HP 3000 Manuals HP 3000 Manuals
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).