modify gpib response sending so it does not hang if read never received

4 files changed, 115 insertions, 122 deletions

diff --git a/globals.h b/globals.h
index 5e5885b..2fa3f17 100644
--- a/globals.h
+++ b/globals.h
@@ -276,6 +276,7 @@ typedef struct {
 	int avrq_reg;
 	int last_rise_time_relay_setting;
 	char gpib_input_buffer[max_gpib_input_length];
+	gchar *pending_output_message;
 } HWregStruct;
 
 
diff --git a/gpib.c b/gpib.c
index 6007cdf..7711e25 100644
--- a/gpib.c
+++ b/gpib.c
@@ -296,7 +296,7 @@ void TNT_4882_Status(int status_register,unsigned int byte,int operation)
 
 	if(set_srq) {					// If SRQ desired
 		TNT_Out(R_auxmr,F_reqt);		// Set request true
-	} else {					
+	} else {
 		TNT_Out(R_auxmr,F_reqf);		// Set request false
 	}
 
@@ -349,11 +349,11 @@ static int TNT_INT_STATUS(void)
 
 	// Get new status
 	INTERFACE_STATUS|= ((mr_isr0&B_to)  ?TIMO :0)|((mr_isr2&B_rem) ?REM :0)
-	                  |((mr_isr1&B_end) ?END  :0)|((mr_isr0&B_eos) ?EOS :0)
-	                  |((mr_spsr&B_pend)?RQS  :0)|((mr_isr0&B_ifc) ?IFC :0)
-	                  |((mr_isr0&B_stbo)?SPOLL:0)|((mr_isr2&B_lok) ?LOK :0)
-	                  |((mr_isr1&B_det) ?DTAS :0)|((mr_isr1&B_dec) ?DCAS:0)
-	                  |((mr_adsr&B_ta)  ?TACS :0)|((mr_adsr&B_la)  ?LACS:0);
+	                   |((mr_isr1&B_end) ?END  :0)|((mr_isr0&B_eos) ?EOS :0)
+	                   |((mr_spsr&B_pend)?RQS  :0)|((mr_isr0&B_ifc) ?IFC :0)
+	                   |((mr_isr0&B_stbo)?SPOLL:0)|((mr_isr2&B_lok) ?LOK :0)
+	                   |((mr_isr1&B_det) ?DTAS :0)|((mr_isr1&B_dec) ?DCAS:0)
+	                   |((mr_adsr&B_ta)  ?TACS :0)|((mr_adsr&B_la)  ?LACS:0);
 
 	INTERFACE_STATUS|=((INTERFACE_STATUS&(LACS|TACS)) ? 0:NACS);
 
@@ -494,7 +494,7 @@ static void TNT_Setup_IO(int IO_type, unsigned long int cnt, int term)
 	TNT_Out(R_cnt3, (char)(twos_cnt>>24));
 
 	TNT_Out(R_imr0,B_glint);			// Set write to imr0 to be sure
-	TNT_Out(R_auxmr,HR_auxrj|0);			// B_to is cleared 
+	TNT_Out(R_auxmr,HR_auxrj|0);			// B_to is cleared
 
 	switch(IO_type) {
 
@@ -632,7 +632,13 @@ int GPIB_check_for_device_clear_signal(void)
 
 	if (TNT_INT_STATUS() & DCAS) {
 		TNT_Out(R_auxmr,F_clrDEC);
+
+		TNT_4882_Status(STB,0x10,CLEAR);        // Clear MAV bit
+		g_free (globals.Registers.pending_output_message);
+
+                TNT_Holdoff_off();
 		TNT_INT_STATUS();
+
 		return TRUE;
 	} else {
 		return FALSE;
@@ -648,7 +654,7 @@ int GPIB_check_for_messages(char *gpib_buf)
 		return FALSE;
 	}
 
-	// If the GPIB has requested data, and no output messages 
+	// If the GPIB has requested data, and no output messages
 	// are in the TNT4882 FIFOs, generate a query error
 
 	if (TNT_update_brq() && !TNT_input_bav() && ib_empty) {
@@ -656,7 +662,7 @@ int GPIB_check_for_messages(char *gpib_buf)
 	}
 
 	// If the TNT4882 is talk addressed, the controller must
-	// be still reading output data in the TNT4882 FIFOs. 
+	// be still reading output data in the TNT4882 FIFOs.
 	// Wait until this process has completed and the TNT4882
 	// is listen addressed.
 
