diff --git a/src/engine/interpreter/c_op.h b/src/engine/interpreter/c_op.h
index 54fd7e9fd3543e12f4847375feb67046d7a632ad..c5373c64bde98e3d8f2eb3b7f0779875536ab8ea 100644
--- a/src/engine/interpreter/c_op.h
+++ b/src/engine/interpreter/c_op.h
@@ -3,14 +3,20 @@
 
 #include <common.h>
 
+#ifdef ISA64
+#define c_shift_mask 0x3f
+#else
+#define c_shift_mask 0x1f
+#endif
+
 #define c_add(a, b) ((a) + (b))
 #define c_sub(a, b) ((a) - (b))
 #define c_and(a, b) ((a) & (b))
 #define c_or(a, b)  ((a) | (b))
 #define c_xor(a, b) ((a) ^ (b))
-#define c_shl(a, b) ((a) << (b))
-#define c_shr(a, b) ((a) >> (b))
-#define c_sar(a, b) ((sword_t)(a) >> (b))
+#define c_shl(a, b) ((a) << (b & c_shift_mask))
+#define c_shr(a, b) ((a) >> (b & c_shift_mask))
+#define c_sar(a, b) ((sword_t)(a) >> (b & c_shift_mask))
 
 #define c_mul_lo(a, b) ((a) * (b))
 #define c_imul_lo(a, b) ((sword_t)(a) * (sword_t)(b))
diff --git a/src/isa/x86/exec/logic.h b/src/isa/x86/exec/logic.h
index c078db7cb18c54668c126586612db90f0ffc9c2e..d7251780f04706e9c238ad40eedc36b90b798d50 100644
--- a/src/isa/x86/exec/logic.h
+++ b/src/isa/x86/exec/logic.h
@@ -96,36 +96,32 @@ static inline make_EHelper(not) {
 
 static inline make_EHelper(shld) {
   rtl_andi(s, dsrc1, dsrc1, 31);
-  if (*dsrc1 != 0) {
-    rtl_shl(s, s0, ddest, dsrc1);
+  rtl_shl(s, s0, ddest, dsrc1);
 
-    rtl_li(s, s1, 32);
-    rtl_sub(s, s1, s1, dsrc1);
-    rtl_shr(s, s1, dsrc2, s1);
+  rtl_li(s, s1, 32);
+  rtl_sub(s, s1, s1, dsrc1);
+  rtl_shr(s, s1, dsrc2, s1);
 
-    rtl_or(s, s0, s0, s1);
+  rtl_or(s, s0, s0, s1);
 
-    operand_write(s, id_dest, s0);
-    rtl_update_ZFSF(s, s0, id_dest->width);
-    // unnecessary to update CF and OF in NEMU
-  }
+  operand_write(s, id_dest, s0);
+  rtl_update_ZFSF(s, s0, id_dest->width);
+  // unnecessary to update CF and OF in NEMU
   print_asm_template3(shld);
 }
 
 static inline make_EHelper(shrd) {
   rtl_andi(s, dsrc1, dsrc1, 31);
-  if (*dsrc1 != 0) {
-    rtl_shr(s, s0, ddest, dsrc1);
+  rtl_shr(s, s0, ddest, dsrc1);
 
-    rtl_li(s, s1, 32);
-    rtl_sub(s, s1, s1, dsrc1);
-    rtl_shl(s, s1, dsrc2, s1);
+  rtl_li(s, s1, 32);
+  rtl_sub(s, s1, s1, dsrc1);
+  rtl_shl(s, s1, dsrc2, s1);
 
-    rtl_or(s, s0, s0, s1);
+  rtl_or(s, s0, s0, s1);
 
-    operand_write(s, id_dest, s0);
-    rtl_update_ZFSF(s, s0, id_dest->width);
-    // unnecessary to update CF and OF in NEMU
-  }
+  operand_write(s, id_dest, s0);
+  rtl_update_ZFSF(s, s0, id_dest->width);
+  // unnecessary to update CF and OF in NEMU
   print_asm_template3(shrd);
 }