The scan_ir_hw_jtag command specifies a scan
pattern to be scanned into the JTAG interface target instruction register. The command
targets a hw_jtag object which is created when the
hw_target is opened in JTAG mode through the use of
the open_hw_target -jtag_mode command. When targeting
the hw_jtag object prior to shifting the scan pattern
specified in the scan_ir_hw_jtag command, the last defined header property (HIR) is
pre-pended to the beginning of the specified data pattern. The last defined trailer
property (TIR) is appended to the end of the data pattern.
The number of bits represented by the hex strings specified for -tdi, -tdo, -mask, or -smask cannot be greater than the maximum specified by <length>.
The scan_ir_hw_jtag command returns a hex array
containing captured TDO data from the hw_jtag, or
returns an error if it fails.