diff --git a/lz4.c b/lz4.c
index ba0d3fd..826b785 100644
--- a/lz4.c
+++ b/lz4.c
@@ -65,14 +65,15 @@
 //**************************************
 // 32 or 64 bits ?
 #if (defined(__x86_64__) || defined(__x86_64) || defined(__amd64__) || defined(__amd64) || defined(__ppc64__) || defined(_WIN64) || defined(__LP64__) || defined(_LP64) )   // Detects 64 bits mode
-#define LZ4_ARCH64 1
+#  define LZ4_ARCH64 1
 #else
-#define LZ4_ARCH64 0
+#  define LZ4_ARCH64 0
 #endif
 
 // Little Endian or Big Endian ?
+// Note : overwrite the below #define if you know your architecture endianess
 #if (defined(__BIG_ENDIAN__) || defined(__BIG_ENDIAN) || defined(_BIG_ENDIAN) || defined(_ARCH_PPC) || defined(__PPC__) || defined(__PPC) || defined(PPC) || defined(__powerpc__) || defined(__powerpc) || defined(powerpc) || ((defined(__BYTE_ORDER__)&&(__BYTE_ORDER__ == __ORDER_BIG_ENDIAN__))) )
-#define LZ4_BIG_ENDIAN 1
+#  define LZ4_BIG_ENDIAN 1
 #else
 // Little Endian assumed. PDP Endian and other very rare endian format are unsupported.
 #endif
@@ -81,7 +82,7 @@
 // For others CPU, the compiler will be more cautious, and insert extra code to ensure aligned access is respected
 // If you know your target CPU supports unaligned memory access, you may want to force this option manually to improve performance
 #if defined(__ARM_FEATURE_UNALIGNED)
-#define LZ4_FORCE_UNALIGNED_ACCESS 1
+#  define LZ4_FORCE_UNALIGNED_ACCESS 1
 #endif
 
 // Uncomment this parameter if your target system or compiler does not support hardware bit count
@@ -95,26 +96,33 @@
 #if __STDC_VERSION__ >= 199901L // C99
 /* "restrict" is a known keyword */
 #else
-#define restrict // Disable restrict
+#  define restrict // Disable restrict
 #endif
 
 #define GCC_VERSION (__GNUC__ * 100 + __GNUC_MINOR__)
 
 #ifdef _MSC_VER  // Visual Studio
-#define inline __forceinline // Visual is not C99, but supports some kind of inline
-#include <intrin.h>          // _BitScanForward
+#  define inline __forceinline           // Visual is not C99, but supports some kind of inline
+#  include <intrin.h>                    // _BitScanForward
+#  if LZ4_ARCH64	// 64-bit
+#    pragma intrinsic(_BitScanForward64) // For Visual 2005
+#    pragma intrinsic(_BitScanReverse64) // For Visual 2005
+#  else
+#    pragma intrinsic(_BitScanForward)   // For Visual 2005
+#    pragma intrinsic(_BitScanReverse)   // For Visual 2005
+#  endif
 #endif
 
 #ifdef _MSC_VER
-#define lz4_bswap16(x) _byteswap_ushort(x)
+#  define lz4_bswap16(x) _byteswap_ushort(x)
 #else
-#define lz4_bswap16(x) ((unsigned short int) ((((x) >> 8) & 0xffu) | (((x) & 0xffu) << 8)))
+#  define lz4_bswap16(x) ((unsigned short int) ((((x) >> 8) & 0xffu) | (((x) & 0xffu) << 8)))
 #endif
 
 #if (GCC_VERSION >= 302) || (__INTEL_COMPILER >= 800) || defined(__clang__)
-# define expect(expr,value)    (__builtin_expect ((expr),(value)) )
+#  define expect(expr,value)    (__builtin_expect ((expr),(value)) )
 #else
-# define expect(expr,value)    (expr)
+#  define expect(expr,value)    (expr)
 #endif
 
