System Debug Reference Manual (32650-90888)

Chapter 8 313

System Debug Windows

Window Real/Virtual Modes

command.)

Window Real/Virtual Modes

System Debug automatically tracks the translation bits in the processor status word

(IPSW). There are two IPSW bits of interest, the C and D bits. These bits indicate if the

machine performs "code" and "data" translation, respectively. If the C bit is off, the

machine interprets all code addresses as REAL addresses rather than virtual addresses.

Likewise, if the D bit is off, any data address is interpreted as a REAL address rather than

a virtual address.

The windows honor this convention by examining the current settings of the bits in the

processor status word. This means that any virtual window displays data based on the

IPSW D bit. Likewise, the NM program window is affected by the C bit.

The NM program window is ﬂagged as REAL when code translation is turned off (for

example, the C bit equals 0). Likewise, virtual windows and user windows aimed at virtual

address space are ﬂagged as REAL when data translation is turned off (for example, the D

bit equals 0).

R - The CM Register Window

The CM register window displays the current values of the compatibility mode registers.

R % Regs DB=001000 DBDST=000160 X=000132 STATUS=(mITroc CCG% 301) PIN=061

SDST=000160 DL=177650 Q=000704 S=000710 CMPC=PROG 000000.001667

CIR=170005 MAPFLAG=1 MAPDST=000000

window banner line

• R % Regs - Abbreviation for the window, the current output display radix, and the name

for the window.

• DB, DBDST - The current DB word offset (CM stack base relative) and DBDST data

segment number. If DBDST is different from SDST (the stack data segment number),

then DB and DBDST are displayed in half-inverse, indicating "split-stack mode."

• X - The current index register.

• STATUS - The current status register. (Refer to the conventions pages for a description

of the format of this value.)

• PIN - The process identiﬁcation number (PIN) for the current process.

window body line(s)

• SDST - The CM stack data segment number.

• DL - The DB relative value of DL.