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/*
HEADER: CUG149;
TITLE: 6801 Cross-Assembler (Portable);
FILENAME: A68.DOC;
VERSION: 3.5;
DATE: 08/27/1988;
DESCRIPTION: "This program lets you use your computer to assemble
code for the Motorola 6800, 6801, 6802, 6803, 6808,
and 68701 microprocessors. The program is written in
portable C rather than BDS C. All assembler features
are supported except relocation, linkage, and macros.";
KEYWORDS: Software Development, Assemblers, Cross-Assemblers,
Motorola, MC6800, MC6801;
SEE-ALSO: CUG113, 6800 Cross-Assembler;
SYSTEM: CP/M-80, CP/M-86, HP-UX, MSDOS, PCDOS, QNIX;
COMPILERS: Aztec C86, Aztec CII, CI-C86, Eco-C, Eco-C88, HP-UX,
Lattice C, Microsoft C, QNIX C;
WARNINGS: "This program has compiled successfully on 2 UNIX
compilers, 5 MSDOS compilers, and 2 CP/M compilers.
A port to BDS C would be extremely difficult, but see
volume CUG113. A port to Toolworks C is untried."
AUTHORS: William C. Colley III;
*/
6800/6801 Cross-Assembler (Portable)
Version 3.5
Copyright (c) 1985 William C. Colley, III
The manual such as it is.
Legal Note: This package may be used for any commercial or
non-commercial purpose. It may be copied and
distributed freely provided that any fee charged
by the distributor of the copy does not exceed the
sum of: 1) the cost of the media the copy is
written on, 2) any required costs of shipping the
copy, and 3) a nominal handling fee. Any other
distribution requires the written permission of
the author. Also, the author's copyright notices
shall not be removed from the program source, the
program object, or the program documentation.
Note to Users of Previous Versions of the Package
This version of the 6800/6801 Cross-Assembler package is a
total rewrite of the old BDS C version. During the recoding, a
few new "bells and whistles" found their way into the program.
They are:
1) Labels can now be as long as an entire line, and all
characters are significant. In older versions, only 8
characters were significant.
2) Listing control has been added to the output routine.
The listing can be broken up into pages and a running
header can be added to the top of each page. See the
TITL and PAGE pseudo-ops for details.
3) Default extensions for the source, list, and object
(hex) files are no longer supplied.
4) Include files are now supported and may be nested.
Alas, as the sage says, "There ain't no such thing as a free
lunch." Massive internal changes had to be made to divorce the
program from the CP/M-80 environment. These changes, the fact
that full-featured, 8-bit C compilers generate less efficient
code than BDS C, and the fact that I have leaned on the over-
powered, slow library function printf() heavily have caused the
package to run about a factor of 4 slower than the older
versions. The package also takes 3-6K more disk space to store
than it used to take.
On the plus side, however, the code is written in "portable"
C, so all of the UNIX users, and the new crop of IBM-PC users
should be able to compile and run the package almost without
modification. The internal structure of the package is cleaner
than ever, so it should be very easy to hack on and turn into
cross-assemblers for other 8-bit processors. Finally, the source
code has shrivelled almost to nothing since many tasks have been
off-loaded onto standard library functions, so the need to
"squeeze" the source code is gone.
