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<style> BODY { font-family:Arial, Helvetica, sans-serif;font-size:12px; }</style>Oh whoops, sorry about that and not replying to the list.<br>
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</div><div>I'll try not to screw up. Generally I think Double is preferred because then everything uses SSE2 and no awkward ferrying of data between it and the floating-point stack is required (come to think of it, only Win64 actually requires the presence of SSE2 and refuses to install if it's not present).</div><div><br>
</div><div>Given that Florian prefers a node micro-optimisation for functions like floor, it should be easy enough to check if the input is of type Single or Double, and drop out if it's Extended (falling back to the actual source code).<br>
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</div><div>I've managed to program a cosine function that is about 8 times faster than FCOS (FCOS is still faster if the input is integral, but other than 0, this is unrealistic since the angle is in radians), but it uses SSE2 rather then x87. It could probably be ported to x87, but will be slower on account that more terms in the Maclaurin Series of cosine will be required for the precision of Extended, among other things (by adjusting the input to be between 0 and pi, I only need 11 terms for Double, and using Horner's Method to factorise the series, the calculation becomes relatively simple, since each step involves subtracting the working value from a reciprocal factorial (a constant) then multiplying by x², something that is easily precomputed ). Also, since I'm using SSE2 and each XMM register can hold 2 Doubles, I can easily adapt the function to compute the sine at the same time (i.e. the sincos function, or a verson in a custom library that takes advantage of "vectorcall" and the System V ABI by having both return values in XMM0).<br>
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</div><div>I figure that offering speed boosts for mathematical functions are a worthwhile investment, especially in writing a game engine, or example (which is my ambition!). sin and cos are certainly easier because they're intrinsics pointing to internal functions, whereas floor is an actual function in a supplementary unit.</div><div><br>
</div><div>Gareth aka. Kit<br>
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<span style="font-weight: bold;">On Mon 04/02/19 13:19 , "Sven Barth" pascaldragon@googlemail.com sent:<br>
</span><blockquote style="BORDER-LEFT: #F5F5F5 2px solid; MARGIN-LEFT: 5px; MARGIN-RIGHT:0px; PADDING-LEFT: 5px; PADDING-RIGHT: 0px"><div dir="auto"><div class="gmail_quote" dir="auto"><div dir="ltr">Am Mo., 4. Feb. 2019, 14:15 hat J. Gareth Moreton <<a href="javascript:top.opencompose('gareth@moreton-family.com','','','')">gareth@moreton-family.com</a>> geschrieben:<br>
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<div>Oh right, okay, so x86_64-win64 is Double (even though Extended is supported), but other x86_64 platforms are Extended, right? A little bit odd, but I'll keep an eye out in that case.</div></blockquote></div><div dir="auto"><br>
</div><div dir="auto">Correct. Though Extended is not considered supported on Win64 by Microsoft themselves and they warn against usage if the x87 (you need to explicitly compile FPC with a specific define to enable Extended on Win64). </div><div dir="auto"><br>
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<div dir="auto">Regards, </div><div dir="auto">Sven</div><div dir="auto"><br>
</div><div dir="auto">PS: you didn't answer to the list </div><div class="gmail_quote" dir="auto"><blockquote class="gmail_quote" style="margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex"><blockquote style="BORDER-LEFT:#f5f5f5 2px solid;MARGIN-LEFT:5px;MARGIN-RIGHT:0px;PADDING-LEFT:5px;PADDING-RIGHT:0px"><div dir="auto"><div dir="auto"><div class="gmail_quote"><blockquote class="gmail_quote" style="margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex">
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