diff options
Diffstat (limited to 'encode_rs_8.c')
-rw-r--r-- | encode_rs_8.c | 109 |
1 files changed, 109 insertions, 0 deletions
diff --git a/encode_rs_8.c b/encode_rs_8.c new file mode 100644 index 0000000..5aaecca --- /dev/null +++ b/encode_rs_8.c @@ -0,0 +1,109 @@ +/* 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 __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 + 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" + +} |