System Debug Reference Manual > Chapter 4 System Debug Command Specifications

D (display)

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Privileged Mode: DA, DCS, DCA, DZ, DSEC

Displays the contents of the specified address.

Syntax


   DA   offset   [count] [base] [recw] [bytew]    ABS relative
   DD   dst.off  [count] [base] [recw] [bytew]    CM data segment
   DDB  offset   [count] [base] [recw] [bytew]    DB relative
   DS   offset   [count] [base] [recw] [bytew]    S relative
   DQ   offset   [count] [base] [recw] [bytew]    Q relative

   DC   logaddr  [count] [base] [recw] [bytew]    Program file
   DCG  logaddr  [count] [base] [recw] [bytew]    Group library
   DCP  logaddr  [count] [base] [recw] [bytew]    Account library
   DCLG logaddr  [count] [base] [recw] [bytew]    Logon group lib
   DCLP logaddr  [count] [base] [recw] [bytew]    Logon account lib
   DCS  logaddr  [count] [base] [recw] [bytew]    System library

   DCU  fname logaddr [count] [base] [recw] [bytew  User library

   DCA  cmabsaddr [count] [base] [recw] [bytew]   Absolute CST
   DCAX cmabsaddr [count] [base] [recw] [bytew]   Absolute CSTX
   DV   virtaddr  [count] [base] [recw] [bytew]   Virtual
   DZ   realaddr  [count] [base] [recw] [bytew]   Real memory
   DSEC ldev.off  [count] [base] [recw] [bytew]   Secondary store

Parameters

offset

DA, DDB, DQ, DS only.

The CM word offset that specifies the relative starting location of the area to be displayed.

dst.off

DD only.

The data segment number and CM word offset that specifies the starting location of the area to be displayed.

logaddr

DC, DCG, DCP, DCLG, DCLP, DCS, DCU only.

A full logical code address (LCPTR) specifies three necessary items:

the logical code file (PROG, GRP, SYS, and so on)
NM: the virtual space ID number (SID)
CM: the logical segment number
NM: the virtual byte offset within the space.
CM: the word offset within the code segment.

Logical code addresses can be specified in various levels of detail:

as a full logical code pointer (LCPTR)

DC procname+20

procedure name lookups return LCPTRs

DC pw+4

predefined ENV variables of type LCPTR

DC SYS(2.200)

explicit coercion to a LCPTR type
as a long pointer(LPTR)

DC 23.2644

sid.offset or seg.offset
as a short pointer (SPTR)

DC 1024

offset only

For NM, the short pointer offset is converted to a long pointer using the function STOLOG, which looks up the SID of the loaded logical file. This is different from the standard short to long pointer conversion, STOL, which is based on the current space registers (SRs).
For CM, the current executing logical segment number and the current executing logical file are used to build an LCPTR.

The logical file is determined based on the command suffix, for example:


   DC  implies PROG
   DCG implies GRP
   DCS implies SYS

The search path used for procedure name lookups is based on the command suffix letter:

DC

Full search path:

NM: PROG, GRP, PUB, USER(s), SYS
CM: PROG, GRP, PUB, LGRP, LPUB, SYS

DCG

Search GRP, the group library.

DCP

Search PUB, the account library.

DCLG

Search LGRP, the logon group library.

DCLP

Search LPUB, the logon account library.

DCS

Search SYS, the system library.

DCU

Search USER, the user library.

For a full description of logical code addresses, refer to the section "Logical Code Addresses" in chapter 2.

fname

DCU only.

The file name of the NM USER library. Since multiple NM libraries can be bound with the XL= option on a RUN command,


   :run nmprog; xl=lib1,lib2.testgrp,lib3

it is necessary to specify the desired NM user library. For example,


   DCU lib1 204c
   DCU lib2.testgrp test20+1c0

If the file name is not fully qualified, then the following defaults are used:

Default account: the account of the program file.
Default group: the group of the program file.

cmabsadr

DCA, DCAX only.

A full CM absolute code address specifies three necessary items:

Either the CST or the CSTX
The absolute code segment number
The CM word offset within the code segment.

