Important Assembler Directives of the Microprocessor Data declaration directives: DB, DW, DD, DQ, DT ASSUME END directives EQU. The words defined in this section are directions to the assembler, not instructions for the Richa Upadhyay Prabhu. Microprocessors. Introduction To Segmentation: The microprocessor has 20 bit . The DW directive is used to tell the assembler to define a variable of type.
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This assembler ignores statement s after an END directive.
The general format for the EQU directive is:. If there is only one value, 8 bytes of consecutive memory locations are reserved. Learn How to Order Essay Online.
The defined variable may have one or more values in the statement. II Use Of Assembler Directives The assembler directives control organization of the program and provide necessary information to the assembler to understand assembly language aseembler to generate machine codes.
It is necessary to do this in any instruction where the type of the operand is not clear.
the use of assembler directives in microprocessor | CustomWritings
Abstract This term paper includes the use of assembler directives in microprocessor and the various assembler directives used in Intel microprocessorits format with various examples.
The general format for ENDP directive is: The above directive informs assembler to reserve 8 bytes of consecutive memory locations for the variable named NUMBER and initialize with the above mentioned number. This is used after the last statement of the program module.
Without this WORD addition, the segment will be located on the next available paragraph byte address, which might waste as much as 15 bytes of memory. The assembler will then put this information in the object code file so that the linker can connect the two modules together. It processes the pseudo operands and directives. The name of the segment is used as the prefix of the ENDS directive. This directive informs assembler to reserve one byte of memory space for the variable named WEIGHT and initialize with value It has been defined with EQU directive in another program module.
The above directive tells the assembler that the name of the stack segment used by the programmer is STACK. The segment named CODE contains the machine codes of the instructions.
When all the modules are working correctly, their object code files are linked together to form the complete program. In the directive statement there may be one or more values. The above directive informs directivess to reserve 10 bytes of consecutive memory locations for the variable named NUMBER and initialize with the above specified values.
The names, procedures and labels declared as external in one program module must be declared public using PUBLIC directive in the program module in which they have been defined.
the use of assembler directives in microprocessor
difectives The directive END informs assembler the end of a program module. If type is not specified, the assembler assumes it NEAR. If there is one initial value, one byte of memory space is reserved for each value. It will initialize the 10 bytes with the values 11, 22, 33, 44, 55, 66, 77, 88, 99, and 00 when the program is loaded into memory to be run. It stores addresses and data of the subroutines, saves the contents a specified register or memory locations after PUSH instruction, etc.
The directive DT defines a variable of ten bytes. The PUBLIC directive is used to tell the assembler that a specified name or label will be accessed from other modules. Receive All Updates Via Facebook. The memory locations are to mlcroprocessor initialized with the values 32, 42, 59, 67 and The above directive statement informs assembler to reserve two bytes of consecutive memory locations for the variable named NUMBER.
This directive informs assembler to reserve 16 bytes of consecutive memory locations. In Intel microprocessor, string instructions may use DI register to point the destination memory address for the data.
The type FAR is used to call a procedure from some other program module. Type NEAR indicates that the procedure is in microprocessot same segment of memory.