With optimize such as -Ox, Windows x64 build will crash anywhere. Because xptcall code didn't consider alignment. Windows x64 has to consider alignment of stack layout (per 16 bytes). I will attach the patch later.

+ ; Builld parameters i presume you mean Build ?

Comment on attachment 331465 [details] [diff] [review] a patch v1 I don't really know this assembly, so I'm going to delegate review to mmoy, if he's willing. The macrology looks fine.

I built 3.0 (Win x64) with and without this code at -O1 and -O2. Both builds at -O1 showed crash problems. Both builds at -O2 didn't show crash problems. So my perception is that this code didn't break anything but that there are still problems in the code at -O1. I didn't see anything that jumped out as a problem in reading through the code though there are some directives that I'm not familiar with. I only have a few remarks on a few comments: A few typos of the forms: Builld -> Build fist -> first In the following, the comment indicates four parameters but the code either indicates three or six parameters: ; ; fist 4 parameters (1st is "this" pointer) are passed in registers. ; ; for floating value - movsd [rsp+64], xmm1 - movsd [rsp+72], xmm2 - movsd [rsp+80], xmm3 + movsd qword ptr [rsp+64], xmm1 + movsd qword ptr [rsp+72], xmm2 + movsd qword ptr [rsp+80], xmm3 ; for integer value mov [rsp+40], rdx mov [rsp+48], r8 mov [rsp+56], r9

Checked in as http://hg.mozilla.org/mozilla-central/rev/1c1ff3725139