1 /*
2  * version 20110505
3  * D. J. Bernstein
4  * Public domain.
5  *
6  * Based on crypto_core/salsa208/armneon/core.c from SUPERCOP 20130419
7  */
8 
9 #define ROUNDS 8
10 static void
salsa20_8_intrinsic(void * input)11 salsa20_8_intrinsic(void * input)
12 {
13   int i;
14 
15   const uint32x4_t abab = {-1,0,-1,0};
16 
17   /*
18    * This is modified since we only have one argument. Usually you'd rearrange
19    * the constant, key, and input bytes, but we just have one linear array to
20    * rearrange which is a bit easier.
21    */
22 
23   /*
24    * Change the input to be diagonals as if it's a 4x4 matrix of 32-bit values.
25    */
26   uint32x4_t x0x5x10x15;
27   uint32x4_t x12x1x6x11;
28   uint32x4_t x8x13x2x7;
29   uint32x4_t x4x9x14x3;
30 
31   uint32x4_t x0x1x10x11;
32   uint32x4_t x12x13x6x7;
33   uint32x4_t x8x9x2x3;
34   uint32x4_t x4x5x14x15;
35 
36   uint32x4_t x0x1x2x3;
37   uint32x4_t x4x5x6x7;
38   uint32x4_t x8x9x10x11;
39   uint32x4_t x12x13x14x15;
40 
41   x0x1x2x3 = vld1q_u8((uint8_t *) input);
42   x4x5x6x7 = vld1q_u8(16 + (uint8_t *) input);
43   x8x9x10x11 = vld1q_u8(32 + (uint8_t *) input);
44   x12x13x14x15 = vld1q_u8(48 + (uint8_t *) input);
45 
46   x0x1x10x11 = vcombine_u32(vget_low_u32(x0x1x2x3), vget_high_u32(x8x9x10x11));
47   x4x5x14x15 = vcombine_u32(vget_low_u32(x4x5x6x7), vget_high_u32(x12x13x14x15));
48   x8x9x2x3 = vcombine_u32(vget_low_u32(x8x9x10x11), vget_high_u32(x0x1x2x3));
49   x12x13x6x7 = vcombine_u32(vget_low_u32(x12x13x14x15), vget_high_u32(x4x5x6x7));
50 
51   x0x5x10x15 = vbslq_u32(abab,x0x1x10x11,x4x5x14x15);
52   x8x13x2x7 = vbslq_u32(abab,x8x9x2x3,x12x13x6x7);
53   x4x9x14x3 = vbslq_u32(abab,x4x5x14x15,x8x9x2x3);
54   x12x1x6x11 = vbslq_u32(abab,x12x13x6x7,x0x1x10x11);
55 
56   uint32x4_t start0 = x0x5x10x15;
57   uint32x4_t start1 = x12x1x6x11;
58   uint32x4_t start3 = x4x9x14x3;
59   uint32x4_t start2 = x8x13x2x7;
60 
61   /* From here on this should be the same as the SUPERCOP version. */
62 
63   uint32x4_t diag0 = start0;
64   uint32x4_t diag1 = start1;
65   uint32x4_t diag2 = start2;
66   uint32x4_t diag3 = start3;
67 
68   uint32x4_t a0;
69   uint32x4_t a1;
70   uint32x4_t a2;
71   uint32x4_t a3;
72 
73   for (i = ROUNDS;i > 0;i -= 2) {
74     a0 = diag1 + diag0;
75     diag3 ^= vsriq_n_u32(vshlq_n_u32(a0,7),a0,25);
76     a1 = diag0 + diag3;
77     diag2 ^= vsriq_n_u32(vshlq_n_u32(a1,9),a1,23);
78     a2 = diag3 + diag2;
79     diag1 ^= vsriq_n_u32(vshlq_n_u32(a2,13),a2,19);
80     a3 = diag2 + diag1;
81     diag0 ^= vsriq_n_u32(vshlq_n_u32(a3,18),a3,14);
82 
83     diag3 = vextq_u32(diag3,diag3,3);
84     diag2 = vextq_u32(diag2,diag2,2);
85     diag1 = vextq_u32(diag1,diag1,1);
86 
87     a0 = diag3 + diag0;
88     diag1 ^= vsriq_n_u32(vshlq_n_u32(a0,7),a0,25);
89     a1 = diag0 + diag1;
90     diag2 ^= vsriq_n_u32(vshlq_n_u32(a1,9),a1,23);
91     a2 = diag1 + diag2;
92     diag3 ^= vsriq_n_u32(vshlq_n_u32(a2,13),a2,19);
93     a3 = diag2 + diag3;
94     diag0 ^= vsriq_n_u32(vshlq_n_u32(a3,18),a3,14);
95 
96     diag1 = vextq_u32(diag1,diag1,3);
97     diag2 = vextq_u32(diag2,diag2,2);
98     diag3 = vextq_u32(diag3,diag3,1);
99   }
100 
101   x0x5x10x15 = diag0 + start0;
102   x12x1x6x11 = diag1 + start1;
103   x8x13x2x7 = diag2 + start2;
104   x4x9x14x3 = diag3 + start3;
105 
106   x0x1x10x11 = vbslq_u32(abab,x0x5x10x15,x12x1x6x11);
107   x12x13x6x7 = vbslq_u32(abab,x12x1x6x11,x8x13x2x7);
108   x8x9x2x3 = vbslq_u32(abab,x8x13x2x7,x4x9x14x3);
109   x4x5x14x15 = vbslq_u32(abab,x4x9x14x3,x0x5x10x15);
110 
111   x0x1x2x3 = vcombine_u32(vget_low_u32(x0x1x10x11),vget_high_u32(x8x9x2x3));
112   x4x5x6x7 = vcombine_u32(vget_low_u32(x4x5x14x15),vget_high_u32(x12x13x6x7));
113   x8x9x10x11 = vcombine_u32(vget_low_u32(x8x9x2x3),vget_high_u32(x0x1x10x11));
114   x12x13x14x15 = vcombine_u32(vget_low_u32(x12x13x6x7),vget_high_u32(x4x5x14x15));
115 
116   vst1q_u8((uint8_t *) input,(uint8x16_t) x0x1x2x3);
117   vst1q_u8(16 + (uint8_t *) input,(uint8x16_t) x4x5x6x7);
118   vst1q_u8(32 + (uint8_t *) input,(uint8x16_t) x8x9x10x11);
119   vst1q_u8(48 + (uint8_t *) input,(uint8x16_t) x12x13x14x15);
120 }
121