I tried this library http://www.agner.org/optimize/#asmlib

mingw doesn't support .lib files, so I converted it to .a using "Object file converter" from the same page. I used command "objconv -felf32 -nu libacof32o.lib libacof32o.a".

I moved resulting .a file in the directory with all other .a files, and added -lacof32o linker flag.

mingw showed error "undefined reference to MersRandomInit" in asmlibran.h. Probably issue is in name mangling.

If somebody knows where I can copypaste random number generator from, please share.

Removed header, c file now looks like

#define WIN32_LEAN_AND_MEAN
#include <windows.h>

extern "C" {
int MersenneBRandom();
}

int WINAPI
main(void)
{
return MersenneBRandom();
}

still says undefined reference.

If I remove libacof32o.a, it clearly complains "ld.exe cannot find -lacof32o". So it sees file itself, but not sure what it sees inside.


If i unpack libacof32o.a and disassemble mersenne32.o from there using "objconv -fnasm mersenne32.o mersenne32.o.asm" command, it shows this among other things:

MersenneBRandom: ; dword
db 0B9H ; 056B _ .
dd MersenneInstance ; 056C _ 00000000 (d)
dd 0FFFC6FE9H ; 0570 _ -233495
db 0FFH ; 0574 _ .


I'm going to google every exe in my C:\msys64\mingw32\bin untill I find which one is related to linking and object files.

Tried compiling with command "g++ main.o mersenne32.o", resulted in "undefined reference to `InstructionSet'"

Tried compiling with command "g++ main.o libacof32o.a", ended as usual.

"objdump -t mersenne32.o" shows this, among others

0000056b g O .CODE 00000004 MersenneBRandom

My mainCRTStartup function looks like _mainCRTStartup@0 in object files. Thought I used C compiler, why is there still name mangling in it. I thought it was a C++ thing.

strcmp is surprisigly faster than gcc 4.8
thanks for the hint vivik.

but... why you dont simply recompile?

Do you even export the function? Either a .def file or __declspec(dllexport) would work with MinGW. When importing it, of course you need __declspec(dllimport). So if it's an asm function then use __declspec(dllimport) in the C header so it imports it.

There is name mangling because of the Win32 API using stdcall -- and mainCRTStartup being stdcall as well.