From ea40092db72306506e683821d7608f3be11fd047 Mon Sep 17 00:00:00 2001
From: ismagom <gomezi@tcd.ie>
Date: Fri, 7 Aug 2015 02:56:45 +0200
Subject: [PATCH] Scrambling using words for XOR

---
 srslte/lib/common/src/sequence.c             |  3 +-
 srslte/lib/scrambling/src/scrambling.c       | 34 +++++++++++++++-----
 srslte/lib/scrambling/test/scrambling_test.c | 22 +++++++++++--
 3 files changed, 48 insertions(+), 11 deletions(-)

diff --git a/srslte/lib/common/src/sequence.c b/srslte/lib/common/src/sequence.c
index a273e0801..d9bd485f4 100644
--- a/srslte/lib/common/src/sequence.c
+++ b/srslte/lib/common/src/sequence.c
@@ -31,6 +31,7 @@
 #include <assert.h>
 
 #include "srslte/common/sequence.h"
+#include "srslte/utils/vector.h"
 
 #define Nc 1600
 
@@ -88,7 +89,7 @@ int srslte_sequence_init(srslte_sequence_t *q, uint32_t len) {
     free(q->c);
   }
   if (!q->c) {
-    q->c = malloc(len * sizeof(uint8_t));
+    q->c = srslte_vec_malloc(len * sizeof(uint8_t));
     if (!q->c) {
       return SRSLTE_ERROR;
     }
diff --git a/srslte/lib/scrambling/src/scrambling.c b/srslte/lib/scrambling/src/scrambling.c
index a995268e3..0e99cca92 100644
--- a/srslte/lib/scrambling/src/scrambling.c
+++ b/srslte/lib/scrambling/src/scrambling.c
@@ -29,6 +29,7 @@
 #include <stdlib.h>
 #include <string.h>
 #include <assert.h>
+#include "srslte/utils/vector.h"
 #include "srslte/scrambling/scrambling.h"
 
 void srslte_scrambling_f(srslte_sequence_t *s, float *data) {
@@ -40,7 +41,7 @@ void srslte_scrambling_f_offset(srslte_sequence_t *s, float *data, int offset, i
   assert (len + offset <= s->len);
 
   for (i = 0; i < len; i++) {
-    data[i] = data[i] * (1 - 2 * s->c[i + offset]);
+    data[i] = data[i] * (1-2*s->c[i + offset]);
   }
 }
 
@@ -58,18 +59,35 @@ void srslte_scrambling_c_offset(srslte_sequence_t *s, cf_t *data, int offset, in
 }
 
 void srslte_scrambling_b(srslte_sequence_t *s, uint8_t *data) {
-  int i;
-
-  for (i = 0; i < s->len; i++) {
-    data[i] = (data[i] + s->c[i]) % 2;
-  }
+  srslte_scrambling_b_offset(s, data, 0, s->len);  
 }
 
 void srslte_scrambling_b_offset(srslte_sequence_t *s, uint8_t *data, int offset, int len) {
   int i;
   assert (len + offset <= s->len);
-  for (i = 0; i < len; i++) {
-    data[i] = (data[i] + s->c[i + offset]) % 2;
+  // Do XOR on a word basis
+  if (!(len%8)) {
+    uint64_t *x = (uint64_t*) data; 
+    uint64_t *y = (uint64_t*) &s->c[offset];
+    for (int i=0;i<len/8;i++) {
+      x[i] = (x[i] ^ y[i]);
+    }
+  } else if (!(len%4)) {
+    uint32_t *x = (uint32_t*) data; 
+    uint32_t *y = (uint32_t*) &s->c[offset];
+    for (int i=0;i<len/8;i++) {
+      x[i] = (x[i] ^ y[i]);
+    }
+  } else if (!(len%2)) {
+    uint16_t *x = (uint16_t*) data; 
+    uint16_t *y = (uint16_t*) &s->c[offset];
+    for (int i=0;i<len/8;i++) {
+      x[i] = (x[i] ^ y[i]);
+    }
+  } else {
+    for (i = 0; i < len; i++) {
+      data[i] = (data[i] + s->c[i + offset]) % 2;
+    }
   }
 }
 
diff --git a/srslte/lib/scrambling/test/scrambling_test.c b/srslte/lib/scrambling/test/scrambling_test.c
index 15ba36316..97e99cb59 100644
--- a/srslte/lib/scrambling/test/scrambling_test.c
+++ b/srslte/lib/scrambling/test/scrambling_test.c
@@ -40,20 +40,25 @@ char *srslte_sequence_name = NULL;
 bool do_floats = false;
 srslte_cp_t cp = SRSLTE_CP_NORM;
 int cell_id = -1;
+int nof_bits = 100; 
 
 void usage(char *prog) {
   printf("Usage: %s [ef] -c cell_id -s [PBCH, PDSCH, PDCCH, PMCH, PUCCH]\n", prog);
+  printf("\t -l nof_bits [Default %d]\n", nof_bits);
   printf("\t -e CP extended [Default CP Normal]\n");
   printf("\t -f scramble floats [Default bits]\n");
 }
 
 void parse_args(int argc, char **argv) {
   int opt;
-  while ((opt = getopt(argc, argv, "csef")) != -1) {
+  while ((opt = getopt(argc, argv, "csefl")) != -1) {
     switch (opt) {
     case 'c':
       cell_id = atoi(argv[optind]);
       break;
+    case 'l':
+      nof_bits = atoi(argv[optind]);
+      break;
     case 'e':
       cp = SRSLTE_CP_EXT;
       break;
@@ -81,6 +86,8 @@ void parse_args(int argc, char **argv) {
 int init_sequence(srslte_sequence_t *seq, char *name) {
   if (!strcmp(name, "PBCH")) {
     return srslte_sequence_pbch(seq, cp, cell_id);
+  } else if (!strcmp(name, "PDSCH")) {
+    return srslte_sequence_pdsch(seq, 1234, 0, 0, cell_id, nof_bits);
   } else {
     fprintf(stderr, "Unsupported sequence name %s\n", name);
     return -1;
@@ -93,7 +100,8 @@ int main(int argc, char **argv) {
   srslte_sequence_t seq;
   uint8_t *input_b, *scrambled_b;
   float *input_f, *scrambled_f;
-
+  struct timeval t[3];
+  
   parse_args(argc, argv);
 
   if (init_sequence(&seq, srslte_sequence_name) == -1) {
@@ -118,9 +126,14 @@ int main(int argc, char **argv) {
       scrambled_b[i] = input_b[i];
     }
 
+    gettimeofday(&t[1], NULL);
     srslte_scrambling_b(&seq, scrambled_b);
+    gettimeofday(&t[2], NULL);
     srslte_scrambling_b(&seq, scrambled_b);
 
+    get_time_interval(t);
+    printf("Texec=%d us for %d bits\n", t[0].tv_usec, seq.len);
+    
     for (i=0;i<seq.len;i++) {
       if (scrambled_b[i] != input_b[i]) {
         printf("Error in %d\n", i);
@@ -146,9 +159,14 @@ int main(int argc, char **argv) {
       scrambled_f[i] = input_f[i];
     }
 
+    gettimeofday(&t[1], NULL);
     srslte_scrambling_f(&seq, scrambled_f);
+    gettimeofday(&t[2], NULL);
     srslte_scrambling_f(&seq, scrambled_f);
 
+    get_time_interval(t);
+    printf("Texec=%d us for %d bits\n", t[0].tv_usec, seq.len);
+
     for (i=0;i<seq.len;i++) {
       if (scrambled_f[i] != input_f[i]) {
         printf("Error in %d\n", i);