Michael wrote an article about quake once that described the inner loop optimization of the software renderer. I recall he was computing a dot product or something that was used over an 8 pixel span. The hack was that he started an fpu divide and then got useful work done on the integer pipeline without a stall, perfectly timing out when the fpu would have his value ready. What a brilliant hack. I recall the satisfaction of knowing so much secret knowledge. :)
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Michael wrote an article about quake once that described the inner loop optimization of the software renderer. I recall he was computing a dot product or something that was used over an 8 pixel span. The hack was that he started an fpu divide and then got useful work done on the integer pipeline without a stall, perfectly timing out when the fpu would have his value ready. What a brilliant hack. I recall the satisfaction of knowing so much secret knowledge. :)