Unobtrusive backport of 32-bit x86 Montgomery improvements from 0.9.9-dev:

you need to use "enable-montasm" to see a difference.  (Huge speed
advantage, but BN_MONT_CTX is not binary compatible, so this can't be
enabled by default in the 0.9.8 branch.)

The CHANGES entry also covers the 64-bit x86 backport in November 2007
by appro.

crypto/perlasm/x86nasm.pl

@@ -154,6 +154,7 @@ sub main'exch	{ &out2("xchg",@_); }
 sub main'cmp	{ &out2("cmp",@_); }
 sub main'lea	{ &out2("lea",@_); }
 sub main'mul	{ &out1("mul",@_); }
+sub main'imul	{ &out2("imul",@_); }
 sub main'div	{ &out1("div",@_); }
 sub main'dec	{ &out1("dec",@_); }
 sub main'inc	{ &out1("inc",@_); }