From mboxrd@z Thu Jan  1 00:00:00 1970
From: quanstro@quanstro.net (erik quanstrom)
Date: Tue,  8 Mar 2011 12:16:29 -0500
Subject: [9fans] 8c puzzling behavior
Message-ID: <a32de54ece05e5c2bfee96835e370414@ladd.quanstro.net>
Topicbox-Message-UUID: b9139e9c-ead6-11e9-9d60-3106f5b1d025

for this

	uvlong u, i;

	i = 31;
	u = 0xff00000000000000ull;

i get

	u & 1<<i		-> 0xff00000000000000ull
	u & 0x80000000		-> 0
	u & (int)0x80000000	-> 0xff00000000000000ull
	u & -2147483648		-> 0

to put a finer point on it,

	(uvlong)(1<<i)		-> 0xffffffff80000000
	(uvlong)(0x80000000)	-> 0x80000000
	(uvlong)(int)0x80000000	-> 0xffffffff80000000
	(uvlong)-2147483648	-> 0x80000000

so it seems clear that constants are treated as if unsigned, regardless,
but variables are not?

can this be correct?  i hate to hazzard guesses about the c standard.

- erik