137 lines
3.3 KiB
C
137 lines
3.3 KiB
C
/* Reed-Solomon encoder
|
|
* Copyright 2004, Phil Karn, KA9Q
|
|
* May be used under the terms of the GNU Lesser General Public License (LGPL)
|
|
*/
|
|
#include <string.h>
|
|
#include "fixed.h"
|
|
#ifdef __VEC__
|
|
#include <sys/sysctl.h>
|
|
#endif
|
|
|
|
|
|
static enum {UNKNOWN = 0, MMX, SSE, SSE2, ALTIVEC, PORT} cpu_mode;
|
|
|
|
static void encode_rs_8_c(data_t *data, data_t *parity, int pad);
|
|
#if __vec__
|
|
static void encode_rs_8_av(data_t *data, data_t *parity, int pad);
|
|
#endif
|
|
#if __i386__
|
|
int cpu_features(void);
|
|
#endif
|
|
|
|
void encode_rs_8(data_t *data, data_t *parity, int pad)
|
|
{
|
|
if (cpu_mode == UNKNOWN) {
|
|
#ifdef __i386__
|
|
int f;
|
|
/* Figure out what kind of CPU we have */
|
|
f = cpu_features();
|
|
if (f & (1 << 26)) { /* SSE2 is present */
|
|
cpu_mode = SSE2;
|
|
}
|
|
else if (f & (1 << 25)) { /* SSE is present */
|
|
cpu_mode = SSE;
|
|
}
|
|
else if (f & (1 << 23)) { /* MMX is present */
|
|
cpu_mode = MMX;
|
|
}
|
|
else { /* No SIMD at all */
|
|
cpu_mode = PORT;
|
|
}
|
|
#elif __x86_64__
|
|
cpu_mode = SSE2;
|
|
#elif __VEC__
|
|
/* Ask the OS if we have Altivec support */
|
|
int selectors[2] = { CTL_HW, HW_VECTORUNIT };
|
|
int hasVectorUnit = 0;
|
|
size_t length = sizeof(hasVectorUnit);
|
|
int error = sysctl(selectors, 2, &hasVectorUnit, &length, NULL, 0);
|
|
if (0 == error && hasVectorUnit) {
|
|
cpu_mode = ALTIVEC;
|
|
}
|
|
else {
|
|
cpu_mode = PORT;
|
|
}
|
|
#else
|
|
cpu_mode = PORT;
|
|
#endif
|
|
}
|
|
switch (cpu_mode) {
|
|
#if __vec__
|
|
case ALTIVEC:
|
|
encode_rs_8_av(data, parity, pad);
|
|
return;
|
|
#endif
|
|
|
|
#if __i386__
|
|
case MMX:
|
|
case SSE:
|
|
case SSE2:
|
|
#endif
|
|
|
|
#ifdef __x86_64__
|
|
case SSE2:
|
|
#endif
|
|
|
|
default:
|
|
encode_rs_8_c(data, parity, pad);
|
|
return;
|
|
}
|
|
}
|
|
|
|
#if __vec__ /* PowerPC G4/G5 Altivec instructions are available */
|
|
|
|
static vector unsigned char reverse = (vector unsigned char)(0, 15, 14, 13, 12,
|
|
11, 10, 9, 8, 7, 6, 5, 4, 3, 2, 1);
|
|
static vector unsigned char shift_right = (vector unsigned char)(15, 16, 17, 18,
|
|
19, 20, 21, 22, 23, 24, 25, 26, 27, 28, 29, 30);
|
|
|
|
/* Lookup table for feedback multiplications
|
|
* These are the low half of the coefficients. Since the generator polynomial is
|
|
* palindromic, we form the other half by reversing this one
|
|
*/
|
|
extern static union {
|
|
vector unsigned char v;
|
|
unsigned char c[16];
|
|
} table[256];
|
|
|
|
static void encode_rs_8_av(data_t *data, data_t *parity, int pad)
|
|
{
|
|
union {
|
|
vector unsigned char v[2];
|
|
unsigned char c[32];
|
|
} shift_register;
|
|
int i;
|
|
|
|
shift_register.v[0] = (vector unsigned char)(0);
|
|
shift_register.v[1] = (vector unsigned char)(0);
|
|
|
|
for (i = 0; i < NN - NROOTS - pad; i++) {
|
|
vector unsigned char feedback0, feedback1;
|
|
unsigned char f;
|
|
|
|
f = data[i] ^ shift_register.c[31];
|
|
feedback1 = table[f].v;
|
|
feedback0 = vec_perm(feedback1, feedback1, reverse);
|
|
|
|
/* Shift right one byte */
|
|
shift_register.v[1] = vec_perm(shift_register.v[0], shift_register.v[1],
|
|
shift_right) ^ feedback1;
|
|
shift_register.v[0] = vec_sro(shift_register.v[0],
|
|
(vector unsigned char)(8)) ^ feedback0;
|
|
shift_register.c[0] = f;
|
|
}
|
|
for (i = 0; i < NROOTS; i++) {
|
|
parity[NROOTS - i - 1] = shift_register.c[i];
|
|
}
|
|
}
|
|
#endif
|
|
|
|
/* Portable C version */
|
|
static void encode_rs_8_c(data_t *data, data_t *parity, int pad)
|
|
{
|
|
|
|
#include "encode_rs.h"
|
|
|
|
}
|