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OpenVMS Delta/XDelta Debugger Manual
The .MAP file for the sample program is shown in Example B-3. Only the
Program Section Synopsis with the psect, module, base address, end
address, and length are listed.
| Example B-3 .MAP File for the Sample
Program |
+--------------------------+
! Program Section Synopsis !
+--------------------------+
Psect Name Module Name Base End Length
---------- ----------- ---- --- ------
$LINKAGE 00010000 000100FF 00000100 ( 256.)
LOG 00010000 000100FF 00000100 ( 256.)
$LITERAL 00010100 00010158 00000059 ( 89.)
LOG 00010100 00010158 00000059 ( 89.)
$READONLY 00010160 00010160 00000000 ( 0.)
LOG 00010160 00010160 00000000 ( 0.)
$INIT 00020000 00020000 00000000 ( 0.)
LOG 00020000 00020000 00000000 ( 0.)
$UNINIT 00020000 0002002F 00000030 ( 48.)
LOG 00020000 0002002F 00000030 ( 48.)
$CODE 00030000 0003027B 0000027C ( 636.)
LOG 00030000 0003027B 0000027C ( 636.)
|
The DELTA debug session is shown in Example B-4.
| Example B-4 DELTA Debugging Session of the
Sample Program |
$ DEFINE LIB$DEBUG SYS$LIBRARY:DELTA (1)
$ RUN/DEBUG LOG (2)
Alpha/VMS DELTA Version 1.5 (3)
Brk 0 at 00030200
00030200! LDA SP,#XFFD0(SP) 30000,1;X
X1 164! CMPEQ R0,#X14,R16 .;B (4)
X1 1AC! BSR R26,#XFFFF94 .;B (5)
;P
Brk 1 at 00030164 (6)
X1+00000164! CMPEQ R0,#X14,R16 R0/ 00000001 ;P
Brk 2 at 000301AC
X1+000001AC! BSR R26,#XFFFF94 O
PID= 00000021 PRCNAM= SWAPPER LOGINTIM= 00:00:00.00 (7)
X1+000001B0! BR R31,#XFFFFE1 ;P
Brk 1 at 00030164
X1+00000164! CMPEQ R0,#X14,R16 R0/ 00000001 ;P
Brk 2 at 000301AC
X1+000001AC! BSR R26,#XFFFF94 O (8)
PID= 00000024 PRCNAM= ERRFMT LOGINTIM= 16:24:01.03
X1+000001B0! BR R31,#XFFFFE1 ;P
Brk 1 at 00030164
X1+00000164! CMPEQ R0,#X14,R16
;B
1 00030164
2 000301AC
0,1;B
;B
2 000301AC
;P
Brk 2 at 000301AC (9)
X1+000001AC! BSR R26,#XFFFF94 O
PID= 00000025 PRCNAM= OPCOM LOGINTIM= 16:24:02.56
X1+000001B0! BR R31,#XFFFFE1 ;P
Brk 2 at 000301AC (10)
X1+000001AC! BSR R26,#XFFFF94 O
PID= 00000026 PRCNAM= AUDIT_SERVER LOGINTIM=16:24:03.66
X1+000001B0! BR R31,#XFFFFE1 ;P
Brk 2 at 000301AC (11)
X1+000001AC! BSR R26,#XFFFF94 X1 84! LDQ R16,#X0040(R2)
[Linefeed] (12)
X1+00000088! LDL R18,#X0010(FP) [Linefeed]
X1+0000008C! JSR R26,(R26) .;B (13)
;B
1 0003008C
2 000301AC
;P (14)
Brk 1 at 0003008C (15)
X1+0000008C! JSR R26,(R26) O
PID= 00000027 PRCNAM= JOB_CONTROL LOGINTIM= 16:24:06.83
X1+00000090! BIS R31,FP,SP ;P
Brk 2 at 000301AC
X1+000001AC! BSR R26,#XFFFF94 ;P
Brk 1 at 0003008C (16)
X1+0000008C! JSR R26,(R26) O
PID= 00000028 PRCNAM= NETACP LOGINTIM= 16:24:22.86
X1+00000090! BIS R31,FP,SP ;P
Brk 2 at 000301AC
X1+000001AC! BSR R26,#XFFFF94
;B
1 0003008C
2 000301AC
0,2;B
0,1;B
;B
;P
PID= 00000029 PRCNAM= EVL LOGINTIM= 16:24:26.67
PID= 0000002A PRCNAM= REMACP LOGINTIM= 16:24:38.21
PID= 0000002B PRCNAM= LATACP LOGINTIM= 16:24:43.18
PID= 0000004C PRCNAM= GODDARD LOGINTIM= 07:40:49.34
PID= 0000002D PRCNAM= SYMBIONT_0001 LOGINTIM= 16:25:47.54
PID= 0000002F PRCNAM= MCCORMICK LOGINTIM= 16:27:45.27
Exit 00000001
8002228C! ADDL R15,SP,SP EXIT
|
- DELTA is enabled as the debugger.
