diff --git a/src/flash/str9xpec.c b/src/flash/str9xpec.c
index 074d751c6..c0c6dfffb 100644
--- a/src/flash/str9xpec.c
+++ b/src/flash/str9xpec.c
@@ -125,7 +125,7 @@ int str9xpec_set_instr(jtag_tap_t *tap, u32 new_instr, tap_state_t end_state)
 		field.num_bits = tap->ir_length;
 		field.out_value = calloc(CEIL(field.num_bits, 8), 1);
 		buf_set_u32(field.out_value, 0, field.num_bits, new_instr);
-		field.out_mask = NULL;
+		
 		field.in_value = NULL;
 		field.in_check_value = NULL;
 		field.in_check_mask = NULL;
@@ -151,7 +151,7 @@ static u8 str9xpec_isc_status(jtag_tap_t *tap)
 	field.tap = tap;
 	field.num_bits = 8;
 	field.out_value = NULL;
-	field.out_mask = NULL;
+	
 	field.in_value = &status;
 	field.in_check_value = NULL;
 	field.in_check_mask = NULL;
@@ -243,7 +243,7 @@ static int str9xpec_read_config(struct flash_bank_s *bank)
 	field.tap = tap;
 	field.num_bits = 64;
 	field.out_value = NULL;
-	field.out_mask = NULL;
+	
 	field.in_value = str9xpec_info->options;
 	field.in_check_value = NULL;
 	field.in_check_mask = NULL;
@@ -395,7 +395,7 @@ static int str9xpec_blank_check(struct flash_bank_s *bank, int first, int last)
 	field.tap = tap;
 	field.num_bits = 64;
 	field.out_value = buffer;
-	field.out_mask = NULL;
+	
 	field.in_value = NULL;
 	field.in_check_value = NULL;
 	field.in_check_mask = NULL;
@@ -409,7 +409,7 @@ static int str9xpec_blank_check(struct flash_bank_s *bank, int first, int last)
 	field.tap = tap;
 	field.num_bits = 64;
 	field.out_value = NULL;
-	field.out_mask = NULL;
+	
 	field.in_value = buffer;
 	field.in_check_value = NULL;
 	field.in_check_mask = NULL;
@@ -511,7 +511,7 @@ static int str9xpec_erase_area(struct flash_bank_s *bank, int first, int last)
 	field.tap = tap;
 	field.num_bits = 64;
 	field.out_value = buffer;
-	field.out_mask = NULL;
+	
 	field.in_value = NULL;
 	field.in_check_value = NULL;
 	field.in_check_mask = NULL;
@@ -577,7 +577,7 @@ static int str9xpec_lock_device(struct flash_bank_s *bank)
 		field.tap = tap;
 		field.num_bits = 8;
 		field.out_value = NULL;
-		field.out_mask = NULL;
+		
 		field.in_value = &status;
 		field.in_check_value = NULL;
 		field.in_check_mask = NULL;
@@ -663,7 +663,7 @@ static int str9xpec_set_address(struct flash_bank_s *bank, u8 sector)
 	field.tap = tap;
 	field.num_bits = 8;
 	field.out_value = &sector;
-	field.out_mask = NULL;
+	
 	field.in_value = NULL;
 	field.in_check_value = NULL;
 	field.in_check_mask = NULL;
@@ -752,7 +752,7 @@ static int str9xpec_write(struct flash_bank_s *bank, u8 *buffer, u32 offset, u32
 			field.tap = tap;
 			field.num_bits = 64;
 			field.out_value = (buffer + bytes_written);
-			field.out_mask = NULL;
+			
 			field.in_value = NULL;
 			field.in_check_value = NULL;
 			field.in_check_mask = NULL;
@@ -770,7 +770,7 @@ static int str9xpec_write(struct flash_bank_s *bank, u8 *buffer, u32 offset, u32
 				field.tap = tap;
 				field.num_bits = 8;
 				field.out_value = NULL;
-				field.out_mask = NULL;
+				
 				field.in_value = scanbuf;
 				field.in_check_value = NULL;
 				field.in_check_mask = NULL;
@@ -812,7 +812,7 @@ static int str9xpec_write(struct flash_bank_s *bank, u8 *buffer, u32 offset, u32
 		field.tap = tap;
 		field.num_bits = 64;
 		field.out_value = last_dword;
-		field.out_mask = NULL;
+		
 		field.in_value = NULL;
 		field.in_check_value = NULL;
 		field.in_check_mask = NULL;
@@ -830,7 +830,7 @@ static int str9xpec_write(struct flash_bank_s *bank, u8 *buffer, u32 offset, u32
 			field.tap = tap;
 			field.num_bits = 8;
 			field.out_value = NULL;
-			field.out_mask = NULL;
+			
 			field.in_value = scanbuf;
 			field.in_check_value = NULL;
 			field.in_check_mask = NULL;
@@ -894,7 +894,7 @@ static int str9xpec_handle_part_id_command(struct command_context_s *cmd_ctx, ch
 	field.tap = tap;
 	field.num_bits = 32;
 	field.out_value = NULL;
-	field.out_mask = NULL;
+	
 	field.in_value = buffer;
 	field.in_check_value = NULL;
 	field.in_check_mask = NULL;
@@ -1019,7 +1019,7 @@ static int str9xpec_write_options(struct flash_bank_s *bank)
 	field.tap = tap;
 	field.num_bits = 64;
 	field.out_value = str9xpec_info->options;
-	field.out_mask = NULL;
+	
 	field.in_value = NULL;
 	field.in_check_value = NULL;
 	field.in_check_mask = NULL;
@@ -1037,7 +1037,7 @@ static int str9xpec_write_options(struct flash_bank_s *bank)
 		field.tap = tap;
 		field.num_bits = 8;
 		field.out_value = NULL;
-		field.out_mask = NULL;
+		
 		field.in_value = &status;
 		field.in_check_value = NULL;
 		field.in_check_mask = NULL;
diff --git a/src/helper/tclapi.c b/src/helper/tclapi.c
index 6582a88e5..7b1798af5 100644
--- a/src/helper/tclapi.c
+++ b/src/helper/tclapi.c
@@ -447,7 +447,6 @@ int Jim_Command_drscan(Jim_Interp *interp, int argc, Jim_Obj *const *args)
 		fields[field_count].num_bits = bits;
 		fields[field_count].out_value = malloc(CEIL(bits, 8));
 		str_to_buf(str, len, fields[field_count].out_value, bits, 0);
-		fields[field_count].out_mask = NULL;
 		fields[field_count].in_value = fields[field_count].out_value;
 		fields[field_count].in_check_mask = NULL;
 		fields[field_count].in_check_value = NULL;
diff --git a/src/jtag/jtag.c b/src/jtag/jtag.c
index 20ffa8158..c665ba206 100644
--- a/src/jtag/jtag.c
+++ b/src/jtag/jtag.c
@@ -579,8 +579,7 @@ int MINIDRIVER(interface_jtag_add_ir_scan)(int num_fields, scan_field_t *fields,
 			{
 				found = 1;
 				(*last_cmd)->cmd.scan->fields[nth_tap].out_value = buf_cpy(fields[j].out_value, cmd_queue_alloc(CEIL(scan_size, 8)), scan_size);
-				(*last_cmd)->cmd.scan->fields[nth_tap].out_mask = buf_cpy(fields[j].out_mask, cmd_queue_alloc(CEIL(scan_size, 8)), scan_size);
-
+				
 				if (jtag_verify_capture_ir)
 				{
 					if (fields[j].in_handler==NULL)
@@ -604,7 +603,6 @@ int MINIDRIVER(interface_jtag_add_ir_scan)(int num_fields, scan_field_t *fields,
 		{
 			/* if a tap isn't listed, set it to BYPASS */
 			(*last_cmd)->cmd.scan->fields[nth_tap].out_value = buf_set_ones(cmd_queue_alloc(CEIL(scan_size, 8)), scan_size);
-			(*last_cmd)->cmd.scan->fields[nth_tap].out_mask = NULL;
 			tap->bypass = 1;
 		}
 