Table of Contents
1.0 How to Use the Cross-Assembler Package .................. 3
2.0 Format of Cross-Assembler Source Lines .................. 4
2.1 Labels ............................................. 5
2.2 Numeric Constants .................................. 5
2.3 String Constants ................................... 6
2.4 Expressions ........................................ 6
3.0 Machine Opcodes ......................................... 7
3.1 Opcodes -- No Arguments ............................ 8
3.2 Opcodes -- One Register Argument ................... 8
3.3 Opcodes -- One Memory Argument ..................... 8
3.4 Opcodes -- One Register or Memory Argument ......... 8
3.5 Opcodes -- One Memory or Immediate Argument ........ 8
3.6 Opcodes -- Two Arguments ........................... 9
3.7 Opcodes -- Relative Branches ....................... 9
3.8 Opcodes -- Direct Addressing ....................... 9
4.0 Pseudo Opcodes .......................................... 10
4.1 Pseudo-ops -- CPU .................................. 10
4.2 Pseudo-ops -- END .................................. 10
4.3 Pseudo-ops -- EQU .................................. 10
4.4 Pseudo-ops -- FCB .................................. 11
4.5 Pseudo-ops -- FCC .................................. 11
4.6 Pseudo-ops -- FDB .................................. 11
4.7 Pseudo-ops -- IF, ELSE, ENDI ....................... 11
4.8 Pseudo-ops -- INCL ................................. 12
4.9 Pseudo-ops -- ORG .................................. 13
4.10 Pseudo-ops -- PAGE ................................. 13
4.11 Pseudo-ops -- RMB .................................. 13
4.12 Pseudo-ops -- SET .................................. 13
4.13 Pseudo-ops -- TITL ................................. 14
5.0 Assembly Errors ......................................... 14
5.1 Error * -- Illegal or Missing Statement ............ 14
5.2 Error ( -- Parenthesis Imbalance ................... 15
5.3 Error " -- Missing Quotation Mark .................. 15
5.4 Error A -- Illegal Addressing Mode ................. 15
5.5 Error B -- Branch Target Too Distant ............... 15
5.6 Error D -- Illegal Digit ........................... 15
5.7 Error E -- Illegal Expression ...................... 15
5.8 Error I -- IF-ENDI Imbalance ....................... 16
5.9 Error L -- Illegal Label ........................... 16
5.10 Error M -- Multiply Defined Label .................. 16
5.11 Error O -- Illegal Opcode .......................... 16
5.12 Error P -- Phasing Error ........................... 16
5.13 Error R -- Illegal Register ........................ 17
5.14 Error S -- Illegal Syntax .......................... 17
5.15 Error T -- Too Many Arguments ...................... 17
5.16 Error U -- Undefined Label ......................... 17
5.17 Error V -- Illegal Value ........................... 17
1
6.0 Warning Messages ........................................ 17
6.1 Warning -- Illegal Option Ignored .................. 18
6.2 Warning -- -l Option Ignored -- No File Name ....... 18
6.3 Warning -- -o Option Ignored -- No File Name ....... 18
6.4 Warning -- Extra Source File Ignored ............... 18
6.5 Warning -- Extra Listing File Ignored .............. 18
6.6 Warning -- Extra Object File Ignored ............... 18
7.0 Fatal Error Messages .................................... 18
7.1 Fatal Error -- No Source File Specified ............ 18
7.2 Fatal Error -- Source File Did Not Open ............ 18
7.3 Fatal Error -- Listing File Did Not Open ........... 19
7.4 Fatal Error -- Object File Did Not Open ............ 19
7.5 Fatal Error -- Error Reading Source File ........... 19
7.6 Fatal Error -- Disk or Directory Full .............. 19
7.7 Fatal Error -- File Stack Overflow ................. 19
7.8 Fatal Error -- If Stack Overflow ................... 19
7.9 Fatal Error -- Too Many Symbols .................... 19
2
1.0 How to Use the Cross-Assembler Package
First, the question, "What does a cross-assembler do?" needs
to be addressed as there is considerable confusion on this point.
A cross-assembler is just like any other assembler except that it
runs on some CPU other than the one for which it assembles code.
For example, this package assembles 6801 source code into 6801
object code, but it runs on an 8080, a Z-80, an 8088, or whatever
other CPU you happen to have a C compiler for. The reason that
cross-assemblers are useful is that you probably already have a
CPU with memory, disk drives, a text editor, an operating system,
and all sorts of hard-to-build or expensive facilities on hand.
A cross-assembler allows you to use these facilites to develop
code for a 6801.
This program requires one input file (your 6801 source code) and
zero to two output files (the listing and the object). The input
file MUST be specified, or the assembler will bomb on a fatal
error. The listing and object files are optional. If no listing
file is specified, no listing is generated, and if no object file
is specified, no object is generated. If the object file is
specified, the object is written to this file in "Intel
hexadecimal" format.
The command line for the cross-assembler looks like this:
A68 source_file { -l list_file } { -o object_file }
where the { } indicates that the specified item is optional.
Some examples are in order:
a68 test68.asm source: test68.asm
listing: none
object: none
a68 test68.asm -l test68.prn source: test68.asm
listing: test68.prn
object: none
a68 test68.asm -o test68.hex source: test68.asm
listing: none
object: test68.hex
a68 test68.asm -l test68.prn -o test68.hex
source: test68.asm
listing: test68.prn
object: test68.hex
The order in which the source, listing, and object files are
specified does not matter. Note that no default file name exten-
sions are supplied by the assembler as this gives rise to porta-
bility problems.
