Download Instruction set of 8086

Instruction set of 8086
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NOP instruction
Do nothing.
No operand is required.
Ex: do nothing, 3 times:
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NOP
NOP
NOP
RET
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NOP and HLT Instructions continued
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HLT instruction
Halt the System.
No operand is required.
Ex:
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MOV AX, 5
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HLT
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Shift Instructions
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Ex.
Multiply
AX by 10
SHL AX, 1
MOV BX, AX
MOV CL,2
SHL AX,CL
ADD AX, BX
Ex. What are the results of
SAR CL, 1
if CL initially contains B6H? DBH
Ex. What are the results of
SHL AL, CL
if AL contains 75H and CL contains 3? A8H
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Rotate Instructions
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Ex. What is the result of ROL BTRE PTR [SI], 1
if SI is pointing to a memory location that contains 41H?
(82H)
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Flag Operations:
CLC - Clear the CF flag
CMC- Complement the CF flag
STC- Set the CF flag
CLD- Clear the DF flag
STD- Set the DF flag
CLI- Clear the IF flag
STI- Set the IF flag
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Flag manipulation Instructions
Continued
External Synchronization:
* HLT- Halt stops the CPU until a hardware interrupts
occurs
WAIT- 8086 enters an idle state if TEST pin=1
LOCK- Forces the 8086(max) LOCK pin to low level and
suspend bus transfer-8086(min) –delay generation of HLDA
in response to HOLD.
ESC mem- Instruction places the contents of the specified
memory location on the data bus
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ASSUME- ASSUME CS: CODE, ASSUME DS:DATA
DB-Define Byte
DD- Define Double word
DQ- Define QUARDWORD
DT- Define TEN Bytes
DW- Define Word
END-End Program
ENDP- End Procedure
ENDS- End Segments
EQU- Equate
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Even- Align on Even Memory Address
EXTRN- For calling procedure externally in other module
GLOBAL- Declare Symbols as PUBLIC or EXTRN
GROUP- Group –related Segments
INCLUDE- Include Source Code from File
LABEL- Used to give a name to the current value
LENGTH- An operator tells the assembler to deermine
NAME- Used to give specific name to assembly module
OFFSET- an operator tells the assembler for offset
ORG- Originate- allows to set the location counter
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PROC- Procedure -to identify the start of a procedure
PTR-Pointer- An operator to assign a specific type to a
variable or to a label
PUBLIC- used to tell the assembler that a specified name or
label will be accessed from other modules.
SEGMENT- Used to indicate the start of a logical segment
SHORT- an operator used to tell the assembler that only a 1byte displacement is needed to code a jump instruction
TYPE- an operator tells the assembler to determine the type
of a specified variable.
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In this unit instruction format and instruction set of 8086 microprocessor
has been covered along with examples. The instructions that has been
covered are Data transfer instructions, Arithmetic instructions, Branch
instructions , Looping instructions, NOP and HLT instructions, Flag
manipulations instructions, Logical instructions, Shift n Rotate
instructions , Directives n Operators, Programming examples
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Micro Computer Systems : The 8086/8088 Family: Architecture,
programming n Design by Liu n Gibson; PHI
Microprocessors and Interfacing : Hall ; TMH
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