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COMMENT VALID 00020 PAGES
C REC PAGE DESCRIPTION
C00001 00001
C00003 00002 INTRODUCTION, LOADING RAID
C00010 00003 THE RAID DISPLAY, ERROR MESSAGES, COMMAND FORMAT
C00016 00004 VALUES sp + - * / () , ,, @ . . = " " ' ' % &
C00025 00005 SCREEN CONTROL I I I cr cr cr cr
C00027 00006 DISPLAY MODES C O D F H T T Q V V A U U J R L
C00038 00007 SYMBOL TABLE COMMANDS : & Z Z : _ K : K
C00044 00008 OPENING CELLS sm sm sm sm > < LF \ < > < > < > _ =
C00051 00009 DEPOSITING IN CELLS cr > < > < < > < > E E
C00058 00010 OPENING INDIRECT LOCATIONS tb tb sm [ ] @ [ ] @
C00062 00011 DYNAMIC LOCATIONS [ ] @ [ ] @
C00074 00012 SEARCHES W N E
C00085 00013 PROGRAM CONTROL G G B B P P P
C00093 00014 STEPPING, EXECUTING S S X X X Y E
C00103 00015 MULTI-STEP S S X S
C00107 00016 MACROS M M
C00109 00017 SHORT SUMMARY OF RAID COMMANDS
C00115 00018 APPENDIX: SYMBOLIC MODE, PRINTING SYMBOLS, BYTE SIZE 0
C00121 00019 APPENDIX: RAID DEFINED LOCATIONS AND TABLE OF POINTERS
C00128 00020 APPENDIX: BREAKPOINTS
C00139 ENDMK
C;
INTRODUCTION, LOADING RAID
This document was written by Phil Petit and revised in March,
1975 by Raphael Finkel.
INTRODUCTION
RAID is an interactive debugging program that uses the displays
and allows dynamic monitoring of memory locations. RAID lives in
core with your program and allows you to do various things with and
to your program, such as stop at selected places and examine your
core image, etc. The major advantage of RAID over DDT is that RAID
uses the displays to give you a constantly updated view of selected
locations in core. It also can be used from a teletype, typing only
those lines that have changed since last time it wanted to display
something.
RAID was written by Phil Petit. It was modified by Dan Swinehart
to use a sorted symbol table. Jeff Rubin has added further
inprovements and fixed some bugs.
LOADING RAID
It is possible to use RAID in a stand-alone fashion, for writing
small programs on the spot, or finding the octal representation of
something, for example. The monitor command R RAID
calls in a fresh copy of RAID and starts it up.
SNAIL knows about RAID; the PREPARE, TRY, and DEBUG commands cause
RAID to be loaded with your program. This saves you the trouble of
remembering the loader switches.
The loader will load RAID with your program if you use the /V or
/H switch. This saves you the trouble of explicitly loading
RAID.REL[1,3]. For example if the binary file for your program was
called FNORP, the loader command /VFNORP$ (where $ means alt-mode)
would cause the loader to load RAID with your program. If you put
this switch after the name of your file, it is also necessary to tell
the loader to load your program symbols; this is done with the /S
switch. Here are some sample commands to load FNORP:
/SFNORP/V$ (Load symbol table, then RAID)
/VFNORP$ (Load RAID, then FNORP, then symbol table)
It is sometimes a good idea to put RAID after all the code, so
addresses in the core image will be close to where they would be
without the RAID. This helps if you are debugging a copy without RAID
in parallel to one with RAID.
Once you have your program and RAID in core, you must get into
RAID. This is done by typing DDT<cr> to the system. This is because
the system can't tell the difference between RAID and DDT. It is also
possible to enter RAID by hitting a breakpoint (ways to set and clear
breakpoints are discussed later) or by jumping to RAID's starting
address (this is the global symbol DDT, and it can also be found in
the right half of JOBDDT).
When RAID is entered, the display screen flashes and the RAID
display will appear. The duplexing of keyboard input moves down to
the bottom of the screen. RAID is now ready to accept commands.
There is also a version of RAID for examining files; it is called
FRAID. The monitor command R FRAID calls in a fresh copy and starts
it up. FRAID first asks if the file to be examined is a DMP file (if
so, the starting address will be noted and FRAID will look for a
symbol table) and whether the file is to be modified. If FRAID is
run in file-modify mode, all changes made in the core version of the
file are immediately written onto the disk.
All of the commands that run a job and set and clear breakpoints
are illegal in FRAID. Furthermore, if the file is a dump file, locations
0 through 73 are non-existant. There are a few commands that work only
in FRAID or which have different meanings in FRAID. These are:
S Simulates setting $IO to -1. Causes I/O instructions to be typed out
S Simulates setting $IO to 0. Causes I/O instructions to not be typed out
E Exits from FRAID. RELEASES the file after finishing all modifications.
THE RAID DISPLAY, ERROR MESSAGES, COMMAND FORMAT
RAID maintains a display of two columns. The left column gives
names of addresses currently being examined; the right column
displays the contents of those addresses. Commands are available for
determining what locations to display, how many to display, and in
what mode to display them.
Keyboard echoing is moved down to the bottom of the screen.
RAID uses special activation mode; this means that some characters
like ";" and "<" activate. It can lead to very unfortunate results
if you activate your commands with a carriage return, since that has
a special (and sometimes irreversable) meaning.
At the top of the screen is either a large OK, a large *, or an
error message. RAID complains if it does not understand your command
by presenting a large "?" in this location on the screen. If you
refer to a symbol FOO and it is not known to RAID, the complaint will
look like "U -- FOO", which means FOO is undefined. If RAID knows
about several symbols FOO, then the error is "M -- FOO" meaning FOO
is multiply defined. RAID will use one of the meanings anyway: the
most deeply nested one it can find in the current block. Other
messages, like "SKIP 2" can appear here, too. These will be
discussed where appropriate.
At the head of the left column is the name of the program whose
symbol table is currently being used. If you load several modules
together, RAID will only use the symbols from one at a time; there
are commands to switch to another one. If your program has block
structure, then RAID can be directed to a particular block in your
program (to disambiguate symbols with the same name). The current
block name is shown at the top of the right column.
Addresses in the left column that are not in the current program
are given in octal; those in the current program are given as offsets
from labeled locations (if there is one of those close enough), or in
octal as a last resort. Symbols not in the current block are
presented with the block name appended, so if FOO is in block BAZ and
we are now in block GARP, the location after FOO would be displayed
as BAZ&FOO+1, assuming that BAZ does not contain GARP.
