[PATCH 3/3] Optimize 64-bit mpn_add_N and mpn_sub_N for sparc T3 and later.
davem at davemloft.net
Tue Mar 5 20:52:29 CET 2013
From: Torbjorn Granlund <tg at gmplib.org>
Date: Tue, 05 Mar 2013 16:01:11 +0100
> They should of course ether have applied the negation to the r1 operand,
> or used an unsigned imm field.
An unsigned imm field would eliminate a very useful existing construct.
Right now you can compose any 32-bit constant sign extended into a
64-bit register using:
sethi %hi(...), reg
xor reg, ..., reg
With an unsigned immediate field, you couldn't do that because
sethi always zero extends.
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