Absolute code addresses can be specified in two ways:

As a long pointer (LPTR)

DCA 23.2644

Implicit CST 23.2644

DCAX 5.3204

Implicit CSTX 5.3204
As a full absolute code pointer (ACPTR)

DCA CST(2.200)

Explicit CST coercion

DCAX CSTX(2.200)

Explicit CSTX coercion

DCAX logtoabs(prog(1.20))

Explicit absolute conversion

The search path used for procedure name lookups is based on the command suffix letter:

DCA: GRP, PUB, LGRP, LPUB, SYS
DCAX: PROG

virtaddr

DV only. The virtual address to be displayed.

Virtaddr can be a short pointer, a long pointer, or a full logical code pointer.

realaddr

DZ only.

The real mode HP Precision Architecture memory address to be displayed.

ldev.off

DSEC only.

The logical device number (LDEV) and offset (in bytes) of the data on disk to be displayed.

count

DA, DC@ (CM), DD, DDB, DS, DQ: The number of CM 16-bit words to be displayed.

DC@ (NM), DV, DZ, DSEC: The number of NM 32-bit words to be displayed. If omitted, then a single value is displayed.

base

The desired representation mode for output values:

% or OCTAL: Octal representation
# or DECIMAL: Decimal representation
$ or HEXADECIMAL: Hexadecimal representation
ASCII: ASCII representation
BOTH: Numeric and ASCII together
CODE: Disassembled code representation
STRING: Packed ASCII representation

This parameter can be abbreviated to as a single character.

By default, and for the numeric portion of B[OTH], the current output base is used.

Display code commands (DC@) automatically set the base to CODE, unless another base is explicitly specified.

Note that the address portion of the display is always formatted using the current output base (see ENV OUTBASE and the SET command), not the specified base parameter.

recw

The number of words to be displayed per line. Large requests may cause lines to wrap around on the terminal, but may be appropriate for offline listings, based on the ENV variable LIST_WIDTH.

By default, either 4 or 8 words will be displayed per line, based on the command, count, and base.

When the base CODE is selected, disassembled code is always displayed one word per line.

bytew

The width in bytes of the displayed values. Values can be displayed as

1 byte: Single bytes (8 bits)
2 bytes: CM (16-bit words)
4 bytes: NM (32-bit words) / CM double-words

If omitted, values are displayed as CM words (2) or NM words (4), based on the current mode (CM/NM) and the specified command.

This parameter is ignored for display code commands (DC@).

Examples


   %cmdebug > dd 77.0
   DST %77.0      % 000655

Display DST 77.0. By default, one word is displayed in the current output base, octal.


   %cmdebug > dd 77.0,20
   DST %77.0
   %0      % 000655 000012 000000 000000 000000 000000 000000 000000
   %10     % 000000 000000 041515 023511 047111 052111 040514 020040

Display DST 77.0 for %20 words. By default, the data is displayed in the current output base, octal, at eight words per line.


   %cmdebug > dd 77.0,20,a
   DST %77.0
   %0      ASCII .. .. .. .. .. .. .. ..
   %10     ASCII .. .. CM 'I NI TI AL

Display DST 77.0 for %20 words in ASCII. The two character ASCII Representations for each word are displayed, separated by blanks. Dots (".") are displayed for nonprintable characters.


   %cmdebug > dd 77.0,20,b
   DST %77.0
   %0      % 000655 000012 000000 000000  .. .. .. ..
   %4      % 000000 000000 000000 000000  .. .. .. ..
   %10     % 000000 000000 041515 023511  .. .. CM 'I
   %14     % 047111 052111 040514 020040  NI TI AL

Display DST 77.0 for %20 words. Display both numeric and ASCII data together. By default, four words are displayed per line.


