Superoptimizing an FPU Emulator

Automated excerpt

For example, if f=1. 01101⋅210 in binary, it would return 0. 00001⋅210=25. This can be implemented with bit twiddling, but the straightforward algorithm breaks for powers of two, so I had to insert an if:if f32::from_bits(x. to_bits() & ! f32::MANTISSA_MASK) == x { // is x a power of two? return x - f32::from_bits(x. to_bits() & (x. to_bits() - 1)); // x, minus x without lowest bit This if really annoyed me. There were several formulas with 5 operations, e. g. this one:return x - f32::from_bits(x. to_bits() & ( (f32::EXPONENT_MASK - (x | f32::EXPONENT_MASK)) ^ ! f32::EXPONENT_MASK return f32::from_bits(x.

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