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From: Aurelien Jarno <aurelien@aurel32.net>
To: Richard Henderson <rth@twiddle.net>
Cc: qemu-devel@nongnu.org, Alexander Graf <agraf@suse.de>
Subject: Re: [Qemu-devel] [PATCH] target-s390x: fix CONVERT TO BINARY (CVD, CVDY)
Date: Mon, 29 Jun 2015 22:24:01 +0200	[thread overview]
Message-ID: <20150629202401.GN931@aurel32.net> (raw)
In-Reply-To: <55910FCB.30900@twiddle.net>

On 2015-06-29 10:28, Richard Henderson wrote:
> On 06/25/2015 08:16 PM, Aurelien Jarno wrote:
> >      for (shift = 4; (shift < 64) && bin; shift += 4) {
> >-        int current_number = bin % 10;
> >-
> >-        dec |= (current_number) << shift;
> >+        dec |= (bin % 10) << shift;
> >          bin /= 10;
> >      }
> 
> You've changed from 32-bit division to 64-bit division just to solve a
> problem with the shift.  Better to just change the type of current_number
> there.

Changing the type of current_number instead of bin would indeed solve
the shift issue, but not the -2^31 case. As we take the absolute value,
we need a 64-bit variable to hold the corresponding 2^31 value.

-- 
Aurelien Jarno                          GPG: 4096R/1DDD8C9B
aurelien@aurel32.net                 http://www.aurel32.net

  reply	other threads:[~2015-06-29 20:24 UTC|newest]

Thread overview: 5+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2015-06-25 19:16 [Qemu-devel] [PATCH] target-s390x: fix CONVERT TO BINARY (CVD, CVDY) Aurelien Jarno
2015-06-29  9:28 ` Richard Henderson
2015-06-29 20:24   ` Aurelien Jarno [this message]
2015-06-30  5:53     ` Richard Henderson
2015-06-30  7:27       ` Alexander Graf

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