Plural right shift #91
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thecppzoo
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Jun 5, 2024
| #include "zoo/swar/SWAR.h" | ||
| #include <cstdint> |
thecppzoo
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Jun 5, 2024
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| B val = msb.value() >> (NB - 1); | ||
| auto msbCopiedToLSB = S{val}; |
thecppzoo
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Jun 5, 2024
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| T res = msbCleared.value() << 1; | ||
| return S{res}; |
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Why so many unnecessary changes?
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was getting seemingly random type errors.
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will try and resolve
thecppzoo
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Jun 5, 2024
inc/zoo/swar/associative_iteration.h
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| /** Transforms a number into a number into a binary tally. | ||
| * E.g. 0b0011 (3) -> 0b0111 |
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You seem to mean this converts a binary to an unary
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yes lol thank you.
thecppzoo
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Jun 5, 2024
inc/zoo/swar/associative_iteration.h
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| static_assert(base2TallyTransform_Plural(S{0b0001'0010'0011'0011}).value() == 0b0001'0011'0111'0111); | ||
| static_assert(base2TallyTransform_Plural(S{0b0000'0001'0010'0011}).value() == 0b0000'0001'0011'0111); | ||
| static_assert(base2TallyTransform_Plural(S{0b0100'0001'0010'0011}).value() == 0b1111'0001'0011'0111); | ||
| static_assert(base2TallyTransform_Plural(S{0b0000'0000'0000'0001}).value() == 0b0000'0000'0000'0001); | ||
| static_assert(base2TallyTransform_Plural(SWAR<8, uint16_t>{0b000000111'00000101}).value() == 0b01111111'00011111); // 7 -> 5 |
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Use whitespace to make the point of the comparison/test evident!
You not only trample the whitespace of others, but fail to use it
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Now is correct. Godbolt for your amusement. https://godbolt.org/z/T51GPhT8M
Generate the smallest mask required to blit out the overflow using (2^shift_size - 1) which basially transforms shift size into a tally representation of itself in binary. Such that 2 -> 11; 3 -> 111; 4 -> 1111; etc. This then only requires the lane index mask and a shift, then or'ing it all back into the result.