diff options
Diffstat (limited to 'src/third-party/base64/lib/arch/ssse3/enc_translate.c')
| -rw-r--r-- | src/third-party/base64/lib/arch/ssse3/enc_translate.c | 33 |
1 files changed, 33 insertions, 0 deletions
diff --git a/src/third-party/base64/lib/arch/ssse3/enc_translate.c b/src/third-party/base64/lib/arch/ssse3/enc_translate.c new file mode 100644 index 0000000..04f288f --- /dev/null +++ b/src/third-party/base64/lib/arch/ssse3/enc_translate.c @@ -0,0 +1,33 @@ +static inline __m128i +enc_translate (const __m128i in) +{ + // A lookup table containing the absolute offsets for all ranges: + const __m128i lut = _mm_setr_epi8( + 65, 71, -4, -4, + -4, -4, -4, -4, + -4, -4, -4, -4, + -19, -16, 0, 0 + ); + + // Translate values 0..63 to the Base64 alphabet. There are five sets: + // # From To Abs Index Characters + // 0 [0..25] [65..90] +65 0 ABCDEFGHIJKLMNOPQRSTUVWXYZ + // 1 [26..51] [97..122] +71 1 abcdefghijklmnopqrstuvwxyz + // 2 [52..61] [48..57] -4 [2..11] 0123456789 + // 3 [62] [43] -19 12 + + // 4 [63] [47] -16 13 / + + // Create LUT indices from the input. The index for range #0 is right, + // others are 1 less than expected: + __m128i indices = _mm_subs_epu8(in, _mm_set1_epi8(51)); + + // mask is 0xFF (-1) for range #[1..4] and 0x00 for range #0: + __m128i mask = _mm_cmpgt_epi8(in, _mm_set1_epi8(25)); + + // Subtract -1, so add 1 to indices for range #[1..4]. All indices are + // now correct: + indices = _mm_sub_epi8(indices, mask); + + // Add offsets to input values: + return _mm_add_epi8(in, _mm_shuffle_epi8(lut, indices)); +} |