@@ -652,7 +650,6 @@ int MINIDRIVER(interface_jtag_add_plain_ir_scan)(int num_fields, scan_field_t *f
 		(*last_cmd)->cmd.scan->fields[i].tap = fields[i].tap;
 		(*last_cmd)->cmd.scan->fields[i].num_bits = num_bits;
 		(*last_cmd)->cmd.scan->fields[i].out_value = buf_cpy(fields[i].out_value, cmd_queue_alloc(num_bytes), num_bits);
-		(*last_cmd)->cmd.scan->fields[i].out_mask = buf_cpy(fields[i].out_mask, cmd_queue_alloc(num_bytes), num_bits);
 		(*last_cmd)->cmd.scan->fields[i].in_value = fields[i].in_value;
 		(*last_cmd)->cmd.scan->fields[i].in_check_value = fields[i].in_check_value;
 		(*last_cmd)->cmd.scan->fields[i].in_check_mask = fields[i].in_check_mask;
@@ -729,7 +726,6 @@ int MINIDRIVER(interface_jtag_add_dr_scan)(int num_fields, scan_field_t *fields,
 				scan_size = fields[j].num_bits;
 				(*last_cmd)->cmd.scan->fields[field_count].num_bits = scan_size;
 				(*last_cmd)->cmd.scan->fields[field_count].out_value = buf_cpy(fields[j].out_value, cmd_queue_alloc(CEIL(scan_size, 8)), scan_size);
-				(*last_cmd)->cmd.scan->fields[field_count].out_mask = buf_cpy(fields[j].out_mask, cmd_queue_alloc(CEIL(scan_size, 8)), scan_size);
 				(*last_cmd)->cmd.scan->fields[field_count].in_value = fields[j].in_value;
 				(*last_cmd)->cmd.scan->fields[field_count].in_check_value = fields[j].in_check_value;
 				(*last_cmd)->cmd.scan->fields[field_count].in_check_mask = fields[j].in_check_mask;
@@ -750,7 +746,6 @@ int MINIDRIVER(interface_jtag_add_dr_scan)(int num_fields, scan_field_t *fields,
 			/* program the scan field to 1 bit length, and ignore it's value */
 			(*last_cmd)->cmd.scan->fields[field_count].num_bits = 1;
 			(*last_cmd)->cmd.scan->fields[field_count].out_value = NULL;
-			(*last_cmd)->cmd.scan->fields[field_count].out_mask = NULL;
 			(*last_cmd)->cmd.scan->fields[field_count].in_value = NULL;
 			(*last_cmd)->cmd.scan->fields[field_count].in_check_value = NULL;
 			(*last_cmd)->cmd.scan->fields[field_count].in_check_mask = NULL;
@@ -840,7 +835,6 @@ void MINIDRIVER(interface_jtag_add_dr_out)(jtag_tap_t *target_tap,
 				buf_set_u32(out_value, 0, scan_size, value[j]);
 				(*last_cmd)->cmd.scan->fields[field_count].num_bits = scan_size;
 				(*last_cmd)->cmd.scan->fields[field_count].out_value = buf_cpy(out_value, cmd_queue_alloc(CEIL(scan_size, 8)), scan_size);
-				(*last_cmd)->cmd.scan->fields[field_count].out_mask = NULL;
 				(*last_cmd)->cmd.scan->fields[field_count].in_value = NULL;
 				(*last_cmd)->cmd.scan->fields[field_count].in_check_value = NULL;
 				(*last_cmd)->cmd.scan->fields[field_count].in_check_mask = NULL;
@@ -860,7 +854,6 @@ void MINIDRIVER(interface_jtag_add_dr_out)(jtag_tap_t *target_tap,
 			/* program the scan field to 1 bit length, and ignore it's value */
 			(*last_cmd)->cmd.scan->fields[field_count].num_bits = 1;
 			(*last_cmd)->cmd.scan->fields[field_count].out_value = NULL;
-			(*last_cmd)->cmd.scan->fields[field_count].out_mask = NULL;
 			(*last_cmd)->cmd.scan->fields[field_count].in_value = NULL;
 			(*last_cmd)->cmd.scan->fields[field_count].in_check_value = NULL;
 			(*last_cmd)->cmd.scan->fields[field_count].in_check_mask = NULL;
@@ -906,7 +899,6 @@ int MINIDRIVER(interface_jtag_add_plain_dr_scan)(int num_fields, scan_field_t *f
 		(*last_cmd)->cmd.scan->fields[i].tap = fields[i].tap;
 		(*last_cmd)->cmd.scan->fields[i].num_bits = num_bits;
 		(*last_cmd)->cmd.scan->fields[i].out_value = buf_cpy(fields[i].out_value, cmd_queue_alloc(num_bytes), num_bits);
-		(*last_cmd)->cmd.scan->fields[i].out_mask = buf_cpy(fields[i].out_mask, cmd_queue_alloc(num_bytes), num_bits);
 		(*last_cmd)->cmd.scan->fields[i].in_value = fields[i].in_value;
 		(*last_cmd)->cmd.scan->fields[i].in_check_value = fields[i].in_check_value;
 		(*last_cmd)->cmd.scan->fields[i].in_check_mask = fields[i].in_check_mask;
@@ -1492,7 +1484,7 @@ int jtag_examine_chain(void)
 	field.tap = NULL;
 	field.num_bits = sizeof(idcode_buffer) * 8;
 	field.out_value = idcode_buffer;
-	field.out_mask = NULL;
+	
 	field.in_value = idcode_buffer;
 	field.in_check_value = NULL;
 	field.in_check_mask = NULL;
@@ -1670,7 +1662,7 @@ int jtag_validate_chain(void)
 	field.tap = NULL;
 	field.num_bits = total_ir_length;
 	field.out_value = ir_test;
-	field.out_mask = NULL;
+	
 	field.in_value = ir_test;
 	field.in_check_value = NULL;
 	field.in_check_mask = NULL;
@@ -2792,7 +2784,6 @@ static int handle_irscan_command(struct command_context_s *cmd_ctx, char *cmd, c
 		fields[i].tap = tap;
 		fields[i].out_value = malloc(CEIL(field_size, 8));
 		buf_set_u32(fields[i].out_value, 0, field_size, strtoul(args[i*2+1], NULL, 0));
-		fields[i].out_mask = NULL;
 		fields[i].in_value = NULL;
 		fields[i].in_check_mask = NULL;
 		fields[i].in_handler = NULL;
@@ -2908,7 +2899,6 @@ static int Jim_Command_drscan(Jim_Interp *interp, int argc, Jim_Obj *const *args
 		fields[field_count].num_bits = bits;
 		fields[field_count].out_value = malloc(CEIL(bits, 8));
 		str_to_buf(str, len, fields[field_count].out_value, bits, 0);
-		fields[field_count].out_mask = NULL;
 		fields[field_count].in_value = fields[field_count].out_value;
 		fields[field_count].in_check_mask = NULL;
 		fields[field_count].in_check_value = NULL;
diff --git a/src/jtag/jtag.h b/src/jtag/jtag.h
index 5dfbbdce4..0699516c9 100644
--- a/src/jtag/jtag.h
+++ b/src/jtag/jtag.h
@@ -271,7 +271,6 @@ typedef struct scan_field_s
 	jtag_tap_t* tap;                /* tap pointer this instruction refers to */
 	int         num_bits;           /* number of bits this field specifies (up to 32) */
 	u8*         out_value;          /* value to be scanned into the device */
-	u8*         out_mask;           /* only masked bits care */
 	u8*         in_value;           /* pointer to a 32-bit memory location to take data scanned out */
 	/* in_check_value/mask, in_handler_error_handler, in_handler_priv can be used by the in handler, otherwise they contain garbage  */
 	u8*          in_check_value;    /* used to validate scan results */
diff --git a/src/jtag/zy1000.c b/src/jtag/zy1000.c
index 69c1ef0ab..7911a5efb 100644
--- a/src/jtag/zy1000.c
+++ b/src/jtag/zy1000.c
@@ -650,7 +650,6 @@ int interface_jtag_add_dr_scan(int num_fields, scan_field_t *fields, tap_state_t
 			/* program the scan field to 1 bit length, and ignore it's value */
 			tmp.num_bits = 1;
 			tmp.out_value = NULL;
-			tmp.out_mask = NULL;
 			tmp.in_value = NULL;
 			tmp.in_check_value = NULL;
 			tmp.in_check_mask = NULL;
diff --git a/src/pld/virtex2.c b/src/pld/virtex2.c
index 26f0f1fef..cec4fe9d1 100644
--- a/src/pld/virtex2.c
+++ b/src/pld/virtex2.c
@@ -56,7 +56,7 @@ int virtex2_set_instr(jtag_tap_t *tap, u32 new_instr)
 		field.num_bits = tap->ir_length;
 		field.out_value = calloc(CEIL(field.num_bits, 8), 1);
 		buf_set_u32(field.out_value, 0, field.num_bits, new_instr);
-		field.out_mask = NULL;
+		
 		field.in_value = NULL;
 		field.in_check_value = NULL;
 		field.in_check_mask = NULL;
@@ -83,7 +83,6 @@ int virtex2_send_32(struct pld_device_s *pld_device, int num_words, u32 *words)
 	scan_field.tap = virtex2_info->tap;
 	scan_field.num_bits = num_words * 32;
 	scan_field.out_value = values;
-	scan_field.out_mask = NULL;
 	scan_field.in_value = NULL;
 	scan_field.in_check_value = NULL;
 	scan_field.in_check_mask = NULL;
@@ -117,7 +116,6 @@ int virtex2_receive_32(struct pld_device_s *pld_device, int num_words, u32 *word
 	scan_field.tap = virtex2_info->tap;
 	scan_field.num_bits = 32;
 	scan_field.out_value = NULL;
-	scan_field.out_mask = NULL;
 	scan_field.in_value = NULL;
 	scan_field.in_check_value = NULL;
 	scan_field.in_check_mask = NULL;
@@ -166,7 +164,7 @@ int virtex2_load(struct pld_device_s *pld_device, char *filename)
 	scan_field_t field;
 
