Branching with Labels in Assembly Language
Branching with labels in assembly language involves using conditional and unconditional jumps to alter the flow of program execution based on specific conditions.
The steps involved in branching with labels in assembly language are as follows:
- Define a label at the point in the program where you want to jump to.
- Use a branching instruction to jump to the label.
The following assembly language code shows how to branch with labels:
This code will jump to the label my_label, regardless of where it is in the program.
Types of branching instructions
There are a number of different branching instructions that can be used in assembly language. The most common branching instructions are:
- jmp: Jumps to the specified address.
- je: Jumps if equal.
- jne: Jumps if not equal.
- jl: Jumps if less than.
- jle: Jumps if less than or equal to.
- jg: Jumps if greater than.
- jge: Jumps if greater than or equal to.
Explanation with examples, using x86 assembly as a reference:
Place labels at specific points in your code where you want to be able to jump to.
Use the jmp instruction for unconditional jumps.
Use conditional jump instructions like je (Jump if Equal) or jne (Jump if Not Equal) to perform conditional branching.
Here's an example that checks if a number is even or odd:
In this example, the program checks the least significant bit of the number (test ax, 1) and jumps to either the even_label or odd_label based on the result. Adjust the code inside each label according to your specific requirements.
Branching with labels involves using conditional and unconditional jumps to direct the flow of program execution based on specific conditions. Labels serve as markers within the code, allowing for the creation of decision points and facilitating both structured and conditional programming in low-level languages.