 #define likely(expr)     expect((expr) != 0, 1)
@@ -133,22 +141,22 @@
 // Basic Types
 //**************************************
 #if defined(_MSC_VER)    // Visual Studio does not support 'stdint' natively
-#define BYTE	unsigned __int8
-#define U16		unsigned __int16
-#define U32		unsigned __int32
-#define S32		__int32
-#define U64		unsigned __int64
+#  define BYTE	unsigned __int8
+#  define U16		unsigned __int16
+#  define U32		unsigned __int32
+#  define S32		__int32
+#  define U64		unsigned __int64
 #else
-#include <stdint.h>
-#define BYTE	uint8_t
-#define U16		uint16_t
-#define U32		uint32_t
-#define S32		int32_t
-#define U64		uint64_t
+#  include <stdint.h>
+#  define BYTE	uint8_t
+#  define U16		uint16_t
+#  define U32		uint32_t
+#  define S32		int32_t
+#  define U64		uint64_t
 #endif
 
 #ifndef LZ4_FORCE_UNALIGNED_ACCESS
-#pragma pack(push, 1)
+#  pragma pack(push, 1)
 #endif
 
 typedef struct _U16_S { U16 v; } U16_S;
@@ -156,7 +164,7 @@ typedef struct _U32_S { U32 v; } U32_S;
 typedef struct _U64_S { U64 v; } U64_S;
 
 #ifndef LZ4_FORCE_UNALIGNED_ACCESS
-#pragma pack(pop)
+#  pragma pack(pop)
 #endif
 
 #define A64(x) (((U64_S *)(x))->v)
@@ -194,31 +202,31 @@ typedef struct _U64_S { U64 v; } U64_S;
 // Architecture-specific macros
 //**************************************
 #if LZ4_ARCH64	// 64-bit
-#define STEPSIZE 8
-#define UARCH U64
-#define AARCH A64
-#define LZ4_COPYSTEP(s,d)		A64(d) = A64(s); d+=8; s+=8;
-#define LZ4_COPYPACKET(s,d)		LZ4_COPYSTEP(s,d)
-#define LZ4_SECURECOPY(s,d,e)	if (d<e) LZ4_WILDCOPY(s,d,e)
-#define HTYPE U32
-#define INITBASE(base)			const BYTE* const base = ip
+#  define STEPSIZE 8
+#  define UARCH U64
+#  define AARCH A64
+#  define LZ4_COPYSTEP(s,d)		A64(d) = A64(s); d+=8; s+=8;
+#  define LZ4_COPYPACKET(s,d)		LZ4_COPYSTEP(s,d)
+#  define LZ4_SECURECOPY(s,d,e)	if (d<e) LZ4_WILDCOPY(s,d,e)
+#  define HTYPE U32
+#  define INITBASE(base)			const BYTE* const base = ip
 #else		// 32-bit
-#define STEPSIZE 4
-#define UARCH U32
-#define AARCH A32
-#define LZ4_COPYSTEP(s,d)		A32(d) = A32(s); d+=4; s+=4;
-#define LZ4_COPYPACKET(s,d)		LZ4_COPYSTEP(s,d); LZ4_COPYSTEP(s,d);
-#define LZ4_SECURECOPY			LZ4_WILDCOPY
-#define HTYPE const BYTE*
-#define INITBASE(base)			const int base = 0
+#  define STEPSIZE 4
+#  define UARCH U32
+#  define AARCH A32
+#  define LZ4_COPYSTEP(s,d)		A32(d) = A32(s); d+=4; s+=4;
+#  define LZ4_COPYPACKET(s,d)		LZ4_COPYSTEP(s,d); LZ4_COPYSTEP(s,d);
+#  define LZ4_SECURECOPY			LZ4_WILDCOPY
+#  define HTYPE const BYTE*
+#  define INITBASE(base)			const int base = 0
 #endif
 
 #if (defined(LZ4_BIG_ENDIAN) && !defined(BIG_ENDIAN_NATIVE_BUT_INCOMPATIBLE))
-#define LZ4_READ_LITTLEENDIAN_16(d,s,p) { U16 v = A16(p); v = lz4_bswap16(v); d = (s) - v; }
-#define LZ4_WRITE_LITTLEENDIAN_16(p,i)  { U16 v = (U16)(i); v = lz4_bswap16(v); A16(p) = v; p+=2; }
+#  define LZ4_READ_LITTLEENDIAN_16(d,s,p) { U16 v = A16(p); v = lz4_bswap16(v); d = (s) - v; }
+#  define LZ4_WRITE_LITTLEENDIAN_16(p,i)  { U16 v = (U16)(i); v = lz4_bswap16(v); A16(p) = v; p+=2; }
 #else		// Little Endian
-#define LZ4_READ_LITTLEENDIAN_16(d,s,p) { d = (s) - A16(p); }
-#define LZ4_WRITE_LITTLEENDIAN_16(p,v)  { A16(p) = v; p+=2; }
+#  define LZ4_READ_LITTLEENDIAN_16(d,s,p) { d = (s) - A16(p); }
+#  define LZ4_WRITE_LITTLEENDIAN_16(p,v)  { A16(p) = v; p+=2; }
 #endif
 