 	field.tap = virtex2_info->tap;
-	field.out_mask = NULL;
+	
 	field.in_value = NULL;
 	field.in_check_value = NULL;
 	field.in_check_mask = NULL;
diff --git a/src/svf/svf.c b/src/svf/svf.c
index 01e5631c0..6c92c1e15 100644
--- a/src/svf/svf.c
+++ b/src/svf/svf.c
@@ -975,7 +975,7 @@ static int svf_run_command(struct command_context_s *cmd_ctx, char *cmd_str)
 			field.tap = tap;
 			field.num_bits = i;
 			field.out_value = &svf_tdi_buffer[svf_buffer_index];
-			field.out_mask = NULL;
+			
 			field.in_value = &svf_tdi_buffer[svf_buffer_index];
 			field.in_check_value = NULL;
 			field.in_check_mask = NULL;
@@ -1076,7 +1076,7 @@ static int svf_run_command(struct command_context_s *cmd_ctx, char *cmd_str)
 			field.tap = tap;
 			field.num_bits = i;
 			field.out_value = &svf_tdi_buffer[svf_buffer_index];
-			field.out_mask = NULL;
+			
 			field.in_value = &svf_tdi_buffer[svf_buffer_index];
 			field.in_check_value = NULL;
 			field.in_check_mask = NULL;
diff --git a/src/target/arm11_dbgtap.c b/src/target/arm11_dbgtap.c
index 2f474212f..d897f108d 100644
--- a/src/target/arm11_dbgtap.c
+++ b/src/target/arm11_dbgtap.c
@@ -87,7 +87,6 @@ void arm11_setup_field(arm11_common_t * arm11, int num_bits, void * out_data, vo
 {
 	field->tap   			= arm11->jtag_info.tap;
 	field->num_bits			= num_bits;
-	field->out_mask			= NULL;
 	field->in_check_mask	= NULL;
 	field->in_check_value	= NULL;
 	field->in_handler		= NULL;
diff --git a/src/target/arm720t.c b/src/target/arm720t.c
index 6cd73e458..60c4dec79 100644
--- a/src/target/arm720t.c
+++ b/src/target/arm720t.c
@@ -112,7 +112,7 @@ int arm720t_scan_cp15(target_t *target, u32 out, u32 *in, int instruction, int c
 	fields[0].tap = jtag_info->tap;
 	fields[0].num_bits = 1;
 	fields[0].out_value = &instruction_buf;
-	fields[0].out_mask = NULL;
+	
 	fields[0].in_value = NULL;
 	fields[0].in_check_value = NULL;
 	fields[0].in_check_mask = NULL;
@@ -122,7 +122,7 @@ int arm720t_scan_cp15(target_t *target, u32 out, u32 *in, int instruction, int c
 	fields[1].tap = jtag_info->tap;
 	fields[1].num_bits = 32;
 	fields[1].out_value = out_buf;
-	fields[1].out_mask = NULL;
+	
 	fields[1].in_value = NULL;
 	if (in)
 	{
diff --git a/src/target/arm7tdmi.c b/src/target/arm7tdmi.c
index c20594983..b0d9e85e4 100644
--- a/src/target/arm7tdmi.c
+++ b/src/target/arm7tdmi.c
@@ -111,7 +111,7 @@ int arm7tdmi_examine_debug_reason(target_t *target)
 		fields[0].tap = arm7_9->jtag_info.tap;
 		fields[0].num_bits = 1;
 		fields[0].out_value = NULL;
-		fields[0].out_mask = NULL;
+		
 		fields[0].in_value = &breakpoint;
 		fields[0].in_check_value = NULL;
 		fields[0].in_check_mask = NULL;
@@ -121,7 +121,7 @@ int arm7tdmi_examine_debug_reason(target_t *target)
 		fields[1].tap = arm7_9->jtag_info.tap;
 		fields[1].num_bits = 32;
 		fields[1].out_value = NULL;
-		fields[1].out_mask = NULL;
+		
 		fields[1].in_value = databus;
 		fields[1].in_check_value = NULL;
 		fields[1].in_check_mask = NULL;
@@ -198,7 +198,7 @@ int arm7tdmi_clock_data_in(arm_jtag_t *jtag_info, u32 *in)
 	fields[0].tap = jtag_info->tap;
 	fields[0].num_bits = 1;
 	fields[0].out_value = NULL;
-	fields[0].out_mask = NULL;
+	
 	fields[0].in_value = NULL;
 	fields[0].in_check_value = NULL;
 	fields[0].in_check_mask = NULL;
@@ -208,7 +208,7 @@ int arm7tdmi_clock_data_in(arm_jtag_t *jtag_info, u32 *in)
 	fields[1].tap = jtag_info->tap;
 	fields[1].num_bits = 32;
 	fields[1].out_value = NULL;
-	fields[1].out_mask = NULL;
+	
 	fields[1].in_value = NULL;
 	fields[1].in_handler = arm_jtag_buf_to_u32_flip; /* deprecated! invoke this from user code! */
 	fields[1].in_handler_priv = in;
@@ -259,7 +259,7 @@ int arm7tdmi_clock_data_in_endianness(arm_jtag_t *jtag_info, void *in, int size,
 	fields[0].tap = jtag_info->tap;
 	fields[0].num_bits = 1;
 	fields[0].out_value = NULL;
-	fields[0].out_mask = NULL;
+	
 	fields[0].in_value = NULL;
 	fields[0].in_check_value = NULL;
 	fields[0].in_check_mask = NULL;
@@ -269,7 +269,7 @@ int arm7tdmi_clock_data_in_endianness(arm_jtag_t *jtag_info, void *in, int size,
 	fields[1].tap = jtag_info->tap;
 	fields[1].num_bits = 32;
 	fields[1].out_value = NULL;
-	fields[1].out_mask = NULL;
+	
 	fields[1].in_value = NULL;
 	switch (size)
 	{
diff --git a/src/target/arm920t.c b/src/target/arm920t.c
index cc6ba0a30..f07cee8d9 100644
--- a/src/target/arm920t.c
+++ b/src/target/arm920t.c
@@ -113,7 +113,7 @@ int arm920t_read_cp15_physical(target_t *target, int reg_addr, u32 *value)
 	fields[0].tap = jtag_info->tap;
 	fields[0].num_bits = 1;
 	fields[0].out_value = &access_type_buf;
-	fields[0].out_mask = NULL;
+	
 	fields[0].in_value = NULL;
 	fields[0].in_check_value = NULL;
 	fields[0].in_check_mask = NULL;
@@ -123,7 +123,7 @@ int arm920t_read_cp15_physical(target_t *target, int reg_addr, u32 *value)
 	fields[1].tap = jtag_info->tap;
 	fields[1].num_bits = 32;
 	fields[1].out_value = NULL;
-	fields[1].out_mask = NULL;
+	
 	fields[1].in_value = NULL;
 	fields[1].in_check_value = NULL;
 	fields[1].in_check_mask = NULL;
@@ -133,7 +133,7 @@ int arm920t_read_cp15_physical(target_t *target, int reg_addr, u32 *value)
 	fields[2].tap = jtag_info->tap;
 	fields[2].num_bits = 6;
 	fields[2].out_value = &reg_addr_buf;
-	fields[2].out_mask = NULL;
+	
 	fields[2].in_value = NULL;
 	fields[2].in_check_value = NULL;
 	fields[2].in_check_mask = NULL;
@@ -143,7 +143,7 @@ int arm920t_read_cp15_physical(target_t *target, int reg_addr, u32 *value)
 	fields[3].tap = jtag_info->tap;
 	fields[3].num_bits = 1;
 	fields[3].out_value = &nr_w_buf;
-	fields[3].out_mask = NULL;
+	
 	fields[3].in_value = NULL;
 	fields[3].in_check_value = NULL;
 	fields[3].in_check_mask = NULL;
@@ -185,7 +185,7 @@ int arm920t_write_cp15_physical(target_t *target, int reg_addr, u32 value)
 	fields[0].tap = jtag_info->tap;
 	fields[0].num_bits = 1;
 	fields[0].out_value = &access_type_buf;
-	fields[0].out_mask = NULL;
+	
 	fields[0].in_value = NULL;
 	fields[0].in_check_value = NULL;
 	fields[0].in_check_mask = NULL;
@@ -195,7 +195,7 @@ int arm920t_write_cp15_physical(target_t *target, int reg_addr, u32 value)
 	fields[1].tap = jtag_info->tap;
 	fields[1].num_bits = 32;
 	fields[1].out_value = value_buf;
-	fields[1].out_mask = NULL;
+	
 	fields[1].in_value = NULL;
 	fields[1].in_check_value = NULL;
 	fields[1].in_check_mask = NULL;
@@ -205,7 +205,7 @@ int arm920t_write_cp15_physical(target_t *target, int reg_addr, u32 value)
 	fields[2].tap = jtag_info->tap;
 	fields[2].num_bits = 6;
 	fields[2].out_value = &reg_addr_buf;
-	fields[2].out_mask = NULL;
+	
 	fields[2].in_value = NULL;
 	fields[2].in_check_value = NULL;
 	fields[2].in_check_mask = NULL;
@@ -215,7 +215,7 @@ int arm920t_write_cp15_physical(target_t *target, int reg_addr, u32 value)
 	fields[3].tap = jtag_info->tap;
 	fields[3].num_bits = 1;
 	fields[3].out_value = &nr_w_buf;
-	fields[3].out_mask = NULL;
+	
 	fields[3].in_value = NULL;
 	fields[3].in_check_value = NULL;
 	fields[3].in_check_mask = NULL;
@@ -252,7 +252,7 @@ int arm920t_execute_cp15(target_t *target, u32 cp15_opcode, u32 arm_opcode)
 	fields[0].tap = jtag_info->tap;
 	fields[0].num_bits = 1;
 	fields[0].out_value = &access_type_buf;
-	fields[0].out_mask = NULL;
+	
 	fields[0].in_value = NULL;
 	fields[0].in_check_value = NULL;
 	fields[0].in_check_mask = NULL;
@@ -262,7 +262,7 @@ int arm920t_execute_cp15(target_t *target, u32 cp15_opcode, u32 arm_opcode)
 	fields[1].tap = jtag_info->tap;
 	fields[1].num_bits = 32;
 	fields[1].out_value = cp15_opcode_buf;
-	fields[1].out_mask = NULL;
+	
 	fields[1].in_value = NULL;
 	fields[1].in_check_value = NULL;
 	fields[1].in_check_mask = NULL;
@@ -272,7 +272,7 @@ int arm920t_execute_cp15(target_t *target, u32 cp15_opcode, u32 arm_opcode)
 	fields[2].tap = jtag_info->tap;
 	fields[2].num_bits = 6;
 	fields[2].out_value = &reg_addr_buf;
-	fields[2].out_mask = NULL;
+	
 	fields[2].in_value = NULL;
 	fields[2].in_check_value = NULL;
 	fields[2].in_check_mask = NULL;
@@ -282,7 +282,7 @@ int arm920t_execute_cp15(target_t *target, u32 cp15_opcode, u32 arm_opcode)
 	fields[3].tap = jtag_info->tap;
 	fields[3].num_bits = 1;
 	fields[3].out_value = &nr_w_buf;
-	fields[3].out_mask = NULL;
