[Ohrrpgce] SVN: james/9631 The "experience to level" command now has a new optional hero slot argum

[James Paige]

If the problem isn't realistic to fix, then we might just have to make
those particular tests more fuzzy.

abs(experience to level(2, bram slot) -- 69) < 2

It ain't ideal but I could live with it.



On Tue, Nov 7, 2017 at 8:23 AM, Ralph Versteegen <teeemcee at gmail.com> wrote:

>
>
> On 8 November 2017 at 05:18, Ralph Versteegen <teeemcee at gmail.com> wrote:
>
>> We have a bit of a problem: the xp formula produces different results in
>> gengcc=1 builds!
>>
>> ! TRACE: ASSERT FAILURE:
>> ! TRACE: autotest.hss:1127: experience to level(2, bram slot) == 69
>> [actual values were 70 == 69]
>>
>> This would be because floating point calculations aren't totally
>> reproduceable between different CPU architectures, compilers, and build
>> options. The biggest problem is that the x87 FPU defaults to using 80 bit
>> registers, so it makes a difference whether a compiler puts an intermediate
>> result in a register or writes it out.
>> In this case, an intermediate result is 34.5, and it gets rounded
>> differently.
>>
>> By coincidence, I read through the long discussion at
>> http://yosefk.com/blog/consistency-how-to-defeat-the-purpose
>> -of-ieee-floating-point.html
>> about this just a week or two ago.
>>
>> I've tried and confirmed that running the following linux-specific code
>> to use 64-bit instead of 80-bit x87 registers fixes the assert failure:
>>
>
> Oh, to be clear, it doesn't fix the failure, it just makes gengcc=0 and
> gengcc=1 consistent, by making them both return 70.
> Of course, we do use floating point in a number of places, so I wonder how
> many of those could lead to a visible change.
>
>
>> #include <fpu_control.h>
>> fpu_control_t cw;
>> _FPU_GETCW(cw);
>> cw = (cw & ~_FPU_EXTENDED) | _FPU_DOUBLE;
>> _FPU_SETCW(cw);
>>
>> I read that this might have negative effects on the accuracy of math
>> functions like pow() implemented with library routines, but it'll be pretty
>> tiny.
>>
>> I was planning on adding this anyway, to make scripts (once we add
>> floating point to HS) more portable between CPUs and builds.
>> But you're never going to avoid 100% of differences. For example the ARM
>> fpu in my phone gives larger errors on some math functions like exp, which
>> actually causes several tests in freebasic's test suite to fail.
>>
>>
>> On 1 November 2017 at 09:55, <subversion at hamsterrepublic.com> wrote:
>>
>>> james
>>> 2017-10-31 13:55:49 -0700 (Tue, 31 Oct 2017)
>>> 208
>>> The "experience to level" command now has a new optional hero slot
>>> argument for checking the experience curve of a specific hero
>>> Also added a test-case to autotest.rpg verifying a customized experience
>>> curve
>>> ---
>>> U   wip/docs/plotdict.xml
>>> U   wip/docs/plotdictionary.html
>>> U   wip/plotscr.hsd
>>> U   wip/scriptcommands.bas
>>> U   wip/testgame/autotest.hss
>>> U   wip/testgame/autotest.rpg
>>> _______________________________________________
>>> Ohrrpgce mailing list
>>> ohrrpgce at lists.motherhamster.org
>>> http://lists.motherhamster.org/listinfo.cgi/ohrrpgce-motherhamster.org
>>>
>>
>>
>
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