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Gez
Why don't I have a custom title by now?!

Posts: 6458
Registered: 07-07

These three warnings have been there for a while, so I suppose that maybe GCC doesn't catch them. They're all instances of purposefully exploiting 32-bit math overflow on angle_t values.

code:1>.\source\r_main.c(248) : warning C4146: unary minus operator applied to unsigned type, result still unsigned
1>.\source\r_main.c(264) : warning C4146: unary minus operator applied to unsigned type, result still unsigned
1>.\source\r_bsp.c(1742) : warning C4146: unary minus operator applied to unsigned type, result still unsigned

The line numbers correspond to r830. The first two are the "octant 7" lines in R_PointToAngle and R_PointToAngle2, the third is in R_CheckBBox, the "angle2 = -clipangle" operation that happens after the check for whether it is "Totally off the left edge" or not.

08-26-09 14:32 #

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Quasar
Moderator

Posts: 4484
Registered: 08-00

It is impossible to eliminate these warnings AFAIK. There is no valid portable idiom in C that will replace what these statements are trying to do to the best of my knowledge.

If you know of one, do share ;)

08-27-09 16:03 #

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exp(x)

Posts: 2226
Registered: 04-04

What about putting a 0 in front of the minus instead of using unary minus?

08-27-09 16:47 #

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Gez
Why don't I have a custom title by now?!

Posts: 6458
Registered: 07-07

Indeed, no warnings with lines modified as such:

code:        x > (y = 0-y) ? 0-tantoangle[SlopeDiv(y,x)] :              // octant 7


      angle2 = 0-clipangle;

08-27-09 17:54 #

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Graf Zahl
Why don't I have a custom title by now?!

Posts: 6962
Registered: 01-03

That reminds me, is Eternity still using the Killoughized version of R_PointToAngle? Interestingly it's both far less readable and creates less efficient code than the original in Doom.exe...

That guy really had a problem with coding style. ;) What he did to these functions was just plain idiotic.

08-27-09 20:14 #

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Quasar
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Posts: 4484
Registered: 08-00

What do you know? Guess I never thought of that ;)

And yes it's still the Killoughized code simply because I never thought to revert it (a number of other such single-expression functions have been unwound through the years, though). Maybe now would be a good time to look into it :)

08-28-09 00:03 #

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exp(x)

Posts: 2226
Registered: 04-04

Quasar said:
What do you know? Guess I never thought of that ;)

Sometimes it's the simple solutions that escape us.

08-28-09 00:16 #

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Gez
Why don't I have a custom title by now?!

Posts: 6458
Registered: 07-07

Two new warnings in r839:

code:1>.\source\p_cmd.c(350) : warning C4013: 'P_InitLightning' undefined; assuming extern returning int
1>.\source\p_cmd.c(355) : warning C4013: 'P_ForceLightning' undefined; assuming extern returning int

08-31-09 14:06 #

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exp(x)

Posts: 2226
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Try including p_anim.h in p_cmd.c

08-31-09 16:26 #

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Quasar
Moderator

Posts: 4484
Registered: 08-00

Guys you gotta give me more than 5 minutes after a commit to catch stuff like that ;) I appreciate the thought and effort, just don't go overboard ^_^

08-31-09 18:34 #

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exp(x)

Posts: 2226
Registered: 04-04

I blame him.

08-31-09 20:12 #

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Creaphis
I will deliberately take a contrary position just for the sake of writing incredibly long arguments

Posts: 3953
Registered: 10-05

Shame on you Quasar.

08-31-09 20:16 #

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entryway
Forum Staple

Posts: 2522
Registered: 01-04

Graf Zahl said:
That reminds me, is Eternity still using the Killoughized version of R_PointToAngle? Interestingly it's both far less readable and creates less efficient code than the original in Doom.exe...

not so much though :)

code:unsigned int i, k, tic;
tic = SDL_GetTicks();
for(i = 0; i < 1e8; i++)
{
  k += R_PointToAngle(k, i);
}
I_Error("%d %d", SDL_GetTicks() - tic, k);

~1412 msec for Boom
~1374 msec for Carmack

So you can save ~0.04 sec with 100 billions of PointToAngle

btw, zdoom version (which is not used, but code is there) is 1710 msec - much slower. Used (precise) version of course is super slow - 8140 msec.

Last edited by entryway on 09-08-09 at 19:55

09-08-09 19:36 #