CCSDSv2 MsgId construction not 16 bits as described in cfe_sb_msg_id_util.h

[johnphamngc]

Describe the bug
CCSDSv2 MsgId construction not 16 bits as described in cfe_sb_msg_id_util.h. It looks like the 8th bit of the APID qualifier subsystem ID is included, making the MsgID 17 bits.

To Reproduce
N/A, code inspection

Expected behavior
MsgId should mask off bit 8 in subsystem ID

Code snips

cFE/fsw/cfe-core/src/sb/cfe_sb_msg_id_util.h

Lines 40 to 58 in a47abba

	/**
	** For MESSAGE_FORMAT_IS_CCSDS_VER_2 the default layout of the message id is:
	** 7 bits from the primary header APID
	** 1 bit for the command/telemetry flag
	** 0 bits from the Playback flag
	** 8 bits from the secondary header APID qualifier (Subsystem)
	** 0 bits from the secondary header APID qualifier as the System
	** = 16 bits total
	**
	** Byte 1 Byte 0
	** 7 6 5 4 3 2 1 0 7 6 5 4 3 2 1 0
	** +-+-+-+-+-+-+-+-+|--------|+-+-+-+-+-+-+-+
	** | APID Qualifier |C/T flg | Pri Hdr APID |
	** +-+-+-+-+-+-+-+-+|--------|+-+-+-+-+-+-+-+
	** This layout may be modified via the 4 macros
	** CFE_SB_CMD_MESSAGE_TYPE, CFE_SB_RD_APID_FROM_MSGID
	** CFE_SB_RD_SUBSYS_ID_FROM_MSGID and CFE_SB_RD_TYPE_FROM_MSGID
	**
	*/

cFE/fsw/cfe-core/src/inc/ccsds.h

Line 346 in a47abba

#define CCSDS_RD_SUBSYSTEM_ID(shdr) ( (((shdr).APIDQSubsystem[0] & 0x01) << 8) + ((shdr).APIDQSubsystem[1]))

cFE/fsw/cfe-core/src/sb/cfe_sb_msg_id_util.c

Lines 137 to 138 in a47abba

	SubSystemId = CCSDS_RD_SUBSYSTEM_ID(MsgPtr->SpacePacket.ApidQ);
	MsgIdVal = (MsgIdVal | (SubSystemId << 8));

System observed on:
N/A

Additional context
N/A

Reporter Info
John N Pham, Northrop Grumman

[skliper]

Note that code has a pending PR to fix (#726)... there's also a problem in the APID not being masked, so it could overload the cmd/tlm bit.