3
2.0 Format of Cross-Assembler Source Lines
The source file that the cross-assembler processes into a
listing and an object is an ASCII text file that you can prepare
with whatever editor you have at hand. The most-significant
(parity) bit of each character is cleared as the character is
read from disk by the cross-assembler, so editors that set this
bit (such as WordStar's document mode) should not bother this
program. All printing characters, the ASCII TAB character ($09),
and newline character(s) are processed by the assembler. All
other characters are passed through to the listing file, but are
otherwise ignored.
The source file is divided into lines by newline char-
acter(s). The internal buffers of the cross-assembler will
accommodate lines of up to 255 characters which should be more
than ample for almost any job. If you must use longer lines,
change the constant MAXLINE in file A68.H and recompile the
cross-assembler. Otherwise, you will overflow the buffers, and
the program will mysteriously crash.
Each source line is made up of three fields: the label
field, the opcode field, and the argument field. The label field
is optional, but if it is present, it must begin in column 1.
The opcode field is optional, but if it is present, it must not
begin in column 1. If both a label and an opcode are present,
one or more spaces and/or TAB characters must separate the two.
If the opcode requires arguments, they are placed in the argument
field which is separated from the opcode field by one or more
spaces and/or TAB characters. Finally, an optional comment can
be added to the end of the line. This comment must begin with a
semicolon which signals the assembler to pass the rest of the
line to the listing and otherwise ignore it. Thus, the source
line looks like this:
{label}{ opcode{ arguments}}{;commentary}
where the { } indicates that the specified item is optional.
Some examples are in order:
column 1
|
v
GRONK LDAA X, OFFSET ; This line has everything.
STAA MAILBOX ; This line has no label.
BEEP ; This line has no opcode.
; This line has no label and no opcode.
; The previous line has nothing at all.
END ; This line has no argument.
4
2.1 Labels
A label is any sequence of alphabetic or numeric characters
starting with an alphabetic. The legal alphabetics are:
! & , . : ? [ \ ] ^ _ ` { | } ~ A-Z a-z
The numeric characters are the digits 0-9. Note that "A" is not
the same as "a" in a label. This can explain mysterious U
(undefined label) errors occurring when a label appears to be
defined.
A label is permitted on any line except a line where the
opcode is IF, ELSE, or ENDIF. The label is assigned the value of
the assembly program counter before any of the rest of the line
is processed except when the opcode is EQU, ORG, or SET.
Labels can have the same name as opcodes, but they cannot
have the same name as operators or registers. The reserved
(operator and register) names are:
A B AND EQ GE GT
HIGH LE LT LOW MOD NE
NOT OR SHL SHR X XOR
If a label is used in an expression before it is assigned a
value, the label is said to be "forward-referenced." For
example:
L1 EQU L2 + 1 ; L2 is forward-referenced here.
L2
L3 EQU L2 + 1 ; L2 is not forward-referenced here.
2.2 Numeric Constants
Numeric constants can be formed in two ways: the Intel
convention or the Motorola convention. The cross-assembler
supports both.
An Intel-type numeric constant starts with a numeric
character (0-9), continues with zero or more digits (0-9, A-F),
and ends with an optional base designator. The base designators
are H for hexadecimal, none or D for decimal, O or Q for octal,
and B for binary. The hex digits a-f are converted to upper case
by the assembler. Note that an Intel-type numeric constant
cannot begin with A-F as it would be indistinguishable from a
label. Thus, all of the following evaluate to 255 (decimal):
0ffH 255 255D 377O 377Q 11111111B
A Motorola-type numeric constant starts with a base
designator and continues with a string of one or more digits.
The base designators are $ for hexadecimal, none for decimal, @
for octal, and % for binary. As with Intel-type numeric
5
constants, a-f are converted to upper case by the assembler.
Thus, all of the following evaluate to 255 (decimal):
$ff 255 @377 %11111111
If a numeric constant has a value that is too large to fit
into a 16-bit word, it will be truncated on the left to make it
fit. Thus, for example, $123456 is truncated to $3456.