   %cmdebug > dd 77.0,100,a,12
   DST %77.0
   %0      ASCII .. .. .. .. .. .. .. .. .. ..
   %12     ASCII CM 'I NI TI AL        . .. ..
   %24     ASCII MI X' PA RM           . .. ..
   %36     ASCII LO AD                 . .. ..
   %50     ASCII GE TS IR              . .. ..
   %62     ASCII RE LS IR              . .. ..
   %74     ASCII FR EE 'P RI

Display DST 77.0, for %100 words, in ASCII, in a width of %12 words per line.


   %cmdebug > dd 77.0,100,s,12
   DST %77.0      "...................."
   DST %77.12     "CM'INITIAL     ....."
   DST %77.24     "MIX'PARM       ....."
   DST %77.36     "LOAD           ....."
   DST %77.50     "GETSIR         ....."
   DST %77.62     "RELSIR         ....."
   DST %77.74     "FREE'PRI"

Display DST 77.0 for %100 words, as a string, in a width of %12 CM words = #10 CM words = 20 characters per line.


   %cmdebug > dd 77.0,20,h,6,1
   DST %77.0
   %0      $ 01 ad 00 0a 00 00 00 00 00 00 00 00
   %6      $ 00 00 00 00 00 00 00 00 43 4d 27 49
   %14     $ 4e 49 54 49 41 4c 20 20

   %cmdebug > dd 77.0,20,h,6,2
   DST %77.0
   %0      $ 01ad 000a 0000 0000 0000 0000
   %6      $ 0000 0000 0000 0000 434d 2749
   %14     $ 4e49 5449 414c 2020

   %cmdebug > dd 77.0,20,h,6,4
   DST %77.0
   %0      $ 01ad000a 00000000 00000000 00000000 00000000 434d2749
   %14     $ 4e495449 414c2020 20202000 930c0000 4d495827 5041524d
   %30     $ 20202020 20202000 00000000 4c4f4144

Display DST 77.0, for 20 words, in hexadecimal.

Display the data as bytes (1), CM 16-bit words (2), and NM 32-bit words (4).

Note that the offset addresses are displayed in octal (the current output base), while the data is displayed in hexadecimal, as requested.


   $nmdebug > dsec 1.0,4,a
   SEC $1.0        ASCII ..HP ESYS ..]@ ....

Display secondary storage at the disk address 1.0 (LDEV=1, byteoffset=0). Display four words in ASCII. This example displays a portion of the volume label.


   %cmdebug > da %1114,3,a
   ABS+%1114   ASCII 82 04  9

   %cmdebug > da %1474,3,a
   ABS+%1474   ASCII  9 82 04

Two examples that display CM ABS relative. Both examples display three words in ASCII.

ABS is CM Bank 0 low core memory. CM SYSGLOB starts at ABS+%1000.

The first example displays the SEL release ID in the form: uu ff vv.

The second example displays the MPE/iX system version ID in the form: vv uu ff.


   $nmdat > wl pc
   SYS $a.728304
   $nmdat > wl vtor(pc)
   $c18304
   $nmdat > dz tr0+((vtor(pc)>>$b)*$10),4
   REAL $00603500 $ 80000000 0000000a 00728000 02400000

The logical code address of PC is SYS $a.728304, which translates to real memory address c18304.

This example displays the 4-word PDIR entry in real memory for the page that contains PC.

Display real memory (DZ) at the address TR0 (start of PDIR) plus the offset to entry, which is calculated by right-shifting the real address of PC by $b (to determine page number), and then multiplying by $10 since each 4-word PDIR entry is $10=#16 bytes long.

Examples of Code Displays


   $nmdebug > dcs sendio+18,7
   SYS $a.219f08
   00219f08  sendio+$18  6bd83d69  STW      24,-332(0,30)
   00219f0c  sendio+$1c  4bda3d51  LDW      -344(0,30),26
   00219f10  sendio+$20  081a0241  OR       26,0,1
   00219f14  sendio+$24  081e025f  OR       30,0,31
   00219f18  sendio+$28  34180050  LDO      40(0),24
   00219f1c  sendio+$2c  ebfe174d  BL       ?ldm_completion+$1e4,31
   00219f20  sendio+$30  37d93dc1  LDO      -288(30),25

Display code in the NM system library, starting at sendio+18, for seven words. By default, the display code commands use the CODE radix and display formatted lines of disassembled code.


