Digital Equipment Corporation PAL-D Disk Assembler User Manual

PAL-D
DISK ASSEMBLER
PROGRAMMERS REFERENCE MANUAL
For additional copies of this document, order No. DEC-D8-ASAB-D from Program Library,
Digital Equipment Corporation, Maynard, Mass. 01754 — Price: $1.50
DIGITAL EQUIPMENT CORPORATION * MAYNARD, MASSACHUSETTS
Ist Printing April 1968
2nd Printing June 1968
3rd Printing March 1969
4th Printing (Rev) September 1969
Your attention is invited to the last two pages of this
manual. The Reader's Comments page, when filled in
and returned, is beneficial to both you and DEC. All
comments received are considered when documenting
subsequent manuals, and when assistance is required ,
a knowledgeable DEC representative will contact you.
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keeping up-to-date with DEC's software.
Copyright © 1968, 1969 by Digital Equipment Corporation
Documents Referenced (available from DEC's Program Library):
Introduction to Programming, C-18
Disk Monitor System, Programmer's Reference Manual, DEC-D8-SDAB-D
Time-Sharing System User's Guide, DEC-T8-MRFB-D
TSS/8 System Manager's Guide, DEC-T8-MBZA-D
The following are registered trademarks of Digital
Equipment Corporation, Maynard, Massachusetts:
DEC PDP
FLIP CHIP FOCAL
DIGITAL COMPUTER LAB
PREFACE
PAL-D, one of the PDP-8 family assembly programs, is designed for use on any PDP-8 family computer
with disk or DECtape secondary storage. It is loaded, optionally stored on disk as a permanently resident
utility program and reproduced in core image as required, under control of the PDP-8/1 Disk Monitor, or
the TSS/8 Time-Sharing Monitor.
PAL-D produces a binary coded object program after two passes of the symbolic coded source program.
An optional third pass produces a listing of the source program and the assembler-generated binary code
expressed as four-digit octal values.
Along with the standard assembly functions PAL-D offers double precision integers, floating point con-
stants, arithmetic and Boolean operators, literals, text facilities and automatic off-page linkage genera-
tion as standard features.
It is assumed that the reader is familiar with assembly language programming. For an elementary
approach to this type of programming, we recommend DEC's publication, No. C-18, "Introduction to
Programming" available from the Program Library, Digital Equipment Corporation, Maynard,
Massachusetts.
CHAPTER 1
]
2
2
2
2
3
3
3
3
3
4
1.4.
4.
4.
‚4.
4.
5
5.
5.
6
6.
6.
6.
‚6.
1.7
1.7.
1.7.
CHAPTER 2
2.1
2.2
2.3
1
2
3
4
1
2
3
A
5
2
3
4
1
2
CONTENTS
INTRODUCTION
PAL-D Language
Syntax
Legal Characters
Ilegal Characters
Format Effectors
Statements
Labels
Operators
Operands
Comments
Symbols
Symbol Distinction
Symbolic Addresses
Symbolic Operators
Symbolic Operands
Symbol Tables
Numbers
Arithmetic and Logical Operators
Evaluating Expressions
Address Assignments
Current Address Indicator
Indirect Addressing
Autoindexing
Literals
Instructions
Memory Reference Instructions
Augmented Instructions
PSEUDO-OPERATORS
Current Location Counter
Extended Memory
Radix Control
Page
2-1
2-1
2-2
2.4
2.5
2.6
2.7
2.8
2.8.1
CHAPTER 3
3.1
3.2
3.2.1
3.2.2
3.2.3
CHAPTER 4
4.1
4.1.1
4.1.2
4.1.3
4.2
CHAPTER 5
CONTENTS (Cont)
Listing Control
Text Facility
End of Program
End of File
Altering the Symbol Table
Internal Representation
PROGRAM PREPARATION AND ASSEMBLER OUTPUT
Program Tape
Assembly
Pass |
Pass 2
Pass 3
LOADING AND ASSEMBLING PROCEDURES
Disk Monitor System
Loading
Saving
Assembling
TSS/8 Monitor System
ERROR DIAGNOSTICS
APPENDIX A USA SCII CHARACTER SET
APPENDIX B SYMBOL LIST
Page
2-2
2-2
2-3
2-3
2-4
4-1
4-1
4-2
4-5
CHAPTER 1
INTRODUCTION
PAL-D, the acronym for Program Assembly Language for the Disk, is the symbolic assembly
program designed primarily for the 4K PDP-8 family of computers with disk or DECtape secondary storage
operated in either stand-alone or time-shared mode.
The PAL-D Assembler makes machine language programming easier, faster, and more efficient.
Basically, the Assembler processes the programmer's source program statements by translating mnemonic
operation codes to the binary codes needed in machine instructions, relating symbols to numeric values,
assigning absolute core addresses for program instructions and data, and preparing an output listing of the
program, which includes notification of any errors detected during the assembly process.
The PAL-D Assembly language is the same under both the Disk Monitor System and the TSS/8
Monitor (time-sharing) System. The assembly system includes the disk version of the Symbolic Tape
Editor for altering or editing the source language tape, the Disk Debugging technique for debugging the
object program by communicating with it in the source language, and various other utility programs.
PAL-D requires the minimum configuration for disk or DECtape systems (see Disk Monitor
System, DEC-D8-SDAB-D) or time sharing systems (see Time-Sharing System User's Guide,
DEC-T8-MRFB-D), and additionally can utilize the high-speed reader/punch and up to three additional
DS32 disk units.
1.1 PAL-D LANGUAGE
The PAL-D Assembler is compatible with the PAL III Assembler. However, PAL-D has the
following additional features.
Operators Symbols and integers may be combined by
using the operators
+Addition & Boolean AND
~Subfraction | Boolean Inclusive OR
Literals Symbolic or integer literals (constants)
are automatically assigned.
Text Facility Text facilities exist for single characters
and blocks of text.
Indirect Linkage Indirect links are automatically generated for
Generation off-page referencing.
1.2 SYNTAX
Programs processed under PAL-D are written using USA SCII characters. Appendix A contains
a complete list of these characters with their octal code equivalents.
1-1
1.2.1 Legal Characters
The following characters are acceptable to PAL-D.
a. The alphabetic characters
ABCD...XYZ
b. The numeric characters
0123456789
с. The special characters
Space
+ Plus
— Minus
/
&
0)
Г]
Exclamation Mark
Carriage Return
Tabulation
Comma
Equal Sign
Semicolon
Dollar Sign
Asterisk
Point (Period)
Slash
Ampersand
Quote
Parentheses
Brackets
d. Ignored characters
Form-Feed
Blank Tape
Code 200
Rubout
Line-Feed
Separates symbols and numbers
(see Section 1.5.1)
Combines symbols or numbers
(add)
Combines symbols or numbers
(subtract)
Combines symbols or numbers
(inclusive OR)
Terminates a line
Formats symbols or numbers or source
tape output
Assigns symbolic address
Direct assignment of symbol values
Terminates coding line
(will not terminate comments)
Indicates end of pass
Sets current location counter; redefines origin
Has value equal to current location counter
Indicates start of comment
Combines symbols or numbers (AND)
Generates USA SCII constant
Defines literal on current page
Defines page 0 literal
Indicates the end of a logical page of
source program
Used for leader/trailer
Used for leader/trailer
Follows tabulation characters for
timing purposes
Follows carriage return and causes tele-
printer paper to roll upward one line
Since certain characters are invisible (i.e., nonprinting), the following symbols are used
throughout this manual to represent their presence.
J
—
Space
Tabulation
Carriage Return
1-2
1.2.2 Illegal Characters
All characters other than those listed above are illegal when not in a comment or TEXT field
and, being illegal, their occurrence causes the error message IC (Illegal Character) to be printed by
PAL-D.
1.2.3 Format Effectors
Tabulations are usually used in the body of a source program to provide a neat page; they can
separate fields from one another, as between a statement and a comment. For example, a line written
GO, TAD TOTAL/MAIN LOOP
is much easier to read if tabs are inserted to form
GO, = TAD TOTAL 4 /MAIN LOOP |
Either the ";" (semicolon) or "y " (carriage return-line feed) character may be used as a
statement terminator. The semicolon is considered identical to carriage return-line feed except that it
will not terminate a comment. Example:
TAD A /THIS IS A COMMENT; TAD BJ
The entire expression between the "/" (slash) and ¢ (carriage return) is considered a comment.
The semicolon also allows the programmer to place several lines of coding on a single line.
If, for example, he wishes to write a sequence of instructions to rotate the contents of the accumulator
and link six places to the right, it might look like
КТК 4
RTR à
RTR
The programmer may place all three RTRs on a single line by separating them with the special character
";" and terminating the line with a carriage return. The above sequence of instructions can then be
— written | |
a RTR; RTR; RTR 4 |
This format is particularly useful when setting aside a section of data storage for a list. For example, a
12-word list could be reserved by specifying the following format.
LIST, 0; 0; 0; 0; 0; 04
0; 0; 0; 0; 0; О,
A neat printout (or program listing) makes subsequent editing, debugging, and interpretation
- much easier than when the coding is laid out in a haphazard fashion.
