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From: "Jeffrey R. Carter" <spam.jrcarter.not@spam.not.acm.org>
Subject: Re: Not good for Ada endorsement
Date: Thu, 15 Jul 2021 23:08:40 +0200	[thread overview]
Message-ID: <scq84o$cc$1@dont-email.me> (raw)
In-Reply-To: <59c3fb8e-6866-4ea9-a1a2-21fdff252095n@googlegroups.com>

On 7/15/21 6:29 PM, Lucretia wrote:
> On Thursday, 15 July 2021 at 16:56:40 UTC+1, Jeffrey R. Carter wrote:
> 
>> A packed array of Boolean requires all the operations above, plus shifting the
>> bit to the LSB and treating the result as a Boolean, so it may not be that
> 
> Don't need to shift to the LSB, only need to shift the 1 to the bit location you want to test, invert and then check against 0.

You know that that is enough, and may be what you're doing manually, but the 
compiler may not know that. If A is a packed array of Boolean, then A (I) has 
type Boolean. Unless the compiler can optimize it (and maybe it can), it would 
normally need to shift the bit down so it can be treated as a value of type 
Boolean, and then apply whatever you do with the resulting Boolean value.

-- 
Jeff Carter
"How'd you like to hide the egg and gurgitate
a few saucers of mocha java?"
Never Give a Sucker an Even Break
101

  parent reply	other threads:[~2021-07-15 21:08 UTC|newest]

Thread overview: 38+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2021-07-07 14:21 Not good for Ada endorsement Richard Iswara
2021-07-07 15:06 ` Luke A. Guest
2021-07-07 15:19   ` Doctor Who
2021-07-07 19:21     ` Simon Wright
2021-07-07 19:49       ` Doctor Who
2021-07-07 20:39         ` Luke A. Guest
2021-07-08  3:46         ` Richard Iswara
2021-07-08  8:20           ` Jeffrey R. Carter
2021-07-08  8:42             ` Dmitry A. Kazakov
2021-07-08  8:52             ` Luke A. Guest
2021-07-08 10:42             ` Jeffrey R. Carter
2021-07-08 10:51               ` Luke A. Guest
2021-07-08 11:12                 ` Jeffrey R. Carter
2021-07-08 17:37                   ` Luke A. Guest
2021-07-08 17:43                     ` Luke A. Guest
2021-07-08 19:16                       ` Luke A. Guest
2021-07-08 19:16                     ` Luke A. Guest
2021-07-09  2:47                       ` Richard Iswara
2021-07-09  8:10                     ` Paul Rubin
2021-07-09  8:24                       ` Egil H H
2021-07-09  8:33                     ` Egil H H
2021-07-09  9:16                       ` Jeffrey R. Carter
2021-07-09  9:21                         ` Jeffrey R. Carter
2021-07-15 15:13                           ` Lucretia
2021-07-15 15:56                             ` Jeffrey R. Carter
2021-07-15 16:29                               ` Anh Vo
2021-07-15 17:30                                 ` Lucretia
2021-07-16 16:27                                   ` Simon Wright
2021-07-16 16:28                                   ` Simon Wright
2021-07-23 17:55                                     ` Luke A. Guest
2021-07-23 17:04                                 ` Anh Vo
2021-07-23 17:12                                   ` Luke A. Guest
2021-07-15 16:29                               ` Lucretia
2021-07-15 16:49                                 ` Dmitry A. Kazakov
2021-07-15 21:08                                 ` Jeffrey R. Carter [this message]
2021-07-11 15:54 ` Dennis Lee Bieber
2021-07-18 23:03 ` Mace Ayres
2021-07-19  1:00   ` Paul Rubin
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