   $nmdebug > dcs sendio+18,7,h
   SYS $a.219f08   $ 6bd83d69 4bda3d51 081a0241 081e025f
   SYS $a.219f18   $ 34180050 ebfe174d 37d93dc1

Display code in the system library, starting at sendio+18, for seven words in hexadecimal. By default, four words are displayed per line.


   %cmdebug > dcs lsearch+11,10
   SYS %12.20262
   %020262:  LSEARCH+%11           051401  S.  STOR  Q+1
   %020263:  LSEARCH+%12           000600  ..  ZERO, NOP
   %020264:  LSEARCH+%13           151607  ..  LDD   Q-7
   %020265:  LSEARCH+%14           041605  C.  LOAD  Q-5
   %020266:  LSEARCH+%15           041604  C.  LOAD  Q-4
   %020267:  LSEARCH+%16           031105  2E  PCAL ?LSEARCH'
   %020270:  LSEARCH+%17           013712  ..  BRE   P+%12
   %020271:  LSEARCH+%20           031107  2G  PCAL ?TRANS'XDST'TO'L

Display code starting at lsearch+11, for %10 words. The procedure is located in the CM system library, SL.PUB.SYS.

Listing Disassembled Code to a File

The following example demonstrates how to dump disassembled code into a file. The example is explained command by command, based on the command numbers that appear within the prompt lines.

Command %10 opens an offline list file with the name codedump. All Debug input and output is recorded into this file, including the code we intend to display.

Command %11 sets the environment variable term_loud to FALSE. This prevents subsequent Debug output from being displayed on the terminal. We capture the output in the list file (codedump), but we do not want the output on the terminal.

Command %12 contains the desired display code command. We display %20 words of disassembled code, starting at the entry point address ?fopen.

Command %13 closes (and saves) the current list file (codedump).

Command %14 uses the SET DEFAULT command to effectively reset the environment variable term_loud back to TRUE. Debug output once again is displayed on the terminal.

Command %15 issues an MPE/iX CI command PRINT CODEDUMP to display the newly created list file with the disassembled code. Note the additional Debug commands that were captured in the list file.


   %10 (%53) cmdebug > list codedump
   %11 (%53) cmdebug > env term_loud false
   %12 (%53) cmdebug > dc ?fopen,20
   %13 (%53) cmdebug > list close
   %14 (%53) cmdebug > set def
   %15 (%53) cmdebug > :print codedump

   Page: 1     DEBUG/XL A.01.00    WED, FEB 23, 1987  11:42 AM

   %11 (%53) cmdebug > env term_loud false
   %12 (%53) cmdebug > dc ?fopen,20
   SYS %22.5000
   %005000:  ?FOPEN                   170404  ..  LRA   P-4
   %005001:  FOPEN+%5                 030400  1.  SCAL  0
   %005002:  FOPEN+%6                 000600  ..  ZERO, NOP
   %005003:  FOPEN+%7                 051451  S)  STOR  Q+%51
   %005004:  FOPEN+%10                140060  .0  BR    P+%60
   %005005:  FOPEN+%11                140003  ..  BR    P+3
   %005006:  ?FSOPEN                  170412  ..  LRA   P-%12
   %005007:  FOPEN+%13                030400  1.  SCAL  0
   %005010:  FOPEN+%14                021001  ".  LDI   1
   %005011:  FOPEN+%15                051451  S)  STOR  Q+%51
   %005012:  FOPEN+%16                140052  .*  BR    P+%52
   %005013:  FOPEN+%17                140003  ..  BR    P+3
   %005014:  ?FJOPEN                  170420  ..  LRA   P-%20
   %005015:  FOPEN+%21                030400  1.  SCAL  0
   %005016:  FOPEN+%22                021002  ".  LDI   2
   %005017:  FOPEN+%23                051451  S)  STOR  Q+%51
   %13 (%53) cmdebug > list close

Limitations, Restrictions

None

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