1.3 STATEMENTS
PAL-D source programs are usually prepared on a Teletype, with the aid of the Editor, as a
sequence of statements. Each statement is written on a single line and is terminated by a carriage
return-line feed sequence. PAL-D statements are virtually format free; that is, elements of a statement
are not placed in numbered columns with rigidly controlled spacing between elements, as in punched-card
oriented assemblers. |
There are four types of elements in a PAL-D statement which are identified by the order of
appearance in the statement, and by the separating, or delimiting, character which follows or precedes
the element. |
Statements are written in the general form
label, operator operand/comment
The Assembler interprets and processes these statements, generating one or more binary instructions or
data words, or performing an assembly process. A statement must contain at least one of these elements
and may contain all four types.
1.3.1 Labels
A label is the symbolic name created by the source programmer to identify the position of the
statement in the program. If present, the label is written first in a statement and terminated by a comma.
1.3.2 Operators
An operator may be one of the mnemonic machine instruction codes (see Appendix B), or
a pseudo-operation (pseudo-op) code which directs assembly processing. The assembly pseudo-op
codes are described in Chapter 2. Operators are terminated with a space if an operand follows or with
a semicolon, slash, or carriage return.
1.3.3 Operands
Operands are usually the symbolic address of the data to be accessed when an instruction is
executed, or the input data or arguments of a pseudo-op. In each case, interpretation of operands in
a statement depends on the statement operator. Operands are terminated by a semicolon, a slash if a
comment follows, or a carriage return-line feed.
1.3.4 Comments
The programmer may add notes to a statement following a slash mark. Such comments do not
affect assembly processing or program execution, but are useful in the program listing for later analysis
or debugging.
1-4
1.4 Symbols
The programmer may create symbols to use as statement labels, as operators, and as operands.
A symbol is a string of one or more alphanumeric characters delimited by a punctuation character. A
symbol contains from one to six characters from the set of 26 alphabetic characters and ten digits 0 through
9; however, the first character must be alphabetic.
1.4.1 Symbol Distinction
The PAL-D Assembler makes a distinction between the types of symbols itisprocessing. These
types are
a. Permanent symbols
JMS a symbol whose value of 4000 (octal) is taken from PAL-D's permanent
operation code symbol table.
b. User-defined symbols
HERE a user-defined symbol; when used as a symbolic address tag, its value is
the address of the statement it tags (this value is assigned by PAL-D).
1.4.1.1 Permanent Symbols - PAL-D has in its permanent symbol table definitions of its operation codes,
operate commands, and many input-output transfer (IOT) microinstructions (see Appendix B). PAL-D's
permanent symbols may be used without prior definition by the user.
1.4.1.2 User-Defined Symbols = User-defined symbols are composed according to the following rules.
a. The characters must be alphabetic (A-Z) or numeric (0-9).
b. The first character must be alphabetic.
c. Only the first six characters of any symbol are meaningful to PAL-D; the remainder,
if any, are ignored.
Note that because of the third rule above, a symbol such as INTEGER would be interpreted as INTEGE
since the seventh character is ignored. Remember, if symbols of more than six characters are used, the
programmer must avoid defining two apparently different symbols whose first characters are identical.
For example, the two symbols GEORGE1 and GEORGE2 differ only in the seventh character, thus the
Assembler treats them as being the same symbol, GEORGE.
| When the symbol following the space is a user-defined symbol, the space acts as an address
field delimiter. Example:
*2117 4
A, CLAY
JMP_ AV
1-5
where A is user-defined symbol with the value 2117. The expression JMP A is evaluated as follows.
JMP 101 000 000 000 (binary representation of permanent symbol JMP)
Address A 000 011 001 111 (binary representation of address A)
The operation codes (op codes) are inclusively ORed to form
JMP A 101 011 001 111
or written more concisely in octal as 5317.
1.4.2 Symbolic Addresses
A symbol used as a label to specify a symbolic address must appear first in the statement and
must be immediately followed by a comma. When used in this way, a symbol is said to be defined, A
defined symbol can reference an instruction or data word at any point in the program. A symbol can be
defined as a label only once. If a programmer attempts to define the same symbol as a label again, the
second or successive attempt is ignored and an error is indicated. The Assembler recognizes only the first
definition. These are legal symbolic addresses:
ADDR,
TOTAL,
SUM,
The following symbolic addresses are illegal:
7ABC, (first character must be alphabetic)
LAB—, (comma must immediately follow label)
1.4.3 Symbolic Operators
Symbols used as operators must be predefined by the Assembler or by the programmer. If a
statement has no label, the operator may appear first in the statement, and must be terminated by a
space, tab, semicolon, or carriage return, The following are examples of legal operators:
TAD (a mnemonic machine instruction operator)
PAGE (an Assembler pseudo-op)
ZIP (legal only ifdefined by the user)
1.4.4 Symbolic Operands
Symbols used as operands must have a value defined by the user. These may be symbolic
references to previously defined labels where the arguments to be used by this instruction are to be found,
or the values of symbolic operands may be constants or character strings.
TOTAL, TAD ACT + TAG
The first operand, ACT, specifies an accumulator register, determined by the value given to the symbol
AC1 by the user. The second operand references a memory location whose name or symbolic address is TAG.
1-6
1.4.5 Symbol Tables
The Assembler processes symbols in source program statements by referencing its symbol tables
which contain all defined symbols along with the binary value assigned to each symbol.
Initially, the Assembler's permanent symbol table contains the mnemonic op codes of the machine
instructions and the Assembler pseudo-op codes, as listed in Appendix B. As the source program is processed,
symbols defined in the source program are added to the user's symbol table.
N
1.4.5.1 Direct Assignment Statements - The programmer i nserts new symbols with their assigned values
directly into the symbol table by using a direct assignment statement of the form
symbol = value
where the value may be a number or expression. For example,
ALPHA=
BETA=17
A direct assignment statement may also be used to give a new symbol the same value as a
previously defined symbol.
BETA=17
GAMMA=BETA
The new symbol, GAMMA, is entered into the user's symbol table with the value 17.
The value assigned to a symbol may be changed.
ALPHA=7
changes the value assigned to the first example from 5 to 7.
The user may also define symbols by use of the comma. When the first symbol of a statement is
terminated by a comma, it is assigned a value equal to the current location counter (CLC). For example,
* 100 /set CLC (origin) to 1004
TAG, CLAY
JMP AY
B, O2
A, ОСА ВИ
The symbol TAG is assigned a value of 0100, the symbol В а value of 0102, and the symbol A a value of
0103.
Direct assignment statements do not generate instructions or data in the object program. These
statements are used to assign values so that symbols can be conveniently used in other statements.
1.5 NUMBERS
Any sequence of numbers delimited by a punctuation character is interpreted numerically by
PAL-D.
|
12
4372
The radix control pseudo-operators (pseudo-ops) indicate to the Assembler the radix to be
used in number interpretation (see Chapter 2). The pseudo-op DECIMAL indicates that all numbers
are to be interpreted as decimal until the next occurrence of the pseudo-op OCTAL. The pseudo-op
OCTAL indicates that all numbers are to be interpreted as octal until the next occurrence of the pseudo-op
DECIMAL.
The radix is initially set to octal and remains octal unless otherwise specified.
1.5.1 Arithmetic and Logical Operators
The arithmetic and logical operators are:
+ Plus 2s complement addition
(modulo 4096)
- Minus 2s complement subtraction
(modulo 4096)
!' Exclamation Mark Boolean inclusive OR
(union)
& Ampersand Boolean AND (intersection)
— Space Interpreted as inclusive OR when used
to separate two symbolic operators. Example:
TAG, CLA CLL #
1.5.2 Evaluating Expressions
Symbols and numbers (exclusive of pseudo-op symbols) may be combined by using the arithmetic
and logical operators to form expressions. Expressions are evaluated from left to right. Example:
A B A+B A-B_ A!B A&B
Value 0002 0003 0005 7777 0003 0002
Value 0007 0005 0014 0002 0007 0005
Value 0700 0007 0707 0671 0707 0000
1.6 ADDRESS ASSIGNMENTS
The PAL-D Assembler sets the origin, or starting address, of the source program to absolute
location (address) 0200 unless the origin is specified by the programmer. As source statements are processed,
PAL-D assigns consecutive memory addresses to the instructions and data words of the object program. This
is done by incrementing the location counter each time a memory location is assigned. A statement which
1-8
generates a single object program storage word increments the location counter by one. Another statement
may generate six storage words, thus incrementing the location counter by six.
Direct assignment statements and some Assembler pseudo-ops do not generate storage words
and therefore do not affect the location counter.
1.6.1 Current Address Indicator
The special character . (point or period) always has a value equal to the value of the
current location counter. It may be used as any integer or symbol (except to the left of an equal sign).
Example: |
*2004
JMP +2)
is equivalent to JMP 0202. Also,
* 300
‚ +2400 4
will produce in location 0300 the quantity 2700. Consider
*2200d
CALL=JMS | .J
0027 ¢
The second line, CALL = JMS ., does not increment the current location counter, therefore, 0027 is
placed in location 2200 and CALL is placed in the user's symbol table with an associated value of 4600
(the octal equivalent of JMS 1.).
1.6.2 Indirect Addressing
When the character | appears in a statement between a memory reference instruction and an oper-
and, the operand becomes the address containing the address of the statement to be executed. Consider
TAD 40
which is a direct address statement, where 40 is interpreted as the address containing the quantity to be
added to the accumulator. Thus, if address 40 contains 0432, then 0432 is added to the accumulator.
Now consider
TAD I 40
which is an indirect address statement, where 40 is interpreted as the address of the address containing
the quantity to be added to the accumulator. Thus, if address 40 contains 432, and address 432 contains
456, then 456 is added to the accumulator.
