This article is about microprocessors. For central processing units more generally, see Ce, Summaries of Microprocessors

Download This article is about microprocessors. For central processing units more generally, see Ce and more Summaries Microprocessors in PDF only on Docsity! Department of Computer Science and Engineering Title: Implement Macro in Assembly Language Programming Microprocessors and Microcontrollers Lab CSE 304 Green University of Bangladesh 1 Objective(s) • To understand 8086 instructions related to Macro using Assembly Language Program. 2 Problem analysis A macro is a symbolic name given to one or more assembly language statements. A macro may be used to generate instructions or data definitions. Syntax for Declaring MACRO: macroName MACRO d1, d2, . . . , dn Statement 1 Statement 2 . . . Statement k ENDM Where d1, d2, . . . ,dn is an optional list of dummy parameters. Dummy parameters are temporary variables; they are not declared by data definition directives (DB, DW). They can be used as input as well as output parameters. A macro definition can appear anywhere in an assembly language program before the END directive. It is usual to place all macro definitions at the beginning of a program before the segment definitions. The difference between macro and procedure is that procedure requires separate memory location to store, where as macro uses the same memory location of the code where the macro actually is being called. Furthermore, in macro parameter values can be passed. 3 Assembly Language Program Example for Macro 1 2 MDSPLY_STRING MACRO STRING ; Declaration of MACRO 3 4 MOV DX, OFFSET STRING 5 6 MOV AH, 09H 7 INT 21H 8 9 ENDM 10 11 ORG 100H 12 13 .DATA 14 MESSAGE1 DB 'Microprocessors and', 0DH, 0AH, '$' 15 MESSAGE2 DB 'Microcontrollers Lab$' 16 17 .CODE 18 MAIN PROC 19 MOV AX, @DATA 20 MOV DS, AX 21 22 MDSPLY_STRING MESSAGE1 ; 1st Call of the MACRO 23 MDSPLY_STRING MESSAGE2 ; 2nd Call of the MACRO 24 25 MOV AH, 4CH ; Return to DOS 26 INT 21H © Dept. of Computer Science and Engineering, GUB