From 47dae3c2302f6a992d9de952808f0be10923dd3a Mon Sep 17 00:00:00 2001
From: Wojciech Kaczmarski <w.kaczmarski@teletra.pl>
Date: Sun, 14 Jan 2024 18:05:07 +0100
Subject: [PATCH] added soft bit (de)randomizer too

---
 SP5WWP/include/m17/m17.h             |  1 +
 SP5WWP/lib/phy/randomize.c           | 16 ++++++++++++++++
 SP5WWP/m17-decoder/m17-decoder-sym.c |  6 +-----
 3 files changed, 18 insertions(+), 5 deletions(-)

diff --git a/SP5WWP/include/m17/m17.h b/SP5WWP/include/m17/m17.h
index ab99e75..3a4a189 100644
--- a/SP5WWP/include/m17/m17.h
+++ b/SP5WWP/include/m17/m17.h
@@ -103,6 +103,7 @@ void soft_XOR(uint16_t* out, const uint16_t* a, const uint16_t* b, const uint8_t
 extern const uint8_t rand_seq[46];
 
 void randomize_bits(uint8_t inp[SYM_PER_PLD*2]);
+void randomize_soft_bits(uint16_t inp[SYM_PER_PLD*2]);
 
 // M17 C library - lib/phy/slice.c
 void slice_symbols(uint16_t out[2*SYM_PER_PLD], const float inp[SYM_PER_PLD]);
diff --git a/SP5WWP/lib/phy/randomize.c b/SP5WWP/lib/phy/randomize.c
index 708c027..e46a0d3 100644
--- a/SP5WWP/lib/phy/randomize.c
+++ b/SP5WWP/lib/phy/randomize.c
@@ -31,3 +31,19 @@ void randomize_bits(uint8_t inp[SYM_PER_PLD*2])
         }
     }
 }
+
+/**
+ * @brief Randomize type-4 unpacked bits.
+ * 
+ * @param inp Input 368 soft type-4 bits.
+ */
+void randomize_soft_bits(uint16_t inp[SYM_PER_PLD*2])
+{
+    for(uint16_t i=0; i<SYM_PER_PLD*2; i++)
+    {
+        if((rand_seq[i/8]>>(7-(i%8)))&1) //flip bit if '1'
+        {
+            inp[i]=soft_bit_NOT(inp[i]);
+        }
+    }
+}
diff --git a/SP5WWP/m17-decoder/m17-decoder-sym.c b/SP5WWP/m17-decoder/m17-decoder-sym.c
index 327b0d4..683e149 100644
--- a/SP5WWP/m17-decoder/m17-decoder-sym.c
+++ b/SP5WWP/m17-decoder/m17-decoder-sym.c
@@ -82,11 +82,7 @@ int main(void)
                 slice_symbols(soft_bit, pld);
 
                 //derandomize
-                for(uint16_t i=0; i<SYM_PER_PLD*2; i++)
-                {
-                    if((rand_seq[i/8]>>(7-(i%8)))&1) //soft NOT. flip soft bit if "1"
-                        soft_bit[i]=soft_bit_NOT(soft_bit[i]);
-                }
+                randomize_soft_bits(soft_bit);
 
                 //deinterleave
                 reorder_soft_bits(d_soft_bit, soft_bit);