When a reference is made to an address not on the same page as the reference, PAL-D sets
the indirect bit (bit 3) of the machine instruction, generating an indirect address linkage to the off-page
reference (see Paging and Off-Page Referencing, Sections 1.7.1.1 and 1 7.1.2).
1-9
In the case of several off-page references to the same address, the indirect address linkage
will be generated only once.
Example: *2117 4
A, CLA J
* 2600 Y
TAD _A
DCA_A
The space preceding the user-defined symbol A acts as an address field delimiter. PAL-D will recognize
that the address tag A is not on the current page (in this case 2600-2777) and will generate a link to it
in the following manner. In location 2600, PAL-D will place the word
1777 (octal equivalent of TAD | 2777)
and in location 2777 (the last location on the current page) the word 2117 (the actual address of A) will
be placed. When it sees the second reference to A it will use the previous link word rather than creating
a new one.
PAL-D will recognize and generate an indirect address linkage only when the address referenced
is to a location on another page, not the current page. The programmer must use the character | to
indicate an explicit indirect address when indirectly addressing to a location on the current page.
PAL-D cannot generate a link for an instruction that is already specified as being an indirect
address. In this case, PAL-D will type the error message II (Illegal Indirect); the error message is ignored
and assembly is continued.
1.6.3 Autoindexing
Interpage references are often necessary for obtaining operands when processing large amounts
of data. The PDP-8 computers have facilities to ease the addressing of this data. When absolute locations
10 to 17 (octal) are indirectly addressed, the content of the location is incremented before it is used as
an address and the incremented number is left in the location. This allows the programmer to address
consecutive memory locations using a minimum of statements.
It must be remembered that initially these locations (10 to 17) must be set to one less than the
first desired address. Because of their characteristics, these locations are called autoindex registers,
No incrementation takes place when locations 10 to 17 are addressed directly.
Example:
Statement is in location 500
Data is on the page starting at 5000
Autoindexing register 10 is used for addressing
0476 1377 TAD (5000-1) / set up auto
0477 3010 DCA 10 / index with 4777
0500 1410 TAD I 10 / C(10) is incremented to 5000 before
use as address
0577 4777 / literal generated by PAL-D
When the statement in location 500 is executed, the content of location 10 will be incremented to 5000
and the content of location 5000 will be added to the content of the accumulator. If the instruction
TAD 1 10 is re-executed, the content of location 5001 is added to the content of the accumulator, and so on.
1.6.4 Literals
Symbolic and integer literals (constants) may be defined as shown below.
CLA J Operator and operand must always
TAD (2) ¢ be separated with a space.
DCA INDEX J
The left parenthesis is a signal to the Assembler that the integer following is to be assigned a location
in the table at the top of the current page. This is the same table in which the indirect address linkages
are stored. In the above example, the quantity 2 is stored in the first free location in a list beginning at
the top of the current page (relative address 177), and the statement in which it appears is encoded with
an address referring to that location.
A literal is assigned to storage the first time it is encountered; subsequent references will be
to the same location.
If the programmer wishes to assign literals to page O rather than the current page, he must use
square brackets, [ 1, in place of parentheses. Whether using parentheses or square brackets, the right
or closing member is optional and may always be replaced with a carriage return.
TAD (777 4
1.6.4.1 Nesting - Literals may be nested as shown below.
*200 #
TAD (TAD (30 J
will generate
0200 1276
0376 1377 (literals assigned to locations
0377 0030 0377 and 0376; top of current page)
This type of nesting may be carried to many levels.
Literals are stored on each page starting at relative address 177 (only 127, 9” 1775 literals
may be placed on page 0) . If literals are being generated for some nonzero page and then the origin
is set to another page, the current page literal buffer is punched out during pass 2. If the origin is reset
to the previously used page, the same literal will be generated if used again. |
If a single character is preceded by a quote ("), the 8-bit value of the USA SCH code for that
character is inserted instead of taking the letter as a symbol. |
Example: CLA
TAD ("Ad
will place the constant 0301 in the accumulator.
1.7 INSTRUCTIONS
There are two basic groups of instructions: memory reference and augmented. Memory
reference instructions require an operand; augmented instructions do not require an operand,
1.7.1 Memory Reference Instructions
In PDP-8 computers, some instructions require a reference to memory. They are appropriately
designated memory reference instructions, and take the following format.
OPERATION MEMORY
CODES 0-5 PAGE
Ñ A “ rman,
o 4 2 3 4 s | 6 7 8 9 10 1
——]— ` v —
INDIRECT ADORESS
ADDRESSING
Memory Reference Instruction Bit Assignments
Bits O through 2 contain the operation code of the instruction to be performed (AND, TAD, DCA, JMS, or
or JMP) . Bit 3 tells the computer if the instruction is indirect, that is, if the address of the instruction
specifies the location of the operand, or if it specifies the location of the address of the operand. Bit 4
tells the computer if the instruction is referencing the current page or page zero. This leaves bits 5
through 11 ( 7 bits) to specify an address. In these 7 bits, 200 octal or 128 decimal locations may be
specified; the page bit increases accessible locations to 400 octal or 256 decimal.
The address field of a memory reference instruction may be any valid expression.
Example: =270 d
*200 y
TAD A-204
1-12
produces, in location 200, the word
1250
which in binary is 001 010 101 000
which is also TAD 250.
1.7.1.1 Paging - To ease the programmer's addressing problems, a convention has been defined that
divides memory into sectors called pages. Each page contain 200 octal locations (128 decimal) numbered
0 to 177 (octal) on that page. There are 40 octal or 32 decimal pages numbered 0 to 37 (octal) . Some
examples of page numbers and the absolute and relative locations (addresses): are shown below. It must
be borne in mind, however, that there is no physical separation of pages in memory.
Absolute Relative
Page Address Address
0 0-177 0-177
1 200 - 377 0 - 177
2 400 - 577 0-177
36 7400 - 7577 0-177
37 7600 - 7777 0-177
The following table offers a comparison of specific absolute and relative addresses on the
same page.
Absolute Relative
Page Address Address
0 10 10
3 617 17
12 2577 177
31 6255 55
37 7777 177
Since only seven bits are necessary to address 200 octal locations, bits 5 to 11 are reserved
for this function.
1.7.1.2 Off-Page Referencing - The page on which an absolute address is contained can be determined
from bit 4 of the instruction. If bit 4 is a 0, the address refers to a location on page 0; if bit 4 isa 1,
the address refers to a location on the current (same) page, that is, the same memory page as the instruction.
1.7.2 Augmented Instructions
Augmented instructions are divided into two groups: operate and input-output transfer
microinstructions.
1.7.2.1 Operate Microinstructions - Within the operate group there are two groups of microinstructions.
Group 1 microinstructions are principally for clear, complement, rotate, and increment operations and
are designated by the presence of a 0 in bit 3 of the machine instruction word. (See Appendix B.)
ROTATE 1
ROTATE POSITION IF AO,
OPERATION AC ANDL 2 POSITIONS
CODE 7 CLA CMA RIGHT IFA!
— A ` —— m4 mt Ps
O 1 2 3 4 5 6 7 8 9 10 11
CONTAINS CLL CML ROTATE IAC
A O TO AC AND L
SPECIFY LEFT
GROUP1
Group 1 Operate Microinstruction Bit Assignments
Group 2 microinstructions are used principally in checking the content of the accumulator and
link and, based on the check, continuing to or skipping the next statement. Group 2 microinstructions are
identified by the presence of a 1 in bit 3 and a 0 in bit 11 of the machine instruction word (See Appendix B).
REVERSE
SKIP
OPERATION SENSING OF
CODE 7 CLA SZA BITS 5,6,7 HLT
у An ~ ——— — ¡—[ ¡—
0 t 2 3 a 5 6 7 8 9 10 11
CONTAINS A! SMA SNL OSR CONTAINS AO
TO SPECIFY TO SPEC:F Y
GROUP 2 GROUP 2
Group 2 Operate Microinstruction Bit Assignments
Group 1 and group 2 microinstructions can not be combined because bit 3 determines only one
or the other.
Within Group 2, there are two groups of skip instructions. They may be referred to as the
OR group and the AND group.
OR Group AND Group
SMA SPA
SZA SNA
SNL SZL
The OR group is designated by a 0 in bit 8, the AND group by a 1 in bit 8. OR and AND group
instructions cannot be combined because bit 8 determines only one or the other.
If the programmer does combine legal skip instructions, it is important to note the conditions
under which a skip may occur.
a. OR Group - If these skips are combined in a statement, the inclusive OR of the conditions
determines the skip.
SZA SNL
The next statement is skipped if
the accumulator contains 0000, or
the link isa 1, or
both conditions exist.
b. AND Group - If the skips are combined in a statement, the logical AND of the conditions
determines the skip.
SNA SZL
The next statement is skipped only if the accumulator differs from 0000 and the link is O.
1.7.2.2 Input-Output Transfer Microinstructions = These microinstructions initiate operation of
peripheral equipment and effect information transfer between the central processor and the input-output
device (s). This is the principal function of the input-output transfer (IOT) microinstructions. Appendix
B lists all valid IOT microinstructions, and each is discussed in detail in the User's Handbook.
CHAPTER 2
PSEUDO-OPERATORS
The programmer may use pseudo-operators (pseudo-ops) to direct the Assembler to perform
certain tasks or to interpret subsequent coding in a certain manner. Some pseudo-ops generate storage
words in the object program, other pseudo-ops direct the Assembler on how to proceed with the assembly.
