instructions plus new instructions. SAP 3 Programming Model

B

C

SL

D

E

H

L

Note: There are two instructions that can be used to control the carry flag. 1. STC - SET CARRY - will set the CY flag if it is not set e.g. if CY=0, STC produces CY=1

A FC

CARRY FLAG INSTRUCTIONS

2. CMC - COMPLEMENT THE CARRY - complements the value of CY

F

ADD INSTRUCTIONS

Note: The additional U s, D, E, H and L are used for more efficient data processing. The F stores flag bits: S (sign flag), Z (zero flag) and others.

ADD REG Example 1:

A = 1111 0001 E = 0000 1000

ADVANTAGE OF MORE U S

Solution:

1. Programs can run faster 2. Simplifies program writing

1111 0001 + 0000 1000 1111 10001

ARITHMETIC INSTRUCTIONS

Answer: CY=0

A=1111 1001

Example 2:

A = 1111 1111 L = 0000 0001

Note: CY = CARRY if operation is ADD CY = CARRY if operation is SUB

Solution:

Note: The 8-bit sum S7……S0 is stored in the accumulator. The CY is stored in a special FF called CARRY FLAG. CY

A7

A6

A5

A2

A1

Note: The CY flag acts like the next higher bit of the accumulator, i.e. CY = AB

1111 1111 + 0000 0001 1 0000 0000 A0

Answer: CY= 1

A=0000 0000

CENG03. COMPUTERSYSTEM ARCHITECTURE. SAP 3. esquivelazzej

ADC INSTRUCTIONS (ADC = Add with carry)

Example 2:

A = 0000 1100 C = 0001 0010

ADD REG

Solution:

Example 1:

A = 1000 0011 E = 0001 0010 CY = 1

0000 1100 - 0001 0010 1 1111 1010

Answer:

Solution:

CY=1

1000 0011 + 0001 0010 1 1001 0110

A=1111 1010

Answer: CY=0

SBB INSTRUCTIONS (SBB = Subtract with borrow)

A=1001 0110

Note: It subtracts the contents of a specified and the CY flag from the accumulator contents. SUB INSTRUCTIONS

Example 1:

SUB REG

A = 1111 1111 E = 0000 0010 CY = 1

Example 1:

A = 0000 1111 C = 0000 0001 Solution:

Solution: -

0000 1111 - 0000 0001 0000 1110

1111 1111 0000 0010 1 1111 1100

Answer:

Answer:

CY=0 CY=0

A=1111 1100

A=0000 1110

CENG03. COMPUTERSYSTEM ARCHITECTURE. SAP 3. esquivelazzej

INCREMENTS

ROTATE ALL LEFT (RAL)

INR REG Note: The INR instruction has no effect on the carry flag, but it does affect the sign flags and zero flags. Example 1:

CY

MSB

A

LSB

Note: The CY flag is included in the rotation of bits.

B = 1111 1111, and The initial flags are S=1, Z=0, CY=0

Example 1:

CY = 1 A = 0111 0100

Answer: B = 0000 0000 S=0, Z=1, CY=0

Answer: CY=0 A = 1110 1001

DECREMENTS ROTATE ALL RIGHT (RAR)

DEC REG Example 1:

E = 0000 0000 S=0, Z=1, CY=0

CY

MSB

A

LSB

Answer: E = 1111 1111 S=1, Z=0, CY=0

Note: The CY flag is included in the rotation of bits. Example 1:

CY = 1 A = 0111 0100 Answer: CY=0 A = 1011 1010

CENG03. COMPUTERSYSTEM ARCHITECTURE. SAP 3. esquivelazzej

ROTATE LEFT WITH CARRY (RLC)

MULTIPLY AND DIVIDE BY 2 Uses of rotate instructions:

CY

MSB

A

LSB

Note: This instruction will rotate the contents of the accumulator to the left and the MSB is saved in the CY flag.

1. Parallel to serial and serial to parallel conversion of data. 2. Has the effect of multiplying or dividing the accumulator contents by a factor of 2. Note: With the carry flag reset, a RAL has the effect of multiplying by 2, while the RAR divides by 2.

Example 1: Example 1:

CY = 1 A = 0111 0100

RAL

Answer:

CY = 0 A = 0000 0111

CY=0 A = 1110 1000

Answer: CY=0 A = 0000 1110 ROTATE RIGHT WITH CARRY (RRC)

Example 2:

CY

MSB

A

LSB

RAL CY = 0 A = 0010 0001

Note: The LSB is saved in the CY flag.

Answer:

Example 1:

CY = 1 A = 0111 0100

CY=0 A = 0100 0010

Answer: CY=0 A = 0011 1010

CENG03. COMPUTERSYSTEM ARCHITECTURE. SAP 3. esquivelazzej

Example 3:

Example program:

RAR

Show a SAP 3 program that adds 700 and 400, with the final answer stored in the H ad L s.

CY = 0 A = 0001 1000 INSTRUCTION

Answer: CY=0 A = 0000 1100

Example 3:

RAR CY = 0 A = 0000 1100 Answer: CY=0 A = 0000 0110

MVI 00H MVI 02H MVI BCH MVI O3H MVI 84H ADD ADD MOV MVI 00H

A, B, C, D, E, C E L, A A,

ADC B ADD D MOV H, A HLT

CENG03. COMPUTERSYSTEM ARCHITECTURE. SAP 3. esquivelazzej