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cleaning up viterbi neon

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master
yagoda 7 years ago
parent f273ec959b
commit 8751645a48
1 changed files with 47 additions and 71 deletions
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108
lib/src/phy/fec/viterbi37_neon.c
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@ -13,7 +13,6 @@
#include "parity.h" #include "parity.h"
//#define DEBUG //#define DEBUG
//#define HAVE_NEON
#ifdef HAVE_NEON #ifdef HAVE_NEON
#include <arm_neon.h> #include <arm_neon.h>
@ -22,8 +21,6 @@ typedef union {
unsigned char c[64]; unsigned char c[64];
uint8x16_t v[4]; uint8x16_t v[4];
} metric_t; } metric_t;
typedef union { typedef union {
unsigned long w[2]; unsigned long w[2];
unsigned char c[8]; unsigned char c[8];
@ -31,18 +28,16 @@ typedef union {
uint8x8_t v[1]; uint8x8_t v[1];
} decision_t; } decision_t;
union branchtab27{ union branchtab27{
unsigned char c[32]; unsigned char c[32];
uint8x16_t v[2]; uint8x16_t v[2];
} Branchtab37_neon[3]; } Branchtab37_neon[3];
int8_t __attribute__((aligned(16))) xr[8]; int8_t __attribute__((aligned(16))) xr[8];
uint8x8_t mask_and; uint8x8_t mask_and;
int8x8_t mask_shift; int8x8_t mask_shift;
int firstGo;
/* State info for instance of Viterbi decoder */ /* State info for instance of Viterbi decoder */
struct v37 { struct v37 {
metric_t metrics1; /* path metric buffer 1 */ metric_t metrics1; /* path metric buffer 1 */
@ -77,7 +72,6 @@ void clear_v37_neon(struct v37 *vp) {
int init_viterbi37_neon(void *p, int starting_state) { int init_viterbi37_neon(void *p, int starting_state) {
struct v37 *vp = p; struct v37 *vp = p;
uint32_t i; uint32_t i;
firstGo = 1;
for(i=0;i<64;i++) for(i=0;i<64;i++)
vp->metrics1.c[i] = 63; vp->metrics1.c[i] = 63;
@ -88,7 +82,6 @@ int init_viterbi37_neon(void *p, int starting_state) {
mask_and = vdup_n_u8(0x80); mask_and = vdup_n_u8(0x80);
mask_shift = vld1_s8(xr); mask_shift = vld1_s8(xr);
vp->old_metrics = &vp->metrics1; vp->old_metrics = &vp->metrics1;
vp->new_metrics = &vp->metrics2; vp->new_metrics = &vp->metrics2;
vp->dp = vp->decisions; vp->dp = vp->decisions;
@ -176,32 +169,31 @@ void print_uint8x16_t(char *s, uint8x16_t val) {
printf("\n"); printf("\n");
} }
static inline int movemask_neon(uint8x16_t movemask_low_in) static inline int movemask_neon(uint8x16_t movemask_low_in) {
{ uint8x8_t lo = vget_low_u8(movemask_low_in);
uint8x8_t lo = vget_low_u8(movemask_low_in); uint8x8_t hi = vget_high_u8(movemask_low_in);
uint8x8_t hi = vget_high_u8(movemask_low_in); lo = vand_u8(lo, mask_and);
lo = vand_u8(lo, mask_and); lo = vshl_u8(lo, mask_shift);
lo = vshl_u8(lo, mask_shift); hi = vand_u8(hi, mask_and);
hi = vand_u8(hi, mask_and); hi = vshl_u8(hi, mask_shift);
hi = vshl_u8(hi, mask_shift);
lo = vpadd_u8(lo, lo); lo = vpadd_u8(lo, lo);
lo = vpadd_u8(lo, lo); lo = vpadd_u8(lo, lo);
lo = vpadd_u8(lo, lo); lo = vpadd_u8(lo, lo);
hi = vpadd_u8(hi, hi); hi = vpadd_u8(hi, hi);
hi = vpadd_u8(hi, hi); hi = vpadd_u8(hi, hi);
hi = vpadd_u8(hi, hi); hi = vpadd_u8(hi, hi);
return ((hi[0] << 8) | (lo[0] & 0xFF)); return ((hi[0] << 8) | (lo[0] & 0xFF));
} }
void update_viterbi37_blk_neon(void *p,unsigned char *syms,int nbits, uint32_t *best_state) { void update_viterbi37_blk_neon(void *p,unsigned char *syms,int nbits, uint32_t *best_state) {
struct v37 *vp = p; struct v37 *vp = p;
decision_t *d; decision_t *d;
uint8_t thirtyone; uint8_t thirtyone;
thirtyone = 31; thirtyone = 31;
if(p == NULL) if(p == NULL)
return; return;
@ -217,19 +209,18 @@ void update_viterbi37_blk_neon(void *p,unsigned char *syms,int nbits, uint32_t *
while(nbits--) { while(nbits--) {
uint8x16_t sym0v,sym1v,sym2v; uint8x16_t sym0v,sym1v,sym2v;
void *tmp; void *tmp;
int i; int i;
// printf("nbits=%d, syms=%d,%d,%d\n", nbits, syms[0], syms[1], syms[2]);fflush(stdout); // printf("nbits=%d, syms=%d,%d,%d\n", nbits, syms[0], syms[1], syms[2]);fflush(stdout);
/* Splat the 0th symbol across sym0v, the 1st symbol across sym1v, etc */ /* Splat the 0th symbol across sym0v, the 1st symbol across sym1v, etc */