Pseudo-ops are maintained in the Assembler's permanent symbol table. |
The function of each PAL-D pseudo-op is described below.
2.1 CURRENT LOCATION COUNTER
The programmer may use the PAGE pseudo-op to reset the current location counter (CLC) to
the first location on a specified page.
PAGE without an argument, the CLC is reset to the first location on the
next succeeding page. Thus, if a program is being assembled into
page 1 and the programmer wishes to begin the next segment of his
program on page 2, he need only insert PAGE, as follows.
JMP .-7J (Last location used on page 1)
PAGE ¢
| CLAY (First location on page 2)
PAGE n resets the CLC to the first location of page n, where n is an integer,
a previously defined symbol, or a symbolic expression. Example:
PAGE 2 (sets the CLC to location 400)
PAGE 6 (sets the CLC to location 1400)
2.2 EXTENDED MEMORY
When using more than one memory bank, the pseudo-op FIELD instructs the Assembler to output
a field setting.
FIELD n where n is an integer, a previously
| defined symbol, or a symbolic
expression within the range 0 <n <7.
This pseudo-op causes a field setting (binary word) of the form
11 XXX 000 where 000 < XXX <111
to be output on the binary tape during pass 2. This word is interpreted by the Loader, which then begins
loading information from the Loader into the new field.
2-1
2.3 RADIX CONTROL
Integers used in a source program are usually taken as octal numbers. If, however, the
programmer wishes to have certain numbers treated as decimal, he may use the pseudo-op DECIMAL.
DECIMAL all integers in subsequent coding are taken as decimal until
the occurrence of the pseudo-op OCTAL.
OCTAL resets the radix to its original octal base.
2.4 LISTING CONTROL
During pass 3, a listing of the source program is printed (punched). The programmer may,
however, control the output of his pass 3 listing by use of the pseudo-op XLIST.
XLIST Those portions of the source program enclosed by XLIST will
not appear in the pass 3 listing.
2.5 TEXT FACILITY
The pseudo-op TEXT enables the user to represent a character or string of characters in USA SCII
code trimmed to six bits and packed two characters to a word. The numerical values generated by TEXT
are left-justified in the storage words they occupy, with the unused bits of the last word filled with Os.
A string of text may be entered by giving the pseudo-op TEXT followed by a space, a delimiting
character, a siring of text, and the same delimiting character.
Example:
TEXT ATEXT STRINGA
The first printing character following TEXT is taken as the delimiting character, and the text string is
the characters which follow until the delimiting character is again encountered.
If the example above were at location 0200, the pass 3 listing would be as follows.
200 2405 TE
201 3024 XT
202 4023 —_S (— denotes a space)
203 2422 TR
204 1116 IN
205 0700 G
NOTE
With TEXT, any printing character
may be used as a delimiting character;
the delimiting character cannot be
used in the text string.
2-2
2.6 END OF PROGRAM
The special symbol $ (dollar sign) indicates the end of a program. When the Assembler en-
counters the $, it terminates the pass.
2.7 END OF FILE
The pseudo-op PAUSE signals the Assembler to stop processing the current input file. The
current pass is not terminated, and processing continues when the user types CTRL/P.
When processing a segmented program, the programmer must use the PAUSE pseudo-op as the
last statement of each segment (tape or file) to halt processing, giving him time to call (or insert, if
paper tape is being used) the succeeding segment of his program.
The PAUSE pseudo-op should be used only at the physical end of a tape or file.
2.8 ALTERING THE SYMBOL TABLE
PAL-D has a permanent symbol table which contains all instructions (symbols and their octal
values) required by the Disk Monitor System. They are referred to as PAL-D's basic instructions or
symbols, and are listed in Appendix B.
When the symbolic program to be assembled requires instructions not already in the table
(e.g., card reader IOT's), the table must be altered to include those instructions. PAL-D has two
pseudo-ops that are used to alter the permanent symbol table:
EXPUNGE deletes the entire permanent symbol table, except pseudo-ops.
FIXTAB appends symbols to the table for duration of the assembly. Alf symbols de-
fined before the occurrence of FIXTAB are temporarily made part of the per-
manent symbol table.
These pseudo-ops can be used to eliminate unneeded symbols from the table, thus providing more storage
for user symbols.
To append the following card reader IOT's to the symbol table, the programmer generates an
ASCII tape of:
RCSF=6631
RCSP=6671
RCRD=6674
FIXTAB
PAUSE
The ASCII tape is then read into core ahead of the symbolic program tape during pass 1. The PAUSE
pseudo -op stops assembly , and the Loader waits for the programmer to put the symbolic program tape
into the tape reader and press CONTinue.
After each assembly, PAL-D's permanent symbol table is restored to contain only the basic
symbols.
2-3
2.8.1 Internal Representation
Each permanent and user-defined symbol occupies four words (locations) in the symbol table
storage area, as shown below.
01 2
Word 1 С, X 45g + Co first 2 characters
Word 2 Ca x 45g + С 4 second 2 characters
Word 3 Cs X 45g + Co third 2 characters
Word 4 octal code or address
where С, , Co, eee, С 6 represent the first character, second character, ..., sixth character respective-
ly. (Symbols may consist of from one to six characters.) Bits 0 and 1 of word 1 and bit 0 of word 2 are
system flags. With a permanent symbol, word 4 contains the octal code of the symbol; with a user-
defined symbol, word 4 contains the address of the symbol. For example: the permanent symbol TAD is
represented as follows.
Word 1 = 24, x 459 + 01 = 1345, or TA
Word 2 = 04, х 45, + 00 = 224, +4000 = 4224, D
8 8 8 .
flag bit
Word 3 = 0000
Word 4 = 1000 (octal code for TAD)
Note that the first digit of the USASCII octal code for each character is always trimmed by the assem-
bler so that the character is represented using six bits of a word. For example, USASCII code for T is
324, it was trimmed to 24; A is 301, it was trimmed to 01; etc.
CHAPTER 3
PROGRAM PREPARATION AND ASSEMBLER OUTPUT
The source language tape (symbolic tape) is prepared using the Editor or an off-line ASR-33
Teletype.
3.1 PROGRAM TAPE
Since the Assembler ignores certain characters, these may be used freely to produce a more
readable symbolic source tape. These useful characters are tab and form-feed.
The Assembler will also ignore extraneous spaces, carriage return-line feed combinations,
rubouts, and blank tape.
The program body consists of statements and pseudo-ops. The program is terminated by the
dollar sign ($). If the program is large, it may be segmented by use of the pseudo-op PAUSE. This often
facilitates editing the source program since each section is physically smaller.
The Assembler initially sets the origin (current location counter) of the source program to 0200.
The programmer may reset the current location counter by use of the asterisk.
The following two programs are identical except that format effectors were used in the second
printout.
*200
/EXAMPLE OF FORMAT
/ GENERATOR
BEGIN, 0/START OF PROGRAM
KCC
KSF/WAIT FOR FLAG
JMP .-1/FLAG NOT SET YET
KRB/READ IN CHARACTER
DCA CHAR
TAD CHAR
TAD MSPACE/IS IT A SPACE?
SNA CLA
HLT/YES
JMP BEGIN + 2/NO: INPUT AGAIN
CHAR, 0/TEMPORARY STORAGE
MSPACE, -240/-ASCII EQUIVALENT
/END OF EXAMPLE
$
* 200
/EXAMPLE OF FORMAT
/ GENERATOR
BEGIN, 0 /START OF PROGRAM
KCC
KSF /WAIT FOR FLAG
JMP .-1 /FLAG NOT SET YET
3-1
KRB /READ IN CHARACTER
DCA CHAR
TAD CHAR
TAD MSPACE /1S IT A SPACE?
SNA CLA
HLT /YES
JMP BEGIN+ 2 /NO: INPUT AGAIN
CHAR, 0 /TEMPORARY STORAGE
MSPACE, -240 /-ASCII EQUIVALENT
/END OF EXAMPLE
$
Both of these programs will produce the same binary code. The second, however, is easier to read.
3.2 ASSEMBLY
PAL-D is a two-pass assembler with an optional third pass which produces a side-by-side
assembly listing of the symbolic source statements, their octal equivalents, and assigned absolute
addresses. When used with the TSS/8 time-sharing monitor the passes are invisible to the user. However,
the user determines whether or not the third pass will be made by his response to PAL-D's OPTION:
every (see Section 4.3.2).
3.2.1 Pass 1
During pass 1, PAL-D processes the source tape (or file) and places in its user's symbol table
the definitions of all symbols used. The user's symbol table is printed (or punched) at the end of pass 2.
If any symbols remain undefined at the end of pass 1, the US (Undefined Symbol) diagnostic is printed
during pass 2 when the undefined symbol is encountered (see Error Diagnostics). The symbol table is
printed (or punched) in alphabetical order on either the teleprinter or high-speed punch. The punched
symbol table may be used to expand DDT-8s symbol table for use in program debugging. If the program
listed above were assembled, PAL-D would output the following symbol table.
BEGIN 0200
CHAR 0213
MSPACE 0214
3.2.2 Pass 2
During pass 2, PAL-D processes the source tape (or file) and generates binary output using the
symbol table equivalences defined during pass 1. The binary output may be loaded in core by the Disk
Monitor System Binary Loader.
The binary coded tape (or file) consists of leader code, an origin setting, and data words.
Every occurrence in the source program of an asterisk causes a new origin setting in the binary output.