 
@@ -663,7 +671,7 @@ int LZ4_uncompress(const char* source,
 		cpy = op+length;
 		if unlikely(cpy>oend-COPYLENGTH)
 		{
-			if (cpy > oend) goto _output_error;
+			if (cpy > oend) goto _output_error;          // Error : request to write beyond destination buffer
 			memcpy(op, ip, length);
 			ip += length;
 			break;    // Necessarily EOF
@@ -672,7 +680,7 @@ int LZ4_uncompress(const char* source,
 
 		// get offset
 		LZ4_READ_LITTLEENDIAN_16(ref,cpy,ip); ip+=2;
-		if (ref < (BYTE* const)dest) goto _output_error;
+		if (ref < (BYTE* const)dest) goto _output_error;   // Error : offset create reference outside destination buffer
 
 		// get matchlength
 		if ((length=(token&ML_MASK)) == ML_MASK) { for (;*ip==255;length+=255) {ip++;} length += *ip++; }
@@ -697,7 +705,7 @@ int LZ4_uncompress(const char* source,
 		cpy = op + length - (STEPSIZE-4);
 		if (cpy>oend-COPYLENGTH)
 		{
-			if (cpy > oend) goto _output_error;
+			if (cpy > oend) goto _output_error;             // Error : request to write beyond destination buffer
 			LZ4_SECURECOPY(ref, op, (oend-COPYLENGTH));
 			while(op<cpy) *op++=*ref++;
 			op=cpy;
@@ -749,19 +757,19 @@ int LZ4_uncompress_unknownOutputSize(
 		cpy = op+length;
 		if ((cpy>oend-COPYLENGTH) || (ip+length>iend-COPYLENGTH))
 		{
-			if (cpy > oend) goto _output_error;
-			if (ip+length > iend) goto _output_error;
+			if (cpy > oend) goto _output_error;          // Error : request to write beyond destination buffer
+			if (ip+length > iend) goto _output_error;    // Error : request to read beyond source buffer
 			memcpy(op, ip, length);
 			op += length;
 			ip += length;
-			if (ip<iend) goto _output_error;
+			if (ip<iend) goto _output_error;             // Error : LZ4 format violation
 			break;    // Necessarily EOF, due to parsing restrictions
 		}
 		LZ4_WILDCOPY(ip, op, cpy); ip -= (op-cpy); op = cpy;
 
 		// get offset
 		LZ4_READ_LITTLEENDIAN_16(ref,cpy,ip); ip+=2;
-		if (ref < (BYTE* const)dest) goto _output_error;
+		if (ref < (BYTE* const)dest) goto _output_error;   // Error : offset creates reference outside of destination buffer
 
 		// get matchlength
 		if ((length=(token&ML_MASK)) == ML_MASK) { while (ip<iend) { int s = *ip++; length +=s; if (s==255) continue; break; } }
@@ -786,7 +794,7 @@ int LZ4_uncompress_unknownOutputSize(
 		cpy = op + length - (STEPSIZE-4);
 		if (cpy>oend-COPYLENGTH)
 		{
-			if (cpy > oend) goto _output_error;
+			if (cpy > oend) goto _output_error;           // Error : request to write outside of destination buffer
 			LZ4_SECURECOPY(ref, op, (oend-COPYLENGTH));
 			while(op<cpy) *op++=*ref++;
 			op=cpy;
diff --git a/lz4.h b/lz4.h
index c928825..10c71a4 100644
--- a/lz4.h
+++ b/lz4.h
@@ -85,7 +85,8 @@ LZ4_uncompress_unknownOutputSize() :
 	return : the number of bytes decoded in the destination buffer (necessarily <= maxOutputSize)
 			 If the source stream is malformed, the function will stop decoding and return a negative result, indicating the byte position of the faulty instruction
 			 This function never writes beyond dest + maxOutputSize, and is therefore protected against malicious data packets
-	note   : This version is slightly slower than LZ4_uncompress()
+	note   : Destination buffer must be already allocated.
+	         This version is slightly slower than LZ4_uncompress()
 */