sym0v = vld1q_dup_u8(syms); // passing a char as opposed to a pointer to a char sym0v = vld1q_dup_u8(syms);
sym1v = vld1q_dup_u8(syms+1); sym1v = vld1q_dup_u8(syms+1);
sym2v = vld1q_dup_u8(syms+2); sym2v = vld1q_dup_u8(syms+2);
syms += 3; syms += 3;
for(i=0;i<2;i++){ for(i=0;i<2;i++) {
uint8x16_t decision0, decision1, metric, m_metric, m0, m1, m2, m3, survivor0, survivor1; uint8x16_t decision0, decision1, metric, m_metric, m0, m1, m2, m3, survivor0, survivor1;
/* Form branch metrics */ /* Form branch metrics */
@ -246,48 +237,35 @@ void update_viterbi37_blk_neon(void *p,unsigned char *syms,int nbits, uint32_t *
m2 = vaddq_u8(vp->old_metrics->v[i],m_metric); m2 = vaddq_u8(vp->old_metrics->v[i],m_metric);
/* Compare and select, using modulo arithmetic */ /* Compare and select, using modulo arithmetic */
decision0 = (uint8x16_t)vcgtq_s8(vsubq_s8((int8x16_t)m0,(int8x16_t)m1),vdupq_n_s8(0)); decision0 = (uint8x16_t)vcgtq_s8(vsubq_s8((int8x16_t)m0,(int8x16_t)m1),vdupq_n_s8(0));
decision1 = (uint8x16_t)vcgtq_s8(vsubq_s8((int8x16_t)m2,(int8x16_t)m3),vdupq_n_s8(0)); decision1 = (uint8x16_t)vcgtq_s8(vsubq_s8((int8x16_t)m2,(int8x16_t)m3),vdupq_n_s8(0));
survivor0 = vorrq_u8(vandq_u8(decision0,m1),vandq_u8(vmvnq_u8(decision0),m0)); survivor0 = vorrq_u8(vandq_u8(decision0,m1),vandq_u8(vmvnq_u8(decision0),m0));
survivor1 = vorrq_u8 (vandq_u8(decision1,m3),vandq_u8(vmvnq_u8(decision1),m2) ); survivor1 = vorrq_u8 (vandq_u8(decision1,m3),vandq_u8(vmvnq_u8(decision1),m2) );
////// equal to _mm_unpacklo_epi8 ////////// /* Pack each set of decisions into 16 bits */
uint8x8_t a1 = vget_low_u8(decision0); uint8x8_t a1 = vget_low_u8(decision0);
uint8x8_t b1 = vget_low_u8(decision1); uint8x8_t b1 = vget_low_u8(decision1);
uint8x8x2_t result = vzip_u8(a1, b1); uint8x8x2_t result = vzip_u8(a1, b1);
uint8x16_t movemask_low_in = vcombine_u8(result.val[0], result.val[1]); uint8x16_t movemask_low_in = vcombine_u8(result.val[0], result.val[1]);
/////////////////////////////////////////
////////equal to _mm_movemask_epi8 //////// d->s[2*i] = movemask_neon(movemask_low_in);
d->s[2*i] = movemask_neon(movemask_low_in);
///////equal to _mm_unpackhi_epi8//////////// a1 = vget_high_u8(decision0);
a1 = vget_high_u8(decision0); b1 = vget_high_u8(decision1);
b1 = vget_high_u8(decision1); result = vzip_u8(a1, b1);
result = vzip_u8(a1, b1); uint8x16_t movemask_hi_in = vcombine_u8(result.val[0], result.val[1]);
uint8x16_t movemask_hi_in = vcombine_u8(result.val[0], result.val[1]);
d->s[2*i+1] = movemask_neon(movemask_hi_in);
a1 = vget_low_u8(survivor0);
b1 = vget_low_u8(survivor1);
result = vzip_u8(a1, b1);
vp->new_metrics->v[2*i] = vcombine_u8(result.val[0], result.val[1]);
////////equal to _mm_movemask////////////// a1 = vget_high_u8(survivor0);
d->s[2*i+1] = movemask_neon(movemask_hi_in); b1 = vget_high_u8(survivor1);
result = vzip_u8(a1, b1);
vp->new_metrics->v[2*i+1] = vcombine_u8(result.val[0], result.val[1]);
a1 = vget_low_u8(survivor0);
b1 = vget_low_u8(survivor1);
result = vzip_u8(a1, b1);
vp->new_metrics->v[2*i] = vcombine_u8(result.val[0], result.val[1]);
a1 = vget_high_u8(survivor0);
b1 = vget_high_u8(survivor1);
result = vzip_u8(a1, b1);
vp->new_metrics->v[2*i+1] = vcombine_u8(result.val[0], result.val[1]);
} }
@ -315,8 +293,7 @@ void update_viterbi37_blk_neon(void *p,unsigned char *syms,int nbits, uint32_t *
/* We cannot use a saturated subtract, because we often have to adjust by more than SHRT_MAX /* We cannot use a saturated subtract, because we often have to adjust by more than SHRT_MAX
* This is okay since it can't overflow anyway * This is okay since it can't overflow anyway
*/ */
for(i=0;i<4;i++) for(i=0;i<4;i++) {
{
vp->new_metrics->v[i] = vsubq_u8(vp->new_metrics->v[i],adjustv); vp->new_metrics->v[i] = vsubq_u8(vp->new_metrics->v[i],adjustv);
} }
@ -326,7 +303,6 @@ void update_viterbi37_blk_neon(void *p,unsigned char *syms,int nbits, uint32_t *
tmp = vp->old_metrics; tmp = vp->old_metrics;
vp->old_metrics = vp->new_metrics; vp->old_metrics = vp->new_metrics;
vp->new_metrics = tmp; vp->new_metrics = tmp;
//firstGo = 0;
} }
if (best_state) { if (best_state) {

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