+	
 	fields[3].in_value = NULL;
 	fields[3].in_check_value = NULL;
 	fields[3].in_check_mask = NULL;
diff --git a/src/target/arm926ejs.c b/src/target/arm926ejs.c
index 8b81c0bfe..fb0584b21 100644
--- a/src/target/arm926ejs.c
+++ b/src/target/arm926ejs.c
@@ -137,7 +137,7 @@ int arm926ejs_cp15_read(target_t *target, u32 op1, u32 op2, u32 CRn, u32 CRm, u3
 	fields[0].tap = jtag_info->tap;
 	fields[0].num_bits = 32;
 	fields[0].out_value = NULL;
-	fields[0].out_mask = NULL;
+	
 	fields[0].in_value = NULL;
 	fields[0].in_check_value = NULL;
 	fields[0].in_check_mask = NULL;
@@ -147,7 +147,7 @@ int arm926ejs_cp15_read(target_t *target, u32 op1, u32 op2, u32 CRn, u32 CRm, u3
 	fields[1].tap = jtag_info->tap;
 	fields[1].num_bits = 1;
 	fields[1].out_value = &access;
-	fields[1].out_mask = NULL;
+	
 	fields[1].in_value = &access;
 	fields[1].in_check_value = NULL;
 	fields[1].in_check_mask = NULL;
@@ -157,7 +157,7 @@ int arm926ejs_cp15_read(target_t *target, u32 op1, u32 op2, u32 CRn, u32 CRm, u3
 	fields[2].tap = jtag_info->tap;
 	fields[2].num_bits = 14;
 	fields[2].out_value = address_buf;
-	fields[2].out_mask = NULL;
+	
 	fields[2].in_value = NULL;
 	fields[2].in_check_value = NULL;
 	fields[2].in_check_mask = NULL;
@@ -167,7 +167,7 @@ int arm926ejs_cp15_read(target_t *target, u32 op1, u32 op2, u32 CRn, u32 CRm, u3
 	fields[3].tap = jtag_info->tap;
 	fields[3].num_bits = 1;
 	fields[3].out_value = &nr_w_buf;
-	fields[3].out_mask = NULL;
+	
 	fields[3].in_value = NULL;
 	fields[3].in_check_value = NULL;
 	fields[3].in_check_mask = NULL;
@@ -227,7 +227,7 @@ int arm926ejs_cp15_write(target_t *target, u32 op1, u32 op2, u32 CRn, u32 CRm, u
 	fields[0].tap = jtag_info->tap;
 	fields[0].num_bits = 32;
 	fields[0].out_value = value_buf;
-	fields[0].out_mask = NULL;
+	
 	fields[0].in_value = NULL;
 	fields[0].in_check_value = NULL;
 	fields[0].in_check_mask = NULL;
@@ -237,7 +237,7 @@ int arm926ejs_cp15_write(target_t *target, u32 op1, u32 op2, u32 CRn, u32 CRm, u
 	fields[1].tap = jtag_info->tap;
 	fields[1].num_bits = 1;
 	fields[1].out_value = &access;
-	fields[1].out_mask = NULL;
+	
 	fields[1].in_value = &access;
 	fields[1].in_check_value = NULL;
 	fields[1].in_check_mask = NULL;
@@ -247,7 +247,7 @@ int arm926ejs_cp15_write(target_t *target, u32 op1, u32 op2, u32 CRn, u32 CRm, u
 	fields[2].tap = jtag_info->tap;
 	fields[2].num_bits = 14;
 	fields[2].out_value = address_buf;
-	fields[2].out_mask = NULL;
+	
 	fields[2].in_value = NULL;
 	fields[2].in_check_value = NULL;
 	fields[2].in_check_mask = NULL;
@@ -257,7 +257,7 @@ int arm926ejs_cp15_write(target_t *target, u32 op1, u32 op2, u32 CRn, u32 CRm, u
 	fields[3].tap = jtag_info->tap;
 	fields[3].num_bits = 1;
 	fields[3].out_value = &nr_w_buf;
-	fields[3].out_mask = NULL;
+	
 	fields[3].in_value = NULL;
 	fields[3].in_check_value = NULL;
 	fields[3].in_check_mask = NULL;
diff --git a/src/target/arm966e.c b/src/target/arm966e.c
index eee964d79..31211031f 100644
--- a/src/target/arm966e.c
+++ b/src/target/arm966e.c
@@ -187,7 +187,7 @@ int arm966e_read_cp15(target_t *target, int reg_addr, u32 *value)
 	fields[0].tap = jtag_info->tap;
 	fields[0].num_bits = 32;
 	fields[0].out_value = NULL;
-	fields[0].out_mask = NULL;
+	
 	fields[0].in_value = NULL;
 	fields[0].in_check_value = NULL;
 	fields[0].in_check_mask = NULL;
@@ -197,7 +197,7 @@ int arm966e_read_cp15(target_t *target, int reg_addr, u32 *value)
 	fields[1].tap = jtag_info->tap;
 	fields[1].num_bits = 6;
 	fields[1].out_value = &reg_addr_buf;
-	fields[1].out_mask = NULL;
+	
 	fields[1].in_value = NULL;
 	fields[1].in_check_value = NULL;
 	fields[1].in_check_mask = NULL;
@@ -207,7 +207,7 @@ int arm966e_read_cp15(target_t *target, int reg_addr, u32 *value)
 	fields[2].tap = jtag_info->tap;
 	fields[2].num_bits = 1;
 	fields[2].out_value = &nr_w_buf;
-	fields[2].out_mask = NULL;
+	
 	fields[2].in_value = NULL;
 	fields[2].in_check_value = NULL;
 	fields[2].in_check_mask = NULL;
@@ -255,7 +255,7 @@ int arm966e_write_cp15(target_t *target, int reg_addr, u32 value)
 	fields[0].tap = jtag_info->tap;
 	fields[0].num_bits = 32;
 	fields[0].out_value = value_buf;
-	fields[0].out_mask = NULL;
+	
 	fields[0].in_value = NULL;
 	fields[0].in_check_value = NULL;
 	fields[0].in_check_mask = NULL;
@@ -265,7 +265,7 @@ int arm966e_write_cp15(target_t *target, int reg_addr, u32 value)
 	fields[1].tap = jtag_info->tap;
 	fields[1].num_bits = 6;
 	fields[1].out_value = &reg_addr_buf;
-	fields[1].out_mask = NULL;
+	
 	fields[1].in_value = NULL;
 	fields[1].in_check_value = NULL;
 	fields[1].in_check_mask = NULL;
@@ -275,7 +275,7 @@ int arm966e_write_cp15(target_t *target, int reg_addr, u32 value)
 	fields[2].tap = jtag_info->tap;
 	fields[2].num_bits = 1;
 	fields[2].out_value = &nr_w_buf;
-	fields[2].out_mask = NULL;
+	
 	fields[2].in_value = NULL;
 	fields[2].in_check_value = NULL;
 	fields[2].in_check_mask = NULL;
diff --git a/src/target/arm9tdmi.c b/src/target/arm9tdmi.c
index 95358c436..7e30bc082 100644
--- a/src/target/arm9tdmi.c
+++ b/src/target/arm9tdmi.c
@@ -128,7 +128,7 @@ int arm9tdmi_examine_debug_reason(target_t *target)
 		fields[0].tap = arm7_9->jtag_info.tap;
 		fields[0].num_bits = 32;
 		fields[0].out_value = NULL;
-		fields[0].out_mask = NULL;
+		
 		fields[0].in_value = databus;
 		fields[0].in_check_value = NULL;
 		fields[0].in_check_mask = NULL;
@@ -138,7 +138,7 @@ int arm9tdmi_examine_debug_reason(target_t *target)
 		fields[1].tap = arm7_9->jtag_info.tap;
 		fields[1].num_bits = 3;
 		fields[1].out_value = NULL;
-		fields[1].out_mask = NULL;
+		
 		fields[1].in_value = &debug_reason;
 		fields[1].in_check_value = NULL;
 		fields[1].in_check_mask = NULL;
@@ -148,7 +148,7 @@ int arm9tdmi_examine_debug_reason(target_t *target)
 		fields[2].tap = arm7_9->jtag_info.tap;
 		fields[2].num_bits = 32;
 		fields[2].out_value = NULL;
-		fields[2].out_mask = NULL;
+		
 		fields[2].in_value = instructionbus;
 		fields[2].in_check_value = NULL;
 		fields[2].in_check_mask = NULL;
@@ -216,7 +216,7 @@ int arm9tdmi_clock_out(arm_jtag_t *jtag_info, u32 instr, u32 out, u32 *in, int s
 	fields[0].tap = jtag_info->tap;
 	fields[0].num_bits = 32;
 	fields[0].out_value = out_buf;
-	fields[0].out_mask = NULL;
+	
 	fields[0].in_value = NULL;
 	if (in)
 	{
@@ -234,7 +234,7 @@ int arm9tdmi_clock_out(arm_jtag_t *jtag_info, u32 instr, u32 out, u32 *in, int s
 	fields[1].tap = jtag_info->tap;
 	fields[1].num_bits = 3;
 	fields[1].out_value = &sysspeed_buf;
-	fields[1].out_mask = NULL;
+	
 	fields[1].in_value = NULL;
 	fields[1].in_check_value = NULL;
 	fields[1].in_check_mask = NULL;
@@ -244,7 +244,7 @@ int arm9tdmi_clock_out(arm_jtag_t *jtag_info, u32 instr, u32 out, u32 *in, int s
 	fields[2].tap = jtag_info->tap;
 	fields[2].num_bits = 32;
 	fields[2].out_value = instr_buf;
-	fields[2].out_mask = NULL;
+	
 	fields[2].in_value = NULL;
 	fields[2].in_check_value = NULL;
 	fields[2].in_check_mask = NULL;
@@ -291,7 +291,7 @@ int arm9tdmi_clock_data_in(arm_jtag_t *jtag_info, u32 *in)
 	fields[0].tap = jtag_info->tap;
 	fields[0].num_bits = 32;
 	fields[0].out_value = NULL;
-	fields[0].out_mask = NULL;
+	
 	fields[0].in_value = NULL;
 	fields[0].in_handler = arm_jtag_buf_to_u32; /* deprecated! invoke this from user code! */
 	fields[0].in_handler_priv = in;
@@ -301,7 +301,7 @@ int arm9tdmi_clock_data_in(arm_jtag_t *jtag_info, u32 *in)
 	fields[1].tap = jtag_info->tap;
 	fields[1].num_bits = 3;
 	fields[1].out_value = NULL;
-	fields[1].out_mask = NULL;
+	
 	fields[1].in_value = NULL;
 	fields[1].in_handler = NULL;
 	fields[1].in_handler_priv = NULL;
@@ -311,7 +311,7 @@ int arm9tdmi_clock_data_in(arm_jtag_t *jtag_info, u32 *in)
 	fields[2].tap = jtag_info->tap;
 	fields[2].num_bits = 32;
 	fields[2].out_value = NULL;
-	fields[2].out_mask = NULL;
+	
 	fields[2].in_value = NULL;
 	fields[2].in_check_value = NULL;
 	fields[2].in_check_mask = NULL;
@@ -363,7 +363,7 @@ int arm9tdmi_clock_data_in_endianness(arm_jtag_t *jtag_info, void *in, int size,
 	fields[0].tap = jtag_info->tap;
 	fields[0].num_bits = 32;
 	fields[0].out_value = NULL;
-	fields[0].out_mask = NULL;
+	
 	fields[0].in_value = NULL;