At the end of the binary coded tape, a binary checksum is produced and trailer code is generated.
3-2
When using the low speed paper tape punch, diagnostic messages are both typed and punched
and will be preceded and followed by rubouts. The Binary Loader will ignore everything enclosed within
rubouts.
3.2.3 Pass 3
During pass 3, PAL-D processes the source tape (or file) and prints out a side-by-side listing
of the generated octal code and the original source language. If the program shown above were assembled,
the pass 3 listing would be
*200
/EXAMPLE OF FORMAT
/GENERATOR
0200 0000 BEGIN, 0 /START OF PROGRAM
0201 6032 KCC
0202 6031 KSF /WAIT FOR FLAG
0203 5202 JMP .-1 /FLAG NOT SET YET
0204 6036 KRB /READ IN CHARACTER
0205 3213 DCA CHAR
0206 1213 TAD CHAR
0207 1214 TAD MSPACE /1S IT A SPACE?
0210 7650 SNA CLA
0211 7402 HLT /YES
0212 5202 JMP BEGIN+2 /NO: INPUT AGAIN
0213 0000 CHAR, O /TEMPORARY STORAGE
0214 7540 MSPACE, -240 /-ASCII EQUIVALENT
/END OF EXAMPLE
3-3
CHAPTER 4
LOADING AND ASSEMBLING PROCEDURES
The PAL-D Assembler is furnished on punched paper tape and is loaded and stored on the disk
during system build time. Loading PAL-D in a TSS/8 system, is performed by the system manager and is
described in detail in the TSS/8 System Manager's Guide, DEC-T8-MBZA-D. However, the user can at
any time build a new system in a Disk Monitor system; therefore, complete loading procedures are detail-
ed below.
4.1 DISK MONITOR SYSTEM
If the Disk Monitor is not present on your disk or DECtape, build it according to instructions
in the Disk Monitor System manual, DEC-D8-SDAB-D.
4.1.1 Loading
The assembler is incorporated in the system by loading the paper tape into core using the disk
Loader. Then the assembler may be saved on the disk or DECtape.
PAL-D is loaded into core in two passes as explained below. Disk system responses are under-
lined; non-underlined characters represent user-supplied data.
«LOAD J call Loader from disk ( ¢ indicates carriage return)
*IN-R: / input to be from high speed reader; T: would indicate input from
Teletype reader
* Loader found device R: valid
*OPT-2 dl two-pass load is specified
ST= J control is to be returned to the Monitor after loading tape into
core; 7600 4 would also transfer control to the Monitor after
loading the tape
Loader is waiting for user to put paper tape in reader and type 1P.
|
After reading tape into core, Loader waits for user to remove tape
and type TP. If checksum error occurs, Monitor types ? in place
of 1.
Loader is waiting for user to put paper tape in reader for second
pass and type ÎP.
After reading tape on second pass, Loader is waiting for user to
<P> 1<1P>1<1P >1<tP> remove tape and type tP. Again, checksum error will cause ? to
be typed in place of 1.
NOTE
!P indicates CTRL-P, and <> indicates
that the enclosed portion is not echoed
(printed when the user types).
4-1
4.1.2 Saving
PAL-D may be saved on the system device as a system program. This is done by typing the
following:
»SAVE PALD!0-7577;6200
Program —— Multiple | Entry
Name Page Save Point
| System Program
: User Program
The PAL-D Assembler is now saved as a system program on the system device. The programmer may now
type PALD J which brings the Assembler into core for use with symbolic source programs.
The user's core resident symbol table can hold 160, . user-defined symbols under the Disk
Monitor System; 24510 under the TSS/8 Monitor System. This may be expanded by saving on the system
device a user file named .SYM which can be used by PAL-D to store extra symbols. Each user-defined
symbol occupies four words. The symbol table can be expanded by 128,0 or 200, locations (one core
page) by saving a file with the following statement.
«SAVE .SYM:0-177;0 # (192 user symbols)
If a larger symbol table area is needed, simply specify additional pages, where each page saved provides
storage for 32 additional symbols. For example:
«SAVE .SYM:0-377;0 J (224 user symbols)
will save two core pages, and
SAVE .SYM:0-1777;0 J (416 user symbols)
will save eight core pages for symbol storage.
The preceding procedures are illustrated in Figure 1.
4.1.3 Assembling
PAL-D is transferred from the system device into core using the Monitor. One of the following
methods is used depending upon the monitor type.
3.3.1 Disk Monitor System - The user begins by typing
-PALD ¢
PAL-D requests on output file by typing
*QUT-
The user selects the output device by typing
T: 4 for the Teletype (low speed reader/punch), or
К: © for the high speed reader/punch, or
S:name d for output to the system device us file name
4-2
HIGH-SPEED READER
PLACE PAL-D TAPE
IN READER *
|
| TYPE CTRL/P |
|
TAPE READS IN AND
STOPS AT TRAILER CODE
|LOADER Types 4 |
WAS THIS
THE SECOND PASS
?
№
RESPOND TO DISK
MONITOR AS SHOWN
ELOW |
‚LOAD
_IN-R: ,
=2
xl
| x
OPT
Te 2
[+
fm — —
WHICH READER
?
R:= HIGH-SPEED READER
T:=LOW-SPEED READER
LOW SPEED READER
| LOADER TYPES '
| TYPE CTRL/P
NO
* PLACE LEADER CODE
OVER READER HEAD.
Figure |
| TYPE CTRL/P
SET TAPE READER
TO FREE
|
PLACE PAL-D TAPE
IN READER *
|
SET TAPE READER TO
START
|
TAPE READS IN,STOPS
AT TRAILER CODE,AND
COMPUTER HALTS
|
SET TAPE READER
TO FREE
| PRESS CONTINUE |
| LOADER TYPES
+ |
WAS THIS
THE SECOND PASS
©
—e| TYPE CTRL/P fe
{MONITOR TYPES — |
TYPE
SAVE PALD !0-7577,6200)
TYPE
.SAVE.SYM:0-1777,0 ,
THIS SAVES PAL-D AS
A SYSTEM PROGRAM
= == == == === == о —
PAL-D iS LOADED
AND READY FOR USE
4-3
THIS CREATES THE SYMBOL
TABLE FILE ON THE DISK
Loading and Saving PAL-D Using the Disk Monitor System
PAL-D now types
*IN-
and waits for the user to select the input files. Up to five input files may be specified (e.g., R:, R:,
S:name, R:, R: d ), but in this example the user selected
R: d input from the high speed reader/punch
NOTE
PAL-D checks the validity of each selected file (i.e.,
valid only ¡f the file was declared when building Moni-
tor), and types * for each valid file and ? for an in-
valid file. When PAL-D finds an invalid file it returns
control to the Monitor, in which case, the user must
start again by calling PALD d .
When PAL-D is satisfied that the input file(s) is valid, it will request third pass listing option by typing
*OPT-
The user may type
TA meaning listing and symbols are to be produced
on the Teletype, or
R A meaning listing and symbols are desired on high
speed punch, or
d meaning symbols only (any other character means
no third pass)
When the high speed punch is selected as a listing device, the alphabetic symbol table produced at the
end of pass 2 is also produced on the high speed punch.
PAL-D will now proceed with the assembly , pausing only when user intervention is required
(i.e., placing a new paper tape in the reader, turning on the punch, etc.). On these occasions,
PAL-D will type an up- arrow (1) on the Teletype to indicate user intervention is required. When the
user has performed the necessary function and is ready to continue with the assembly, he types CTRL-P
(which does not echo).
At the end of pass 2, PAL-D outputs the user's symbol table in alphabetical order (in addition
fo the assembled binary output). This symbol table listing may be terminated at any time by typing
CTRL-P, and PAL-D will proceed to initiate pass 3, if requested.
Assembly may be terminated and control returned to the Monitor at any time by typing
CTRL-C. When the assembly is complete, control will automatically be returned to the Monitor.
*With the low-speed reader: set reader to FREE, place tape in reader, type CTRL/P, and then set reader
to START.
With the high-speed reader: place tape in reader and then type CTRL/P.
4-4
4.2 ~ T55/8 MONITOR SYSTEM
Assembling with PAL-D in TSS/8 requires no operator intervention between passes. The sym-
bol table is typed out at the end of pass two and the listing at the end of pass three. The assembly may
be terminated at any point by typing CTRL/C. Control will revert from PAL-D to the Monitor program
which will type out a dot
and wait for the next instruction from the teletype. In the illustrations which follow, underlined
characters are those typed out by the system; non-underlined characters represent user-supplied data.
Time sharing assemblies are requested as follows.
In response to the monitor's dot
the user types the RUN (or simply R) command, a space and the name of the system program.
+ RPALD y
PAL-D is brought into core and signals its readiness by requesting an input file name.
INPUT: BIN2 }
The user reply in this case was BIN2, a user symbol for a source program to be assembled.
PAL-D next requests the name of an output file.
OUTPUT: TYPE2 4
The user response was TYPE2, the name under which the assembled program will be stored.
Optionally, the user may type the RETURN key to specify no output file.
OUTPUT: J
This is useful in debugging. A program may be corrected and reassembled any number of times with
production of an output file postponed until a satisfactory version is achieved.
PAL-D's final query is whether the user wants a program listing.
OPTION:
There are two effective responses only: N signifying No and ¢ (RETURN key) signifying Yes. When it
receives the final response, PAL-D reads in the user source program from disk (source programs are stored
prior fo assembly) and proceeds with the assembly. After assembly, PAL-D returns control to the Monitor
which types
and waits for the user to supply the next command.
