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PDP10, PDP11, VAX: Fixed DMC/DMR DDCMP implementation to only send a single NAK when a data packet arrives out of order.

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This commit is contained in:
Mark Pizzolato 2014-05-31 13:26:46 -07:00
parent a8a0182f74
commit 959ebe7210
1 changed files with 20 additions and 8 deletions
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28
PDP11/pdp11_dmc.c
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@ -437,6 +437,10 @@ typedef struct {
When retransmitting and receiving acknowledgments
asynchronously with respect to transmission, X will
have some value less than or equal to N. */
uint8 NAKed; /* The value of R sent in the most recent NAK message. This
is used to avoid sending additional NAKs when one has already
been sent while the remaining packets in the transmit pipeline
are still arriving. */
t_bool SACK; /* Send ACK flag. This flag is set when either R
is incremented, meaning a new sequential data
message has been received which requires an ACK
@ -604,7 +608,7 @@ void ddcmp_SetTequalAplus1 (CTLR *controller);
void ddcmp_IncrementT (CTLR *controller);
void ddcmp_SetNAKreason3 (CTLR *controller);
void ddcmp_SetNAKReasonCRCError (CTLR *controller);
void ddcmp_NAKMissingPackets (CTLR *controller);
void ddcmp_NAKMissingPacket (CTLR *controller);
void ddcmp_IfTleAthenSetTeqAplus1 (CTLR *controller);
void ddcmp_IfAltXthenStartTimer (CTLR *controller);
void ddcmp_IfAgeXthenStopTimer (CTLR *controller);
@ -668,7 +672,7 @@ DDCMP_STATETABLE DDCMP_TABLE[] = {
ddcmp_NotifyMaintRcvd}},
{22, Run, {ddcmp_ReceiveStack}, Run, {ddcmp_SetSACK}},
{23, Run, {ddcmp_ReceiveDataMsg,
ddcmp_NUMGtRplus1}, Run, {ddcmp_NAKMissingPackets}},
ddcmp_NUMGtRplus1}, Run, {ddcmp_NAKMissingPacket}},
{24, Run, {ddcmp_ReceiveDataMsg,
ddcmp_NUMEqRplus1}, Run, {ddcmp_GiveBufferToUser}},
{25, Run, {ddcmp_ReceiveMessageError}, Run, {ddcmp_SetSNAK,
@ -827,7 +831,7 @@ DDCMP_ACTION_NAME ddcmp_Actions[] = {
NAME(IncrementT),
NAME(SetNAKreason3),
NAME(SetNAKReasonCRCError),
NAME(NAKMissingPackets),
NAME(NAKMissingPacket),
NAME(IfTleAthenSetTeqAplus1),
NAME(IfAltXthenStartTimer),
NAME(IfAgeXthenStopTimer),
@ -867,7 +871,7 @@ char *ddcmp_link_state(DDCMP *link)
{
static char buf[512];
sprintf (buf, "(R:%d,N:%d,A:%d,T:%d,X:%d,SACK:%d,SNAK:%d,SREP:%d)", link->R, link->N, link->A, link->T, link->X, link->SACK, link->SNAK, link->SREP);
sprintf (buf, "(R:%d,N:%d,A:%d,T:%d,X:%d,SACK:%d,SNAK:%d,SREP:%d,NAKed:%d)", link->R, link->N, link->A, link->T, link->X, link->SACK, link->SNAK, link->SREP, link->NAKed);
return buf;
}
@ -3030,7 +3034,7 @@ void ddcmp_SetNAKReasonCRCError (CTLR *controller)
{
controller->link.nak_reason = controller->link.nak_crc_reason;
}
void ddcmp_NAKMissingPackets (CTLR *controller)
void ddcmp_NAKMissingPacket (CTLR *controller)
{
uint8 R = controller->link.R;
QH *qh = &controller->xmt_queue->hdr;
@ -3042,12 +3046,18 @@ while (ddcmp_compare (controller->link.rcv_pkt[DDCMP_NUM_OFFSET], GE, R, control
sim_debug(DBG_INF, controller->device, "%s%d: No Buffers cause NAKMissingPackets to stop\n", controller->device->name, controller->index);
break;
}
if (ddcmp_compare (controller->link.rcv_pkt[DDCMP_NUM_OFFSET], GE, controller->link.NAKed, controller)) {
sim_debug(DBG_INF, controller->device, "%s%d: NAK for prior missing packet %d already sent, still waiting\n", controller->device->name, controller->index, controller->link.NAKed);
break;
}
buffer->transfer_buffer = (uint8 *)malloc (DDCMP_HEADER_SIZE);
buffer->count = DDCMP_HEADER_SIZE;
ddcmp_build_nak_packet (buffer->transfer_buffer, 2, R, DDCMP_FLAG_SELECT);
controller->link.NAKed = R;
R = R + 1;
ASSURE (insqueue (&buffer->hdr, qh));
qh = &buffer->hdr;
break; /* Only generate a single NAK */
}
dmc_ddcmp_start_transmitter (controller);
}
@ -3103,14 +3113,15 @@ void ddcmp_ReTransmitMessageT (CTLR *controller)
{
BUFFER *buffer = dmc_buffer_queue_head(controller->ack_wait_queue);
size_t i;
uint8 T = controller->link.T;
for (i=0; i < controller->ack_wait_queue->count; ++i) {
if ((!buffer->transfer_buffer) ||
ddcmp_compare (buffer->transfer_buffer[DDCMP_NUM_OFFSET], NE, controller->link.T, controller)) {
ddcmp_compare (buffer->transfer_buffer[DDCMP_NUM_OFFSET], NE, T, controller)) {
buffer = (BUFFER *)buffer->hdr.next;
continue;
}
ddcmp_build_data_packet (buffer->transfer_buffer, buffer->count - (DDCMP_HEADER_SIZE + DDCMP_CRC_SIZE), DDCMP_FLAG_SELECT|DDCMP_FLAG_QSYNC, controller->link.T, controller->link.R);
ddcmp_build_data_packet (buffer->transfer_buffer, buffer->count - (DDCMP_HEADER_SIZE + DDCMP_CRC_SIZE), DDCMP_FLAG_SELECT|DDCMP_FLAG_QSYNC, T, controller->link.R);
buffer = (BUFFER *)remqueue (&buffer->hdr);
ASSURE (insqueue (&buffer->hdr, controller->xmt_queue->hdr.prev)); /* Insert at tail */
break;
@ -3397,7 +3408,8 @@ for (table=DDCMP_TABLE; table->Conditions[0] != NULL; ++table) {
}
if (!match)
continue;
sim_debug (DBG_INF, controller->device, "%s%d: ddcmp_dispatch(%X) - %s conditions matching for rule %d(%s), initiating actions (%s)%s\n", controller->device->name, controller->index, EventMask, states[table->State], table->RuleNumber, ddcmp_conditions(table->Conditions), ddcmp_actions(table->Actions), ddcmp_link_state(&controller->link));
sim_debug (DBG_INF, controller->device, "%s%d: ddcmp_dispatch(%X) - %s conditions matching for rule %2d(%s)%s,\n"
" initiating actions (%s)\n", controller->device->name, controller->index, EventMask, states[table->State], table->RuleNumber, ddcmp_conditions(table->Conditions), ddcmp_link_state(&controller->link), ddcmp_actions(table->Actions));
while (*action != NULL) {
(*action)(controller);
++action;