Lines are sometimes marked with special signs in the space
between the columns. These signs are "." (dot), "" (arrow), "x"
(ex), and "" (swap). Swap means that dot, arrow, and ex all appear
on the same line. RAID on a teletype uses "<" for ex, ">" for arrow,
and "<=>" for swap.
Dot points to the line that is currently "open"; many commands
refer to the dotted line. The significance of being open is that it
is possible to deposit new information in the open word. Arrow
points to the line that is currently "being looked at", but it
cannot be modified unless the dot is moved there. Ex points to the
line holding the next instruction to be executed if it is on the
screen. This can happen if RAID is invoked while the program is in
execution or when a breakpoint is encountered.
Many RAID commands involve control bits. For the sake of
clarity and conciseness, we adopt the following conventions for this
document: The symbol means <control>, means <meta>, and means
<control-meta>. These can be simulated by $, $$, and $$$,
respectively, where $ means <altmode>. In addition, will be used
to refer to a value. Thus [ means some value (without any control
bits), followed by <meta>[. We will also have occasion to use the
sign to refer to any character.
VALUES sp + - * / () , ,, @ . . = " " ' ' % &
Commands to RAID often have parts that consist of values. By
convention, we will refer to values by the symbol in this
discussion. A value can be:
A string of octal digits
Examples: 463, 400321
A string of decimal digits preceeded with =
Examples: =293, -=30098
Note that it is not legal to say =-30098.
Two strings of decimal digits separated by a dot. (i.e. a floating point
number.
Examples: 123.456 0.003 17.
Note that .123 is not a valid floating point number.
A defined symbol in your program
Examples: FOO, BAR
If the character is typed then the following
characters are used as an identifier even if they
wouldn't have been had they been typed without the .
This is useful for identifiers starting with digits.
An example is 13P, which is the identifier "13P".
&
If you have several labels with the same name, but in
different blocks, you can specify which block you mean
with this symbol. For example, the variable FOO in
block BL1 can be called BL1&FOO. There are also
commands for setting the default block; see the page on
symbol table manipulation.
$M $C $nB etc
RAID has some predefined symbols that are of use to
the sophisticated user. See the page on RAID defined
symbols.
A machine instruction
Examples: MOVE, HRLZI A,FOO+3
A UUO
Examples: BEEP B, SPWBUT A,
A string constant, in one of several modes:
"
" followed by a chr., followed by a string not
containing that chr., followed by that chr., has the
value of the left adjusted ascii of the first 5 or
fewer characters in the string. For example, "/POT/
has the same value as ASCII /POT/ has in the assembler,
namely -- 502372400000
"
is just like " except that up to =17 words can be
typed between the delimiters. (Extra characters are
discarded.) These words are deposited in successive
locations (starting with dot) when you type a carriage
return (this is one of the commands used for modifying
cells). If carriage return is not used to terminate
the command, the whole string is discarded.
'
is just like " except that it is sixbit. For example,
'/DSK/ has the same value as SIXBIT /DSK/ has in the
assembler, namely -- 446353000000
'
this causes the string of characters following it, up
to the first non-letter non-digit character to be
converted to radix50, and has that value. Only 6
characters are used.
A byte constant:
%
followed by a string of values (not containing comma)
separated by commas, causes the values in the string
after the first to be considered bytes of a size
indicated by the first value in the string. For
example, %3,5,4,3,7,0,7,1 has the value 543707100000.
If the byte size is zero, the byte descripter is taken
from a special location in RAID. This is discussed in
the appendix.
A byte pointer constant:
.
followed by two or three values (not containing comma)
separated by commas, causes a byte pointer to be assembled
with the same value that FAIL would generate for
POINT VAL1,VAL2,VAL3 with the exception that decimal radix
is not forced for VAL1 and VAL3 as in FAIL. If the trailing
comma and VAL3 are omitted, then 44 octal is used for the
position field.
A special symbol:
Here is a list of the special symbols:
@ @ has the value 20,, i.e. the indirect bit
. "." has the same special meaning as in the assembler
i.e. the place you currently are. This line is marked
on the display with the dot.
. has the value of the contents of dot.
. has the value of the contents of .
An arithmetic expression involving any of the above:
Here is a list of the legal arithmetic expressions. Note that
all arithmetic is integer:
sp that is, the first value, a space, and then the
second one. The value of this is the sum of the
two values except that if the second one is an
octal constant, it is truncated to =18 bits.
+ sum of the two values, =36 bits
- difference of the two values
* product (multiplication)
/ quotient (integer division)
() this causes the two halves of to be swapped and all
=36 bits added to the rest of the expression.
, if not followed immediately by another comma, this
causes the value to be truncated to four bits and
shifted left =23 bits into the accumulator field.
,, this causes to be placed in the left half (i.e.
shifted left 18 places).
, this truncates to =18 bits.
,, this truncates to =18 bits.
SCREEN CONTROL I I I cr cr cr cr
When Raid is run on a Data Disc terminal it notices whether you have
cleared the screen recently or not (esc C, break P, break N). If you
have, then Raid will output the entire display again the next time it
executes a command. There are some commands that explicitly change
the display:
I
This causes the number of lines RAID is willing to display to be
set to . This number is initially =21.
I
This causes the number of lines RAID is willing to display to be
increased by 1. The limit is =21. RAID starts with the full
complement.
I
This causes the screen to be cleared of all displayed locations.
It does not change the number of locations RAID is willing to
display.
I
This is the same as I except that protected locations are not
cleared.
cr cr cr cr
Note that all forms of carriage return are equivalent.
Carriage return, not preceded by a value, causes the screen to be
updated and refreshed.
DISPLAY MODES C O D F H T T Q V V A U U J R L
Locations are opened and displayed in various formats, called
modes. RAID initially opens locations in symbolic mode This means
that words are displayed, as much as possible, as machine
instructions in standard assembler format. All this can be changed
by the mode commands listed below. All the mode commands use one or
more control bits (they are all typed with one or more control keys),
and the significance of the different combinations of control bits is
the same for all of them. If a mode command is typed with only the
bit, the mode of the location pointed to by the arrow is changed, and
nothing else. If it is typed with , then the mode in which future
locations (that is, locations not yet displayed anywhere on the
screen) are opened is changed, until a carriage return is typed, at
which point the mode reverts to the "standard" mode -- initially
symbolic. If it is typed with both control bits () the mode for
future locations is changed as with , but the "standard" mode is
also changed. Note that with both the and the , none of the modes
of locations already on the screen is changed.