NOTE
When running under the Disk Monitor system PAL-D
requires a dollar sign ($) as the last entry in a source
program. Under the TSS/8 Monitor PAL-D does not
require one but if it does not find one it types a message
to warn the user that his program may not be assembled
properly by an assembly program other than time-sharing
PAL-D.
4-5
The following listing was reproduced from a time sharing run. It illustrates the initial dialogue,
the symbol table produced at the end of pass 2 (any error messages would also appear at this point) and
the listing, in octal notation, produced at the end of pass 3.
.R PALD
INITIAL INPUT :BIN2
DIALOGUE OUTPUT : TYP2
OPTION:
COUNT 0415
CRLF 0417
SYMBOL LOOP 0406
TABLE OUT 0425
REG 0416
START 400
/PROGRAM TO TYPE OUT "123456789"
*7 4700
0400 7200 START. CLA
9401 4217 JMS CRLF
A402 1377 TAD (-12
7403 3215 DCA COUNT
0494 1376 TAD (260 /ASCII FOR ZERO
0405 3216 DCA REG
0406 1216 LOOP» TAD REG
0407 4225 JMS OUT
9410 2216 ISZ REG
p411 2215 1SZ COUNT
A412 5206 JMP LOOP
0413 4217 JMS CRLF
A414 7402 HLT
PROGRAM 9415 0000 COUNT, ©
LISTING 0416 09090 REG» 7
0417 0000 CRLF» 0
9420 1375 TAD (215 /ASCII FORK CAKKIAGE RETURN
9421 4225 JMS OUT
n422 1374 TAD (212 /ASCII FOR LINE FEED
0423 4225 JMS OUT
й424 5617 JMP I CRLF
24205 00900 OUT» 0
0426 6046 TLS
0427 6041 TSF
0430 5227 JMP .-1
0431 7200 CLA
10432 5625 JMP 1 OUT
‘9574 0212
areas [oo
2577 7766
BS
4-6
CHAPTER 5
ERROR DIAGNOSTICS
PAL-D makes many error checks as it processes source language statements. When an error is
detected, the Assembler prints an error message. The format of the error messages is
ERROR CODE ADDRESS
where ERROR CODE is a two-letter code which specifies the type of error, and ADDRESS is either the
absolute octal address where the error occurred or the address of the error relative to the last symbolic
tag (if there was one) on the current page.
The programmer should examine each error indication to determine whether correction is
required.
PAL-D's error messages are listed and explained below.
Error
Code Explanation
BE Two PAL-D internal tables have overlapped - This situation
can usually be corrected by decreasing the level of literal
~ nesting or number of current page literals used prior to this
| point on the page. |
DE | Systems device error - An error was detected when trying to
read or write the system device; after three failures, control is re-
turned fo the Monitor.
DF Systems device full - The capacity of the systems device has been
exceeded; assembly is terminated and control is returned to the Monitor.
IC [legal character - An illegal character was encountered in other than
.a comment or TEXT field; the character is ignored and the assembly
continued. |
ID Illegal redefinition of a symbol = An attempt was made to give a
- previously defined symbol a new value by other means than the
equal sign; the symbol was not redefined.
IE Illegal equals - An equal sign was used in the wrong context.
Examples:
TADA +=B (the expression to the left of the equal sign is not
a single symbol or, the expression to the right of
A +B=C the equal sign was not previously defined)
H legal indirect - An off-page reference was made; a link could
not be generated because the indirect bit was already set.
5-1
Error
Code
ND
PE
PH
SE
US
ZE
Explanation
Example:
*200
TADIA ¢
PAGE 4
A, 72401
The program terminator, $, is missing (with TSS/8 only).
Current nonzero page exceeded - An attempt was made to
a. override a literal with an instruction, or
b. override an instruction with a literal; this can be
corrected by
(1) decreasing the number of literals on the page or
(2) decreasing the number of instructions on the page.
Phase error - PAL-D has received input files in an incorrect order;
Assembly is terminated and control is returned to the Monitor.
Symbol table exceeded - Assembly is terminated and control is
returned to the Monitor; the symbol table may be expanded to
contain up to 1184 user symbols by saving a file named .SYM
on the system device.
Undefined symbol - À symbol has been processed during pass 2
that was not defined before the end of pass |.
Page O exceeded - Same as PE except with reference to page 0.
APPENDIX A
USA SCI! CHARACTER SET
Character Code Character Code Character Code
A 301 0 260 ! 241
B 302 1 261 и 242
С 303 2 262 # 243
D 304 3 263 $ 244
E 305 4 264 % 245
F 306 5 265 & 246
G 307 6 266 247
H 310 7 267 ( 250
I 311 8 270 ) 251
J 312 9 271 * 252
K 313 | + 253
L 314 , 254
M 315 - 255
N 316 | . 256
O 317 - / 257
P 320 | : 272
Q 321 ; 273
R 322 = 275
S 323 ? 277
T 324 [ 333
U 325 ] 335
у 326 BELL 207
W 327 TAB 211
X 330 LINE FEED 212
Y 331 CARRIAGE-RETURN 215
Z 332 SPACE 240
RUBOUT 377
Mnemonic
AND
TAD
ISZ
DCA
JMS
JMP
NOP
IAC
RAL
RTL
RAR
RTR
CML
CMA
CLL
CLA
HLT
OSR
SKP
SNL
SZL
SZA
SNA
SMA
SPA
CIA
STL
GLK
STA
LAS
DECIMAL
EXPUNGE
FIELD
FIXTAB
|
OCTAL
PAGE
Code
APPENDIX B
SYMBOL LIST
Operation
MEMORY REFERENCE INSTRUCTIONS
0000
1000
2000
3000
4000
5000
logical AND
2s complement add
increment & skip if zero
deposit & clear AC
jump to subroutine
jump
GROUP 1 OPERATE MICROINSTRUCTIONS
7000
7001
7004
7006
7010
7012
7020
7040
7100
7200
no operation
increment AC
rotate AC & link left one
rotate AC & link left two
rotate AC 8 link right one
rotate AC 8 link right two
complement link
complement AC
clear link
clear AC
GROUP 2 OPERATE MICROINSTRUCTIONS
7402
7404
7410
7420
7430
7440
7450
7500
7510
halts the computer
inclusive OR switch register with AC
skip unconditionally
skip on nonzero link
skip on zero link
skip on zero AC
skip on nonzero AC
skip on minus AC
skip on plus AC (zero is positive)
COMBINED OPERATE MICROINSTRUCTIONS
7041
7120
7204
7240
7604
complement & increment AC
set link to 1
get link (put link in AC, bit 11)
set AC =-1
load AC with switch register
PSEUDO-OPERATORS
B-1
Event Time
— — —— o | еж
PSEUDO-OPERATORS
PAUSE
TEXT
XLIST
Z
Mnemonic Code Operation Event Time
IOT MICROINSTRUCTIONS FOR DISK MONITOR
Program Interrupt
ION 6001 turn interrupt on
IOF 6002 turn interrupt off
Keyboard/Reader
KSF 6031 skip if keyboard/reader flag = 1
KCC 6032 clear AC & keyboard/reader flag
KRS 6034 read keyboard/reader buffer
KRB 6036 clear AC & read keyboard buffer, & clear
keyboard flag
Teleprinter/Punch
TSF 6041 skip if teleprinter/punch flag = 1
TCF 6042 clear teleprinter/punch flag
TPC 6044 load teleprinter/punch buffer,
select & print
TLS 6046 load teleprinter/punch buffer,
select & print, and clear teleprinter/punch
flag
High-Speed Reader (Type PC02)
RSF 6011 skip ¡f reader flag = |
RRB 6012 read reader buffer & clear flag
RFC 6014 clear flag & buffer & fetch character
High-Speed Punch (Type PCO3)
PSF 6021 skip if punch flag = 1
PCF 6022 clear flag & buffer
PPC 6024 load buffer & punch character
PLS 6026 clear flag & buffer, load & punch
Disk File and Control (type DF32)
DCMA 6601 clear disk memory request & interrupt flags
DMAR 6603 load disk from AC, clear AC, read into core,
clear interrupt flag
DMAW 6605 load disk from AC, write onto disk from core,
clear interrupt flag
DCEA 6611 clear disk extended address & memory address
extension register
DSAC 6612 skip if address confirmed flag = 1
DEAL 6615 clear disk extended address & memory address
extension register & load same from AC
DEAC 6616 clear AC, load AC from disk extended address
register, skip if address confirmed flag = 1
DFSE 6621 skip if parity error, data request late, or
write lock switch flag = 0 (no error)
B-2
Mnemonic
DFSC
DMAC
Code
6622
6626
Operation Event Time
skip if completion flag = 1 (date
transfer completed)
clear AC, load AC from disk memory
address register
DECtape Transport (Type TU55) and Control (Type TCOI)
DTRA 6761
DTCA 6762
DTXA 6764
DTSF 6771
DTRB 6772
DTLB 6774
Memory Extension Control (Type 183)
CDF 62n1
CIF 62n2
RDF 6214
RIF 6224
RMF 6244
RIB 6234
Program Interrupt
read status register A
clear status register A
load status register A
skip on flags
read status register B
load status register B
“N — N —
change to data field n
change to instruction field n
read data field into AC 6-8
read instruction field into AC 6-8
restore memory field
read interrupt buffer
IOT MICROINSTRUCTIONS FOR TSS/8 MONITOR
IOT 6000
Keyboard/Reader
KSF 6031
KCC 6032
KRS 6034
KRB 6036
KSB 6400
SBC 6401
KSR 6030
Teleprinter/Punch
TSF 6041
TCF 6042
TPC 6044
TLS 6046
SAS 6040
High-Speed Reader (Type РСО2)
RSF 6011
RRB 6012
RFC 6014
RRS 6010
(See Time-Sharing System User's Guide ,
DEC-T8-MRFB-D .)
