If you want to control the computer, you have options. Qemu can give you fine grained CPU level logging you want: http://moyix.blogspot.jp/2014/07/breaking-spotify-drm-with-p... -- this is an article that walks through logging them instructions. (https://github.com/panda-re/panda)
Finally there are RE frameworks where you can instrument (hook) function calls (Frida being a good cross platform option).
I would try AFL first. But playing with Panda can be really fun too.
(edit: and a colleague just pointed out -- https://github.com/angr, which will also let you work right at the level you want to, I think).
If you want to control the computer, you have options. Qemu can give you fine grained CPU level logging you want: http://moyix.blogspot.jp/2014/07/breaking-spotify-drm-with-p... -- this is an article that walks through logging them instructions. (https://github.com/panda-re/panda)
Finally there are RE frameworks where you can instrument (hook) function calls (Frida being a good cross platform option).
I would try AFL first. But playing with Panda can be really fun too.
(edit: and a colleague just pointed out -- https://github.com/angr, which will also let you work right at the level you want to, I think).