C
This sets the mode to symbolic. This means that words will be
displayed as machine instructions, if possible, and that fields
(address, index, etc.) will be displayed as symbols from your
symbol table (see below) plus or minus an offset, if possible.
See the page on symbolic mode for a full discussion of the
parameters that determine what it does.
O
This sets the mode to octal. Words are displayed as octal
(base =8) numbers, except that a space is inserted between the
left and right halves of words if the left half is not zero.
Numbers are always displayed as positive quantities, so -1 is
shown as "777777 777777".
D
This displays words as decimal numbers, preceded by an equal-sign
(=). Negative quantities are shown properly; -1 is displayed as
"-=1".
F
This displays words as decimal floating-point numbers, unless
they are not normalized, in which case they are displayed in
decimal mode (above).
H
This is half-word mode. The left and right halves of the word
are displayed, symbolically (i.e. as symbols from your symbol
table, plus or minus an offset), separated by a double comma,
except if the left half is zero, in which case only the right
half is displayed.
T
This is ascii, or 7-bit type-out mode. The word is considered to
contain 5 characters of 7 bits each, left adjusted in the word.
These 5 characters, plus a possible sixth ("@") if the low order
bit is on, are displayed. If the high order 7 bits (first
character) in the word is 0 (null), the word is considered to
contain right adjusted ascii. Note that otherwise, nulls are
ignored; the word 404010200206 will be displayed as "ABC ", not
as "A B C".
Carriage return, line feed, tab, and backspace appear on a
datadisk as a small CR, LF, TB, and BS, respectively, on a III as
a small CR, LF, TAB, BS, and on a teletype as <<CR>>, <<LF>>,
<<TAB>>, <<BS>>. An altmode is displayed as <<ALT>> on a
teletype.
T
This is for other character type-out modes. Legal values for
are: 7 for ascii (as above), 6 for sixbit, and 5 for radix50.
The extra 4 bits on the left of a word in radix50 are shown as
two octal digits to the left of the string.
Q
This is byte-pointer mode. The word is displayed in exactly the
format used by the assembler POINT pseudo-op, that is, the word
POINT followed by a size field, followed by a comma, then the
address, index, etc., then possibly another comma and a position.
The size and position are decimal.
V
This is byte mode -- the output analog of the % input mode. The
word is typed out as an appropriate number of bytes, separated by
commas. The bytes themselves are typed in octal. The is the
byte size and should not be negative. A byte size of 0 has a
special meaning that is described in the appendix.
A
This is absolute mode. This one is different from all the others
in that it does not change the basic mode of the of the word
displayed, but merely causes addresses and other fields to be
typed as numbers instead of symbols. One way to get out of this
mode is to switch to C mode.
U
This is the same as symbolic mode except that the address field
(right half of the word) is considered to be up to three
right-adjusted ascii characters and is typed that way.
U
This is as above except that indicates: if it is 5, then
radix50 for the address field, if it is 6, then sixbit, and if it
is 7, then ascii, as above.
J
This is flag mode. If certain bits are being used with special
meanings in a flag word, it is nice to know exactly which flags
are on. Each of the =36 bits in the word can be given a special
name. The table of names should be in radix50 and occupy =36
words; the first of which refers to bit zero, the high-order bit.
A zero entry in this table means that the bit has no special
meaning.
In order to point RAID to the name table, a table pointer should
be placed in location $M+3 in RAID. The right half should point
to the table. The left half can point to another table pointer
in the same format as the one in $M+3; thus you can link together
many flag tables. Which table is used depends on . If is
absent, the first table will be used. (This is table zero.)
Otherwise, the linked list whose header is in $M+3 will be traced
to find the specified table. If the list stops before then (the
left half of some table pointer is zero) then symbolic mode is
used.
Words displayed in flag mode have the names of all the bits that
are on listed, separated by ! (which means "or" to the assembler
and is not a legal radix50 character), followed by the octal
corresponding to unnamed bits. If you change the table, RAID will
not update those words being diplayed in flag mode, but newly
displayed locations will be treated properly.
R
This is right flag mode. It is just like J, except only the
right half of the word is treated as flags; the left half is
displayed in symbolic.
L
This is left flag mode. It is just like R, except that the right
half of the word is treated as left flags.
SYMBOL TABLE COMMANDS : & Z Z : _ K : K
:
This points RAID at the symbol table for the program indicated by
. In this case, should be a single identifier. The name of
the program will be shown at the top of the left column.
&
If you don't use block structure, ignore this command. It points
RAID at the symbols for the block indicated by , which again
should be a single identifier. If the block is defined in the
current program, that one will be used; otherwise, the correct
program will be chosen and its name dispalyed at the top of the
left column. The name of the block will be shown at the top of
the right column. All symbols will be displayed appropriately for
this block.
Z
A list is kept of the names of the last few blocks opened. This
command goes back blocks, and re-opens that one. There is
never more than one copy of the same block name in the list. If
is omitted, 1 is assumed.
Z
The above list is forgotten. Then a new one is started,
beginning with the currently open block.
:
should be a single identifier. This identifier is created and
placed in your symbol table in the block you are currently
inside. The address of the identifier will be the current value
of dot, i.e. the location currently pointed to. Since ":" does
not activate, this command will not take effect until the next
activation character, so it is good practice to end this command
with a carriage return. Note that if is already in the symbol
table, then this command redefines it.
1_2
This command differs in format from the standard. 1 should be a
single identifier; 2 may be any value. This command creates a
symbol with the name 1 and sets its address to 2. 2 should be
followed by a carriage return. Note that if 1 is already in the
symbol table, then this command redefines it.
K
This causes the symbol (which should be a single identifier) to
have a bit turned on in its symbol table entry that causes RAID
to not use the symbol for typing out the contents of locations.
This is called half-killing the symbol. In other words, this has
the same effect as using double left arrow (__) in the assembler.
:
This removes the symbol table bit that half-killed the symbol,
thus resurrecting it. It will now be used for typing out contents
of locations.
K
This causes the symbol to be deleted from the symbol table.
OPENING CELLS sm sm sm sm > < LF \ < > < > < > _ =
;
This causes the location to be opened. If it is already on the
screen, RAID just moves dot and arrow to that position,
otherwise, it displays it in the next location on the screen.
