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cppasm

cppasm is a C++ generator for x86 assembly code.

Generated assembly source code syntax is: AT&T.

The Idea

The idea behind this generator is to encapsulate every instruction and CPU register in its own C++ class. Every class name can be found in the Intel developer's manuals, e.g. imm8 class represents an 8-bit immediate value, m16 class represents a memory address of a 16-bit data word.

All instructions are implemented as function objects, e.g. instruction instance of MOV can be used like this:

#include "cppasm.h"

int main(int argc, char *argv[])
{
    MOV(EAX, EBX);

    return 0;
}

cppasm provides global instances for many instructions and CPU registers, so EAX and EBX are global instances of corresponding CPU registers and the output of the above code is simply (AT&T syntax):

    mov %ebx, %eax

Examples

Take a look at the examples to see how to use the generator. The examples follow the same pattern. There is a generate.cpp, generator for some assembly function in the output subdirectory, and an example.cpp, a simple application using generated assembly function. Following examples are available:

• clflush
• collatz
• cpuid
• div-arithm
• fpuconst
• isbn-10
• isbn-13
• lea-arithm
• macheps
• rc4
• rdtsc
• thousand-nops
• xorshift-rng
• xorshift-rng-2

Source code

The generator source code files can be found under src.

Compiler

I am using mingw-w64 to compile the C++ source files and assemble generated assembly files.

Tests

The idea behind testing the generator is to generate as much as possible of supported instructions and to assemble it using GNU assembler. The test is successful, if the assembler does not complain. Additionally, the generated assembler code has been reviewed and added to the git repository, so git status output must be checked for any changes. The tests are divided into 32-bit and 64-bit tests. The test code is also compiled with Visual Studio 2022, but the source code is just compiled only and the assembly source code output is ignored, because the AT&T syntax is not compatible with Visual Studio tools.

Improved tests can be found using googletest framework.

Notes

This C++ generator does not attempt to convince people to write assembly source code. Programmers, who write functions or programs in assembly language, have their reasons for it.

I hope, anyone, a hobby programmer or someone, who is just tired thinking about portability of his code all the time, will find this generator helpful.