@@ -702,8 +708,8 @@ int GPIB_handle_new_input(char *gpib_buf)
 	                && !( !TNT_input_bav() && (INTERFACE_STATUS & END))	// proper transaction end
 	                && !( !TNT_input_bav() && TNT_In(R_isr3)&B_done)	// proper transaction end
 	                && !( !TNT_input_bav() && (INTERFACE_STATUS & TIMO))	// improper timeout
-	                && !( !TNT_input_bav() && TNT_update_brq() && ib_empty)	// brq message true, 
-										// GPIB requesting data
+	                && !( !TNT_input_bav() && TNT_update_brq() && ib_empty)	// brq message true,
+	                // GPIB requesting data
 	     ) {
 
 		// choose the most efficient fifo-emptying method based on FIFO flags
@@ -743,12 +749,12 @@ int GPIB_handle_new_input(char *gpib_buf)
 	}
 
 	if (TNT_update_brq() && !TNT_input_bav() && ib_empty)
-							// abandon if brq with no commands to process
+		// abandon if brq with no commands to process
 	{
 		queue_error_for_gpib_only(query_error_unterminated);
 		prev_brq=1;				// reset brq
 		TNT_update_brq();			// update it so that it doesn't get confused
-							// in idle state
+		// in idle state
 		return FALSE;
 	}
 
@@ -770,150 +776,141 @@ static void TNT_Holdoff_off()
 }
 
 
-int GPIB_send_query_response(gpointer *ignore_this, char *in_string)
+void GPIB_start_query_response(gpointer *ignore_this, char *in_string)
 {
 	g_assert (ignore_this == NULL);
 	g_assert (in_string != NULL);
 
 	if (!globals.HWDetect.gpib) {
-		return OK;
+		return;
 	}
 
-	if (GPIB_response_already_pending()) {
-		// if MAV already, data will be lost. Set QYE bit in STB.
+	if (globals.Registers.pending_output_message != NULL) {
 		queue_error_for_gpib_only(query_error_interrupted);
+		g_free (globals.Registers.pending_output_message);
 	}
 
-	// needs to be freed
-	gchar *term_string = g_strdup_printf ("%s\n", in_string);
-
-	// just a pointer
-	char *out_buffer = term_string;
+	globals.Registers.pending_output_message = g_strdup_printf ("%s\n", in_string);
+	TNT_4882_Status(STB,0x10,SET);		// Set MAV bit
+}
 
-	// message must be available if this function has been called
 
-	unsigned long int out_cnt;
-	unsigned long int count_sent;		// Local count variable
-	int i;
+void GPIB_finish_query_response()
+{
+	if (!globals.HWDetect.gpib) {
+                return;
+        }
 
-	out_cnt = strlen (out_buffer);
+	if (globals.Registers.pending_output_message == NULL) {
+		return;
+	}
 
-	TNT_4882_Status(STB,0x10,SET);		// Set MAV bit
+	// just a pointer
+	char *out_buffer = globals.Registers.pending_output_message;
+	int i;
+	unsigned long int out_cnt = strlen (out_buffer);
+	unsigned long int count_sent;		// Local count variable
 
 	TNT_INT_STATUS();
 
 	// if the TNT4882 isn't talk addressed, wait until it is, or until the GPIB sends a clear signal,
 	// or until the GPIB writes more data to the TNT4882, generating a query error.
 
-	while (!(INTERFACE_STATUS&TACS)) {
+	if (!(INTERFACE_STATUS&TACS)) {
 		TNT_RFD_Holdoff();
-		if (INTERFACE_STATUS&DCAS) {
-			//* device has been cleared. return to idle state
-			TNT_4882_Status(STB,0x10,CLEAR);	// Clear MAV bit
-			TNT_Holdoff_off();
+		if (GPIB_check_for_device_clear_signal()) {
+			return;
 
