# HG changeset patch
# User Merten Sach <msach@mailbox.tu-berlin.de>
# Date 1331145997 -3600
# Node ID 29d8b41926f0583d82028c3cf5d069fd26e67219

Initial commit - compiles but has still the wrong name

diff -r 000000000000 -r 29d8b41926f0 LossyCom.c
--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/LossyCom.c	Wed Mar 07 19:46:37 2012 +0100
@@ -0,0 +1,101 @@
+
+/*
+ * For a detailed description see header file.
+ */
+
+#include "LossyCom.h"
+
+#include "VMS_Implementations/VMS_impl/vmalloc.h"
+
+/*
+ * Initializes the central exchange structure.
+ * Allocates memory to fit the number of endpoints.
+ * Returns NULL if an error occurs.
+ */
+lossyCom__exchange_t* lossyCom__initialize(uint16_t numEndpoints)
+{
+    lossyCom__exchange_t* exchange;
+    
+    exchange = VMS_WL__malloc(sizeof(lossyCom__exchange_t));
+    if(exchange == NULL)
+        return NULL;
+    
+    exchange->triggerCounter = 0;
+    exchange->numEndpoints = numEndpoints;
+    exchange->outboxArray = VMS_WL__malloc(sizeof(lossyCom__msg_t)*numEndpoints);
+    if(exchange->outboxArray == NULL){
+        VMS_WL__free(exchange);
+        return NULL;
+    }
+    
+    return exchange;    
+}
+
+void lossyCom__initialize_endpoint(lossyCom__endpoint_t* localEndpoint,
+                                   lossyCom__exchange_t* centralExchange,
+                                   lossyCom__endpointID_t endpointID,
+                                   lossyCom__msgHandler* msgHandler)
+{
+    localEndpoint->localTriggerCopy = 0;
+    localEndpoint->endpointID = endpointID;
+    localEndpoint->centralExchangePtr = centralExchange;
+    localEndpoint->msgHandler = msgHandler;    
+}
+
+void inline lossyCom__broadcastMsg(lossyCom__endpoint_t* localEndpoint,
+                                   lossyCom__msgBody_t msg)
+{
+    lossyCom__sendMsg(localEndpoint,
+                      BROADCAST_ID,
+                      msg);
+}
+
+void inline lossyCom__sendMsg(lossyCom__endpoint_t* localEndpoint,
+                       lossyCom__endpointID_t receiverEndpointID,
+                       lossyCom__msgBody_t msg)
+{
+    lossyCom__msg_t msgDraft;
+    uint16_t triggerCopy;
+    
+    msgDraft = (0 | msg);
+    msgDraft |= ((lossyCom__msg_t)receiverEndpointID << ENDPOINT_ID_SHIFT);
+    
+    triggerCopy = localEndpoint->centralExchangePtr->triggerCounter +1;
+    msgDraft |= ((lossyCom__msg_t)triggerCopy << TRIGGER_SHIFT);
+    
+    //write msg to central exchange
+    localEndpoint->centralExchangePtr->outboxArray[localEndpoint->endpointID] =
+            msgDraft;
+    
+    localEndpoint->centralExchangePtr->triggerCounter = triggerCopy;
+}
+
+void inline lossyCom__receiveMsg(lossyCom__endpoint_t* localEndpoint)
+{
+    uint16_t remoteTriggerCopy;
+    lossyCom__endpointID_t senderEndpointID;
+    lossyCom__msg_t msgCopy;
+    uint16_t msgTrigger;
+    lossyCom__msgBody_t msgBody;
+    
+    senderEndpointID = 0;
+    remoteTriggerCopy = localEndpoint->centralExchangePtr->triggerCounter;
+    //new message arrived if trigger counter is higher than the last time read
+    while(senderEndpointID < localEndpoint->centralExchangePtr->numEndpoints)
+    {
+        if(senderEndpointID != localEndpoint->endpointID)
+        {
+            msgCopy = localEndpoint->centralExchangePtr->outboxArray[senderEndpointID];
+            msgTrigger = 0xFFFF & (msgCopy >> TRIGGER_SHIFT);
+            if(msgTrigger > localEndpoint->localTriggerCopy &&
+                    msgTrigger <= remoteTriggerCopy)
+            {
+                msgBody = 0xFFFFFFFF & msgCopy;
+                (*(localEndpoint->msgHandler))(senderEndpointID, msgBody);
+            }
+        }
+        senderEndpointID++;
+    }
+    //save last parsed msg
+    localEndpoint->localTriggerCopy = remoteTriggerCopy;
+}
\ No newline at end of file
diff -r 000000000000 -r 29d8b41926f0 LossyCom.h
--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/LossyCom.h	Wed Mar 07 19:46:37 2012 +0100
@@ -0,0 +1,89 @@
+/*
+ * This describes a best effort communication channel. Mainly designed for
+ * communication between Core-Controllers, so they can inform each other about
+ * their status and pass work around. This is to avoid idling cores that occupy
+ * the Masterlock.