Both dot and arrow are moved to the opened location.
;
This causes the location to be opened as above, except that the
location is also protected. A star appears on the screen to the
left of the protected location; that location cannot be erased
from the screen. If you protect too many locations, then RAID
will refuse to open any new locations until there is room on the
screen.
;
This command causes the location RAID is currently pointing to
with the arrow to be protected.
;
The location RAID is currently pointing to with the arrow becomes
unprotected. Any argument is ignored. You must be pointing to
the location you want unprotected.
> LF
< \
Note that linefeed is always equivalent to >, and \ is always
equivalent to <. This is true for all combinations of control
keys.
These commands cause RAID to open the next higher (>) or lower
(<) location from the one with the arrow. Both the dot and the
arrow are moved to this location. For example, if it is
currently pointing at location 36, > would cause it to display
(and point at) location 37. If the location is not already on
the screen, the pointer moves down (>) or up (<) one position to
display this next location, wrapping around the screen if
necessary.
> lf
< \
These cause RAID to move its dot and arrow down (>) or up (<)
one position from the current location of arrow without changing
the display in any other way. As always, the pointer and dot
wrap around the screen if necessary.
> lf
< \
These are like > or < without any control, except that the new
location is displayed in the same mode as the location marked
with the arrow. For example, if you open the first word of your
teletype buffer, and change the mode for it to ascii, you can
then open the second word of the buffer in ascii by using this
command.
> lf
< \
These are the same as > and < except the location to which the
arrow and dot are moved is displayed according to the mode of the
line that currently has the arrow.
_
This causes RAID to open, on the screen, the next location your
program is going to execute, i.e. the next step location, or the
last break-point you hit. The arrow, the dot, and the ex are all
moved to this point.
=
Either of these (they are completely identical) causes a word
inside RAID to have (not the contents of , but itself)
deposited into it, and that location to be displayed on the
screen with an arrow. The location is displayed in octal mode,
but the mode can be changed, as with any other location
displayed. This command does not move dot. This, then, is a way
of seeing what some value is in other modes. For example, you
might want to see what the octal value of the label FOO is (say
FOO=), or what the symbolic representation of 346 might be.
DEPOSITING IN CELLS cr > < > < < > < > E E
The only cell into which a value may be deposited is the one with
the dot. Many commands move the arrow but not the dot, so they can
become separated. Many commands can be prefaced by a value and will
store that value in dot before the command is executed. This feature
will be noted on each command that has it.
Note that FRAID (File RAID) in file-modify mode treats depositing
in a cell by modifying the file on disk.
cr cr cr cr
Note that all forms of carriage return are equivalent.
Carriage return, preceded by a value, causes that value to be
placed in the location currently open, that is, the line with the
dot. If the mode of the first or only part of typed can be
recognized by the input format as text, Decimal, Octal, Real or
Symbolic, will be displayed in that mode, no matter what the
current mode settings are. You may then change the mode.
> lf
< \
> lf
< \
> lf
< \
> lf
< \
Note that linefeed is always equivalent to >, and \ is always
equivalent to <. This is true for all combinations of control
keys.
These commands have the same function as the equivalent forms
without , except that the is first placed in the location
pointed to, as with carriage return.
E
E
The contents of are converted to text as if for displaying. If
is omitted, "." is assumed. The mode used is 's current
screen mode if is on the screen; otherwise the current display
mode. This text is sent to the system line editor, allowing you
to edit it using the standard line editor commands. This text
can then be activated with a carriage return, in which case the
resulting value will be deposited in dot. (See the descripton of
the carriage-return command for details.)
Note that this can lead to unfortunate results, since many of the
display modes are incompatible with their associated input modes.
For example, octal mode has a space between the two halves. Byte
pointer mode (Q mode) has the word POINT. Sometimes what is
loaded is NOT the mode displayed; this is true, for example of V
mode (byte mode). So use this command with caution.
Once the text is in the line editor, special characters like ;
and < will not activate, but they may be used anyway, followed by
a carriage return to activate them. The carriage return will be
interpreted as the "refresh screen" command, and won't hurt
anything. Any character that normally causes activation in the
line editor (like , where is any character) will always cause
activation.
OPENING INDIRECT LOCATIONS tb tb sm [ ] @ [ ] @
tb
tb
Tab causes the location whose address is in the right half of the
word currently pointed to by the right arrow to be opened with
both the dot and the arrow. Note that if tab is preceded by a
value, that value is first placed in the location pointed to, and
THEN the location indicated by the right half OF THAT VALUE is
opened. Tab is identical in action to [ and [ below.
;
A semicolon, with no control bits and not preceded by a value,
causes the location indicated by the right half of the word
currently pointed to by the right arrow to be displayed, as with
tab, except that dot stays behind in the old place. Since dot is
not changed, if something is deposited, it is deposited in the
old location (where the dot is). Note, however, that if a
further semicolon is typed (by itself), the location opened will
be the one indicated by the right half of the new word, the word
pointed to by the arrow. Note also that typing this command
preceded by a value converts it to a different command; see
above. Semicolon is identical in action to [ below.
[
]
@
[
@
]
Each of these displays a new location based on the contents of
the location currently marked by the arrow. The arrow is moved
to the new location, but the dot is not changed. [ uses the
right half of the contents as its address, ] uses the left half,
and @ uses the effective address. If a value is used, it is
deposited in the location pointed to by dot before the new
location is opened, so if dot and arrow are on the same line, the
new value will be used to calculate which location to display.
[
]
@
[
@
]
Each of these opens a new location based on the contents of the
location currently marked by the arrow. Both the arrow and dot
are moved to the new location. [ uses the right half of the
contents as its address, ] uses the left half, and @ uses the
effective address. If a value is used, it is deposited in the
location pointed to by dot before the new location is opened, so
if dot and arrow are on the same line, the new value will be used
to calculate which location to display.
DYNAMIC LOCATIONS [ ] @ [ ] @
[
]
@
[
@
]
This command is a bit complicated. It causes the location
currently pointed to by the arrow to be protected, then opens and
protects the location addressed by that location. As usual, [
uses the right half as a pointer, ] uses the left half, and @ the
effective address. However, if the value of the first location
changes, the display will be updated to show the new location that
the first location points to.