 	switch (size)
 	{
@@ -384,7 +384,7 @@ int arm9tdmi_clock_data_in_endianness(arm_jtag_t *jtag_info, void *in, int size,
 	fields[1].tap = jtag_info->tap;
 	fields[1].num_bits = 3;
 	fields[1].out_value = NULL;
-	fields[1].out_mask = NULL;
+	
 	fields[1].in_value = NULL;
 	fields[1].in_handler = NULL;
 	fields[1].in_handler_priv = NULL;
@@ -394,7 +394,7 @@ int arm9tdmi_clock_data_in_endianness(arm_jtag_t *jtag_info, void *in, int size,
 	fields[2].tap = jtag_info->tap;
 	fields[2].num_bits = 32;
 	fields[2].out_value = NULL;
-	fields[2].out_mask = NULL;
+	
 	fields[2].in_value = NULL;
 	fields[2].in_check_value = NULL;
 	fields[2].in_check_mask = NULL;
diff --git a/src/target/arm_adi_v5.c b/src/target/arm_adi_v5.c
index 0ce994c78..db6b60d89 100644
--- a/src/target/arm_adi_v5.c
+++ b/src/target/arm_adi_v5.c
@@ -76,7 +76,7 @@ int adi_jtag_dp_scan(arm_jtag_t *jtag_info, u8 instr, u8 reg_addr, u8 RnW, u8 *o
 	fields[0].num_bits = 3;
 	buf_set_u32(&out_addr_buf, 0, 3, ((reg_addr >> 1) & 0x6) | (RnW & 0x1));
 	fields[0].out_value = &out_addr_buf;
-	fields[0].out_mask = NULL;
+	
 	fields[0].in_value = ack;
 	fields[0].in_check_value = NULL;
 	fields[0].in_check_mask = NULL;
@@ -86,7 +86,7 @@ int adi_jtag_dp_scan(arm_jtag_t *jtag_info, u8 instr, u8 reg_addr, u8 RnW, u8 *o
 	fields[1].tap = jtag_info->tap;
 	fields[1].num_bits = 32;
 	fields[1].out_value = outvalue;
-	fields[1].out_mask = NULL;
+	
 	fields[1].in_value = invalue;
 	fields[1].in_handler = NULL;
 	fields[1].in_handler_priv = NULL;
@@ -112,7 +112,7 @@ int adi_jtag_dp_scan_u32(arm_jtag_t *jtag_info, u8 instr, u8 reg_addr, u8 RnW, u
 	fields[0].num_bits = 3;
 	buf_set_u32(&out_addr_buf, 0, 3, ((reg_addr >> 1) & 0x6) | (RnW & 0x1));
 	fields[0].out_value = &out_addr_buf;
-	fields[0].out_mask = NULL;
+	
 	fields[0].in_value = ack;
 	fields[0].in_check_value = NULL;
 	fields[0].in_check_mask = NULL;
@@ -123,7 +123,7 @@ int adi_jtag_dp_scan_u32(arm_jtag_t *jtag_info, u8 instr, u8 reg_addr, u8 RnW, u
 	fields[1].num_bits = 32;
 	buf_set_u32(out_value_buf, 0, 32, outvalue);
 	fields[1].out_value = out_value_buf;
-	fields[1].out_mask = NULL;
+	
 	fields[1].in_value = NULL;
 	if (invalue)
 	{
diff --git a/src/target/arm_jtag.c b/src/target/arm_jtag.c
index cfb85a440..c1dcd6fa0 100644
--- a/src/target/arm_jtag.c
+++ b/src/target/arm_jtag.c
@@ -52,7 +52,7 @@ int arm_jtag_set_instr(arm_jtag_t *jtag_info, u32 new_instr,  in_handler_t handl
 		field.num_bits = tap->ir_length;
 		field.out_value = t;
 		buf_set_u32(field.out_value, 0, field.num_bits, new_instr);
-		field.out_mask = NULL;
+		
 		field.in_value = NULL;
 		field.in_check_value = NULL;
 		field.in_check_mask = NULL;
diff --git a/src/target/avrt.c b/src/target/avrt.c
index 2697f5113..86ada2b2a 100644
--- a/src/target/avrt.c
+++ b/src/target/avrt.c
@@ -232,7 +232,6 @@ int mcu_write_ir(jtag_tap_t *tap, u8 *ir_in, u8 *ir_out, int ir_len, int rti)
 		field[0].tap = tap;
 		field[0].num_bits = tap->ir_length;
 		field[0].out_value = ir_out;
-		field[0].out_mask = NULL;
 		field[0].in_value = ir_in;
 		field[0].in_check_value = NULL;
 		field[0].in_check_mask = NULL;
@@ -258,7 +257,6 @@ int mcu_write_dr(jtag_tap_t *tap, u8 *dr_in, u8 *dr_out, int dr_len, int rti)
 		field[0].tap = tap;
 		field[0].num_bits = dr_len;
 		field[0].out_value = dr_out;
-		field[0].out_mask = NULL;
 		field[0].in_value = dr_in;
 		field[0].in_check_value = NULL;
 		field[0].in_check_mask = NULL;
diff --git a/src/target/embeddedice.c b/src/target/embeddedice.c
index bd7fd3ae0..c59a2ede4 100644
--- a/src/target/embeddedice.c
+++ b/src/target/embeddedice.c
@@ -251,7 +251,7 @@ int embeddedice_read_reg_w_check(reg_t *reg, u8* check_value, u8* check_mask)
 	fields[0].tap = ice_reg->jtag_info->tap;
 	fields[0].num_bits = 32;
 	fields[0].out_value = reg->value;
-	fields[0].out_mask = NULL;
+	
 	fields[0].in_value = NULL;
 	fields[0].in_check_value = NULL;
 	fields[0].in_check_mask = NULL;
@@ -262,7 +262,7 @@ int embeddedice_read_reg_w_check(reg_t *reg, u8* check_value, u8* check_mask)
 	fields[1].num_bits = 5;
 	fields[1].out_value = field1_out;
 	buf_set_u32(fields[1].out_value, 0, 5, reg_addr);
-	fields[1].out_mask = NULL;
+	
 	fields[1].in_value = NULL;
 	fields[1].in_check_value = NULL;
 	fields[1].in_check_mask = NULL;
@@ -273,7 +273,7 @@ int embeddedice_read_reg_w_check(reg_t *reg, u8* check_value, u8* check_mask)
 	fields[2].num_bits = 1;
 	fields[2].out_value = field2_out;
 	buf_set_u32(fields[2].out_value, 0, 1, 0);
-	fields[2].out_mask = NULL;
+	
 	fields[2].in_value = NULL;
 	fields[2].in_check_value = NULL;
 	fields[2].in_check_mask = NULL;
@@ -313,7 +313,7 @@ int embeddedice_receive(arm_jtag_t *jtag_info, u32 *data, u32 size)
 	fields[0].tap = jtag_info->tap;
 	fields[0].num_bits = 32;
 	fields[0].out_value = NULL;
-	fields[0].out_mask = NULL;
+	
 	fields[0].in_value = NULL;
 	fields[0].in_check_value = NULL;
 	fields[0].in_check_mask = NULL;
@@ -324,7 +324,7 @@ int embeddedice_receive(arm_jtag_t *jtag_info, u32 *data, u32 size)
 	fields[1].num_bits = 5;
 	fields[1].out_value = field1_out;
 	buf_set_u32(fields[1].out_value, 0, 5, embeddedice_reg_arch_info[EICE_COMMS_DATA]);
-	fields[1].out_mask = NULL;
+	
 	fields[1].in_value = NULL;
 	fields[1].in_check_value = NULL;
 	fields[1].in_check_mask = NULL;
@@ -335,7 +335,7 @@ int embeddedice_receive(arm_jtag_t *jtag_info, u32 *data, u32 size)
 	fields[2].num_bits = 1;
 	fields[2].out_value = field2_out;
 	buf_set_u32(fields[2].out_value, 0, 1, 0);
-	fields[2].out_mask = NULL;
+	
 	fields[2].in_value = NULL;
 	fields[2].in_check_value = NULL;
 	fields[2].in_check_mask = NULL;
@@ -430,7 +430,7 @@ int embeddedice_send(arm_jtag_t *jtag_info, u32 *data, u32 size)
 	fields[0].tap = jtag_info->tap;
 	fields[0].num_bits = 32;
 	fields[0].out_value = field0_out;
-	fields[0].out_mask = NULL;
+	
 	fields[0].in_value = NULL;
 	fields[0].in_check_value = NULL;
 	fields[0].in_check_mask = NULL;
@@ -441,7 +441,7 @@ int embeddedice_send(arm_jtag_t *jtag_info, u32 *data, u32 size)
 	fields[1].num_bits = 5;
 	fields[1].out_value = field1_out;
 	buf_set_u32(fields[1].out_value, 0, 5, embeddedice_reg_arch_info[EICE_COMMS_DATA]);
-	fields[1].out_mask = NULL;
+	
 	fields[1].in_value = NULL;
 	fields[1].in_check_value = NULL;
 	fields[1].in_check_mask = NULL;
@@ -452,7 +452,7 @@ int embeddedice_send(arm_jtag_t *jtag_info, u32 *data, u32 size)
 	fields[2].num_bits = 1;
 	fields[2].out_value = field2_out;
 	buf_set_u32(fields[2].out_value, 0, 1, 1);
-	fields[2].out_mask = NULL;
+	
 	fields[2].in_value = NULL;
 	fields[2].in_check_value = NULL;
 	fields[2].in_check_mask = NULL;
@@ -499,7 +499,7 @@ int embeddedice_handshake(arm_jtag_t *jtag_info, int hsbit, u32 timeout)
 	fields[0].tap = jtag_info->tap;
 	fields[0].num_bits = 32;
 	fields[0].out_value = NULL;
-	fields[0].out_mask = NULL;
+	
 	fields[0].in_value = field0_in;
 	fields[0].in_check_value = NULL;
 	fields[0].in_check_mask = NULL;
@@ -510,7 +510,7 @@ int embeddedice_handshake(arm_jtag_t *jtag_info, int hsbit, u32 timeout)
 	fields[1].num_bits = 5;
 	fields[1].out_value = field1_out;
 	buf_set_u32(fields[1].out_value, 0, 5, embeddedice_reg_arch_info[EICE_COMMS_CTRL]);
-	fields[1].out_mask = NULL;
+	
 	fields[1].in_value = NULL;
 	fields[1].in_check_value = NULL;
 	fields[1].in_check_mask = NULL;
@@ -521,7 +521,7 @@ int embeddedice_handshake(arm_jtag_t *jtag_info, int hsbit, u32 timeout)
 	fields[2].num_bits = 1;
 	fields[2].out_value = field2_out;
 	buf_set_u32(fields[2].out_value, 0, 1, 0);
-	fields[2].out_mask = NULL;
+	
 	fields[2].in_value = NULL;
 	fields[2].in_check_value = NULL;
 	fields[2].in_check_mask = NULL;
diff --git a/src/target/etb.c b/src/target/etb.c
index 5af9b910e..deecf1410 100644
--- a/src/target/etb.c
+++ b/src/target/etb.c
@@ -70,7 +70,7 @@ static int etb_set_instr(etb_t *etb, u32 new_instr)
 		field.num_bits = tap->ir_length;
 		field.out_value = calloc(CEIL(field.num_bits, 8), 1);
 		buf_set_u32(field.out_value, 0, field.num_bits, new_instr);
-		field.out_mask = NULL;
+		
 		field.in_value = NULL;
 		field.in_check_value = NULL;
 		field.in_check_mask = NULL;
@@ -95,7 +95,7 @@ static int etb_scann(etb_t *etb, u32 new_scan_chain)
