Appendix C. Machine encodings
This appendix describes the structure of the MDENC field in the message descriptor (see MQMD - Message descriptor).
The MDENC field is a 32-bit integer that is divided into four separate subfields; these subfields identify:
- The encoding used for binary integers
- The encoding used for packed-decimal integers
- The encoding used for floating-point numbers
- Reserved bits
Each subfield is identified by a bit mask which has 1-bits in the positions corresponding to the subfield, and 0-bits elsewhere. The bits are numbered such that bit 0 is the most significant bit, and bit 31 the least significant bit. The following masks are defined:
- ENIMSK
- Mask for binary-integer encoding.
This subfield occupies bit positions 28 through 31 within the MDENC field.
- ENDMSK
- Mask for packed-decimal-integer encoding.
This subfield occupies bit positions 24 through 27 within the MDENC field.
- ENFMSK
- Mask for floating-point encoding.
This subfield occupies bit positions 20 through 23 within the MDENC field.
- ENRMSK
- Mask for reserved bits.
This subfield occupies bit positions 0 through 19 within the MDENC field.