Mixing c and assembly language programs

The APCS comprises a family of variants. Each of these variants is exclusive. This means that one can only be used with the code that conforms to it. The choice of a variant will depend on if: The program counter is bit or bit The stack checking limit is implicit memory management hardware or explicit performed by the code The code is non-reentrant or reentrant Floating-point values are passed in floating point registers.

Subroutine invocation This article assumes that you have prior knowledge of assembly language and microprocessors. If you are not well-versed in these areas then we recommend that you get the help of our programming experts or attend classes. Passing parameters Parameters are passed on the stack by high-level languages like C.

This is because such languages use memory differently and a common area is needed for subroutine interfacing. As a result, the accepted standard is stack. The data value of a short numeric integer is usually pushed on stack. Also, a pointer to the string is passed if the parameter is an alphanumeric string. We can pass floating-point format numbers either by direct value or pointer.

Collectives on Stack Overflow. Learn more. Mixing C and Assembly files Ask Question. Asked 10 years, 2 months ago. Active 3 years, 8 months ago. Viewed 23k times. Improve this question. MetallicPriest MetallicPriest Try and make this more specific - it's rather broad and vague as it stands - otherwise it will probably be closed as "not a real question". Also recall the earlier advice in your earlier questions about using gcc -S MetallicPriest did you ever find out how to accomplish what you asked?

I'm having the same problems. Add a comment. Active Oldest Votes. Improve this answer. Here's an example of a trick to achieve the "naked function" effect. You don't even need the dummy function as a wrapper as basic inline assembly can be placed at global scope.

Peter Cordes k 41 41 gold badges silver badges bronze badges. You can't use extended inline assembly at global scope. A basic assembly statement is always implicitly volatile per the documentation. Your x86 vs. Also, movzx eax, al is slightly better on both, because it's shorter.

In the main function, we push and pop the stack and put our operations in between. We move all the parameters in to the appropriate registers, and then we call the function. View the discussion thread. Skip to main content. How to Mix C and Assembly. Creating a Static Library with Assembly The first step to calling an assembly function from C is to package it as a static library. DATA hello: db 'Hello world!