Suppose you wanted to keep track of the top location of the
stack. You would say P; which would cause the push-down pointer
(which everyone but DEC calls P) to be displayed (and pointed
to). Then you would say [ . This would cause the P location to
be protected, then would open the location addressed by the right
half of P, and cause it to be protected. However, from then on,
whenever P changed, the location you just displayed would change
to be the location addressed by the right half of P, that is, the
top location of the stack.
A few special things are true of the dynamic location opened by
this command. First of all, you should avoid putting the dot on
this location on the screen and trying to deposit in it. You
will wind up depositing in a table inside RAID, and your screen
will do funny things. You are somewhat protected by the fact the
location displayed by this command is marked only with the arrow,
not the dot, so the only way of pointing to it is with the >
command and its friends. If you open this same location by
normal means, it will be opened on another place on the screen,
and you can deposit in it there. If in the P example above, the
right half of P addressed location 300, and you said 300; , you
would get location 300 opened in two places on the screen. The
old one would be the dynamic one, and the new one would be an
ordinary one.
It is possible to "chain" this command with itself (in any
combination with the [, ], and @ variants), for as many locations
as there is room on the screen. If in the P example above, you
had said [ twice, instead of once, you would have opened the
location addressed by the right half of the word on the top of
the stack. This is all dynamic -- now to two levels -- so that
if P changes, you have displayed, not only the new thing that P
points to, but also the new thing that the new top of the stack
points to.
The way to undo the dynamic chaining is to unprotect all the
special locations on the screen; they will eventually be reused
for something else.
Note, finally, that if this command is preceded by a value, that
value is deposited in the location currently pointed to (by the
dot), as above, BEFORE the operation takes place.
SEARCHES W N E
W
This is the word-search command. The general effect is to find
all words that have in them. Specifically, RAID searches
core, between certain limits, which may be set (see below); the
initial bounds run over the whole core image except for locations
0-140 and the symbol table (but include RAID), as far as I can
tell. The search is for words that match (not the contents of
, but itself) in all bit positions that are on in location
$M. That is to say, two words are compared by XORing them, and
then ANDing the result with location $M. If this produces 0, the
words match. RAID continues to search, opening each location
that matches, until it comes to the end of the range, or until
it has found enough matches to half-fill the display locations
available, at which time it stops and prints a big star (*) on
your screen. You may, at this point, type (the "or" key) to
continue the search, and RAID will pick up where it left off,
stopping when it has again half-filled the screen; or you may
type any other command. (No characters are lost.) However, if
you do not let a search run to completion, the next search you do
will take up where the last one left off. You can, at any time
later, type and continue the last search you did. If the
search comes to an end, then OK will be displayed instead of a
star.
N
This is not-word search. This works exactly like word search,
except that words are considered to match only if they are
different in some bit that is on in $M.
E
This is effective address search. It works like word-search
except that for each word examined, the effective address is
calculated, and this effective address is matched with . The
mask in $M is not consulted, and words are considered to match if
and the effective address are exactly the same.
("or" or "and"; they are equivalent)
This causes the last search you did to be continued. If you have
done no searches, or if the last search you did has already run
to completion, this command does nothing.
This causes the lower () or upper () search bound, for the
next search only, to be set to . At the completion of the next
search, this bound will be set back to its original value.
Activate these commands with a carriage return.
This causes the lower () or upper () search bound to be set
permanently to . This sets the value to which the search bound
will be reset at the completion of a search.
PROGRAM CONTROL G G B B P P P
The following section describes the RAID commands that allow you
to run your program in various ways. These include the commands for
manipulating breakpoints, which cause your program to pause when it
gets to selected places, so that you can poke at it and see what's
wrong. There are also single step features that allow you to run
your program one instruction at a time while displaying important
locations. None of these commands is legal in FRAID (File RAID).
Associated with several commands (including the searches above),
is a big star (*), whicd RAID prints on your screen to let you know
it is done with something that may have taken it a while. This
star, in all cases, is removed the next time RAID recieves input --
usually as soon as you type anything.
G
This is the go command. It causes RAID to start running your
program at location . RAID actually transfers to your program.
Your program will continue to run until it hits a breakpoint, you
type Call, or your program exits or does something the system
doesn't like.
G
The go command, without a value, starts your program at its
starting address, i.e. the address in the right half of JOBSA,
which is location 120.
B
This causes RAID to plant a breakpoint at location in your
program. What RAID actually does, is change this location to a
JSR to a certain location in RAID, remembering what the location
used to be. This means that when your program gets here, it will
JSR to RAID, at which point RAID will put the location back to
what it was, open the break-point location on the screen marked
with dot, arrow, and ex, and print a big star on the screen. You
are now in RAID and can type commands to it.
B
This removes the break-point, if any, at location .
B
This removes all break-points.
P
This causes RAID to continue running your program from where it
left off. If your program hit a breakpoint, RAID will continue
your program with the breakpoint instruction (executing the real
instruction there), and your program will run until it hits
another (or the same) break-point, etc. If you have been
stepping your program (see below), RAID starts it up at the next
location to be executed. Don't use this command to start up your
program the first time; use G instead.
P
This causes RAID to procede (as above) from the current
break-point (the last one you hit), times. That is, it has the
effect of saying P, times, as long as you hit the same
breakpoint each time. If you hit other breakpoints in between,
you will stop, then if you procede from them and hit the old
breakpoint, the counting will continue. See the appendix on
breakpoints for details of getting out of this.
P
This instruction places a temporary breakpoint at dot, and then
proceeds as if you had typed P. This breakpoint is removed as
soon as you have stopped there once. Any value given with this
instruction is ignored. There is no restriction on the number of
temporary breakpoints in existence, except that the total number
of breakpoints of any kind cannot exceed =16.
STEPPING, EXECUTING S S X X X Y E
S
This is the basic step command. It causes the next location in
your program (the next location to be executed; the one with ex)
to be stepped. This means that the instruction has its effect,
and then you are back in RAID. It is as if you had planted a
break-point on the next instruction you would get to, and
proceded. After stepping, RAID opens the next location (the next
one you will execute) marked with dot, arrow, and ex. It does
not print a star. If the instruction you step skips one
instruction, RAID also displays the instruction skipped. This
command has a different meaning in FRAID; it simulates setting
$IO to -1, thus causing I/O instructions to be typed out.
S
This is exactly like S except that instead of stepping the next
instruction of your program, it steps the instruction currently
pointed to by dot. It then opens the location that that gets you
to, and it becomes the next location to be executed. The dot,
arrow, and ex all appear on this new location. Note that this is
a way of getting started with stepping, if you haven't run any of
your program yet, or if you want to change the flow of your
program. This command has a different meaning in FRAID; it
simulates setting $IO to 0, thus causing I/O instructions not to
be typed out.
