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Re: Cygwin 64bit triplet
- From: Corinna Vinschen <corinna-cygwin at cygwin dot com>
- To: cygwin-developers at cygwin dot com
- Date: Thu, 21 Feb 2013 13:39:48 +0100
- Subject: Re: Cygwin 64bit triplet
- References: <20130220211406.253d7332@YAAKOV04>
- Reply-to: cygwin-developers at cygwin dot com
On Feb 20 21:14, Yaakov wrote:
> The bootstrap toolchain provided so far has used the x86_64-pc-cygwin
> triplet. The problem is, now that we've managed to get far enough
> (before I threw a wrench into everything today :-)
Even with this change to the size of sszie_t, we have a *very* good
chance that our installations still work. The reason is a curious
behaviour of the x86_64 CPU when using 32 bit register writes:
Every time, a 32 bit value is transfered into a register, the upper 32
bit are zeroed out:
before: rax == 0x123456789abcdef
movl #0x42, %eax
after: rax == 0x42
Consider that the first four arguments to a function are always stored
in registers ($rcx, $rdx, $r8, $r9), and consider that return values up
to 64 bit are returned in $rax.
==> There's a good chance we don't see a big difference.
I, just tested to run the "old" tcsh in mintty with the "new" Cygwin
DLL and everything still appears to work.
Corinna Vinschen Please, send mails regarding Cygwin to
Cygwin Maintainer cygwin AT cygwin DOT com