I have generalized anxiety disorder that involves a number of different symptoms, but what matters here is poor attention and concentration, decreased verbal skills and fatigue when I feel anxious, especially when I'm under stress. The key difference with the linked question on epilepsy is that the mind disturbances due to GAD are less extreme but last for longer, potentially for days or even weeks.
I've been working as a software engineer for quite a few years and have a portfolio of successful projects (nothing grand, though) and recommendations from my previous employers.
I know that ADA requires the employer to provide "reasonable accommodations", but how far this can actually go in my case and what adjustments can I reasonably ask for? (Think of the standard interviewing process that companies like Google and Microsoft use that involves "show me how you're thinking outside the box" tasks, etc. This question is only about the accommodations in the job interview process)