System Debug Reference Manual (32650-90888)

234 Chapter6
System Debug Command Specifications M-X
MR
DB The stack base relative word offset of DB.
DBDST The DB data segment number.
CIR The current instruction register.
CMPC The full logical CM program counter address.
• Only the offset part can be modified.
• CIR will also be modified.
Q The Q register word offset, DB relative.
S The S register word offset, DB relative.
SDST The stack data segment number.
STATUS The CM status register.
• The segment number portion cannot be modified.
X The X (index) register.
NOTE CM registers can not be modified when the user initially entered Debug in
NM (nmdebug).
nm_register The NM register whose contents are to be modified.
NOTE NM registers can not be modified when the user initially entered Debug in
CM (cmdebug).
Modifying PC modifies PCOF and PCSF. It sets PCOB to PCOF+4 and to
PCSF. The original priv bits are retained. That is, when PC is modified, the
priv bits are unaffected.
To fully understand the use and conventions for the various registers, refer
to the Precision Architecture and Instruction Reference Manual and
Procedure Calling Conventions Reference Manual. The procedure calling
conventions manual is of particular importance for understanding how the
language compilers utilize the registers to pass parameters, return values,
and hold temporary values. The following tables list the NM registers
available within System Debug. Many registers have aliases through
which they may be referenced. Alias names in
italics are not available in
System Debug.
Access rights abbreviations are listed below. PM indicates that privileged
mode (PM) capability is required.
d Display access
D PM display access
m Modify access
M PM modify access