1/* Reed-Solomon encoder
2 * Copyright 2004, Phil Karn, KA9Q
3 * May be used under the terms of the GNU Lesser General Public License (LGPL)
4 */
5#include <string.h>
6#include "fixed.h"
7#ifdef __VEC__
8#include <sys/sysctl.h>
9#endif
10
11
12static enum {UNKNOWN=0,MMX,SSE,SSE2,ALTIVEC,PORT} cpu_mode;
13
14static void encode_rs_8_c(data_t *data, data_t *parity,int pad);
15#if __vec__
16static void encode_rs_8_av(data_t *data, data_t *parity,int pad);
17#endif
18#if __i386__
19int cpu_features(void);
20#endif
21
22void encode_rs_8(data_t *data, data_t *parity,int pad){
23  if(cpu_mode == UNKNOWN){
24#ifdef __i386__
25    int f;
26    /* Figure out what kind of CPU we have */
27    f = cpu_features();
28    if(f & (1<<26)){ /* SSE2 is present */
29      cpu_mode = SSE2;
30    } else if(f & (1<<25)){ /* SSE is present */
31      cpu_mode = SSE;
32    } else if(f & (1<<23)){ /* MMX is present */
33      cpu_mode = MMX;
34    } else { /* No SIMD at all */
35      cpu_mode = PORT;
36    }
37#elif __VEC__
38    /* Ask the OS if we have Altivec support */
39    int selectors[2] = { CTL_HW, HW_VECTORUNIT };
40    int hasVectorUnit = 0;
41    size_t length = sizeof(hasVectorUnit);
42    int error = sysctl(selectors, 2, &hasVectorUnit, &length, NULL, 0);
43    if(0 == error && hasVectorUnit)
44      cpu_mode = ALTIVEC;
45    else
46      cpu_mode = PORT;
47#else
48    cpu_mode = PORT;
49#endif
50  }
51  switch(cpu_mode){
52#if __vec__
53  case ALTIVEC:
54    encode_rs_8_av(data,parity,pad);
55    return;
56#endif
57#if __i386__
58  case MMX:
59  case SSE:
60  case SSE2:
61#endif
62  default:
63    encode_rs_8_c(data,parity,pad);
64    return;
65  }
66}
67
68#if __vec__ /* PowerPC G4/G5 Altivec instructions are available */
69
70static vector unsigned char reverse = (vector unsigned char)(0,15,14,13,12,11,10,9,8,7,6,5,4,3,2,1);
71static vector unsigned char shift_right = (vector unsigned char)(15,16,17,18,19,20,21,22,23,24,25,26,27,28,29,30);
72
73/* Lookup table for feedback multiplications
74 * These are the low half of the coefficients. Since the generator polynomial is
75 * palindromic, we form the other half by reversing this one
76 */
77extern static union { vector unsigned char v; unsigned char c[16]; } table[256];
78
79static void encode_rs_8_av(data_t *data, data_t *parity,int pad){
80  union { vector unsigned char v[2]; unsigned char c[32]; } shift_register;
81  int i;
82
83  shift_register.v[0] = (vector unsigned char)(0);
84  shift_register.v[1] = (vector unsigned char)(0);
85
86  for(i=0;i<NN-NROOTS-pad;i++){
87    vector unsigned char feedback0,feedback1;
88    unsigned char f;
89
90    f = data[i] ^ shift_register.c[31];
91    feedback1 = table[f].v;
92    feedback0 = vec_perm(feedback1,feedback1,reverse);
93
94    /* Shift right one byte */
95    shift_register.v[1] = vec_perm(shift_register.v[0],shift_register.v[1],shift_right) ^ feedback1;
96    shift_register.v[0] = vec_sro(shift_register.v[0],(vector unsigned char)(8)) ^ feedback0;
97    shift_register.c[0] = f;
98  }
99  for(i=0;i<NROOTS;i++)
100    parity[NROOTS-i-1] = shift_register.c[i];
101}
102#endif
103
104/* Portable C version */
105static void encode_rs_8_c(data_t *data, data_t *parity,int pad){
106
107#include "encode_rs.h"
108
109}
110