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Debug only Privileged Mode Freezes a code segment, data segment, or virtual address (range) in memory. Syntax | |
FC logaddr [bytelength] Program file
FCG logaddr [bytelength] Group library
FCP logaddr [bytelength] Account library
FCLG logaddr [bytelength] Logon group library
FCLP logaddr [bytelength] Logon account library
FCS logaddr [bytelength] System library
FCU fname logaddr [bytelength] User library
FCA cmabsaddr CM absolute CST
FCAX cmabsaddr CM absolute CST
FDA dstoff CM data segment
FVA virtaddr [bytelength] Virtual address
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Parameters | |
- logaddr
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): - FC procname+20
Procedure name lookups return LCPTRs. - FC pw+4
Predefined ENV variables of type LCPTR. - FC SYS(2.200)
Explicit coercion to a LCPTR type.
As a long pointer (LPTR): - FC 23.2644
sid.offset or seg.offset
The logical file is determined based on the command suffix: FCS implies SYS, and so on.
As a short pointer (SPTR): 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 a LCPTR.
The search path used for procedure name lookups is based on the
command suffix letter: - FC
Full search path: NM: PROG, GRP, PUB, USER(s), SYS. CM: PROG, ``GRP, PUB, LGRP, LPUB, SYS.
- FCG
Search GRP, the group library. - FCP
Search PUB, the account library. - FCLG
Search LGRP, the logon group library. - FCLP
Search LPUB, the logon account library. - FCS
Search SYS, the system library. - FCU
Search USER, the user library.
For a full description of logical code addresses, refer to the section
"Logical Code Addresses" in chapter 2. - cmabsaddr
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): - FCA 23.2644
Implicit CST 23.2644 - FCAX 5.3204
Implicit CSTX 5.3204
As a full absolute code pointer (ACPTR): - FCA CST(2.200)
Explicit CST coercion - FCAX CSTX(2.200)
Explicit CSTX coercion - FCAX logtoabs(prog(1.20))
Explicit absolute conversion
The search path used for procedure name lookups is based on the
command suffix letter: - FCA
GRP, PUB, LGRP, LPUB, SYS - FCAX
PROG
- fname
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
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it is necessary to specify the desired NM user library. For example,
FCU lib1 204c
FCU lib2.testgrp test20+1c0
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If the file name is not fully qualified, the following defaults are used: Default account: the account of the program file. Default group: the group of the program file.
- dstoff
A data segment address (specified as DST.OFFSET) of the data segment to be
frozen in memory. The segment remains frozen until it is explicitly
unfrozen (see UDA command). - virtaddr
The starting virtual address of the page(s) that are to be
frozen in memory. The pages remain frozen until they are explicitly
unfrozen (see UVA command). Virtaddr can be a short pointer, a long pointer, or a full
logical code pointer. - bytelength
This parameter is valid only when in nmdebug. It indicates the desired number
of bytes to be frozen. Based on the starting virtual
address and the specified bytelength, the appropriate number of virtual
pages are frozen. If omitted, the default is four bytes. The
implementation of this command dictates that the smallest unit that is
actually frozen is one page of virtual memory. That is, if you say 1 byte,
the whole page on which that byte resides is made resident.
Examples | |
Freeze the current CM code segment, as indicated by the CM logical
address CMPC. Freeze CM logical code segment SYS 12.
$nmdebug > fva 22.104, #1000
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Freeze 1000 bytes starting at virtual address 22.104. |
