Date: Thu, 1 Dec 2011 00:39:38 +0000 From: Alexander Best <arundel@freebsd.org> To: Igor Mozolevsky <mozolevsky@gmail.com> Cc: freebsd-wireless@freebsd.org Subject: Re: comparing floating points via "==" or "!=" Message-ID: <20111201003938.GA52503@freebsd.org> In-Reply-To: <CADWvR2iUB4mDFuwbWzqe6bnjShTZEQzQ-ubAx8h7yqGwjcUHKA@mail.gmail.com> References: <20111130224422.GA36424@freebsd.org> <CADWvR2herXkcMaZXFKm_ALBXnVFDhRCNZ-9%2B-MwHVx5XJPG4AA@mail.gmail.com> <20111201000243.GB44877@freebsd.org> <CADWvR2irEU0ANHNG4mvC1voVP6Y3YMTQxs5d35o5SbBTJ8JyfQ@mail.gmail.com> <20111201001158.GA48051@freebsd.org> <CADWvR2iUB4mDFuwbWzqe6bnjShTZEQzQ-ubAx8h7yqGwjcUHKA@mail.gmail.com>
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[-- Attachment #1 --]
On Thu Dec 1 11, Igor Mozolevsky wrote:
> On 1 December 2011 00:11, Alexander Best <arundel@freebsd.org> wrote:
>
> > i sorry. since sys/dev/ath/ath_rate/sample/tx_schedules.h also handles a lot
> > of integer values, i thought you referred to abs(3), because you saw also
> > some issues with the integer computations in that file. so i thought you were
> > referring to yet another issue in that file.
>
> Oh, I see! No, I was referring to a generic |a-b| expression, not
> abs(3) specifically. Retrospectively, using |a-b| would've been better
> :-)
so wrapping fabs(3) inside a macro, like in the following example might work.
cheers.
alex
ps: just a 60 second hack. ;)
>
> Cheers,
>
> --
> Igor
[-- Attachment #2 --]
Index: sys/dev/ath/ath_rate/sample/tx_schedules.h
===================================================================
--- sys/dev/ath/ath_rate/sample/tx_schedules.h (revision 228164)
+++ sys/dev/ath/ath_rate/sample/tx_schedules.h (working copy)
@@ -40,6 +40,11 @@
#include <sys/cdefs.h>
__FBSDID("$FreeBSD$");
+#define TOLERANCE 0.00001
+
+#define F(_r1, _r2)\
+ ((fabs(_r1-_r2) < TOLLERANCE) ? 1 : 0)
+
#define A(_r) \
(((_r) == 6) ? 0 : (((_r) == 9) ? 1 : (((_r) == 12) ? 2 : \
(((_r) == 18) ? 3 : (((_r) == 24) ? 4 : (((_r) == 36) ? 5 : \
@@ -56,7 +61,7 @@
};
#define NA1(_r) \
- (((_r) == 6.5) ? 8 : (((_r) == 13) ? 9 : (((_r) == 19.5)? 10 : \
+ ((F(_r, 6.5) ? 8 : (((_r) == 13) ? 9 : (((_r) == 19.5)? 10 : \
(((_r) == 26) ? 11 : (((_r) == 39) ? 12 : (((_r) == 52) ? 13 : \
(((_r) == 58.5)? 14 : (((_r) == 65) ? 15 : 0))))))))
#define NA2(_r) \
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