added @marshmellows new viking demod.

[proxmark3-svn] / common / lfdemod.c

diff --git a/common/lfdemod.c b/common/lfdemod.c
index 9a4051c9b125a29bc7baabf1a82d2d4b1e37de73..a3689357489e5a2958fb99b238a2fc81d50581b5 100644 (file)
--- a/common/lfdemod.c
+++ b/common/lfdemod.c
@@ -599,6 +599,26 @@ int IOdemodFSK(uint8_t *dest, size_t size)
        return -5;
 }
 
+// by marshmellow
+// find viking preamble 0xF200 in already demoded data
+int VikingDemod_AM(uint8_t *dest, size_t *size) {
+       if (justNoise(dest, *size)) return -1;
+       //make sure buffer has data
+       if (*size < 64*2) return -2;
+
+       size_t startIdx = 0;
+       uint8_t preamble[] = {1,1,1,1,0,0,1,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0};
+       uint8_t errChk = preambleSearch(dest, preamble, sizeof(preamble), size, &startIdx);
+       if (errChk == 0) return -4; //preamble not found
+       uint32_t checkCalc = bytebits_to_byte(dest+startIdx,8) ^ bytebits_to_byte(dest+startIdx+8,8) ^ bytebits_to_byte(dest+startIdx+16,8)
+           ^ bytebits_to_byte(dest+startIdx+24,8) ^ bytebits_to_byte(dest+startIdx+32,8) ^ bytebits_to_byte(dest+startIdx+40,8) 
+           ^ bytebits_to_byte(dest+startIdx+48,8) ^ bytebits_to_byte(dest+startIdx+56,8);
+       if ( checkCalc != 0xA8 ) return -5;
+       if (*size != 64) return -5;
+       //return start position
+       return (int) startIdx;
+}
+
 // by marshmellow
 // takes a array of binary values, start position, length of bits per parity (includes parity bit),
 //   Parity Type (1 for odd; 0 for even; 2 Always 1's), and binary Length (length to run) 
@@ -1505,30 +1525,3 @@ int pskRawDemod(uint8_t dest[], size_t *size, int *clock, int *invert)
        *size = numBits;
        return errCnt;
 }
-// on successful return 1 otherwise return 0
-int VikingDecode(uint8_t *BitStream, 
-                                       size_t size,
-                                       size_t *startIdx,
-                                       uint8_t *id_bits,
-                                       size_t id_bits_size)
-{
-    //no arguments needed - built this way in case we want this to be a direct call from "data " cmds in the future
-    //  otherwise could be a void with no arguments
-    //set defaults
-    uint32_t i = 0;
-    uint32_t lastcheckindex = size - (id_bits_size * 2);
-    int found = 0;
-    while (i < lastcheckindex)
-    {
-        if (memcmp(BitStream + i,id_bits,id_bits_size) == 0)
-        {
-            *startIdx = i;
-            found = 1;
-            break;
-        }
-        i++;
-    }
-    return found;
-}
-
-