Because x64 inline hook is complicated, I'm planning supports only IAT and EAT hook, or using a third-party hook library such as PolyHook or Detours.
So your pull request will not be merged. But your winmm.asm is great, which uses macro to reduce duplicate code. I will use it.
Thanks for your work!
Add x64 hook support. Test in local.
The picture below is keepassXC x64