The EQU directive
only tells the assembler to substitute a value for a symbol or label
, and doesn’t involve any type of ROM or RAM. EQU directives are typically placed at the beginning of an assembly program.
What is EQU assembler directive?
In assembly code, the assembler directive EQU is
used to assign a label to a number
, which can be a literal, a file register number or an individual register bit. In BIN4, ‘porta’ and ‘portb’ are the port data registers (05 and 06) and ‘timer’ is the first spare register (0C), which will be used as a counter register.
What is EQU instruction?
The EQU instruction
assigns absolute or relocatable values to symbols
. Use it to: Assign single absolute values to symbols. Assign the values of previously defined symbols or expressions to new symbols, thus letting you use different mnemonics for different purposes.
What is equ microprocessor?
The EQU directive is
used to give name to some value or symbol
. Each time the assembler finds the given names in the program, it will replace the name with the value or a symbol. The value can be in the range 0 through 65535 and it can be another Equate declared anywhere above or below.
What do you mean by EQU and $-?
The action of EQU is
to define the given label name to the value of its (only) operand
. This definition is absolute, and cannot change later. So, for example, message db ‘hello, world’ msglen equ $-message. defines msglen to be the constant 12. msglen may not then be redefined later.
What does EQU stand for?
| Acronym Definition | EQU Equal to | EQU Equivalent Unit | EQU Extremely Qualified User | EQU Estimated Quarterly Usage |
|---|
How do you use EQU in PLC?
The EQU, also known as the Equal, instruction is used
to compare two values
. The EQU instruction is an input instruction which will return TRUE if the two values within “Source A” and “Source B” fields are equal to each other. If that condition is met, the instruction will allow what’s on the right of it to execute.
Which directive ends a procedure?
The ENDP directive
marks the end of the main procedure.
What are assembler directives give examples?
Examples of common assembler directives are
ORG (origin), EQU (equate), and DS. B (define space for a byte)
. Directives are NOT part of the Motorola assembly language machine instructions, such as ‘ldaa’ or ‘movb’. Machine instructions generate machine code, assembler directives do not.
Why are assembler directives required?
The assembler directives control organization of the program and
provide necessary information to the assembler to understand assembly language programs to generate machine codes
. They indicate how an operand or a section of program is to be processed by the assembler.
What is the difference between 8085 and 8086 microprocessor?
| Property 8085 Microprocessor 8086 Microprocessor | Data Bus Size 8-Bit 16-Bit | Address Bus Size 16-bit 20-bit | Clock Speed 3MHz Varies in range 5.8 – 10 MHz | Duty Cycle for clock 50% 33% |
|---|
What is the difference between procedure and macro?
The main difference between Macro and Procedure is that the Macro is used for a small number of instructions;
less than ten instructions
, but Procedure is used for a large number of instructions; higher than ten instructions.
What is the difference between microprocessor and microcontroller?
Microprocessor consists of only a Central Processing Unit, whereas Micro Controller contains a CPU, Memory, I/O all integrated into one chip. … The microprocessor uses an external bus to interface to RAM, ROM, and other peripherals, on the other hand, Microcontroller
uses an internal controlling bus
.
What is Ltorg statement?
Use the LTORG instruction so
that the assembler can collect and assemble literals into a literal pool
. A literal pool contains the literals you specify in a source module either after the preceding LTORG instruction, or after the beginning of the source module.
Which assembler directive is used in FAR procedure?
The
PROC directive
is used to identify the start of a procedure. The PROC directive follows a name you give the procedure. After the PROC directive, the term near or the term far is used to specify the type of the procedure.
What are directives in 8086?
Introduction: Assembler directives are
the directions to the assembler which indicate how an operand or section of the program is to be processed
. These are also called pseudo operations which are not executable by the microprocessor.