2.3 String Constants
A string constant is zero or more characters enclosed in
either single quotes (' ') or double quotes (" "). Single quotes
only match single quotes, and double quotes only match double
quotes, so if you want to put a single quote in a string, you can
do it like this: "'". In all contexts except the FCC statement,
the first character or two of the string constant are all that
are used. The rest is ignored. Noting that the ASCII codes for
"A" and "B" are $41 and $42, respectively, will explain the
following examples:
"" and '' evaluate to $0000
"A" and 'A' evaluate to $0041
"AB" evaluates to $4142
Note that the null string "" is legal and evaluates to $0000.
2.4 Expressions
An expression is made up of labels, numeric constants, and
string constants glued together with arithmetic operators,
logical operators, and parentheses in the usual way that
algebraic expressions are made. Operators have the following
fairly natural order of precedence:
Highest anything in parentheses
unary +, unary -
*, /, MOD, SHL, SHR
binary +, binary -
LT, LE, EQ, GE, GT, NE
NOT
AND
OR, XOR
Lowest HIGH, LOW
A few notes about the various operators are in order:
1) The remainder operator MOD yields the remainder from
dividing its left operand by its right operand.
2) The shifting operators SHL and SHR shift their left
operand to the left or right the number of bits
specified by their right operand.
6
3) The relational operators LT, LE, EQ, GE, GT, and NE can
also be written as <, <= or =<, =, >= or =>, and <> or
><, respectively. They evaluate to $FFFF if the
statement is true, 0 otherwise.
4) The logical opeators NOT, AND, OR, and XOR do bitwise
operations on their operand(s).
5) HIGH and LOW extract the high or low byte, of an
expression.
6) The special symbol * can be used in place of a label or
constant to represent the value of the program counter
before any of the current line has been processed.
Some examples are in order at this point:
2 + 3 * 4 evaluates to 14
(2 + 3) * 4 evaluates to 20
NOT %11110000 XOR %00001010 evaluates to %00000101
HIGH $1234 SHL 1 evaluates to $0024
@001 EQ 0 evaluates to 0
@001 = 2 SHR 1 evaluates to $FFFF
All arithmetic is unsigned with overflow from the 16-bit
word ignored. Thus:
32768 * 2 evaluates to 0
3.0 Machine Opcodes
The opcodes of the 6800 and 6801 processors are divided into
groups below by the type of arguments required in the argument
field of the source line. Opcodes that are peculiar to the 6801
are marked with an asterisk. A few notes on the source line
syntax are in order at this point:
1) Arguments can be supplied in any order. Thus, for
example, the following two source lines are equivalent:
LABEL ADD A X, 0 ;Mumble.
LABEL ADD A 0, X ;Mumble.
2) Multiple arguments may be separated from one another by
spaces, tabs, or commas except that an expression must
be separated from a following argument by a comma.
3) In the indexed addressing mode, the expression giving
the offset may be omitted. The default offset is 0.
4) The register designators A and B may be appended to the
opcode itself. Thus, for example, the following two
source lines are equivalent:
7
LABEL CLRA ;Mumble.
LABEL CLR A ;Mumble.
3.1 Opcodes -- No Arguments
The following opcodes allow no arguments at all in their
argument fields:
ABA ABX * ASLD * CBA CLC CLI
CLV DAA DES DEX INS INX
LSLD * LSRD * MUL * NOP PSHX * PULX *
RTI RTS SBA SEC SEI SEV
SWI TAB TAP TBA TPA TSX
TXS WAI
3.2 Opcodes -- One Register Argument
The following opcodes require one argument that is either
one of the register specifiers A or B:
PSH PUL
3.3 Opcodes -- One Memory Argument
The opcodes in this group require one argument from the
following list:
1) X, expression where expression is 0 thru 255
2) expression where expression is arbitrary
The opcodes are:
JMP JSR STD * STS STX
3.4 Opcodes -- One Register or Memory Argument
The opcodes in this group require one argument as per the
previous group or one of the register specifiers A or B. The
opcodes are:
ASL ASR CLR COM DEC INC
LSL LSR NEG ROL ROR TST
3.5 Opcodes -- One Memory or Immediate Argument
The opcodes in this group require one argument from the
following list:
8
1) X, expression where expression is 0-255
2) #expression where expression is arbitrary
3) expression where expression is arbitrary
The opcodes are:
ADDD * CPX LDD * LDS LDX SUBD *
3.6 Opcodes -- Two Arguments
The opcodes in this group require one of the register
specifiers A or B in addition to an argument from the following
list:
1) X, expression where expression is 0-255
2) #expression where expression is -128 thru 255 (not
permitted with opcode STA)
3) expression where expression is arbitrary
The opcodes are:
ADC ADD AND BIT CMP EOR
LDA ORA SBC STA SUB
3.7 Opcodes -- Relative Branches
The opcodes in this group require one argument that is an
expression whose value is in the range *-126 thru *+129. The
opcodes are:
BCC BCS BEQ BGE BGT BHI
BHS BLE BLO BLS BLT BMI
BNE BPL BRA BRN * BSR BVC
BVS
3.8 Opcodes -- Direct Addressing
Many opcodes of the 6800 and 6801 CPUs allow both one-byte
direct (or zero-page) addressing and two-byte extended
addressing. There is no way to explicitly call for one form of
addressing over the other. The assembler will choose direct
addressing if ALL of the following conditions are met:
1) The required expression contains no forward references.