 		field.num_bits = 5;
 		field.out_value = calloc(CEIL(field.num_bits, 8), 1);
 		buf_set_u32(field.out_value, 0, field.num_bits, new_scan_chain);
-		field.out_mask = NULL;
+		
 		field.in_value = NULL;
 		field.in_check_value = NULL;
 		field.in_check_mask = NULL;
@@ -186,7 +186,7 @@ static int etb_read_ram(etb_t *etb, u32 *data, int num_frames)
 	fields[0].tap = etb->tap;
 	fields[0].num_bits = 32;
 	fields[0].out_value = NULL;
-	fields[0].out_mask = NULL;
+	
 	fields[0].in_value = NULL;
 	fields[0].in_check_value = NULL;
 	fields[0].in_check_mask = NULL;
@@ -197,7 +197,7 @@ static int etb_read_ram(etb_t *etb, u32 *data, int num_frames)
 	fields[1].num_bits = 7;
 	fields[1].out_value = malloc(1);
 	buf_set_u32(fields[1].out_value, 0, 7, 4);
-	fields[1].out_mask = NULL;
+	
 	fields[1].in_value = NULL;
 	fields[1].in_check_value = NULL;
 	fields[1].in_check_mask = NULL;
@@ -208,7 +208,7 @@ static int etb_read_ram(etb_t *etb, u32 *data, int num_frames)
 	fields[2].num_bits = 1;
 	fields[2].out_value = malloc(1);
 	buf_set_u32(fields[2].out_value, 0, 1, 0);
-	fields[2].out_mask = NULL;
+	
 	fields[2].in_value = NULL;
 	fields[2].in_check_value = NULL;
 	fields[2].in_check_mask = NULL;
@@ -257,7 +257,7 @@ int etb_read_reg_w_check(reg_t *reg, u8* check_value, u8* check_mask)
 	fields[0].tap = etb_reg->etb->tap;
 	fields[0].num_bits = 32;
 	fields[0].out_value = reg->value;
-	fields[0].out_mask = NULL;
+	
 	fields[0].in_value = NULL;
 	fields[0].in_check_value = NULL;
 	fields[0].in_check_mask = NULL;
@@ -268,7 +268,7 @@ int etb_read_reg_w_check(reg_t *reg, u8* check_value, u8* check_mask)
 	fields[1].num_bits = 7;
 	fields[1].out_value = malloc(1);
 	buf_set_u32(fields[1].out_value, 0, 7, reg_addr);
-	fields[1].out_mask = NULL;
+	
 	fields[1].in_value = NULL;
 	fields[1].in_check_value = NULL;
 	fields[1].in_check_mask = NULL;
@@ -279,7 +279,7 @@ int etb_read_reg_w_check(reg_t *reg, u8* check_value, u8* check_mask)
 	fields[2].num_bits = 1;
 	fields[2].out_value = malloc(1);
 	buf_set_u32(fields[2].out_value, 0, 1, 0);
-	fields[2].out_mask = NULL;
+	
 	fields[2].in_value = NULL;
 	fields[2].in_check_value = NULL;
 	fields[2].in_check_mask = NULL;
@@ -354,7 +354,7 @@ int etb_write_reg(reg_t *reg, u32 value)
 	fields[0].num_bits = 32;
 	fields[0].out_value = malloc(4);
 	buf_set_u32(fields[0].out_value, 0, 32, value);
-	fields[0].out_mask = NULL;
+	
 	fields[0].in_value = NULL;
 	fields[0].in_check_value = NULL;
 	fields[0].in_check_mask = NULL;
@@ -365,7 +365,7 @@ int etb_write_reg(reg_t *reg, u32 value)
 	fields[1].num_bits = 7;
 	fields[1].out_value = malloc(1);
 	buf_set_u32(fields[1].out_value, 0, 7, reg_addr);
-	fields[1].out_mask = NULL;
+	
 	fields[1].in_value = NULL;
 	fields[1].in_check_value = NULL;
 	fields[1].in_check_mask = NULL;
@@ -376,7 +376,7 @@ int etb_write_reg(reg_t *reg, u32 value)
 	fields[2].num_bits = 1;
 	fields[2].out_value = malloc(1);
 	buf_set_u32(fields[2].out_value, 0, 1, 1);
-	fields[2].out_mask = NULL;
+	
 	fields[2].in_value = NULL;
 	fields[2].in_check_value = NULL;
 	fields[2].in_check_mask = NULL;
diff --git a/src/target/etm.c b/src/target/etm.c
index c60cc0d7b..ab368781e 100644
--- a/src/target/etm.c
+++ b/src/target/etm.c
@@ -339,7 +339,7 @@ int etm_read_reg_w_check(reg_t *reg, u8* check_value, u8* check_mask)
 	fields[0].tap = etm_reg->jtag_info->tap;
 	fields[0].num_bits = 32;
 	fields[0].out_value = reg->value;
-	fields[0].out_mask = NULL;
+	
 	fields[0].in_value = NULL;
 	fields[0].in_check_value = NULL;
 	fields[0].in_check_mask = NULL;
@@ -350,7 +350,7 @@ int etm_read_reg_w_check(reg_t *reg, u8* check_value, u8* check_mask)
 	fields[1].num_bits = 7;
 	fields[1].out_value = malloc(1);
 	buf_set_u32(fields[1].out_value, 0, 7, reg_addr);
-	fields[1].out_mask = NULL;
+	
 	fields[1].in_value = NULL;
 	fields[1].in_check_value = NULL;
 	fields[1].in_check_mask = NULL;
@@ -361,7 +361,7 @@ int etm_read_reg_w_check(reg_t *reg, u8* check_value, u8* check_mask)
 	fields[2].num_bits = 1;
 	fields[2].out_value = malloc(1);
 	buf_set_u32(fields[2].out_value, 0, 1, 0);
-	fields[2].out_mask = NULL;
+	
 	fields[2].in_value = NULL;
 	fields[2].in_check_value = NULL;
 	fields[2].in_check_mask = NULL;
@@ -431,7 +431,7 @@ int etm_write_reg(reg_t *reg, u32 value)
 	fields[0].num_bits = 32;
 	fields[0].out_value = malloc(4);
 	buf_set_u32(fields[0].out_value, 0, 32, value);
-	fields[0].out_mask = NULL;
+	
 	fields[0].in_value = NULL;
 	fields[0].in_check_value = NULL;
 	fields[0].in_check_mask = NULL;
@@ -442,7 +442,7 @@ int etm_write_reg(reg_t *reg, u32 value)
 	fields[1].num_bits = 7;
 	fields[1].out_value = malloc(1);
 	buf_set_u32(fields[1].out_value, 0, 7, reg_addr);
-	fields[1].out_mask = NULL;
+	
 	fields[1].in_value = NULL;
 	fields[1].in_check_value = NULL;
 	fields[1].in_check_mask = NULL;
@@ -453,7 +453,7 @@ int etm_write_reg(reg_t *reg, u32 value)
 	fields[2].num_bits = 1;
 	fields[2].out_value = malloc(1);
 	buf_set_u32(fields[2].out_value, 0, 1, 1);
-	fields[2].out_mask = NULL;
+	
 	fields[2].in_value = NULL;
 	fields[2].in_check_value = NULL;
 	fields[2].in_check_mask = NULL;
diff --git a/src/target/feroceon.c b/src/target/feroceon.c
index 8ef74c1da..507bd695b 100644
--- a/src/target/feroceon.c
+++ b/src/target/feroceon.c
@@ -135,7 +135,7 @@ int feroceon_dummy_clock_out(arm_jtag_t *jtag_info, u32 instr)
 	fields[0].tap = jtag_info->tap;
 	fields[0].num_bits = 32;
 	fields[0].out_value = out_buf;
-	fields[0].out_mask = NULL;
+	
 	fields[0].in_value = NULL;
 	fields[0].in_handler = NULL;
 	fields[0].in_handler_priv = NULL;
@@ -145,7 +145,7 @@ int feroceon_dummy_clock_out(arm_jtag_t *jtag_info, u32 instr)
 	fields[1].tap = jtag_info->tap;
 	fields[1].num_bits = 3;
 	fields[1].out_value = &sysspeed_buf;
-	fields[1].out_mask = NULL;
+	
 	fields[1].in_value = NULL;
 	fields[1].in_check_value = NULL;
 	fields[1].in_check_mask = NULL;
@@ -155,7 +155,7 @@ int feroceon_dummy_clock_out(arm_jtag_t *jtag_info, u32 instr)
 	fields[2].tap = jtag_info->tap;
 	fields[2].num_bits = 32;
 	fields[2].out_value = instr_buf;
-	fields[2].out_mask = NULL;
+	
 	fields[2].in_value = NULL;
 	fields[2].in_check_value = NULL;
 	fields[2].in_check_mask = NULL;
diff --git a/src/target/mips_ejtag.c b/src/target/mips_ejtag.c
index df6fc23a4..d1931c6fd 100644
--- a/src/target/mips_ejtag.c
+++ b/src/target/mips_ejtag.c
@@ -49,7 +49,7 @@ int mips_ejtag_set_instr(mips_ejtag_t *ejtag_info, int new_instr, in_handler_t h
 		field.num_bits = tap->ir_length;
 		field.out_value = t;
 		buf_set_u32(field.out_value, 0, field.num_bits, new_instr);
-		field.out_mask = NULL;
+		
 		field.in_value = NULL;
 		field.in_check_value = NULL;
 		field.in_check_mask = NULL;
@@ -72,7 +72,7 @@ int mips_ejtag_get_idcode(mips_ejtag_t *ejtag_info, u32 *idcode, in_handler_t ha
 	field.tap = ejtag_info->tap;
 	field.num_bits = 32;
 	field.out_value = NULL;
-	field.out_mask = NULL;
+	
 	field.in_value = (void*)idcode;
 	field.in_check_value = NULL;
 	field.in_check_mask = NULL;
@@ -99,7 +99,7 @@ int mips_ejtag_get_impcode(mips_ejtag_t *ejtag_info, u32 *impcode, in_handler_t
 	field.tap = ejtag_info->tap;
 	field.num_bits = 32;
 	field.out_value = NULL;
-	field.out_mask = NULL;
+	
 	field.in_value = (void*)impcode;
 	field.in_check_value = NULL;
 	field.in_check_mask = NULL;
@@ -130,7 +130,7 @@ int mips_ejtag_drscan_32(mips_ejtag_t *ejtag_info, u32 *data)
 	field.num_bits = 32;
 	field.out_value = t;
 	buf_set_u32(field.out_value, 0, field.num_bits, *data);
-	field.out_mask = NULL;
+	
 	field.in_value = (u8*)data;
 	field.in_check_value = NULL;
 	field.in_check_mask = NULL;
diff --git a/src/target/xscale.c b/src/target/xscale.c
index d270bf4f7..3ec843739 100644
--- a/src/target/xscale.c
+++ b/src/target/xscale.c
@@ -225,7 +225,7 @@ int xscale_jtag_set_instr(jtag_tap_t *tap, u32 new_instr)
 		field.num_bits = tap->ir_length;
 		field.out_value = calloc(CEIL(field.num_bits, 8), 1);
 		buf_set_u32(field.out_value, 0, field.num_bits, new_instr);
-		field.out_mask = NULL;
+		
 		field.in_value = NULL;
 		jtag_set_check_value(&field, tap->expected, tap->expected_mask, NULL);
 
