What is leaf function in assembly?

A leaf function is a function that calls no other functions. This property means that the function is always at the end of a calling sequence. The compiler can tell that a leaf function calls no other functions and takes advantage of this information.

Does the link register need to be saved for leaf functions?

The answer is that since the LR is indeed clobbered, in the general case you need to save the LR somehow before making another function call. Typically you would save the LR by pushing it onto the stack before the function call, and popping it after—just like we described for the x86 architecture.

What are functions of leaf?

Leaf function The main function of a leaf is to produce food for the plant by photosynthesis. Chlorophyll, the substance that gives plants their characteristic green colour, absorbs light energy. The internal structure of the leaf is protected by the leaf epidermis, which is continuous with the stem epidermis.

What is a leaf procedure?

A leaf procedure is one that doesn’t all any other procedures. A non-leaf procedure is one that does call another procedure. Non-leaf procedures pose an additional, but simple, challenge; we make procedure calls.

What is PC and LR?

LR is the link register a shortcut for r14. And PC is the program counter a shortcut for typing r15. When you perform a call, called a branch link instruction, bl, the return address is placed in r14, the link register. the program counter pc is changed to the address you are branching to.

How and when is the link register used?

R14, link register (LR) R14 is also called the Link Register (LR). This is used for holding the return address when calling a function or subroutine. At the end of the function or subroutine, the program control can return to the calling program and resume by loading the value of LR into the Program Counter (PC).

What are the 2 main functions of leaves?

Conclusion: The leaf carries out two important functions i.e. photosynthesis and transpiration.

What is non-leaf function?

A non-leaf function is one that calls other func- tion(s); a leaf function is one that does not itself make any function calls.

What is bl instruction?

The BL instruction copies the address of the next instruction into r14 (lr, the link register), and causes a branch to label . Machine-level B and BL instructions have a range of ±32Mb from the address of the current instruction. However, you can use these instructions even if label is out of range.

What is bl in ARM?

ARM uses the branch and link instruction (BL) to call a function and moves the link register to the PC (MOV PC, LR) to return from a function.