+ * 
+ * The communication entities poll a central trigger counter that increases when
+ * there are new messages. However it's not guaranteed that the increase of the
+ * counter reflects the number of new messages.
+ * 
+ * The messages consist of a single 64bit word so it can be written in one 
+ * operation and therefore avoiding inconsistent messages.
+ * 
+ * The messages are handled with a handler function provided by the receiver
+ * when acquiring the communication endpoint.
+ * 
+ * The message passing is handled by a central struct that is used w/o any lock.
+ * It consists of a array messages for the number of communicating entities. The
+ * number of entities is fixed at initialization.
+ */
+
+#include <stdint.h>
+
+
+
+/***********************************
+ * Type Definitions
+ ***********************************/
+
+#define BROADCAST_ID 65535
+#define ENDPOINT_ID_SHIFT 32
+#define TRIGGER_SHIFT 48
+
+/*
+ * A message consists of the 
+ * 16bit saved trigger value when the message was sent
+ * 16bit receiver identifier, this is the index of the slot in the array
+ *  65536 is the broadcast identifier
+ * 32bit message body, the message format is defined by the endpoints
+ */
+typedef uint64_t lossyCom__msg_t;
+typedef uint32_t lossyCom__msgBody_t;
+typedef uint16_t lossyCom__endpointID_t;
+
+/*
+ * Message Handler that has two arguments the sender endpoint ID and the Msg
+ * Example: 
+ * void handler_func(lossyCom__endpointID_t senderID, lossyCom__msgBody_t msg);
+ */
+typedef void  (*lossyCom__msgHandler) (lossyCom__endpointID_t, lossyCom__msgBody_t);
+
+/*
+ * Central communication structure.
+ */
+typedef struct{
+    uint16_t triggerCounter;
+    uint16_t numEndpoints;
+    lossyCom__msg_t* outboxArray;
+}lossyCom__exchange_t;
+
+/*
+ * Endpoint data structure.
+ */
+typedef struct {
+    uint16_t localTriggerCopy;
+    lossyCom__endpointID_t endpointID;
+    lossyCom__exchange_t* centralExchangePtr;
+    lossyCom__msgHandler* msgHandler;
+} lossyCom__endpoint_t;
+
+/***********************************
+ * Function Declarations
+ ***********************************/
+
+lossyCom__exchange_t* lossyCom__initialize(uint16_t numEndpoints);
+
+void lossyCom__initialize_endpoint(lossyCom__endpoint_t* localEndpoint,
+                                   lossyCom__exchange_t* exchange,
+                                   lossyCom__endpointID_t endpointID,
+                                   lossyCom__msgHandler* msgHandler);
+
+void lossyCom__broadcastMsg(lossyCom__endpoint_t* localEndpoint,
+                            lossyCom__msgBody_t msg);
+
+void lossyCom__sendMsg(lossyCom__endpoint_t* localEndpoint,
+                       lossyCom__endpointID_t receiverEndpointID,
+                       lossyCom__msgBody_t msg);
+
+void lossyCom__receiveMsg(lossyCom__endpoint_t* localEndpoint);
\ No newline at end of file