I was looking through the code for 6.12.1 and am a bit confused about 11.1.3 in the runtime system documentation docs/rts/rts.tex. http://citeseerx.ist.psu.edu/viewdoc/download?doi=10.1.1.79.641&rep=rep1&type=pdf It says the arguments passing convention to a known combinator differs from that of the others in that it starts the arguments with R1 instead of R2 (R1 points to the associated memory data structure for non-combinators). The thing I'm confused with is I would expect this would require treating combinators special, and yet I don't see an combinator specific stuff (in either ClosureTypes.h or the generated AutoApply.cmm) to treat them special. Ive also looking at functions like plusInt and a few of my own, but, apart from internal functions like stg_app_*, I'm not finding any code using the the combinator passing convention. Am I missing something? Thanks! -Tyson