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USING DEBUG WITH PRIVILEGED MODE CAPABILITY Additional commands and capabilities are available when you use DEBUG in privileged mode. Mainly, privileged mode allows you to display and modify data up to the stack limit, Z, to display and establish breakpoints in system code as well as in your own program, and to display disc sector contents. Four additional commands are allowed in privileged mode; also, most commands have enhanced capabilities. (Refer to Table 3-1 for a list of the new commands and the extra capabilities for the standard commands.) In addition to the extra DEBUG capabilities, a user with privileged mode can use the MPE :DEBUG command to debug the Command Interpreter. (Refer to the MPE Commands Reference Manual for a discussion of this command.)
WARNING The normal checks and limitations that apply to the stan- dard users in MPE are bypassed in privileged mode. It is possible for a privileged mode program to destroy system integrity, including the MPE operating system software itself. Hewlett-Packard cannot be responsible for system integrity when programs written by users operate in privileged mode.
Use of DEBUG in privileged mode is essentially identical to use with standard capabilities. A minor difference is that the message printed at the initial entry into DEBUG and at each breakpoint includes the word PRIV to indicate that you are operating in privileged mode. For example, at the first entry point, the following message is printed: *DEBUG* PRIV 0.170 (Enter DEBUG in privileged mode at location 170.) At a subsequent breakpoint, the following might be printed: *BREAK* PRIV 2.360 (Break in privileged mode in segment 2, location 360.) The following discussion of using DEBUG in privileged mode gives only a summary of the additional capabilities within the various functional areas. Table 3-1. Privileged Mode Command Capabilities -------------------------------------------------------------------------------------------- | | | | PRIVILEGED COMMAND | CAPABILITY | | | | -------------------------------------------------------------------------------------------- | | | | A{S} | Establish breakpoint mode as private (P) or system global | | {P} | (S) | | | | -------------------------------------------------------------------------------------------- | | | | DV [ ldev] + startsector | Display specified number of sectors (count) from specified | | [ ,count] [ ,mode] | device (ldev) or system disc, from specified sector number | | | (startsector), in octal, decimal, or ASCII (mode). | | | | -------------------------------------------------------------------------------------------- | | | | F{CO} | Freeze code (CO) or data (DA) in the specified segment | | {DA}segnum | (segnum) so that it is not swapped. | | | | -------------------------------------------------------------------------------------------- | | | | U{CO} | Unfreeze frozen code (CO) or data (DA) in specified segment | | {DA}segnum | (segnum). | | | | -------------------------------------------------------------------------------------------- | | | | STANDARD COMMAND | PRIVILEGED CAPABILITY | | | | -------------------------------------------------------------------------------------------- | | | | B[[S] segment.]... | Segment location is extended to include system segmented | | [A] | library (S) or absolute code segment (A). | | | | -------------------------------------------------------------------------------------------- | | | | C[[S] segment.]... | Segment location is extended to include system segmented | | [A] | library (S) or absolute code segment (A). | | | | -------------------------------------------------------------------------------------------- | | | | D[A] | Display base extensions allow display of absolute relative | | [SY] | (A), system global relative (SY), code segment relative | | [CO] | (CO), data segment relative (DA), current absolute DB | | [DA] | relative (DX), and extended absolute address (EA). | | [DX] | | | [EA]... | | | | | -------------------------------------------------------------------------------------------- | | | | DR | When all registers displayed, display includes PCB (process | | | control block index), CST (abso ute code segment index), | | | STAK (stack segment index), DST (extra data segment index). | | | Also, if operating in absolute mode, DX (absolute location | | | of DB register) and EA (current block number). | | | | -------------------------------------------------------------------------------------------- | | | | L[ ldev] | Switches display to specified logical device number (ldev). | | | | -------------------------------------------------------------------------------------------- | | | | M[A] | The modify base (modbase) extensions allow modification of | | [SY] | absolute relative (A), system global relative (SY), data | | [DA] | segment relative (DA). Also, in absolute mode, current | | [DX] | absolute DB relative (DX) and extended absolute address | | [EA]... | (EA). | | | | -------------------------------------------------------------------------------------------- | | | | MR ,ST | All ST bits, rather than only bits 2-7 can be modified. | | | | -------------------------------------------------------------------------------------------- | | | | R[ [S] segment.]... | Segment location is extended to include system segmented | | | library (S). | | | | -------------------------------------------------------------------------------------------- | | | | T | Trace is extended to show absolute code segment index (CST). | | | | --------------------------------------------------------------------------------------------