# HG changeset patch
# User Me
# Date 1289690358 28800
# Node ID fef69b887df4de1e8b47e22deffe9620337d626f
# Parent  ad29ff7a02095401d12127bdb0f72beade34ea75
Working version of singleton!  Woohoo.  Messes with return addr on stack.

diff -r ad29ff7a0209 -r fef69b887df4 SSR.h
--- a/SSR.h	Sat Nov 13 14:38:33 2010 -0800
+++ b/SSR.h	Sat Nov 13 15:19:18 2010 -0800
@@ -37,9 +37,9 @@
 
 typedef struct
  {
+   void           *endInstrAddr;
    int32           hasBeenStarted;
    int32           hasFinished;
-   void           *endInstrAddr;
    PrivQueueStruc *waitQ;
  }
 SSRSingleton;
@@ -80,7 +80,7 @@
    void              *ptrToFree;
 
    int32              singletonID;
-   SSRSingleton     **singletonAddr;
+   SSRSingleton     **singletonPtrAddr;
 
    PtrToAtomicFn      fnToExecInMaster;
    void              *dataForFn;
diff -r ad29ff7a0209 -r fef69b887df4 SSR_Request_Handlers.c
--- a/SSR_Request_Handlers.c	Sat Nov 13 14:38:33 2010 -0800
+++ b/SSR_Request_Handlers.c	Sat Nov 13 15:19:18 2010 -0800
@@ -407,16 +407,16 @@
                       SSRSemEnv *semEnv )
  { SSRSingleton *singleton;
 
-   if( *(semReq->singletonAddr) == NULL )
+   if( *(semReq->singletonPtrAddr) == NULL )
     { singleton                 = VMS__malloc( sizeof(SSRSingleton) );
       singleton->waitQ          = makeVMSPrivQ();
       singleton->endInstrAddr   = 0x0;
       singleton->hasBeenStarted = FALSE;
       singleton->hasFinished    = FALSE;
-      *(semReq->singletonAddr)  = singleton;
+      *(semReq->singletonPtrAddr)  = singleton;
     }
    else
-      singleton = *(semReq->singletonAddr);
+      singleton = *(semReq->singletonPtrAddr);
    handleStartSingleton_helper( singleton, requestingPr, semEnv );
  }
 
@@ -462,7 +462,7 @@
  {
    SSRSingleton   *singleton;
 
-   singleton = *(semReq->singletonAddr);
+   singleton = *(semReq->singletonPtrAddr);
    handleEndSingleton_helper( singleton, requestingPr, semEnv );
   }
 
diff -r ad29ff7a0209 -r fef69b887df4 SSR_lib.c
--- a/SSR_lib.c	Sat Nov 13 14:38:33 2010 -0800
+++ b/SSR_lib.c	Sat Nov 13 15:19:18 2010 -0800
@@ -526,18 +526,24 @@
 
       //
    reqData.reqType       = singleton_data_start;
-   reqData.singletonAddr = singletonAddr;
+   reqData.singletonPtrAddr = singletonAddr;
 
    VMS__send_sem_request( &reqData, animPr );
-   if( animPr->dataRetFromReq ) //either 0 or addr of label in end singleton
-    { animPr->procrID += 10000;
-      asm volatile("movl         %0,      %%eax;  \
-                    jmp                  *%%eax"  \
+   if( animPr->dataRetFromReq ) //either 0 or end singleton's return addr
+    {    //Assembly code changes the return addr on the stack to the one
+         // saved into the singleton by the end-singleton-fn
+         //The return addr is at 0x4(%%ebp)
+      asm volatile("movl        %0,      %%eax;   \
+                    movl    (%%eax),     %%ebx;   \
+                    movl    (%%ebx),     %%eax;   \
+                    movl     %%eax,  0x4(%%ebp);" \
       /* outputs */ :                             \
-      /* inputs  */ : "m"(animPr->dataRetFromReq) \
+      /* inputs  */ : "m"(singletonAddr) \
       /* clobber */ : "memory", "%eax", "%ebx", "%ecx", "%edx","%edi","%esi"\
                    );
     }
+   //now, simply return
+   //will exit either from the start singleton call or the end-singleton call
  }
 
 /*Uses ID as index into array of flags.  If flag already set, resumes from
@@ -566,25 +572,34 @@
  }
 
 void
-SSR__end_data_singleton(  SSRSingleton **singletonAddr, VirtProcr *animPr )
+SSR__end_data_singleton(  SSRSingleton **singletonPtrAddr, VirtProcr *animPr )
  {
    SSRSemReq  reqData;
 
       //don't need this addr until after singleton struct has reached
       // this function for first time
-//   write_return_addr_into_singleton( (*(singletonAddr))->endInstrAddr );
-   (*(singletonAddr))->endInstrAddr =  &&EndDataSingletonInstrAddr;
+      //do assembly that saves the return addr of this fn call into the
+      // data singleton -- that data-singleton can only be given to exactly
+      // one instance in the code of this function.  However, can use this
+      // function in different places for different data-singletons.
+//   (*(singletonAddr))->endInstrAddr =  &&EndDataSingletonInstrAddr;
 
-   reqData.reqType     = singleton_data_end;
-   reqData.singletonAddr = singletonAddr;
+         //Assembly code takes the return addr off the stack and saves
+         // into the singleton.  The first position in the singleton is the
+         // "endInstrAddr" field, and the return addr is at 0x4(%%ebp)
+      asm volatile("movl 0x4(%%ebp),     %%eax;   \
+                    movl        %0,      %%ebx;   \
+                    movl    (%%ebx),     %%ecx;   \
+                    movl     %%eax,     (%%ecx);" \
+      /* outputs */ :                             \
+      /* inputs  */ : "m"(singletonPtrAddr) \
+      /* clobber */ : "memory", "%eax", "%ebx", "%ecx", "%edx","%edi","%esi"\
+                   );
+
+   reqData.reqType          = singleton_data_end;
+   reqData.singletonPtrAddr = singletonPtrAddr;
 
    VMS__send_sem_request( &reqData, animPr );
-   printf("foo");
-   return;
-EndDataSingletonInstrAddr:
-   printf("bar");
-   animPr->procrID += 2000;
-   return;
  }
 
 /*This executes the function in the masterVP, so it executes in isolation