skip if keyboard/reader flag = 1
clear AC & keyboard/reader flag
read keyboard/reader buffer
clear AC & read keyboard buffer, & clear
keyboard flag
set keyboard break
set buffer control flags
read keyboard string
skip if teleprinter/punch flag = 1
clear teleprinter/punch flag
load teleprinter/punch buffer,
select & print
load teleprinter/punch buffer,
select & print, and clear teleprinter/punch
flag
send a string
skip if reader flag = 1
read reader buffer & clear flag
clear flag & buffer & fetch character
read reader string
B-3
Operation Event Time
skip if punch flag = 1
clear flag & buffer
load buffer & punch character
clear flag & buffer, load & punch
punch string
load status register A 3
skip on flags ]
read status register B 2
user run time
time of day
return clock rate
Date
quantum synchronization
set timer
skip on TSS/8
user
set switch register
check status
assign device
release device
duplex
console
Remame File
Open File
Close File
Read File
Protect File
Write File
Create File
Extend File
Reduce File
File Information
Segment Size
Segment Count
Account Number
Mnemonic Code
High-Speed Punch (Type PC03)
PSF 6021
PCF 6022
PPC 6024
PLS 6026
PST 6020
DECtape Transport (Type TU55) and Control (Type TCO1)
DTXA 6764
DTSF 6771
DTRB 6772
Program Control
URT 6411
TOD 6412
RCR 6413
DATE 6414
SYN 6415
STM 6416
TSS 6420
USE 6421
SSW 6430
CKS 6200
ASD 6440
REL 6442
DUP 6402
CON 6422
File Control
REN 6600
OPEN 6601
CLOS 6602
RFILE 6603
PROT 6604
WFILE 6605
CRF 6610
EXT 6611
RED 6612
FINF 6613
SIZE 6614
SEGS 6406
ACT 6617
WHO 6616
Who
PAL-D INDEX
Absolute location 10 to 17, 1-10
Absolute and relative addresses, 1-13
Accumulator, 1-15
Accumulator Register, 1-6
Additional features, 1-1
Addition/Subtraction, 2's complement, see 2s
complement, addition/subtraction
Address Assignments, 1-8
Autoindexing, 1-10
Current Address Indicator, 1-9
Indirect Addressing, 1-9
Literals, 1-11
Location counter, 1-8
Origin, 1-8
Starting address, 1-8
Address field, 1-12
Address Indicator, Current, see Current Address
Indicator
Alphabetic Characters, 1-2
Altering Symbol Table, 2-3
ASCII, 2-3
Basic instructions, 2-3
CONT, 2-3
Disk Monitor System, 2-3
EXPUNGE, 2-3
FIXTAB, 2-3
IOT's symbol table, 2-3
Pass 1, 2-3
Permanent symbol table, 2-3
Symbolic program, 2-3
Ampersand, 1-8
AND group, 1-14, 1-1
Arithmetic and Logical Operators, 1-8
Ampersand, 1-8
Boolean AND, 1-8
Boolean inclusive OR, 1-8
Exclamation Mark, 1-8
Minus, 1-8
Modulo 4096, 1-8
Plus, 1-8
Space, 1-8
2s complement addition/subtraction, 1-8
ASCII, 2-3
Assembler, 1-1, 1-4, 3-2
Assembly, 3-3, 4-2
Listing, 4-2
Pass 1, 4-2
Pass 2, 4-2
Pass 3, 4-3
Third pass, 4-2
Asterisk, 4-1, 4-2
Augmented Instructions, 1-14
Input-Output Transfer Microinstructions, 1-14,
1-15
Operate Microinstructions, 1-14
Autoindexing, 1-10
Absolute location 10 to 17, 1-10
Autoindex registers, 1-10
Incrementation, 1-11
Interpage references, 1-10
Autoindex registers, 1-10
Basic instructions, 2-3
BE, 5-1
PAL-D INDEX (Cont)
Binary coded tape, 4-2
Binary Loader, 4-3
Binary representation, 1-6
Binary word, 2-1
Boolean AND, 1-8
Boolean inclusive OR, 1-8
Build Monitor, 3-1
Carriage Return (4), 1-3
Carriage return-line feed (as terminator), 1-3
Central processor, 1-15
Characters, Alphabetic, see Alphabetic
Chraacters
, ignored, see ignored characters
, Legal, see Legal Characters
, Numeric, see Numeric characters
, Special, see Special Characters
, Symbols for nonprinting, see Symbols
for nonprinting characters
Checksum, 4-2
Checksum error, 3-1
CLC, 2-1
Clear, 1-14
Combined Operate Microinstructions, B-1
Combining symbols and numbers, 1-8
Comma, 1-6
COMMENT, 1-3
Comments, 1-4
Notes, 1-4
Complement, 1-14
Condition, skip, 1-15
CONT, 2-3
CTRL/C (tC), 3-3
CTRL/P (tP), 3-3
Current Address indicator, 1-9
Incrementation, 1-9
Point or period, 1-9
Current Location counter, 2-1, 4-1
CLC, 2-1
Integer, 2-1
п, 2-1
PAGE n, 2-1
PAGE, 2-1
Current page, 1-12
Current page literal, 5-1
Current page literal buffer, 1-12
Data words, 4-2
DDT-8, 4-2
DE, 5-1
Debugging, 4-2
DECIMAL, 2-2
DECtape, 3-1, 4-1
Defined symbol, 1-6
Delimitor, 2-2
Device error, 5-1
Device full, 5-1
DF, 5-1
DF32 Disk, 1-1
DS32 Disk, 1-1
Direct Assignment, 1-7
Symbols, 1-7
Symbol Table, 1-7
Disk Debugging Tape, 1-1
Disk Monitor System, 2-3, 3-1
Dollar Sign ($), 2-3, 4-1, 5-2
Editor, 1-4, 4-1
Elements of statement, 1-4
End of File, 2-3
PAUSE, 2-3
PAUSE pseudo-op, 2-3
Segmented program, 2-3
End of Program, 2-3
Dollar Sign ($), 2-3
Error checks, 5-1
Error code, 5-1
Error Diagnostics, 4-2, 5-1
BE, 5-1
Current page literals, 5-1
DE, 5-1
Device error, 5-1
Device full, 5-1
DF, 5-1
Dollar Sign ($), 5-2
Error checks, 5-1
Error code, 5-1
Error message, 5-1
Error message format, 5-1
IC, 5-1
ID, 5-1
IE, 5-1
II, 5-1
Illegal character, 5-1
Illegal equals, 5-1
Illegal indirect, 5-1
Illegal redefinition, 5-1
Literal nesting, 5-1
Nonzero page, 5-2
Page 0 exceeded, 5-2
PE, 5-2
PH, 5-2
Phase error, 5-2
PAL-D INDEX (Cont)
Program terminator, 5-2
SE, 5-2
Source language, 5-1
SYM, 5-2
Symbol table exceeded, 5-2
Undefined symbol, 5-2
US, 5-2
ZE, 5-2
Error message, 5-1, 5-2
Error messages format, see Format of error messages
Evaluating Expressions, 1-8
Arithmetic operator, 1-8
Combining symbols and numbers, 1-8
Expression evaluating, 1-8
Logical operator, 1-8
Evaluation, 1-6
Exclamation mark, 1-8
EXPUNGE, 2-3
Extended Memory, 2-1
Binary word, 2-1
FIELD, 2-1
FIELD n, 2-1
Field setting, 2-1
Loader, 2-1
Pass 2, 2-1
FIELD, 2-1
FIELD n, 2-1
Fields, 1-3
File, End of, see End of File
FIXTAB, 2-3
Format Effectors, 1-3, 4-1
Carriage Return ( ¢), 1-3
Carriage return~line feed (as terminator), 1-3
COMMENT, 1-3
Fields, 1-3
List, 1-3
Semicolon (as terminator), 1-3
Slash (/), 1-3
Statement terminator, 1-3
Tabulations, 1-3
Format of error messages, 5-1
Format memory reference instruction, 1-12
General Form of statement, 1-4
Group 1 microinstructions, 1-14
Group 2 microinstructions, 1-14
Group 1 operate microinstructions, B-1
Group 2 operate microinstructions, B~1
I, 1-9, 1-10
IC, 5-1
ID, 5-1
IE, 5-1
Ignored characters, 1-2, 4-1
II, 1-10, 5-1
Illegal characters, 1-3, 5-1
Comment field, 1-3
Error message, 1-3
IC, 1-3
TEXT field, 1-3
Illegal equals, 5-1
Illegal indirect, 5-1
Illegal redefinition, 5-1
Inclusive OR, 1-15
Increment, 1-14
Incrementation, 1-9, 1-11
PAL-D INDEX (Cont)
Indirect Addressing, 1-9
I, 1-9, 1-10
II, 1-10
Illegal indirect, 1-10
Indirect address linkage, 1-9, 1-10
Indirect bit, 1-9
Off-page reference, 1-9, 1-10
Indirect address linkage, 1-92, 1-10
Indirect bit, 1-9
Input file, 3-3
Input-output device, 1-15
Input-Output Transfer microinstructions, 1-15