-			/* added by MJC - June 20/06 */
-			/* reset interface if a device clear is received */
-			TNT_Out(R_auxmr,F_clrDEC);
-			TNT_INT_STATUS();
-
-			return OK;
 		} else if (!TNT_input_bav()) {
-			// if no bytes are available, we're still waiting for the 
+			// if no bytes are available, we're still waiting for the
 			// GPIB to request data. Repeat loop.
 			TNT_Setup_IO(INPUT,out_cnt,EOI|EOS);
 			TNT_INT_STATUS();
 			TNT_Holdoff_off();
+			return;
+
 		} else {
 			// abandon if input bytes available, and generate query error
 			TNT_Holdoff_off();
 			queue_error_for_gpib_only(query_error_interrupted);
 			TNT_4882_Status(STB,0x10,CLEAR);	// Clear MAV bit
 			prev_brq=1;				// reset brq
-			TNT_update_brq();			// update it so that it doesn't get 
-								// confused in idle state
-			return OK;
+			TNT_update_brq();			// update it so that it doesn't get
+			return;					// confused in idle state
 		}
-	}
-
-	TNT_Setup_IO(OUTPUT,out_cnt,EOI|EOS);
-
-	count_sent=0;
-	INTERFACE_STATUS=0;	// Clear I/O status bits
-	DATA_COUNT=0;		// Clear count global
+	} else {
+		// We are talk-addressed. Send some data.
 
-	if(out_cnt==0) {
-		INTERFACE_STATUS|=UCMPL;
-		return OK;
-	}
+		TNT_Setup_IO(OUTPUT,out_cnt,EOI|EOS);
 
-	// send data until completed or interrupted
-	while( 		!(INTERFACE_STATUS&(DCAS|TIMO|END|ERR|LACS))
-	                && !(TNT_In(R_isr3)&B_done)
-	     ) {
+		count_sent=0;
+		INTERFACE_STATUS=0;	// Clear I/O status bits
+		DATA_COUNT=0;		// Clear count global
 
-		// choose the most efficient fifo-filling method based on flags
-		switch(TNT_In(R_isr3)&(B_nff|B_intsrc2|B_nef)) {
-		case (B_nff):
-		case (B_nff|B_intsrc2):			// 16 words in fifo are empty
-			for(i=0; i<16; i++) {
-				TNT_Out(R_fifob,*((char  *)(out_buffer++)));
-			}
-			break;
+		if(out_cnt==0) {
+			INTERFACE_STATUS|=UCMPL;
+			return;
+		}
 
-		case (B_nff|B_intsrc2|B_nef):		// 8 words in fifo are empty
-			for(i=0; i<8; i++) {
+		// send data until completed or interrupted
+		while( 		!(INTERFACE_STATUS&(DCAS|TIMO|END|ERR|LACS))
+		                && !(TNT_In(R_isr3)&B_done)
+		     ) {
+
+			// choose the most efficient fifo-filling method based on flags
+			switch(TNT_In(R_isr3)&(B_nff|B_intsrc2|B_nef)) {
+			case (B_nff):
+			case (B_nff|B_intsrc2):			// 16 words in fifo are empty
+				for(i=0; i<16; i++) {
+					TNT_Out(R_fifob,*((char  *)(out_buffer++)));
+				}
+				break;
+
+			case (B_nff|B_intsrc2|B_nef):		// 8 words in fifo are empty
+				for(i=0; i<8; i++) {
+					TNT_Out(R_fifob,*((char  *)(out_buffer++)));
+				}
+				break;
+
+			case (B_nff|B_nef):			// 1 word in fifo is empty
 				TNT_Out(R_fifob,*((char  *)(out_buffer++)));
+				break;
 			}
-			break;
 
-		case (B_nff|B_nef):			// 1 word in fifo is empty
-			TNT_Out(R_fifob,*((char  *)(out_buffer++)));
-			break;
+			TNT_INT_STATUS();			// Get current status
 		}
 
-		TNT_INT_STATUS();			// Get current status
-	}
-
-	TNT_DONE_Handler(OUTPUT,&count_sent);		// Finish up and get count
-	DATA_COUNT+=count_sent;				// Update total transfer count
-	out_cnt-=count_sent;				// Update total requested count
-	out_buffer=out_buffer+((int) count_sent);	// Update buffer pointer
-
-	INTERFACE_STATUS|=UCMPL;			// Set the user complete bit
+		TNT_DONE_Handler(OUTPUT,&count_sent);		// Finish up and get count
+		DATA_COUNT+=count_sent;				// Update total transfer count
+		out_cnt-=count_sent;				// Update total requested count
+		out_buffer=out_buffer+((int) count_sent);	// Update buffer pointer
 
-	g_free (term_string);
+		INTERFACE_STATUS|=UCMPL;			// Set the user complete bit
 
-	if (INTERFACE_STATUS&DCAS) {
-		TNT_4882_Status(STB,0x10,CLEAR);	// Clear MAV bit
+		g_free (globals.Registers.pending_output_message);
 
