8/7/2019 05_03_2011_9.55_10.50

1/9

Compiled by

Venugopala Rao A S

Sr. Lecturer, Dept of CSE, SSE Mukka.

Microprocessors

06CS45

8/7/2019 05_03_2011_9.55_10.50

2/9

8086 Family Assembler Language Programmingy LOOP Short_Label

y It is limited for short jump

y CX = CX 1

y If CX != 0, Then JMP to Short_Label ,

y LOOPE/LOOPZ Short_Label

y CX = CX 1

y If (CX != 0 & ZF=1) Then JMP will take place to Short_Label

y

LOOPNE/LOOPNZ Short_Labely CX = CX 1

y If CX != 0 & ZF=0 Then JMP will take place to Short_Label

2 Venugopal Rao A S, SSE Mukka

8/7/2019 05_03_2011_9.55_10.50

3/9

8086 Family Assembler Language Programmingy Logical instructions:

y AND instruction:

y AND Destination, Source

y Performs logic AND operation for each bit of the destination and

source; stores the result into destination

y Destination and source can not be both memory locations at the

same time

y It modifies flags: CF OF PF SF ZF

y E.g.

y MOV AL, 01100001b

y AND AL, 11011111b ; AL = 01000001b ('A') RET

3 Venugopal Rao A S, SSE Mukka

8/7/2019 05_03_2011_9.55_10.50

4/9

8086 Family Assembler Language Programmingy OR Instruction:

y Performs logic OR operation for each bit of the destination and

source; stores the result into destinationy Destination and source can not be both memory locations at the

same time

y It modifies flags: CF OF PF SF ZF

yE.g.y MOV AL, 01000001b

y OR AL, 00100000b ; AL = 01100001b

y NOT Instruction:

y

NOT destinationy Inverts each bit of the destination operand

y Destination can be a register or a memory location

y It does not modify flags

4 Venugopal Rao A S, SSE Mukka

8/7/2019 05_03_2011_9.55_10.50

5/9

8086 Family Assembler Language Programmingy XOR instruction:

y XOR Destination, Source

y Performs logic XOR operation for each bit of the destination and

source; stores the result into destination

y Destination and source can not be both memory locations at the

same time

y It modifies flags: CF OF PF SF ZF

y E.g.

y MOV AL, 00000111b

y XOR AL, 00000010b

5 Venugopal Rao A S, SSE Mukka

8/7/2019 05_03_2011_9.55_10.50

6/9

8086 Family Assembler Language Programmingy Bit manipulation Instructions:

y SHL(SAL) Destination, Count

y Left shift destination bits; the number of bits shifted is given by

operand Count

y During the shift operation, the MSB of the destination is shifted into

CF and zero is shifted into the LSB of the destination

y Operand Count can be either an immediate data or register CL

y Destination can be a register or a memory location

y It modifies flags: CF OF PF SF ZF

y E.g.

y MOV AL, 11100000b

y SHL AL, 1 ; AL = 11000000b, CF=1.

6 Venugopal Rao A S, SSE Mukka

CF 0Destination

LSBMSB

8/7/2019 05_03_2011_9.55_10.50

7/9

Bit Manipulation Instructions

SHL(SAL) Destination, Count

Left shift destination bits; the number of bits shifted is given by operand Count

During the shift operation, the MSB ofthe destination is shifted into CF and

zero is shifted into the LSB ofthe destination

Operand Count can be either an immediate data orregister CL

Destination can be a register or a memory location

It modifies flags: CF OF PF SF ZF

CF 0

SHR Destination, Count

Right shift destination bits; the number of bits shifted is given by operand Count

During the shift operation, the LSB ofthe destination is shifted into CF and

zero is shifted into the MSB ofthe destination

Operand Count can be either an immediate data orregister CL

Destination can be a register or a memory location

It modifies flags: CF OF PF SF ZF

CF0 Destination

Destination

LSBMSB

LSB

MSB

8/7/2019 05_03_2011_9.55_10.50

8/9

Bit Manipulation Instructions

SAR Destination, Count

Right shift destination bits; the number of bits shifted is given by operand Count

The LSB ofthe destination is shifted into CF and the MSB ofthe destination remians

the same

Operand Count can be either an immediate data orregister CL

Destination can be a register or a memory location It modifies flags: CF PF SF ZF

CFDestination

LSBMSB

8/7/2019 05_03_2011_9.55_10.50

9/9

Bit Manipulation Instructions

ROL Destination, Count

Left shift destination bits; the number of bits shifted is given by operand Count

The MSB ofthe destination is shifted into CF, it also goes to the LSB ofthe destination

Operand Count can be either an immediate data orregister CL

Destination can be a register or a memory location

It modifies flags: CF OF

CF Destination

ROR Destination, Count

Right shift destination bits; the number of bits shifted is given by operand Count

The LSB ofthe destination is shifted into CF, it also goes to the MSB ofthe destination

Operand Count can be either an immediate data orregister CL Destination can be a register or a memory location

It modifies flags: CF OF

CFDestination

LSBMSB

LSBMSB