ASSEMBLER DIRECTIVES OF 8085 MICROPROCESSOR PDF
Using the Section Directive · Setting up the Linker · Running the Assembler from the Command Line MICROPROCESSOR INSTRUCTION REFERENCE ACI. The most commonly used assembler directives are ORG, DB, DW, EQU, and END. For example, 0 ORG C 1 00H directive informs the assembler to assemble. Assembly Language Format Assembler Example Description. Directive. ORG ( Origin) ORG H The *Please Refer to Assembly Code Summary.
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DQ — Define Quadword This directive is used to define a variable of type quadword or to reserve storage location of type quadword in memory. This directive is used to define a variable of type quadword or to reserve storage location of type quadword in memory.
Assembler directives- These are the statements that direct the assembler to do something. MODEL- This directive is used for selecting a standard memory model for the assembly language program. Newer Post Older Post Home. GROUP This directive is used to group the logical segments named after the directive into one logical group segment.
DB — Define Byte.
8085 Assembler User Guide
Download our mobile app and study on-the-go. EQU This directive is used to give a name to some value or to a symbol. ENDS This directive is used with name of the segment to indicate the end of that logic segment.
They are classified into the following categories based on the function performed by them- Simplified segment directives Data allocation directives Segment directives Macros related directives Code label directives Scope directives Listing control directives Miscellaneous microprocesspr.
Each memory model has various limitations depending on the maximum space available for code and data. The works directly with od 4 physical segments: A series of words o be read much more quickly if they are at even address.
This directive is used to declare a byte type variable or to store a byte in memory location.
DQ — Define Quadword. This directive is used to give a name to some value or to a symbol. DD — Define Doubleword This directive is used to define a variable of type doubleword or to reserve storage location of type doubleword in memory.
CODE- This assembler directive indicates micrporocessor beginning of the code segment. CODE [name] The name in this format is optional. Assembly language consists of two types of statements viz.
Assembler User Guide
END- This is placed at the end of a source and it acts as the last statement of a program. This directive tells the assembler the name of the logical segment it should use for a specified segment. Define Double word [DD]- It defines the data items that are a double word four bytes in length. This directive is used to insert a block of source code from the named file into the current source module.
As the name says, it directs the assembler to do a task. EVEN This directive instructs the assembler to increment the location of the counter to the next even address if it is not already in the even address. DW — Define Word. Write short notes on assembler directives.
When EVEN is used the location counter will simply incremented to next address and NOP instruction is inserted in that incremented location. The specialty of these statements is that they are effective only during the assembly of a program but they do not generate any code that is machine executable. DW — Define Word This directive is used to define a variable of type word or to reserve storage location of type word in memory.
Executable statements- These are the statements to be executed by the processor. Define Quad word [DQ]- This directive is used to tell the assembler to declare variable 4 words in length or to reserve 4 words of storage micropricessor memory.
The assembler directives can be divided into two categories namely the general purpose directives and the special directives. This directive is used to define a variable which is 10 bytes in length or to reserve 10 bytes of storage in the memory. DB — Define Byte This directive is used to declare a byte type variable or to store a byte in od location.
DT — Define Ten Bytes.
This shortens the source code. This directive is used to group the logical segments named after the directive into one logical group segment.