[Libre-soc-dev] Power ISA v3.0B FP "STORE" function, potential specification discrepancy
programmerjake at gmail.com
Sun May 16 18:24:17 BST 2021
On Sat, May 15, 2021, 06:02 Luke Kenneth Casson Leighton <lkcl at lkcl.net>
> No Denormalization Required (includes Zero / Infin-
> ity / NaN)
> if FRS1:11 > 896 or FRS1:63 = 0 then
> WORD0:1 <- FRS0:1
> WORD2:31 <- FRS5:34
> should that be "FRS[12:63] = 0", testing the mantissa for zero?
> or is it genuinely testing "both exponent and mantissa for zero"?
yes, it's both mantissa and exponent for zero, since that's +-0.0. if you
tested just exponent for zero you'd miss sending subnormal f64 numbers
through the rest of the algorithm.
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