1 /*
2 * Process 2x16 bytes in each iteration.
3 * Comments removed for brevity. See range-neon.c for details.
4 */
5 #if defined(__aarch64__) && defined(__ARM_NEON)
6
7 #include <stdio.h>
8 #include <stdint.h>
9 #include <arm_neon.h>
10
11 int utf8_naive(const unsigned char *data, int len);
12
13 static const uint8_t _first_len_tbl[] = {
14 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 1, 1, 2, 3,
15 };
16
17 static const uint8_t _first_range_tbl[] = {
18 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 8, 8, 8, 8,
19 };
20
21 static const uint8_t _range_min_tbl[] = {
22 0x00, 0x80, 0x80, 0x80, 0xA0, 0x80, 0x90, 0x80,
23 0xC2, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF,
24 };
25 static const uint8_t _range_max_tbl[] = {
26 0x7F, 0xBF, 0xBF, 0xBF, 0xBF, 0x9F, 0xBF, 0x8F,
27 0xF4, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
28 };
29
30 static const uint8_t _range_adjust_tbl[] = {
31 2, 3, 0, 0, 0, 0, 0, 0, 0, 4, 0, 0, 0, 0, 0, 0,
32 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 3, 0, 0, 0, 0, 0,
33 };
34
35 /* Return 0 on success, -1 on error */
utf8_range2(const unsigned char * data,int len)36 int utf8_range2(const unsigned char *data, int len)
37 {
38 if (len >= 32) {
39 uint8x16_t prev_input = vdupq_n_u8(0);
40 uint8x16_t prev_first_len = vdupq_n_u8(0);
41
42 const uint8x16_t first_len_tbl = vld1q_u8(_first_len_tbl);
43 const uint8x16_t first_range_tbl = vld1q_u8(_first_range_tbl);
44 const uint8x16_t range_min_tbl = vld1q_u8(_range_min_tbl);
45 const uint8x16_t range_max_tbl = vld1q_u8(_range_max_tbl);
46 const uint8x16x2_t range_adjust_tbl = vld2q_u8(_range_adjust_tbl);
47
48 const uint8x16_t const_1 = vdupq_n_u8(1);
49 const uint8x16_t const_2 = vdupq_n_u8(2);
50 const uint8x16_t const_e0 = vdupq_n_u8(0xE0);
51
52 uint8x16_t error1 = vdupq_n_u8(0);
53 uint8x16_t error2 = vdupq_n_u8(0);
54 uint8x16_t error3 = vdupq_n_u8(0);
55 uint8x16_t error4 = vdupq_n_u8(0);
56
57 while (len >= 32) {
58 /******************* two blocks interleaved **********************/
59
60 #if defined(__GNUC__) && !defined(__clang__) && (__GNUC__ < 8)
61 /* gcc doesn't support vldq1_u8_x2 until version 8 */
62 const uint8x16_t input_a = vld1q_u8(data);
63 const uint8x16_t input_b = vld1q_u8(data + 16);
64 #else
65 /* Forces a double load on Clang */
66 const uint8x16x2_t input_pair = vld1q_u8_x2(data);
67 const uint8x16_t input_a = input_pair.val[0];
68 const uint8x16_t input_b = input_pair.val[1];
69 #endif
70
71 const uint8x16_t high_nibbles_a = vshrq_n_u8(input_a, 4);
72 const uint8x16_t high_nibbles_b = vshrq_n_u8(input_b, 4);
73
74 const uint8x16_t first_len_a =
75 vqtbl1q_u8(first_len_tbl, high_nibbles_a);
76 const uint8x16_t first_len_b =
77 vqtbl1q_u8(first_len_tbl, high_nibbles_b);
78
79 uint8x16_t range_a = vqtbl1q_u8(first_range_tbl, high_nibbles_a);
80 uint8x16_t range_b = vqtbl1q_u8(first_range_tbl, high_nibbles_b);
81
82 range_a =
83 vorrq_u8(range_a, vextq_u8(prev_first_len, first_len_a, 15));
84 range_b =
85 vorrq_u8(range_b, vextq_u8(first_len_a, first_len_b, 15));
86
87 uint8x16_t tmp1_a, tmp2_a, tmp1_b, tmp2_b;
88 tmp1_a = vextq_u8(prev_first_len, first_len_a, 14);
89 tmp1_a = vqsubq_u8(tmp1_a, const_1);
90 range_a = vorrq_u8(range_a, tmp1_a);
91
92 tmp1_b = vextq_u8(first_len_a, first_len_b, 14);
93 tmp1_b = vqsubq_u8(tmp1_b, const_1);
94 range_b = vorrq_u8(range_b, tmp1_b);
95
96 tmp2_a = vextq_u8(prev_first_len, first_len_a, 13);
97 tmp2_a = vqsubq_u8(tmp2_a, const_2);
98 range_a = vorrq_u8(range_a, tmp2_a);
99
100 tmp2_b = vextq_u8(first_len_a, first_len_b, 13);
101 tmp2_b = vqsubq_u8(tmp2_b, const_2);
102 range_b = vorrq_u8(range_b, tmp2_b);
103
104 uint8x16_t shift1_a = vextq_u8(prev_input, input_a, 15);
105 uint8x16_t pos_a = vsubq_u8(shift1_a, const_e0);
106 range_a = vaddq_u8(range_a, vqtbl2q_u8(range_adjust_tbl, pos_a));
107
108 uint8x16_t shift1_b = vextq_u8(input_a, input_b, 15);
109 uint8x16_t pos_b = vsubq_u8(shift1_b, const_e0);
110 range_b = vaddq_u8(range_b, vqtbl2q_u8(range_adjust_tbl, pos_b));
111
112 uint8x16_t minv_a = vqtbl1q_u8(range_min_tbl, range_a);
113 uint8x16_t maxv_a = vqtbl1q_u8(range_max_tbl, range_a);
114
115 uint8x16_t minv_b = vqtbl1q_u8(range_min_tbl, range_b);
116 uint8x16_t maxv_b = vqtbl1q_u8(range_max_tbl, range_b);
117
118 error1 = vorrq_u8(error1, vcltq_u8(input_a, minv_a));
119 error2 = vorrq_u8(error2, vcgtq_u8(input_a, maxv_a));
120
121 error3 = vorrq_u8(error3, vcltq_u8(input_b, minv_b));
122 error4 = vorrq_u8(error4, vcgtq_u8(input_b, maxv_b));
123
124 /************************ next iteration *************************/
125 prev_input = input_b;
126 prev_first_len = first_len_b;
127
128 data += 32;
129 len -= 32;
130 }
131 error1 = vorrq_u8(error1, error2);
132 error1 = vorrq_u8(error1, error3);
133 error1 = vorrq_u8(error1, error4);
134
135 if (vmaxvq_u8(error1))
136 return -1;
137
138 uint32_t token4;
139 vst1q_lane_u32(&token4, vreinterpretq_u32_u8(prev_input), 3);
140
141 const int8_t *token = (const int8_t *)&token4;
142 int lookahead = 0;
143 if (token[3] > (int8_t)0xBF)
144 lookahead = 1;
145 else if (token[2] > (int8_t)0xBF)
146 lookahead = 2;
147 else if (token[1] > (int8_t)0xBF)
148 lookahead = 3;
149
150 data -= lookahead;
151 len += lookahead;
152 }
153
154 return utf8_naive(data, len);
155 }
156
157 #endif
158