1 files changed, 128 insertions, 6 deletions

diff --git a/erts/emulator/beam/macros.tab b/erts/emulator/beam/macros.tab
index 7703dd5598..b7ec1f4805 100644
--- a/erts/emulator/beam/macros.tab
+++ b/erts/emulator/beam/macros.tab
@@ -104,14 +104,136 @@ GC_TEST_PRESERVE(NeedHeap, Live, PreserveTerm) {
 
 
 // Make sure that there are NeedStack + NeedHeap + 1 words available
-// on the combined heap/stack segment, then allocates NeedHeap + 1
-// words on the stack and saves CP.
+// on the combined heap/stack segment, then decrement the stack
+// pointer by (NeedStack + 1) words. Finally clear the word reserved
+// for the continuation pointer at the top of the stack.
+//
+// Stack frame layout:
+//
+//       +-----------+
+// y(N)  | Term      |
+//       +-----------+
+//            .
+//            .
+//            .
+//       +-----------+
+// y(0)  | Term      |
+//       +-----------+
+// E ==> | NIL or CP |
+//       +-----------+
+//
+// When the function owning the stack frame is the currently executing
+// function, the word at the top of the stack is NIL. When calling
+// another function, the continuation pointer will be stored in the
+// word at the top of the stack. When returning to the function
+// owning the stack frame, the word at the stack top will again be set
+// to NIL.
+
 AH(NeedStack, NeedHeap, Live) {
     unsigned needed = $NeedStack + 1;
     $GC_TEST(needed, $NeedHeap, $Live);
     E -= needed;
-    *E = make_cp(c_p->cp);
-    c_p->cp = 0;
+    *E = NIL;
+}
+
+
+//
+// Helpers for call instructions
+//
+
+DISPATCH() {
+    BeamInstr dis_next;
+
+    dis_next = *I;
+    CHECK_ARGS(I);
+
+    if (FCALLS > 0 || FCALLS > neg_o_reds) {
+        FCALLS--;
+        Goto(dis_next);
+    } else {
+        goto context_switch;
+    }
+}
+
+DISPATCH_ABS(CallDest) {
+    SET_I((BeamInstr *) $CallDest);
+    DTRACE_LOCAL_CALL(c_p, erts_code_to_codemfa(I));
+
+    $DISPATCH();
+}
+
+DISPATCH_EXPORT(Export) {
+    BeamInstr dis_next;
+    Export *ep;
+
+    ep = (Export*)($Export);
+
+    DTRACE_GLOBAL_CALL_FROM_EXPORT(c_p, ep);
+
+    SET_I(ep->addressv[erts_active_code_ix()]);
+    CHECK_ARGS(I);
+    dis_next = *I;
+
+    if (ERTS_UNLIKELY(FCALLS <= 0)) {
+        if (ERTS_PROC_GET_SAVED_CALLS_BUF(c_p) && FCALLS > neg_o_reds) {
+            save_calls(c_p, ep);
+        } else {
+            goto context_switch;
+        }
+    }
+
+    FCALLS--;
+    Goto(dis_next);
+}
+
+DISPATCH_FUN(I) {
+    BeamInstr dis_next;
+
+    SET_I($I);
+
+    dis_next = *I;
+    CHECK_ARGS(I);
+
+    if (FCALLS > 0 || FCALLS > neg_o_reds) {
+        FCALLS--;
+        Goto(dis_next);
+    } else {
+        goto context_switch_fun;
+    }
+}
+
+DISPATCH_REL(CallDest) {
+    $SET_I_REL($CallDest);
+    DTRACE_LOCAL_CALL(c_p, erts_code_to_codemfa(I));
+
+    $DISPATCH();
+}
+
+DISPATCH_RETURN() {
+    if (FCALLS > 0 || FCALLS > neg_o_reds) {
+        FCALLS--;
+        Goto(*I);
+    } else {
+        c_p->current = NULL;
+        c_p->arity = 1;
+        goto context_switch3;
+    }
+}
+
+// Save the continuation pointer in the reserved slot at the
+// top of the stack as preparation for doing a function call.
+
+SAVE_CONTINUATION_POINTER(IP) {
+    ASSERT(VALID_INSTR(*($IP)));
+    *E = (BeamInstr) ($IP);
+}
+
+// Return to the function whose continuation pointer is stored
+// at the top of the stack and set that word to NIL.
+
+RETURN() {
+    SET_I(cp_val(*E));
+    *E = NIL;
 }
 
 NEXT0() {
@@ -167,7 +289,7 @@ BIF_ERROR_ARITY_1(Fail, BIF, Op1) {
     }
     reg[0] = $Op1;
     SWAPOUT;
-    I = handle_error(c_p, I, reg, &bif_export[$BIF]->info.mfa);
+    I = handle_error(c_p, I, reg, &bif_trap_export[$BIF].info.mfa);
     goto post_error_handling;
 }
 
@@ -179,6 +301,6 @@ BIF_ERROR_ARITY_2(Fail, BIF, Op1, Op2) {
     reg[0] = $Op1;
     reg[1] = $Op2;
     SWAPOUT;
-    I = handle_error(c_p, I, reg, &bif_export[$BIF]->info.mfa);
+    I = handle_error(c_p, I, reg, &bif_trap_export[$BIF].info.mfa);
     goto post_error_handling;
 }