@@ -261,14 +261,14 @@ int xscale_read_dcsr(target_t *target)
 	fields[0].tap = xscale->jtag_info.tap;
 	fields[0].num_bits = 3;
 	fields[0].out_value = &field0;
-	fields[0].out_mask = NULL;
+	
 	fields[0].in_value = NULL;
 	jtag_set_check_value(fields+0, &field0_check_value, &field0_check_mask, NULL);
 
 	fields[1].tap = xscale->jtag_info.tap;
 	fields[1].num_bits = 32;
 	fields[1].out_value = NULL;
-	fields[1].out_mask = NULL;
+	
 	fields[1].in_value = xscale->reg_cache->reg_list[XSCALE_DCSR].value;
 	fields[1].in_handler = NULL;
 	fields[1].in_handler_priv = NULL;
@@ -278,7 +278,7 @@ int xscale_read_dcsr(target_t *target)
 	fields[2].tap = xscale->jtag_info.tap;
 	fields[2].num_bits = 1;
 	fields[2].out_value = &field2;
-	fields[2].out_mask = NULL;
+	
 	fields[2].in_value = NULL;
 	jtag_set_check_value(fields+2, &field2_check_value, &field2_check_mask, NULL);
 
@@ -339,14 +339,14 @@ int xscale_receive(target_t *target, u32 *buffer, int num_words)
 	fields[0].tap = xscale->jtag_info.tap;
 	fields[0].num_bits = 3;
 	fields[0].out_value = NULL;
-	fields[0].out_mask = NULL;
+	
 	fields[0].in_value = NULL;
 	jtag_set_check_value(fields+0, &field0_check_value, &field0_check_mask, NULL);
 
