diff --git a/cpu.c b/cpu.c
index 24e29e34..c6f4d9ca 100644
--- a/cpu.c
+++ b/cpu.c
@@ -2049,6 +2049,9 @@ int     aswitch;
         DO_AUTOMATIC_TRACING();
     }
 
+    /* An instruction that ended with RETURN_INTCHECK continues here */
+intcheck_resume:
+
     /* Set `execflag' to 0 in case EXecuted instruction did a longjmp() */
     regs->execflag = 0;
 
@@ -2107,6 +2110,12 @@ enter_fastest_no_txf_loop:
 
     /* Perform automatic instruction tracing if it's enabled */
     DO_AUTOMATIC_TRACING();
+    /* Instruction ended with RETURN_INTCHECK? (see opcode.h) */
+    if (regs->intcheck)
+    {
+        regs->intcheck = 0;
+        goto intcheck_resume;
+    }
     goto fastest_no_txf_loop;
 
 #if defined( FEATURE_073_TRANSACT_EXEC_FACILITY )
@@ -2144,6 +2153,12 @@ enter_txf_faster_loop:
 
     /* Perform automatic instruction tracing if it's enabled */
     DO_AUTOMATIC_TRACING();
+    /* Instruction ended with RETURN_INTCHECK? (see opcode.h) */
+    if (regs->intcheck)
+    {
+        regs->intcheck = 0;
+        goto intcheck_resume;
+    }
 
 //txf_slower_loop:
 
@@ -2178,6 +2193,12 @@ enter_txf_slower_loop:
 
     /* Perform automatic instruction tracing if it's enabled */
     DO_AUTOMATIC_TRACING();
+    /* Instruction ended with RETURN_INTCHECK? (see opcode.h) */
+    if (regs->intcheck)
+    {
+        regs->intcheck = 0;
+        goto intcheck_resume;
+    }
     goto txf_facility_loop;
 
 #endif /* defined( FEATURE_073_TRANSACT_EXEC_FACILITY ) */
diff --git a/hstructs.h b/hstructs.h
index 15ab0ec3..82429749 100644
--- a/hstructs.h
+++ b/hstructs.h
@@ -261,7 +261,8 @@ struct REGS {                           /* Processor registers       */
                 hostint:1,              /* 1=Host generated interrupt*/
                 host:1,                 /* REGS are hostregs         */
                 guest:1,                /* REGS are guestregs        */
-                diagnose:1;             /* Diagnose instr executing  */
+                diagnose:1,             /* Diagnose instr executing  */
+                intcheck:1;             /* 1=RETURN_INTCHECK done    */
         unsigned int                    /* Flags (intlock serialized)*/
                 dummy:1,                /* 1=Dummy regs structure    */
                 configured:1,           /* 1=CPU is online           */
diff --git a/inline.h b/inline.h
index 5aee0a93..cbcf625c 100644
--- a/inline.h
+++ b/inline.h
@@ -823,7 +823,7 @@ static inline void ARCH_DEP( per1_gra )( REGS* regs )
     RELEASE_INTLOCK( regs );
 
     if (OPEN_IC_PER_GRA( regs ))
-        RETURN_INTCHECK( regs );
+        RETURN_INTCHECK_LONGJMP( regs );
 #endif
 }
 
@@ -877,7 +877,7 @@ inline void ARCH_DEP( per3_zero )( REGS* regs )
         regs->peradr = regs->periaddr;
         ON_IC_PER_ZEROADDR( regs );
         if (OPEN_IC_PER_ZEROADDR( regs ))
-            RETURN_INTCHECK( regs );
+            RETURN_INTCHECK_LONGJMP( regs );
     }
 #else
     UNREFERENCED( regs );
diff --git a/opcode.h b/opcode.h
index 8b8e778c..fc6868cd 100644
--- a/opcode.h
+++ b/opcode.h
@@ -632,10 +632,31 @@ do { \
 /*         Simple helper macro that instructions can use             */
 /*         to force an immediate check for interrupts.               */
 /*-------------------------------------------------------------------*/
+/* RETURN_INTCHECK may be used ONLY in the body of a DEF_INST        */
+/* instruction function: outside SIE mode it ends the instruction    */
+/* with a normal return. INVALIDATE_AIA makes the next               */
+/* UNROLLED_EXECUTE break out of the run_cpu loop, and the 'intcheck'*/
+/* flag makes run_cpu continue at the point where a longjmp(progjmp) */
+/* would have landed (execflag reset, then the interrupt check).     */
+/* This avoids a longjmp (a wasm exception throw, slow in some       */
+/* engines) for LPSW, SSM, STNSM, STOSM, SVC, LCTL and the others.   */
+/* Helper functions (not DEF_INST) use RETURN_INTCHECK_LONGJMP.      */
+/*-------------------------------------------------------------------*/
 
-#define RETURN_INTCHECK(_regs)                                        \
+#define RETURN_INTCHECK_LONGJMP(_regs)                                \
         longjmp((_regs)->progjmp, SIE_NO_INTERCEPT)
 
+#define RETURN_INTCHECK(_regs)                                        \
+  do                                                                  \
+  {                                                                   \
+    if (SIE_MODE( _regs ))                                            \
+        RETURN_INTCHECK_LONGJMP( _regs );                             \
+    INVALIDATE_AIA( _regs );                                          \
+    (_regs)->intcheck = 1;                                            \
+    return;                                                           \
+  }                                                                   \
+  while (0)
+
 /*-------------------------------------------------------------------*/
 /*                Instruction validity checking                      */
 /*-------------------------------------------------------------------*/