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| From | jgk@panix.com (Joe keane) |
|---|---|
| Newsgroups | comp.arch, comp.lang.c |
| Subject | Re: ffs16 |
| Date | 2012-04-25 21:25 +0000 |
| Organization | Public Access Networks Corp. |
| Message-ID | <jn9q4m$4dk$1@reader1.panix.com> (permalink) |
| References | <jn1tku$pga$1@reader1.panix.com> <v65g69-41e2.ln1@ntp6.tmsw.no> <jn6tjv$a39$1@reader1.panix.com> <9kmj69-hhi2.ln1@ntp6.tmsw.no> |
Cross-posted to 2 groups.
In article <9kmj69-hhi2.ln1@ntp6.tmsw.no>,
Terje Mathisen <"terje.mathisen at tmsw.no"> wrote:
>When did you last time the uint16->float->exponent trick?
just now
time in us
'server'
239 testfx
270 testfy
'PC'
211 testfx
186 testfy
-- fhsx.c
static const char fhstab[256] =
{
99, 0, 1, 1, 2, 2, 2, 2, 3, 3, 3, 3, 3, 3, 3, 3,
4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4,
5, 5, 5, 5, 5, 5, 5, 5, 5, 5, 5, 5, 5, 5, 5, 5,
5, 5, 5, 5, 5, 5, 5, 5, 5, 5, 5, 5, 5, 5, 5, 5,
[...]
};
extern int kk_fhsx(int mask)
{
int ret;
ret = (mask & 0xFF00) != 0 ? fhstab[mask >> 8 & 0xFF] + 8 :
fhstab[mask & 0xFF];
return ret;
}
-- fhsy.c
union u
{
float f;
unsigned int u;
};
extern int kk_fhsy(int mask)
{
union u t;
int bex;
int ret;
t.f = (float) mask;
bex = t.u >> 23;
ret = bex - 127;
return ret;
}
-- testfx.c
#include <stdio.h>
static void testfx(int *sump);
extern int kk_fhsx(int mask);
[main]
static void testfx(int *sump)
{
int m;
for (m = 0x1; m <= 0xFFFF; m++)
{
int mask;
int ret;
mask = 31 * m & 0xFFFF;
ret = kk_fhsx(mask);
/* *sump += ret; */
}
}
-- testfy.c
#include <stdio.h>
static void testfy(int *sump);
extern int kk_fhsy(int mask);
[main]
static void testfy(int *sump)
{
int m;
for (m = 0x1; m <= 0xFFFF; m++)
{
int mask;
int ret;
mask = 31 * m & 0xFFFF;
ret = kk_fhsy(mask);
/* *sump += ret; */
}
}
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ffs16 jgk@panix.com (Joe keane) - 2012-04-22 21:36 +0000
Re: ffs16 Keith Thompson <kst-u@mib.org> - 2012-04-22 15:23 -0700
Re: ffs16 Eric Sosman <esosman@ieee-dot-org.invalid> - 2012-04-22 20:37 -0400
Re: ffs16 Philip Lantz <prl@canterey.us> - 2012-04-24 06:36 -0700
Re: ffs16 Eric Sosman <esosman@ieee-dot-org.invalid> - 2012-04-24 20:32 -0400
Re: ffs16 Philip Lantz <prl@canterey.us> - 2012-04-25 00:30 -0700
Re: ffs16 Terje Mathisen <"terje.mathisen at tmsw.no"> - 2012-04-23 16:22 +0200
Re: ffs16 Eric Sosman <esosman@ieee-dot-org.invalid> - 2012-04-23 21:46 -0400
Re: ffs16 Terje Mathisen <"terje.mathisen at tmsw.no"> - 2012-04-24 14:16 +0200
Re: ffs16 Eric Sosman <esosman@ieee-dot-org.invalid> - 2012-04-24 20:40 -0400
Re: ffs16 jgk@panix.com (Joe keane) - 2012-04-24 19:06 +0000
Re: ffs16 Terje Mathisen <"terje.mathisen at tmsw.no"> - 2012-04-25 00:38 +0200
Re: ffs16 jgk@panix.com (Joe keane) - 2012-04-25 20:08 +0000
Re: ffs16 "James Van Buskirk" <not_valid@comcast.net> - 2012-04-25 15:06 -0600
Re: ffs16 "James Van Buskirk" <not_valid@comcast.net> - 2012-04-25 16:30 -0600
Re: ffs16 jgk@panix.com (Joe keane) - 2012-04-25 21:25 +0000
Re: ffs16 Terje Mathisen <"terje.mathisen at tmsw.no"> - 2012-04-26 01:38 +0200
Re: ffs16 jgk@panix.com (Joe keane) - 2012-04-26 19:34 +0000
Re: ffs16 jgk@panix.com (Joe keane) - 2012-04-26 20:41 +0000
Re: ffs16 Terje Mathisen <"terje.mathisen at tmsw.no"> - 2012-04-27 02:47 +0200
Re: ffs16 MitchAlsup <MitchAlsup@aol.com> - 2012-04-23 13:01 -0700
Re: ffs16 Terje Mathisen <"terje.mathisen at tmsw.no"> - 2012-04-24 03:28 +0200
Re: ffs16 nmm1@cam.ac.uk - 2012-04-24 09:15 +0100
Re: ffs16 Chris Gray <cg@GraySage.com> - 2012-04-24 13:37 -0600
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