 	fields[1].tap = xscale->jtag_info.tap;
 	fields[1].num_bits = 32;
 	fields[1].out_value = NULL;
-	fields[1].out_mask = NULL;
+	
 	fields[1].in_value = NULL;
 	fields[1].in_handler = NULL;
 	fields[1].in_handler_priv = NULL;
@@ -356,7 +356,7 @@ int xscale_receive(target_t *target, u32 *buffer, int num_words)
 	fields[2].tap = xscale->jtag_info.tap;
 	fields[2].num_bits = 1;
 	fields[2].out_value = NULL;
-	fields[2].out_mask = NULL;
+	
 	fields[2].in_value = NULL;
 	jtag_set_check_value(fields+2, &field2_check_value, &field2_check_mask, NULL);
 
@@ -458,14 +458,14 @@ int xscale_read_tx(target_t *target, int consume)
 	fields[0].tap = xscale->jtag_info.tap;
 	fields[0].num_bits = 3;
 	fields[0].out_value = NULL;
-	fields[0].out_mask = NULL;
+	
 	fields[0].in_value = &field0_in;
 	jtag_set_check_value(fields+0, &field0_check_value, &field0_check_mask, NULL);
 
 	fields[1].tap = xscale->jtag_info.tap;
 	fields[1].num_bits = 32;
 	fields[1].out_value = NULL;
-	fields[1].out_mask = NULL;
+	
 	fields[1].in_value = xscale->reg_cache->reg_list[XSCALE_TX].value;
 	fields[1].in_handler = NULL;
 	fields[1].in_handler_priv = NULL;
@@ -475,7 +475,7 @@ int xscale_read_tx(target_t *target, int consume)
 	fields[2].tap = xscale->jtag_info.tap;
 	fields[2].num_bits = 1;
 	fields[2].out_value = NULL;
-	fields[2].out_mask = NULL;
+	
 	fields[2].in_value = NULL;
 	jtag_set_check_value(fields+2, &field2_check_value, &field2_check_mask, NULL);
 
@@ -554,14 +554,14 @@ int xscale_write_rx(target_t *target)
 	fields[0].tap = xscale->jtag_info.tap;
 	fields[0].num_bits = 3;
 	fields[0].out_value = &field0_out;
-	fields[0].out_mask = NULL;
+	
 	fields[0].in_value = &field0_in;
 	jtag_set_check_value(fields+0, &field0_check_value, &field0_check_mask, NULL);
 
 	fields[1].tap = xscale->jtag_info.tap;
 	fields[1].num_bits = 32;
 	fields[1].out_value = xscale->reg_cache->reg_list[XSCALE_RX].value;
-	fields[1].out_mask = NULL;
+	
 	fields[1].in_value = NULL;
 	fields[1].in_handler = NULL;
 	fields[1].in_handler_priv = NULL;
@@ -571,7 +571,7 @@ int xscale_write_rx(target_t *target)
 	fields[2].tap = xscale->jtag_info.tap;
 	fields[2].num_bits = 1;
 	fields[2].out_value = &field2;
-	fields[2].out_mask = NULL;
+	
 	fields[2].in_value = NULL;
 	jtag_set_check_value(fields+2, &field2_check_value, &field2_check_mask, NULL);
 
@@ -729,14 +729,14 @@ int xscale_write_dcsr(target_t *target, int hold_rst, int ext_dbg_brk)
 	fields[0].tap = xscale->jtag_info.tap;
 	fields[0].num_bits = 3;
 	fields[0].out_value = &field0;
-	fields[0].out_mask = NULL;
+	
 	fields[0].in_value = NULL;
 	jtag_set_check_value(fields+0, &field0_check_value, &field0_check_mask, NULL);
 
 	fields[1].tap = xscale->jtag_info.tap;
 	fields[1].num_bits = 32;
 	fields[1].out_value = xscale->reg_cache->reg_list[XSCALE_DCSR].value;
-	fields[1].out_mask = NULL;
+	
 	fields[1].in_value = NULL;
 	fields[1].in_handler = NULL;
 	fields[1].in_handler_priv = NULL;
@@ -746,7 +746,7 @@ int xscale_write_dcsr(target_t *target, int hold_rst, int ext_dbg_brk)
 	fields[2].tap = xscale->jtag_info.tap;
 	fields[2].num_bits = 1;
 	fields[2].out_value = &field2;
-	fields[2].out_mask = NULL;
+	
 	fields[2].in_value = NULL;
 	jtag_set_check_value(fields+2, &field2_check_value, &field2_check_mask, NULL);
 
@@ -805,7 +805,7 @@ int xscale_load_ic(target_t *target, int mini, u32 va, u32 buffer[8])
 	fields[0].tap = xscale->jtag_info.tap;
 	fields[0].num_bits = 6;
 	fields[0].out_value = &cmd;
-	fields[0].out_mask = NULL;
+	
 	fields[0].in_value = NULL;
 	fields[0].in_check_value = NULL;
 	fields[0].in_check_mask = NULL;
@@ -815,7 +815,7 @@ int xscale_load_ic(target_t *target, int mini, u32 va, u32 buffer[8])
 	fields[1].tap = xscale->jtag_info.tap;
 	fields[1].num_bits = 27;
 	fields[1].out_value = packet;
-	fields[1].out_mask = NULL;
+	
 	fields[1].in_value = NULL;
 	fields[1].in_check_value = NULL;
 	fields[1].in_check_mask = NULL;
@@ -863,7 +863,7 @@ int xscale_invalidate_ic_line(target_t *target, u32 va)
 	fields[0].tap = xscale->jtag_info.tap;
 	fields[0].num_bits = 6;
 	fields[0].out_value = &cmd;
-	fields[0].out_mask = NULL;
+	
 	fields[0].in_value = NULL;
 	fields[0].in_check_value = NULL;
 	fields[0].in_check_mask = NULL;
@@ -873,7 +873,7 @@ int xscale_invalidate_ic_line(target_t *target, u32 va)
 	fields[1].tap = xscale->jtag_info.tap;
 	fields[1].num_bits = 27;
 	fields[1].out_value = packet;
-	fields[1].out_mask = NULL;
+	
 	fields[1].in_value = NULL;
 	fields[1].in_check_value = NULL;
 	fields[1].in_check_mask = NULL;
diff --git a/src/xsvf/xsvf.c b/src/xsvf/xsvf.c
index 3613897f4..1baa1263c 100644
--- a/src/xsvf/xsvf.c
+++ b/src/xsvf/xsvf.c
@@ -486,7 +486,7 @@ static int handle_xsvf_command(struct command_context_s *cmd_ctx, char *cmd, cha
 					field.tap = tap;
 					field.num_bits = xsdrsize;
 					field.out_value = dr_out_buf;
-					field.out_mask = NULL;
+					
 					field.in_value = NULL;
 
 					jtag_set_check_value(&field, dr_in_buf, dr_in_mask, NULL);
@@ -705,7 +705,7 @@ static int handle_xsvf_command(struct command_context_s *cmd_ctx, char *cmd, cha
 					field.tap = tap;
 					field.num_bits = bitcount;
 					field.out_value = ir_buf;
-					field.out_mask = NULL;
+					
 					field.in_value = NULL;
 					field.in_check_value = NULL;
 					field.in_check_mask = NULL;
@@ -937,7 +937,7 @@ static int handle_xsvf_command(struct command_context_s *cmd_ctx, char *cmd, cha
 					field.tap = tap;
 					field.num_bits = xsdrsize;
 					field.out_value = dr_out_buf;
-					field.out_mask = NULL;
+					
 					field.in_value = NULL;
 
 					if (attempt > 0 && verbose)