- The example program LOG is invoked with
DELTA.
- DELTA displays a version number and the
first executable instruction. The base address of the program
(determined from the map file) is virtual address 30000. The base
address is placed in base register 1 with ;X. Now references to an
address can use the address offset notation. For example, a reference
to the first instruction is X1+200 (or the base address 30000 + offset
200). Also, DELTA displays some address locations as offsets to the
base address.
- The instruction at address 30164 is
displayed in instruction mode using !. Its address location is
expressed as the base address plus an offset. In the listing file, the
offset is 164. (This is the point where the return status from
SYS$GETJPIW is checked.) The base address in base address register X1
is 30000. The address reference, then, is X1+164. Note the + sign is
implied when not specified.
A simple breakpoint is set at that
address using the ;B command. The address reference for ;B is the .
symbol, representing the current address. X1+164;B would have done the
same thing.
- The same commands (! command to view the
instruction and ;B to set a breakpoint) are repeated for the
instruction at offset 1AC. (This is the point at which the print_line
function is called.)
- Program execution halts at the first
breakpoint. DELTA displays the breakpoint message (Brk 1 at 00030164)
with the breakpoint number 1 and the virtual address. The virtual
address is 30164, which is the base address (30000) plus the offset
164. DELTA then displays the instruction in instruction mode (CMPEQ
R0,#X14,R16). The contents of the general register 0 are displayed with
the / command. DELTA displays the contents of R0, which is 1. Program
execution continues using the ;P command.
- The function print_line is executed, and the
output (PID, process name, and login time) is displayed.
- The O command halts program execution at the
instruction where the function returns control (BR R31,#XFFFFE1). (This
is the point at which control passes to checking the conditions of the
while loop.) Program execution continues with ;P.
- Breakpoint 2 is encountered. DELTA displays
the breakpoint message, and the instruction. The function is executed
with the O command and the function output is displayed. The next
instruction where the function returns control is displayed. Program
execution continues with the ;P command.
- Breakpoint 2 is encountered again. DELTA
displays the breakpoint message, and the instruction. The function is
executed with the O command and the function output is displayed. The
next instruction where the function returns control is displayed.
Program execution continues with the ;P command.
- Breakpoint 2 is encountered again. The
instruction at offset 84 (in print_line) is displayed using !. This
instruction is part of the setup for the call to the printf function.
- Successive address locations are displayed
by pressing the Linefeed key two times. These instructions are the
remainder of the setup and the call to printf.
- A breakpoint at X1+8C (the current address)
is set using the ;B command. This breakpoint is in the function
print_line. The . symbol represents the current address. Note that
breakpoint 1 was cleared earlier and is now reused by DELTA for the new
breakpoint.
- Program execution continues with the ;P
command.
- Program execution stops at the new
breakpoint 1, which is in the print_line function. DELTA displays the
breakpoint message and the instruction at the new breakpoint. The O
command halts program execution at the instruction where the function
returns control, stepping over the routine call. Note the O command
must be used in this case, as opposed to the ;P command, because the
printf function resides in read-only protected memory. Program
execution is continued with the ;P command.
- Program execution stops at breakpoint 1 in
the print_line function. Program execution is continued using a
combination of the O and ;P commands.
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