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| Title: | -={ H A C K E R S }=- |
| Notice: | Write locked - see NOTED::HACKERS |
| Moderator: | DIEHRD::MORRIS |
|
| Created: | Thu Feb 20 1986 |
| Last Modified: | Mon Aug 03 1992 |
| Last Successful Update: | Fri Jun 06 1997 |
| Number of topics: | 680 |
| Total number of notes: | 5456 |
592.0. "Linker option problem" by EAGLE1::DANTOWITZ (David - BXB1-1/E11 DTN: 293-5356) Wed Oct 28 1987 10:25
I've received no response in the VMSNOTES library, perhaps someone here
can help out.
[The data must be at the fixed locations so that the program can also run
without VMS and without VAX memory management.]
Thanks,
David
<<< VAXWRK::NOTES$DEVICE:[NOTES$LIBRARY]VMSNOTES.NOTE;1 >>>
================================================================================
Note 1676.0 LINK option problem 2 replies
EAGLE1::DANTOWITZ "David - BXB1-1/E11 DTN: 293-5356" 89 lines 22-OCT-1987 10:43
--------------------------------------------------------------------------------
I have an image that requires several arrays to be at fixed locations
in the virtual address space. I presently use one of two methods to
accomplish this:
1) Declare the data structures in specific PSECT's and tell the
linker where to base each PSECT. (option file 1)
2) Base the entire image after the addresses reserved for the
data structures and then use CRETVA to map the virtual address
space. (option file 2)
Both of these methods work fine for the fixed location arrays. The
problem I have comes about with some user system services that
are also linked in.
Using option file 2 the system services are linked properly. Using
option file 1 the system services are NOT linked properly. In fact
what appears to happen with option file 1 is that the calls to the
system services are missing one level of indirection.
After the two option files I've included the information from the
two link maps.
I'm lost. Hope someone can help out.
David
File 1 File 2
CLUSTER = T_cl,%X19000 BASE = %X96000
COLLECT = T_cl,T_psect CLUSTER=USS,,,USS$DIR:Uss/SHARE
CLUSTER = P_cl,%X7C800
COLLECT = P_cl,P_psect
CLUSTER = M_cl,%X80C00
COLLECT = M_cl,M_psect
CLUSTER = J_cl, %X81000
COLLECT = J_cl,Junk_psect
CLUSTER=USS,,,USS$DIR:Uss/SHARE
MAP information using option file 1
+------------------------+
! Image Section Synopsis !
+------------------------+
Cluster Type Pages Base Addr Disk VBN PFC Protection and Paging Global Sec. Name Match Majorid Minorid
------- ---- ----- --------- -------- --- --------------------- ---------------- ----- ------- -------
USS 4 1 P-00000000-R 0 0 READ ONLY USS_001 LESS/EQUAL 1 1
4 1 P-00000200-R 0 0 READ ONLY USS_002 LESS/EQUAL 1 1
+------------------------+
! Symbol Cross Reference !
+------------------------+
Symbol Value Defined By Referenced By ...
------ ----- ---------- -----------------
USS$A 00000248-RX USS ABC
USS$B 0000024C-RX USS UTIL
USS$C 00000250-RX USS ABC
MAP information using option file 2
+------------------------+
! Image Section Synopsis !
+------------------------+
Cluster Type Pages Base Addr Disk VBN PFC Protection and Paging Global Sec. Name Match Majorid Minorid
------- ---- ----- --------- -------- --- --------------------- ---------------- ----- ------- -------
USS 4 1 P-0015A600 0 0 READ ONLY USS_001 LESS/EQUAL 1 1
4 1 P-0015A800 0 0 READ ONLY USS_002 LESS/EQUAL 1 1
+------------------------+
! Symbol Cross Reference !
+------------------------+
Symbol Value Defined By Referenced By ...
------ ----- ---------- -----------------
USS$A 0015A610 USS ABC
USS$B 0015A600 USS UTIL
USS$C 0015A608 USS ABC
| T.R | Title | User | Personal
Name | Date | Lines |
|---|
| 592.1 | Make the code position-independant! | JON::MORONEY | Question Authority (and Authority will question you) | Thu Oct 29 1987 09:05 | 12 |
| re .0:
I don't know how to use the linker in such a way, but you may want to look into
using the position-independant features of the VAX instruction set. Code
produced in this way will run anywhere in memory. This way you won't care if
VMS is running, memory mapping is on, etc.
For example, to reference something that looks like FOO: .BLKW 100, use
MOVAW FOO,R5 instead of MOVL #FOO,R5 since the first instruction only depends
on the offset of FOO from the instruction and not the absolute position of FOO.
-Mike
|
| 592.2 | F(A)=G(A), but F<>G | EAGLE1::DANTOWITZ | David - BXB1-1/E11 DTN: 293-5356 | Thu Oct 29 1987 09:47 | 11 |
| Thanks for the suggestion. Unfortunately it's not possible.
The code itself is not position dependent. The opcodes and operand
specifiers are explicit, not their function. The program is a type of
diagnostic/exerciser and the instructions and addresses are all checked
for consistency. MOVAW FOO,R5 is not equivalent to MOVL #F00,R5 because
it is a different instruction.
I'm still looking for a LINKER guru.
David
|