X
This is the basic execute instruction. It has the same effect as
S, except if the instruction to be stepped (executed), is a
subroutine call instruction (JSR, PUSHJ, JSA, or JSP), or a user
UUO. In these cases, it treats the instruction and the
subroutine (or UUO routine) it calls as one instruction. This
means that your program starts running at the subroutine call (or
UUO), and runs until it returns, and stops on the instruction it
returns to. This instruction is then opened with dot, arrow, and
ex. Note that if you STEP a user UUO, you wind up inside your
UUO routines. There is a restriction involved in this command,
and it applies also to the next two commands (the other two X
commands). The restriction concerns how many locations a
subroutine (or UUO) may skip. The maximum is 7. If you execute
a subroutine call, or a UUO, (currently no system UUO skips more
than 1, except INIT, which is handled as a special case by
RAID), and it skips more than 7 locations, you will wind up in a
funny place in RAID and all sorts of wrong things will happen.
A few words should be said about break-points in executed
subroutines. In general, they work. You may hit a break-point
inside a subroutine, the call to which was executed, and you may
then step and execute other instructions. When you procede from
the breakpoint, you will get back when the subroutine exits, just
as if you hadn't hit any breakpoints. You should NOT step the
subroutine return, as you will wind up stepping locations inside
RAID. If you do this accidently, and haven't gone too far, you
may procede (P) and the right thing will happen. You may nest
executes to a level of 8. You should avoid executing subroutine
calls which you don't return from, as you will remain inside the
subroutine, as far as RAID is concerned, until you do return, and
this will decrease the number of levels you can nest subroutines.
X
This works just like X except that it starts with the
instruction currently pointed to by dot.
X
This causes the instruction ( itself, not the instruction at
) to be executed as though it was in your program. Executing
the instruction has no effect on which instruction is the next
instruction to be executed, even if is a jump or skip. may
be a subroutine call, in which case the right things happen. The
restrictions listed above for executing subroutine calls apply.
Note that executing a JRST with this command has no effect
(except possibly on flags). The number of instructions skipped,
if any, will be displayed at the top of the screen: "SKIP 2", for
example.
Y
This has the same effect as X if is a subroutine call.
Otherwise, the instruction is just plain (vanilla) executed,
regardless of what it is. Even jumps are not interpreted. If
the instruction does not jump, it should not skip more than two,
and control reverts to RAID as with X. If the instruction does
jump, you are off and running, as with G, until you hit a
breakpoint or something. The purpose of this instruction is to
augment the G command. Its principal utility is for saving a DMP
copy of your program. You could type Call and then save it, but
that would leave RAID in a funny state. You could type EXITX,
but this would be like a subroutine that never returns,
decreasing the number of levels available for subroutine
nestings. EXITY will cleanly get you to the monitor so you can
save the core image.
E
This is like typing EXITY at RAID, except that all files that
are open are closed. This exits RAID back to the monitor in such
a way that the core image may be correctly saved and retrieved
later. This command is legal from FRAID (unlike EXITY), and it
releases the file after finishing all modifications.
MULTI-STEP S S X S
S
This is the multi-step command. It has, except as noted below,
the same effect as repeatedly saying S. It steps the current
location, updates the screen (displaying the next instruction to
be executed), steps the next instruction, updates the screen, and
so on. It keeps running until either you type a key, in which
case it stops and returns control to RAID (the character you type
may be anything, and is ignored); or it gets to a subroutine call
or subroutine return instruction. PUSHJ, JSR, and UUOs are
treated as subroutine calls. Subroutine return instructions are:
POPJ, JRA, and JRST @. When it reaches one of these, it pauses
and displays a big star.
If you type S it steps the instruction; if you type X it
executes it. (If it is a subroutine call, this makes a
difference.) It then procedes with multi-stepping. There are
several other responses: If you type S, then RAID will no
longer stop on subroutine calls, but will always step them. If
you type S, then RAID will no longer stop at subroutine
returns. If you type S, then both things happen. If you
type X, then RAID will no longer stop at subroutine call,
but will always execute them. If you type X, RAID will no
longer stop at subroutine returns. If you type X, both
things happen. This state of affairs remains in effect until you
stop the stepping, or change it in the same way you set it,
except that it is cleared at the start of each new multi-step
command.
The multi-step mode can be terminated at any time by hitting some
other character (the space key is recommened), which is then
ignored.
S
If a value is specified to the S command then that many instructions
are executed before doing the S, unless a decision of the type mentioned
above is required.
MACROS M M
RAID has a facility for storing and executing macros, that is,
sequences of commands (stored as characters) which you might want to
invoke often, and would rather not type each time.
M
The value should be the address of the first word of an ASCIZ
string which is to constitute the macro body. If is a byte pointer,
then it is assumed that it points at the character before the first
one. Recall that altmodes can be used to simulate control bits in RAID;
this is useful if you want to put commands like H in the string.
This command causes (which may be any single character, with or
without control bits) to be defined as a macro with the body that
points to. If is some character such that already has some
meaning, this command will replace that old meaning with the new
one. Digits are good to use for macro names. Some characters,
like the comma, will not work at all.
This command invokes the macro which has been given the name ,
which may be any single character. Any on this command is
ignored.
M
This command invokes the macro whose address (as for M, above)
is in without assigning it any particular name.
SHORT SUMMARY OF RAID COMMANDS
E = effective address, W = whole word, RH = right half,
@ = indirect, = control, = meta, = control-meta, = any bucky
= required argument, = optional argument, = any character
() = default for optional argument
pointers on the display: . x
SCREEN CONTROL
I -- # SCREEN ENTRIES = OR CUR+1
I -- ZERO ALL SCREEN ENTRIES
I -- ZERO UNPROTECTED SCREEN ENTRIES
cr-- REFRESH SCREEN
DISPLAY MODES
C -- CYMBOLIC MODE
O -- OCTAL MODE
D -- DECIMAL MODE
F -- FLOATING POINT MODE
H -- HALF-WORD MODE
T -- CHARACTER MODE ((7)=7 => ASC, 6 => SIXB, 5 => RAD50)
Q -- BYTE POINTER MODE
V -- BYTE MODE (=0 => byte mask in $M+1, otherwise bits)
A -- ABSOLUTE MODE
U -- E AS CHARACTER MODE
J -- W AS FLAG MODE IN TABLE (0)
R -- RH AS RIGHT-HALF FLAG MODE IN TABLE (0)
L -- RH AS LEFT-HALF FLAG MODE IN TABLE (0)
SYMBOL TABLE COMMANDS
: -- NEW PROGRAM NAME
& -- NEW BLOCK NAME
Z -- OPEN RECORDED BLOCK (1) BACK
Z -- ZERO ALL BLOCK RECORDS
: -- DEFINE SYMBOL = .
