[Posting] Re: Start
From:streu
Thread:Start
Forum:Titan 19
In reply to:Re: Start
Date:Sun, 2022-01-30 15:01 GMT

There might be more hidden bugs like this one that only show up in 32 bits. We'll keep an eye for anything odd.

There actually are some 32/64 bit differences that I know of when floating point (fractional numbers) is involved, but I hope you only notice those as an improvement :smile:

The 32-bit version of PHost occasionally gave you one point happiness less than expected. The 64-bit version matches what VPA and PCC predict, and what you get by computing manually.

Likewise, mines-destroy-mines would occasionally destroy one mine too much.

The reason is that i386 (32-bit) FPUs round a little different than most people expect; when you ask for a 8-byte variable, you occasionally get a 10-byte variable instead, which gives the result a few more digits and thus makes it a little bigger. The happiness formula uses sin/cos, and the mines-destroy-mines formula uses square-roots, which are affected by this.

--Stefan