-		// added by MJC - June 20/06
-		// reset interface if a device clear is received
-		TNT_Out(R_auxmr,F_clrDEC);
-		TNT_INT_STATUS();
-
-		return OK;				// abandon if SDC or DCL
-	}
+		if (GPIB_check_for_device_clear_signal()) {
+			return;
+		}
 
-	if ((INTERFACE_STATUS&LACS) && (TNT_In(R_isr3)&B_nef)) {
-		// abandon gracefully if listen-addressed with data in buffer
-		queue_error_for_gpib_only(query_error_interrupted);
-		TNT_4882_Status(STB,0x10,CLEAR);	// Clear MAV bit
-		prev_brq=1;				// reset brq
-		TNT_update_brq();			// update it so that it doesn't get
-							// confused in idle state
-		TNT_Setup_IO(INPUT,cnt,EOI|EOS);
-		return OK;
-	}
+		if ((INTERFACE_STATUS&LACS) && (TNT_In(R_isr3)&B_nef)) {
+			// abandon gracefully if listen-addressed with data in buffer
+			queue_error_for_gpib_only(query_error_interrupted);
+			TNT_4882_Status(STB,0x10,CLEAR);	// Clear MAV bit
+			prev_brq=1;				// reset brq
+			TNT_update_brq();			// update it so that it doesn't get
+			// confused in idle state
+			TNT_Setup_IO(INPUT,cnt,EOI|EOS);
+			return;
+		}
 
-	if(DATA_COUNT>0) {
-		TNT_4882_Status(STB,0x10,CLEAR);	// Clear MAV bit
-		prev_brq=1;				// brq was active during send */
-		TNT_update_brq();			// update it so that it doesn't get
-							// confused in idle state
+		if(DATA_COUNT>0) {
+			TNT_4882_Status(STB,0x10,CLEAR);	// Clear MAV bit
+			prev_brq=1;				// brq was active during send */
+			TNT_update_brq();			// update it so that it doesn't get
+			// confused in idle state
+		}
 	}
-
-	return OK;
 }
 
 
@@ -936,16 +933,6 @@ void GPIB_check_remote_status (int *is_remote, int *is_lockout)
 }
 
 
-unsigned char GPIB_response_already_pending ()
-{
-	if (!globals.HWDetect.gpib) {
-		return 0;
-	}
-
-	return TNT_In(R_spsr) & 0x10;
-}
-
-
 void GPIB_go_to_local ()
 {
 	if (!globals.HWDetect.gpib) {
diff --git a/gpib.h b/gpib.h
index 2da0cc1..610d74e 100644
--- a/gpib.h
+++ b/gpib.h
@@ -12,9 +12,9 @@ int GPIB_check_for_device_clear_signal(void);
 int GPIB_check_for_device_clear_signal(void);
 int GPIB_check_for_messages(char *gpib_buf);
 int GPIB_handle_new_input(char *gpib_buf);
-int GPIB_send_query_response(gpointer *ignore_this, char *in_string);
+void GPIB_start_query_response(gpointer *ignore_this, char *in_string);
+void GPIB_finish_query_response();
 void GPIB_check_remote_status (int *is_remote, int *is_lockout);
-unsigned char GPIB_response_already_pending ();
 void GPIB_go_to_local ();
 void GPIB_clear_events ();
 unsigned int GPIB_get_ESR ();
diff --git a/instr-daemon.c b/instr-daemon.c
index 255b294..4924961 100644
--- a/instr-daemon.c
+++ b/instr-daemon.c
@@ -413,14 +413,19 @@ static gboolean periodic_poll (void)
 			globals.VxiLocks.command_in_progress = TRUE;
 
 			GPIB_check_for_device_clear_signal();
+
 			if (GPIB_check_for_messages(globals.Registers.gpib_input_buffer)) {
 				if (GPIB_handle_new_input(globals.Registers.gpib_input_buffer)) {
-					Parser_main(globals.Registers.gpib_input_buffer, 0, GPIB_send_query_response, NULL);
+					Parser_main(globals.Registers.gpib_input_buffer, 0, GPIB_start_query_response, NULL);
 				}
 			}
+
+			// send response if appropriate
+			GPIB_finish_query_response();
+
 			GPIB_check_for_device_clear_signal();
 
-			// tell VXI servers that the 4882 subsystem is avilable again
+			// tell VXI servers that the 4882 subsystem is available again
 			globals.VxiLocks.command_in_progress = FALSE;
 		}