_ -- DEFINE SYMBOL=ADDRESS (1=2)
K -- HALF-KILL SYMBOL
: -- REVIVE HALF-KILLED SYMBOL
K -- ANNIHILATE SYMBOL
OPENING CELLS
; -- . TO
; -- . TO
; -- FREEZE (.)
; -- UNFREEZE
= -- DISPLAY VALUE OF
-- DISPLAY VALUE OF
_ -- . TO x
LF -- ALWAYS EQUIVALENT TO >
\ -- ALWAYS EQUIVALENT TO <
> -- . TO .+1
< -- . TO .-1
< -- . UP ONE ON SCREEN
> -- . DOWN ONE ON SCREEN
> -- . TO .+1 IN MODE OF .
< -- . TO .-1 IN MODE OF .
> -- . UP ONE ON SCREEN IN MODE OF .
< -- . DOWN ONE ON SCREEN IN MODE OF .
DEPOSITING IN CELLS
cr -- DEPOSIT IN .
cr -- DEPOSIT IN .
> -- DEPOSIT IN ., THEN DO >
< -- DEPOSIT IN ., THEN DO <
[ -- DEPOSIT IN ., THEN DO [
] -- DEPOSIT IN ., THEN DO ]
@ -- DEPOSIT IN ., THEN DO @
TB -- DEPOSIT IN ., THEN DO TB
E -- EDIT .
OPENING INDIRECT LOCATIONS
[ -- TO @R()
] -- TO @L()
@ -- TO @E()
[ -- . TO @R()
] -- . TO @L()
@ -- . TO @E()
; -- TO @R()
TB -- . TO @R()
DYNAMIC LOCATIONS
@ -- FREEZE , @E()
[ -- FREEZE , @R()
] -- FREEZE , @L()
SEARCHES
W -- SEARCH FOR WORD
E -- SEARCH FOR EFFECTIVE ADDRESS OF
N -- SEARCH FOR WORD
-- CONTINUE SEARCH
-- CONTINUE SEARCH
-- SET TEMP LOWER SEARCH BOUND
-- PERMANENT LOWER SEARCH BOUND
-- TEMP UPPER SEARCH BOUND
-- PERMANENT UPPER SEARCH BOUND
PROGRAM CONTROL (NOT IN FRAID)
G -- RELEASE CONTROL AT (@JOBSA)
B -- PLANT BREAKPOINT AT
B -- REMOVE BREAKPOINT AT
P -- PROCEED TO TEMP BREAKPOINT AT .
P -- PROCEED TO NEXT BREAKPOINT, REPEAT (0) TIMES
STEPPING, EXECUTING (NOT IN FRAID)
S -- SINGLE-STEP ONCE FROM x
X -- SINGLE-EXECUTE ONCE FROM x
S -- SINGLE-STEP ONCE FROM .
X -- SINGLE-EXECUTION ONCE FROM .
X -- EXECUTE SIMULATING INSTRUCTION
Y -- EXECUTE DIRECT INSTRUCTION
MULTI-STEP (NOT IN FRAID)
S -- MULTIPLE-STEP
S -- STEP TIMES THEN S
S -- STEP THIS JUMP
X -- EXECUTE THIS JUMP
-- UNLESS S OR X, TERMINATE MULTI-STEP
EXIT
E -- EXIT FROM RAID BY SIMULATING EXITY
FRAID SPECIAL COMMANDS
S -- $IO _ -1
S -- $IO _ 0
MACROS
M -- DEFINE MACRO AT CALLED
M -- EXECUTE MACRO AT
-- EXECUTE MACRO CALLED
APPENDIX: SYMBOLIC MODE, PRINTING SYMBOLS, BYTE SIZE 0
SYMBOLIC MODE
This describes how symbolic mode decides how to display a word.
If the left half of the word is 0, it is displayed in halfword mode.
If the left half is all ones, the word is printed as a negative
number. If the left-hand nine bits (opcode) is 0 or 777, the word is
printed in halfword mode. Otherwise, if there is an entry for the
opcode, the word is printed as an instruction. If there is no opcode
entry, an opdef entry is searched for, and if that fails, perhaps it
is a UUO. If none of these works, the word printed in half-word
mode.
If the word is printed as an instruction, the index and
accumulator fields are printed as symbols only if there is an exact
match, otherwise as numbers.
PRINTING SYMBOLS
When RAID is going to print a number, unless it is in absolute
mode, or some mode where numbers are always printed as numbers, it
tries to print the number as a symbol, plus or minus an offset. To
do this, RAID first searches the symbol table for the two best
matches with the number it has, one greater, the other less. If the
number is less than 140, RAID requires an exact match, or it prints
it as a number. Otherwise, if it has found an exact match, it prints
that symbol. If not, it goes through some contortions to decide
which close match to use, and whether or not it will use either.
There are four parameters it uses in deciding. These parameters are
stored starting at location $C. The first parameter, the one at $C,
is the maximum plus offset. The second one, at $C+1, is the maximum
minus offset. Both of these numbers start out at 77, but may be
changed. The value is anded with 777 before use. The third parameter
we will call S, and is initially 10, the fourth parameter we will
call Q, and is initially 40. We will call the plus offset P, and the
minus offset M. RAID first compares P and M with their respective
maxima. If both are too big, the number is printed as a number. If P
is too big but M is not, then M is used (the minus one). If M is too
large, but P is not, then P is used. If both are within the limits,
then the fuction F=((P*Q)/100)-S-M is calculated, where 100 is octal.
If F is positive, M is used, otherwise, P is used. This means that S
and Q are relative weighting parameters; S is additive weighting, and
Q is multiplicative. Notice that if Q=100 and S=0, RAID uses the
smaller of M and P. If Q is instead 40, P is used unless it is twice
as big as M. On the other hand, if Q=100, but S=10, P is used unless
it is greater that M by more than 10.
