On Tue, Mar 04, 2008 at 05:07:03PM -0800, Justin Bailey wrote:
I'm trying to get a feel for the assembly output by GHC on my platform. Below is a module containing one function and the associated assembly. I've put in comments what I think is going on, but I'd appreciate it if anyone could give me some pointers. I'd really like to know three things:
* Why does _Add_unsafeShiftR_info check if (%esi) is 3? * What's going on in _s86_info? * At the end of _s87_info, 8 is added to %ebp and then jumped to. Is that a jump to the I# constructor and, if so, how did it's address get to that offset from %ebp?
Thanks in advance for any assistance!
It would be more helpful if you didn't try to go from Haskell to assembly in one step - it's a lot easier to understand each big step of the GHC pipeline individually. Haskell | \-> Core (ghc -ddump-simpl Foo.hs > Foo.core; or -fext-core if you want something ugly but parsable; an unrestricted but simple expression-functional language) | \-> STG (ghc -ddump-stg ...) (Much more regular than Core; more like functional C) | \-> C-- (ghc -ddump-cmm) (just what it says: Simplified C for compiler writers. The universal assembly language for the 21st century) | \-> assembly Stefan