clarify 'yieldparameter'. Eliminate variable 'unused', reduce coroutine stackspace

2 files changed, 13 insertions, 16 deletions

diff --git a/generic/tclBasic.c b/generic/tclBasic.c
index ae7a3dc..1131a09 100644
--- a/generic/tclBasic.c
+++ b/generic/tclBasic.c
@@ -233,8 +233,8 @@ MODULE_SCOPE const TclStubs tclStubs;
  * after particular kinds of [yield].
  */
 
-#define CORO_ACTIVATE_YIELD    PTR2INT(NULL)
-#define CORO_ACTIVATE_YIELDM   PTR2INT(NULL)+1
+#define CORO_ACTIVATE_YIELD    (0)
+#define CORO_ACTIVATE_YIELDM   (1)
 
 #define COROUTINE_ARGUMENTS_SINGLE_OPTIONAL     (-1)
 #define COROUTINE_ARGUMENTS_ARBITRARY           (-2)
@@ -9724,9 +9724,6 @@ TclNRCoroutineActivateCallback(
     TCL_UNUSED(int) /*result*/)
 {
     CoroutineData *corPtr = (CoroutineData *)data[0];
-    int type = PTR2INT(data[1]);
-    int numLevels, unused;
-    int *stackLevel = &unused;
 
     if (!corPtr->stackLevel) {
         /*
@@ -9743,8 +9740,8 @@ TclNRCoroutineActivateCallback(
          * the interp's environment to make it suitable to run this coroutine.
          */
 
-        corPtr->stackLevel = stackLevel;
-        numLevels = corPtr->auxNumLevels;
+        corPtr->stackLevel = &corPtr;
+        int numLevels = corPtr->auxNumLevels;
         corPtr->auxNumLevels = iPtr->numLevels;
 
         SAVE_CONTEXT(corPtr->caller);
@@ -9757,7 +9754,7 @@ TclNRCoroutineActivateCallback(
          * Coroutine is active: yield
          */
 
-        if (corPtr->stackLevel != stackLevel) {
+        if (corPtr->stackLevel != &corPtr) {
 	    NRE_callback *runPtr;
 
 	    iPtr->execEnvPtr = corPtr->callerEEPtr;
@@ -9781,6 +9778,7 @@ TclNRCoroutineActivateCallback(
             return TCL_ERROR;
         }
 
+        int type = PTR2INT(data[1]);
         if (type == CORO_ACTIVATE_YIELD) {
             corPtr->nargs = COROUTINE_ARGUMENTS_SINGLE_OPTIONAL;
         } else if (type == CORO_ACTIVATE_YIELDM) {
@@ -9792,7 +9790,7 @@ TclNRCoroutineActivateCallback(
 	corPtr->yieldPtr = NULL;
         corPtr->stackLevel = NULL;
 
-        numLevels = iPtr->numLevels;
+        int numLevels = iPtr->numLevels;
         iPtr->numLevels = corPtr->auxNumLevels;
         corPtr->auxNumLevels = numLevels - corPtr->auxNumLevels;
 
@@ -9939,7 +9937,6 @@ TclNRCoroInjectObjCmd(
     Tcl_Obj *const objv[])
 {
     CoroutineData *corPtr;
-    ExecEnv *savedEEPtr = iPtr->execEnvPtr;
 
     /*
      * Usage more or less like tailcall:
@@ -9968,6 +9965,7 @@ TclNRCoroInjectObjCmd(
      * to happen when the coro is resumed.
      */
 
+    ExecEnv *savedEEPtr = iPtr->execEnvPtr;
     iPtr->execEnvPtr = corPtr->eePtr;
     TclNRAddCallback(interp, InjectHandler, corPtr,
             Tcl_NewListObj(objc - 2, objv + 2), INT2PTR(corPtr->nargs), NULL);
@@ -9983,10 +9981,9 @@ TclNRCoroProbeObjCmd(
     int objc,
     Tcl_Obj *const objv[])
 {
-    CoroutineData *corPtr;
     ExecEnv *savedEEPtr = iPtr->execEnvPtr;
-    int numLevels, unused;
-    int *stackLevel = &unused;
+    int numLevels;
+    CoroutineData *corPtr;
 
     /*
      * Usage more or less like tailcall:
@@ -10036,7 +10033,7 @@ TclNRCoroProbeObjCmd(
      * the interp's environment to make it suitable to run this coroutine.
      */
 
-    corPtr->stackLevel = stackLevel;
+    corPtr->stackLevel = &corPtr;
     numLevels = corPtr->auxNumLevels;
     corPtr->auxNumLevels = iPtr->numLevels;
 
diff --git a/generic/tclExecute.c b/generic/tclExecute.c
index 0279218..a890d83 100644
--- a/generic/tclExecute.c
+++ b/generic/tclExecute.c
@@ -2453,7 +2453,7 @@ TEBCresume(
 	    fflush(stdout);
 	}
 #endif
-	yieldParameter = 0;
+	yieldParameter = PTR2INT(NULL);	/*==CORO_ACTIVATE_YIELD*/
 	Tcl_SetObjResult(interp, OBJ_AT_TOS);
 	goto doYield;
 
@@ -2508,7 +2508,7 @@ TEBCresume(
 	TclSetTailcall(interp, valuePtr);
 	corPtr->yieldPtr = valuePtr;
 	iPtr->execEnvPtr = corPtr->eePtr;
-	yieldParameter = (PTR2INT(NULL)+1);	/*==CORO_ACTIVATE_YIELDM*/
+	yieldParameter = PTR2INT(NULL)+1;	/*==CORO_ACTIVATE_YIELDM*/
 
     doYield:
 	/* TIP #280: Record the last piece of info needed by