BYTE SIZE 0
If the byte size in the V mode command, or in the %
input string is 0, the bytes are interpreted acording to a mask in
location $M+1. Bytes may be any sizes, and the boundaries are
indicated by a change from 0's to 1's, or vice-versa, in this mask.
For example, if $M+1 contains 707070707070, this would indicate 3-bit
bytes. 770077007700 would indicate 6-bit bytes. 741703607417 would
indicate 4-bit bytes. 770770770770 would indicate a 6-bit byte,
followed by a 3-bit byte, followed by a 6-bit byte, followed by a
3-bit byte, etc. 252525000000 would indicate 18 one-bit bytes
followed by a 18-bit byte.
APPENDIX: RAID DEFINED LOCATIONS AND TABLE OF POINTERS
These are all global symbols. You can declare them EXTERNAL,
then write clever programs to poke at them. Note that in this
context, $ refers to a dollar-sign, not an altmode.
DDT
This is the starting address of RAID.
DDTEND
This is the first unused location after RAID. If you have a
program without RAID which runs into trouble at user location
12345, say, then you can find the offending instruction by
loading the program with RAID and examining location
12345+DDTEND-140.
$C
This and the three locations following it are the parameters for
deciding how to print symbols. See above.
$M
This location is the search mask. It is initially set to -1.
See the search commands.
$M+1
This is the byte mask for 0 byte size. See above.
$M+3
This is the flag name table pointer. See section on the J
display mode.
$IO
If non-zero, words which represent machine I/O instructions
(CONI, DATAO, BLKO, etc.) will be printed as such in symbolic
mode. Otherwise they will be treated as the UUO's PPIOT, MAIL,
INTUUO, etc., which share some of the same Opcodes, or as simply
negative numbers if no such UUO exists for this word. Changing
this location has no effect on words currently being displayed;
to see what a displayed location has under this mode, switch it
to octal and back to symbolic. FRAID has the commands S and S
to set this cell to -1 and 0, respectively.
$I
This is the location where RAID keeps its current idea of your
program counter -- the address of the next instruction to be
executed. Breakpoints JSR to this location. The left half
contains your program flags. If you change the left half of this
word, you will change what program flags get restored each time
your program is started up.
$1B to $20B
These 20 locations, and the four locations following each of
them, are the breakpoint table. For a detailed description of
what each contains, see the appendix on breakpoints. The first
word is the address of the breakpoint. The location is -1 if
this breakpoint is unused. The second location is the multiple
procede count. The third location is the conditional skip
instruction. The fourth location is string-breakpoint byte
pointer. The fifth location is the real contents of the
breakpoint location.
There is a table just before DDT of pointers to useful entities
in Raid:
DDT-1 address of $SBP routine
DDT-2 address of $RBP routine
DDT-3 address of $M
DDT-4 address of $IO
DDT-5 address of $1B
DDT-6 address of $I
DDT-7 address of $C
DDT-10 address of DDTEND
DDT-11 address of $BGDDT
DDT-12 address of $RPTCNT
These are useful for programs which want to avoid undefined globals
and runtime testing of availability, if Raid is not loaded.
The lefthalf of JOBDDT is 40 (version 1).
APPENDIX: BREAKPOINTS
You may have a maximum of 20 (octal) breakpoints at any one time.
The breakpoint information is contained in a table, with five
locations for each breakpoint. The first location of each of the 20
entries is given a label of the form $nB, where n is a number from 1
to 20. Entries are assigned to breakpoints in the order in which
breakpoints are created, starting with $1B.
This first location of each entry contains the address of the
breakpoint in your core. It is -1 if this breakpoint is unused. The
left half is non-zero (40,, bit on) if the breakpoint is temporary.
The second location in each entry ($nB+1), contains the multiple
procede count for that breakpoint. This is where RAID puts the count
if you say P. This count is counted down by 1 each time you hit
this breakpoint and the breakpoint is ignored (you procede
automatically) if the count is still positive. Depositing a number
here will have the same effect as using multiple procede. Depositing
0 here will get you out of a multiple procede.
The third word of each entry is the skip instruction. If this
instruction is non-zero when RAID hits this breakpoint, RAID executes
the instruction (which may be a subroutine call), and what RAID does
with the breakpoint depends on whether or not this instruction skips.
skip 0: normal
If the instruction does not skip, RAID does the normal thing
(what it would have done if this word had been 0), namely,
it counts the multiple procede count and procedes if it is
positive, stops if it is zero or negative.
skip 1: stop
If the instruction skips once, RAID does not count the
multiple procede count, but rather it stops at the
breakpoint anyway.
skip 2: procede
If the instruction skips twice, RAID does not count the
multiple procede count, but rather it procedes (ignores the
breakpoint), anyway.
The fourth location in each entry ($nB+3) is the string
breakpoint pointer. If it is not zero, then it is assumed that the
right half points to (addresses) the start of an ASCIZ string. The
left half, if non-zero, implies that the word is a byte pointer such
that ILDB on it will fetch the first string character. If it's zero,
a byte pointer to the first character in the word will be
constructed. This ASCIZ string is then scanned by the input scanner,
just as if you were typing those characters on your keyboard, every
time you stop at this breakpoint. This means that if you want to
display a certain location each time you hit a certain breakpoint,
you can put in the appropriate location a pointer to an ASCIZ string
consisting of FOO; (to open location FOO). When the string runs out,
RAID takes input from the keyboard. You can use the " feature to
create long strings, if you need them. Instead of using control bits,
use the altmode equivalents.
The real contents of the breakpoint location are stored in the
fifth of the locations in the table entry (at $nB+4). Changing this
location, however, has no effect, because the real contents are
replaced in your core while you are talking to RAID, and the JSR is
placed there only while your program is running.
If a program that is loaded with Raid executes the instruction
JSR AC,$SBP ($SBP is a global defined in Raid) a breakpoint will
be set at the location specified in AC. There is no way to specify
the count, skip instruction or string yet. Executing a
JSR AC,$RBP will cause any breakpoint set at the location specified
in AC to be removed. Pointers to $SBP and $RBP can be found in the
table immediately preceding DDT.
A program may simulate hitting a breakpoint by executing
JSR $I ($I is a global defined in Raid). You may then procede from
this breakpoint in the usual way. When Raid is entered by transferring
to location DDT (or RAID), Raid simulates a breakpoint from the contents
of JOBOPC. Thus if you type <call>DD<cr> at your program, you may procede
it by typing P at Raid.