Central processor, 1-15
Input-output device, 1-15
IOT, 1-15
Operation of peripheral equipment, 1-15
Instructions, 1-12
Augmented instructions, 1-14
Memory reference instructions, 1-12
Integer, 2-1
Interpage references, 1-10
IOT, 1-5, 1-15
IOT microinstructions, B-2
IOT's symbol table, 2-3
Labels, 1-4, also see Symbols 1-5
Language, 1-1
Leader code, 4-2
Left parenthesis, 1-11
Legal characters, 1-2
Alphabetic characters, 1-2
Ignored characters, 1-2
Nonprinting characters, 1-2
PAL-D INDEX (Cont)
Numeric characters, 1-2
Special characters, 1-2
Link, 1-15
List, 1-3
Listing, 2-2, 4-2, 4-3
Listing control, 2-2
Pass 3, 2-2
XLIST, 2-2
Literal buffer, current page, see Current Page
literal buffer
Literal nesting, 5-1
Literals, 1-11, 1-12
Left parenthesis, 1-11
Nesting literals, 1-11
Square brackets, 1-11
Loader , 2-1, 3-1
Loading PAL-D, 3-1
Checksum error, 3-1
CTRL/P (+P), 3-1
Loader, 3-1
Question Mark (?), 3-1
Two-pass load, 3-1
Location counter, 1-8, 1-9
Logical AND, 1-15
Logical operator, 1-8
Low speed paper tape punch, 4-3
Machine instruction, 1-14
Memory , Extended, see Extended Memory
Memory page, 1-13
Memory Reference instructions, 1-12, B-1
Address Field, 1-12
Current page, 1-12
Format memory reference instruction, 1-12
Off-page referencing, 1-13
Page zero, 1-12
Paging, 1-13
Minus, 1-8
Monitor, 3-1, 3-2
n, page, 2-1
Names file, 4-1
ND, 4-6, 5-2
Nesting literals, 1-11
Current page literal buffer, 1-12
Literals, 1-12
Nonzero page, 1-12
Pass 2, 1-12
Quote, 1-12
Relative address 177, 1-12
Nonprinting characters, 1-2
Nonzero page, 1-12, 5-2
Notes, 1-4 |
Numbers, 1-7
Arithmetic and logical operators, 1-8
Evaluating expressions, 1-8
Pseudo-operators, 1-8
Radix, 1-8
Radix control, 1-8
Numeric characters, 1-2
OCTAL, 2-2
Octal code, 4-3
Off-page referencing, 1-9, 1-10, 1-13
Current page, 1-13
Memory page, 1-13
Operands, 1-4
Operate microinstructions, 1-14
Accumulator, 1-15
AND group, 1-14, 1-15
Clear, 1-14
Complement, 1-14
Condition skip, 1-15
Group 1 microinstructions, 1-14
Group 2 microinstructions
Inclusive OR, 1-15
Increment, 1-14
Link, 1-15
Logical AND, 1-15
Machine instruction, 1-14
OR group, 1-14, 1-15
Rotate, 1-14
Skipping, 1-14
Operation of peripheral equipment, 1-15
Operators, 1-4
Operators, Arithmetic and Logical, see
Arithmetic and Logical Operators
OR group, 1-14, 1-15
ORed operation codes, 1-7
Origin, 1-8, 4-1
Origin setting, 4-2
Output device, 3-2
Output file, 3-2
PAGE, 2-1
PAGE n, 2-1
Page zero, 1-12
Page 0 exceeded, 5-2
Paging, 1-13
Absolute and relative addresses, 1-13
PAL-D Assembler, 3-2
PAL~D INDEX (Cont)
PAL-D, definition, 1-1
PAL III Assembler, 1-1
Paper tape, 3-1
Paper tape punch, low speed, see Low speed paper
tape punch
Pass 1, 2-3, 4-2
Debugging, 4-2
DDT-8, 4-2
Error Diagnostics, 4-2
Source tape, 4-2
US (Undefined Symbol), 4-2
User's symbol table, 4-2
Pass 2, 1-12, 2-1, 4-2
Asterisk, 4-2
Binary coded tape, 4-2
Binary loader, 4-3
Checksum, 4-2
Data words, 4-2
Diagnostic messages, 4-3
Leader code, 4-2
Low speed paper tape punch, 4-3
Origin setting, 4-2
Rubouts, 4-3
Trailer code, 4-2
Pass 3, 2-1, 2-2, 4-3
Listing, 4-3
Octal code, 4-3
Source language, 4-3
Source tape, 4-3
PAUSE, 2-3, 4-1
PAUSE pseudo-op, 2-3
PE, 5-2
Period or point, 1-9
Permanent symbol table, 1-5, 1-7, 2-1, 2-3
PAL-D INDEX (Cont)
PH, 5-2
Phase error, 5-2
Plus, 1-8
Point or period, 1-9
Program, End of , see End of Program
Program tape, 4-1
Asterisk, 4-1 |
Current location counter, 4-1
Dollar sign ($), 4-1
Format effectors, 4-1
Ignored characters, 4-1
Origin, 4-1
PAUSE, 4-1
Program terminator, 5-2
Pseudo-op codes, 1-7
Pseudo-operators, 1-8, 2-1, 3-1
Pseudo-ops, 2-1, 2-2
Question Mark (?), 3-1
Quote, 1-12
Radix, 1-8, 2-2
RADIX Control, 1-8, 2-2
DECIMAL, 2-2
OCTAL, 2-2
Pseudo-op, 2-2
Radix, 2-2
Relative address 177, 1-12
Relative addresses, Absolute and, see Absolute
and relative addresses
Requirements, 1-1
Rotate, 1-14
Rubouts, 4-3
Saving PAL-D, 3-2
PAL-D Assembler, 3-2
Expanding user's symbol table, 3-2
SE, 5-2
Segmented program, 2-3
Semicolon (as terminator), 1-3
Skipping, 1-14
Slash ( / ), 1-3
Source language, 4-3, 5-1
Source language tape, 4-1
Source programs, 1-4
Source tape, 4-2, 4-3
Space, 1-8
Special characters, 1-2
Square brackets, 1-11
Statements, 1-4
Assembler, 1-4
Comments, 1-4
Editor, 1-4
Elements, 1-4
General form, 1-4
Labels, 1-4
Operands, 1-4
Operators, 1-4
Source programs, 1-4
Teletype, 1-4
Statement terminator, 1-3
Starting address, 1-8
String, 1-5
String of text, 2-2
SYM, 3-2, 5-2
Symbol Distinction, 1-5
Permanent symbols, 1-5
PAL-D INDEX (Cont)
User-defined symbols, 1-5
Symbol list, B-1
Combined operate microinstructions, B-1
Group 1 operate microinstructions, B-1
Group 2 operate microinstructions, B-1
IOT microinstructions, B-2
Memory reference instructions, B-1
Pseudo -operators, B-1
Symbol table, Altering, see Altering symbol table
Symbol table exceeded, 5-2
Symbol Tables, 1-7
Direct assignment statements, 1-7
Mnemonic op codes, 1-7
Permanent symbol table, 1-7
Pseudo-op codes, 1-7
User's symbol table, 1-7
Value assigned, 1-7
Symbol table, User's, see User's symbol table
Symbol used as a label, 1-6
Symbolic addresses, 1-6
Comma, 1-6
Defined symbol, 1-6
Symbol used as a label, 1-6
Symbolic Operands, 1-6
Accumulator register, 1-6
Values of symbolic operands, 1-6
Symbolic operands, Values of, see Values of
symbolic operands
Symbolic operators, 1-6
Terminator, 1-6
Symbolic program, 2-3
Symbolic tape, 4-1
Symbolic Tape Editor, 1-1
Symbols, 1-5, 1-7
String, 1-5
Symbol Distinction, 1-5
Symbolic Addresses, 1-6
Symbolic Operands, 1-6
Symbolic operators, 1-6
Symbol tables, 1-7
Symbols for nonprinting characters, 1-2
Symbols, User-defined, see User-defined symbols
Syntax, 1-1
Illegal characters, 1-3
Format effectors, 1-3
Legal characters, 1-2
Tables, Symbol, see Symbol tables
Tabulations, 1-3
TCO1 DECtape, 1-1
Teletype, 1-4
Terminator, 1-6
TEXT, 2-2
Text Facility, 2-2
Delimitor, 2-2
String of text, 2-2
TEXT, 2-2
USASCII, 2-2
Third pass, 4-2
Trailer code, 4-2
Transferring PAL-D, 3-2
2s complement addition/subtraction, 1-8
Undefined symbol, 5-2
US (Undefined symbol), 4-2, 5-2
USASCII, 2-2,4-1
USASCII Character Set, A-1
User-defined symbols, 1-5
User intervention, 3-3
User's symbol table, 1-7, 3-2, 4-2
Using PAL-D, 3-2
Assembly, 3-3
CTRL/C (tC), 3-3
CTRL/P (1P), 3-3
Input file, 3-3
Monitor, 3-2
Output device, 3-2
Output file, 3-2
Transferring PAL-D, 3-2
User intervention, 3-3
Value assigned, 1-7
Values of symbolic operands, 1-6
XLIST, 2-2
ZE, 5-2
PAL-D INDEX (Cont)
PAL-D ASSEMBLER
DEC-D8-ASAB-D
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