diff --git a/stix/lib/bigint.c b/stix/lib/bigint.c
index 008d1f4..2a08c49 100644
--- a/stix/lib/bigint.c
+++ b/stix/lib/bigint.c
@@ -513,22 +513,31 @@ stix_oop_t stix_strtoint (stix_t* stix, const stix_ooch_t* str, stix_oow_t len,
 		/* get log2(radix) in a fast way under the fact that
 		 * radix is a power of 2. */
 	#if defined(__GNUC__) && (defined(__x86_64) || defined(__amd64) || defined(__i386) || defined(i386))
+
 		/* use the Bit Scan Forward instruction */
 		__asm__ volatile (
 			"bsf %1,%0\n\t"
-			: "=&r"(exp) /* output */
+			: "=r"(exp) /* output */
 			: "r"(radix) /* input */
 		);
 
-	#elif defined(__GNUC__) && defined(__arm__)
 
+	#elif defined(USE_THIS_UGLY_CODE) && defined(__GNUC__) && defined(__arm__) && (defined(__ARM_ARCH_5__) || defined(__ARM_ARCH_6__) || defined(__ARM_ARCH_7__) || defined(__ARM_ARCH_8__))
+
+		/* clz is available in ARMv5T and above */
 		__asm__ volatile (
 			"clz %0,%1\n\t"
-			: "=&r"(exp) /* output */
+			: "=r"(exp) /* output */
 			: "r"(radix) /* input */
+		);
 
-		/* TODO: ARM - use clz,  PPC - use cntlz, cntlzw, cntlzd, SPARC - use lzcnt, MIPS clz */
+		/* TODO: in ARMv6T2 and above, RBIT can be used before clz to avoid this calculation  */
+		exp = (STIX_SIZEOF(exp) * 8) - exp - 1; 
+
+
+		/* TODO: PPC - use cntlz, cntlzw, cntlzd, SPARC - use lzcnt, MIPS clz */
 	#else
+
 		static unsigned int exp_tab[] = 
 		{
 			0, 0, 1, 0, 2, 0, 0, 0, 3, 0, 0, 0, 0, 0, 0, 0, 4, 
@@ -537,6 +546,7 @@ stix_oop_t stix_strtoint (stix_t* stix, const stix_ooch_t* str, stix_oow_t len,
 		exp = exp_tab[radix];
 	#endif
 
+printf ("<<%d>>>>>>\n",exp);
 		start = ptr; /* this is the real start */
 		ptr = end - 1;
 
diff --git a/stix/lib/exec.c b/stix/lib/exec.c
index c43bee0..6541012 100644
--- a/stix/lib/exec.c
+++ b/stix/lib/exec.c
@@ -26,8 +26,10 @@
 
 #include "stix-prv.h"
 
+#if defined(USE_DYNCALL)
 /* TODO: defined dcAllocMem and dcFreeMeme before builing the dynload and dyncall library */
-#include <dyncall.h> /* TODO: remove this. make dyXXXX calls to callbacks */
+#	include <dyncall.h> /* TODO: remove this. make dyXXXX calls to callbacks */
+#endif
 
 /* TODO: context's stack overflow check in various part of this file */
 /* TOOD: determine the right stack size */
@@ -1363,6 +1365,7 @@ static int prim_ffi_close (stix_t* stix, stix_ooi_t nargs)
 
 static int prim_ffi_call (stix_t* stix, stix_ooi_t nargs)
 {
+#if defined(USE_DYNCALL)
 	stix_oop_t rcv, fun, sig, args;
 
 	STIX_ASSERT (nargs == 3);
@@ -1526,8 +1529,10 @@ printf ("CALL ERROR %d %d\n", dcGetError (dc), DC_ERROR_UNSUPPORTED_MODE);
 		dcFree (dc);
 	}
 
-	
 	return 1;
+#else
+	return 0;
+#endif
 }
 
 static int prim_ffi_getsym (stix_t* stix, stix_ooi_t nargs)
@@ -1572,7 +1577,6 @@ printf ("wrong function name...\n");
 }
 
 
-
 struct prim_t
 {
 	stix_ooi_t          nargs;   /* expected number of arguments */