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jdupuy/BitReverse.c

Last active April 24, 2024 12:01
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Revisions

  1. jdupuy revised this gist Apr 24, 2024. 1 changed file with 25 additions and 6 deletions.
    31 changes: 25 additions & 6 deletions BitReverse.c
    View file
    Original file line number Diff line number Diff line change
    @@ -1,3 +1,22 @@
    uint8_t BitReverse(uint8_t x)
    {
    x = ((x & 0x0F) << 4) | ((x & 0xF0) >> 4);
    x = ((x & 0x33) << 2) | ((x & 0xCC) >> 2);
    x = ((x & 0x55) << 1) | ((x & 0xAA) >> 1);

    return x;
    }

    uint16_t BitReverse(uint16_t x)
    {
    x = ((x & 0x00FF) << 8) | ((x & 0xFF00) >> 8);
    x = ((x & 0x0F0F) << 4) | ((x & 0xF0F0) >> 4);
    x = ((x & 0x3333) << 2) | ((x & 0xCCCC) >> 2);
    x = ((x & 0x5555) << 1) | ((x & 0xAAAA) >> 1);

    return x;
    }

    uint32_t BitReverse(uint32_t x)
    {
    x = ( x << 16) | ( x >> 16);
    @@ -11,12 +30,12 @@ uint32_t BitReverse(uint32_t x)

    uint64_t BitReverse(uint64_t x)
    {
    x = ( x << 32) | ( x >> 32);
    x = ((x & 0x0000FFFF) << 16) | ((x & 0xFFFF0000) >> 16);
    x = ((x & 0x00FF00FF) << 8) | ((x & 0xFF00FF00) >> 8);
    x = ((x & 0x0F0F0F0F) << 4) | ((x & 0xF0F0F0F0) >> 4);
    x = ((x & 0x33333333) << 2) | ((x & 0xCCCCCCCC) >> 2);
    x = ((x & 0x55555555) << 1) | ((x & 0xAAAAAAAA) >> 1);
    x = ( x << 32) | ( x >> 32);
    x = ((x & 0x0000FFFF0000FFFF) << 16) | ((x & 0xFFFF0000FFFF0000) >> 16);
    x = ((x & 0x00FF00FF00FF00FF) << 8) | ((x & 0xFF00FF00FF00FF00) >> 8);
    x = ((x & 0x0F0F0F0F0F0F0F0F) << 4) | ((x & 0xF0F0F0F0F0F0F0F0) >> 4);
    x = ((x & 0x3333333333333333) << 2) | ((x & 0xCCCCCCCCCCCCCCCC) >> 2);
    x = ((x & 0x5555555555555555) << 1) | ((x & 0xAAAAAAAAAAAAAAAA) >> 1);

    return x;
    }
  2. jdupuy created this gist Apr 24, 2024.
    22 changes: 22 additions & 0 deletions BitReverse.c
    View file
    Original file line number Diff line number Diff line change
    @@ -0,0 +1,22 @@
    uint32_t BitReverse(uint32_t x)
    {
    x = ( x << 16) | ( x >> 16);
    x = ((x & 0x00FF00FF) << 8) | ((x & 0xFF00FF00) >> 8);
    x = ((x & 0x0F0F0F0F) << 4) | ((x & 0xF0F0F0F0) >> 4);
    x = ((x & 0x33333333) << 2) | ((x & 0xCCCCCCCC) >> 2);
    x = ((x & 0x55555555) << 1) | ((x & 0xAAAAAAAA) >> 1);

    return x;
    }

    uint64_t BitReverse(uint64_t x)
    {
    x = ( x << 32) | ( x >> 32);
    x = ((x & 0x0000FFFF) << 16) | ((x & 0xFFFF0000) >> 16);
    x = ((x & 0x00FF00FF) << 8) | ((x & 0xFF00FF00) >> 8);
    x = ((x & 0x0F0F0F0F) << 4) | ((x & 0xF0F0F0F0) >> 4);
    x = ((x & 0x33333333) << 2) | ((x & 0xCCCCCCCC) >> 2);
    x = ((x & 0x55555555) << 1) | ((x & 0xAAAAAAAA) >> 1);

    return x;
    }