What is a constant in assembly?
A constant is a memory location whose value cannot be changed during the execution of the program. In IJVM, constants are global. They can be accessed by any method. Constants are declared and initialized in the constant section of an assembly language program: General Format.
What is x86 assembly instructions?
The x86 instruction set refers to the set of instructions that x86-compatible microprocessors support. The instructions are usually part of an executable program, often stored as a computer file and executed on the processor.
What is the purpose of constant 200 used in start 200 statement?
START < constant > :- This directive indicates that the first word of the target program will start on ROM memory location with address < constant > . START < 200> ROM location will be 200 where first machine code will reside. END Directive :- This directive indicates the end of the source program.
What does EQU mean in assembly?
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 Ltorg in assembler?
The LTORG directive instructs the assembler to assemble the current literal pool immediately.
Which directive define the constant?
Expression. You can use the #define directive to define a constant using an expression. In this example, the constant named AGE would also contain the value of 10.
How many instructions are in x86?
According to Intel’s XED, as of this writing, there are 1503 defined x86 instructions (“iclasses” in XED lingo), from AAA to XTEST (this includes AMD-specific extensions too, by the way).
What is DC in assembler?
The DC instruction causes the assembler to generate the binary representation of the data constant you specify into a particular location in the assembled source module; this is done at assembly time. The DC instruction’s name — Define Constant — is misleading: DC simply creates initial data in an area of the program.
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.
What is DC B in assembly?
“DC.B” (I assume ‘define constant (byte)’ is used to tell the assembler that you with the final assembled program to have a byte of data embedded in it at the relative position in the source file”.
What is use of Ltorg?
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.