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avoid repeated construction of one, two, tree values vectors

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Kovid Goyal 2024-01-08 10:42:30 +05:30
parent 4589a62738
commit ea5858e10b
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GPG key ID: 06BC317B515ACE7C
1 changed files with 8 additions and 7 deletions
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15
kitty/simd-string-impl.h
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@ -150,6 +150,7 @@ FUNC(utf8_decode_to_esc)(UTF8Decoder *d, const uint8_t *src, size_t src_sz) {
src_sz = d->num_consumed - 1;
} else d->num_consumed = src_sz;
const integer_t one = set1_epi8(1), two = set1_epi8(2), three = set1_epi8(3);
// Classify the bytes
print_register_as_bytes(vec);
integer_t state = set1_epi8(0x80);
@ -176,11 +177,11 @@ FUNC(utf8_decode_to_esc)(UTF8Decoder *d, const uint8_t *src, size_t src_sz) {
integer_t count = and_si(state, set1_epi8(0x7)); // keep lower 3 bits of state
print_register_as_bytes(count);
// count contains 0 for ASCII and number of bytes in sequence for other bytes
#define subtract_shift_and_add(target, amt, s) add_epi8(target, shift_right_by_##amt(subtract_saturate_epu8(target, set1_epi8(s))))
#define subtract_shift_and_add(target, amt, s) add_epi8(target, shift_right_by_##amt(subtract_saturate_epu8(target, s)))
// shift 02 bytes by 1 and subtract 1
integer_t counts = subtract_shift_and_add(count, one_byte, 1);
integer_t counts = subtract_shift_and_add(count, one_byte, one);
// shift 03 and 04 bytes by 2 and subtract 2
counts = subtract_shift_and_add(counts, two_bytes, 2);
counts = subtract_shift_and_add(counts, two_bytes, two);
// counts now contains the number of bytes remaining in each utf-8 sequence of 2 or more bytes
print_register_as_bytes(counts);
#undef subtract_shift_and_add
@ -201,12 +202,12 @@ FUNC(utf8_decode_to_esc)(UTF8Decoder *d, const uint8_t *src, size_t src_sz) {
or_si(
vec, and_si(shift_left_by_bits16(vec_right1, 6), set1_epi8(0xc0))
),
cmpeq_epi8(counts, set1_epi8(1))
cmpeq_epi8(counts, one)
);
print_register_as_bytes(output1);
// The next byte is made up of 4 bits (5, 4, 3, 2) from locations with count == 2 and the first 4 bits from locations with count == 3
integer_t count2_locations = cmpeq_epi8(counts, set1_epi8(2));
integer_t count2_locations = cmpeq_epi8(counts, two);
integer_t output2 = and_si(vec, count2_locations);
output2 = shift_right_by_bits32(output2, 2); // selects the bits 5, 4, 3, 2
output2 = or_si(output2, and_si(shift_left_by_bits16(vec_right1, 4), set1_epi8(0xf0))); // move 4 bits left and mask lower four bits and OR
@ -214,8 +215,8 @@ FUNC(utf8_decode_to_esc)(UTF8Decoder *d, const uint8_t *src, size_t src_sz) {
print_register_as_bytes(output2);
// The last byte is made up of bits 5 and 6 from count == 3 and 3 bits from count == 4
integer_t count3_locations = cmpeq_epi8(counts, set1_epi8(3));
integer_t output3 = and_si(set1_epi8(3), shift_right_by_bits32(vec, 4)); // bits 5 and 6 from count == 3
integer_t count3_locations = cmpeq_epi8(counts, three);
integer_t output3 = and_si(three, shift_right_by_bits32(vec, 4)); // bits 5 and 6 from count == 3
// bits from count == 4 locations, placed at count == 3 locations shifted left by 2 bits
output3 = or_si(output3, and_si(set1_epi8(0xfc), shift_left_by_bits16(vec_right1, 2)));
output3 = and_si(output3, count3_locations); // keep only count3 bytes