2) The expression evaluates to 0-255.
9
3) The opcode allows direct addressing.
Otherwise, the assembler will choose extended addressing. Note
that this makes it desireable to declare your zero-page RAM
locations at the top of the program so that these locations will
not generate forward references and foil the assembler's attempts
to use direct addressing and shrink the object program.
4.0 Pseudo Opcodes
Unlike 6800/6801 opcodes, pseudo opcodes (pseudo ops) do not
represent machine instructions. They are, rather, directives to
the assembler. These directives require various numbers and
types of arguments. They will be listed individually below.
4.1 Pseudo-ops -- CPU
By default, the assembler does not recognize the additional
opcodes of the 6801 CPU. This prevents the assembler from
generating invalid 6800 object code. The additional 6801 opcodes
are turned on and off by this pseudo-op which requires one
argument whose value is either 6800 or 6801 (decimal). Thus:
CPU 6800 ;turns additional opcodes off
CPU 6801 ;turns additional opcodes on
4.2 Pseudo-ops -- END
The END pseudo-op tells the assembler that the source
program is over. Any further lines of the source file are
ignored and not passed on to the listing. If an argument is
added to the END statement, the value of the argument will be
placed in the execution address slot in the Intel hex object
file. The execution address defaults to the program counter
value at the point where the END was encountered. Thus, to
specify that the program starts at label START, the END statement
would be:
END START
If end-of-file is encountered on the source file before an
END statement is reached, the assembler will add an END statement
to the listing and flag it with a * (missing statement) error.
4.3 Pseudo-ops -- EQU
The EQU pseudo-op is used to assign a specific value to a
label, thus the label on this line is REQUIRED. Once the value
is assigned, it cannot be reassigned by writing the label in
column 1, by another EQU statement, or by a SET statement. Thus,
for example, the following statement assigns the value 2 to the
10
label TWO:
TWO EQU 1 + 1
The expression in the argument field must contain no forward
references.
4.4 Pseudo-ops -- FCB
The FCB (Form Constant Bytes) pseudo-op allows arbitrary
bytes to be spliced into the object code. Its argument is a
chain of zero or more expressions that evaluate to -128 thru 255
separated by commas. If a comma occurs with no preceding
expression, a $00 byte is spliced into the object code. The
sequence of bytes $FE $FF, $00, $01, $02 could be spliced into
the code with the following statement:
FCB -2, -1, , 1, 2
4.5 Pseudo-ops -- FCC
The FCC (Form Constant Characters) pseudo-op allows
character strings to be spliced into the object code. Its
argument is a chain of zero or more string constants separated by
blanks, tabs, or commas. If a comma occurs with no preceding
string constant, an S (syntax) error results. The string
contants are not truncated to two bytes, but are instead copied
verbatim into the object code. Null strings result in no bytes
of code. The message "Kaboom!!" could be spliced into the code
with the following statement:
FCC "Kaboom!!" ;This is 8 bytes of code.
4.6 Pseudo-ops -- FDB
The FDB (Form Double Bytes) pseudo-op allows 16-bit words to
be spliced into the object code. Its argument is a chain of zero
or more expressions separated by commas. If a comma occurs with
no preceding expression, a word of $0000 is spliced into the
code. The word is placed into memory high byte in low address,
low byte in high address as per standard Motorola order. The
sequence of bytes $FE $FF $00 $00 $01 $02 could be spliced into
the code with the following statement:
FDB $FEFF, , $0102
4.7 Pseudo-ops -- IF, ELSE, ENDI
These three pseudo-ops allow the assembler to choose whether
or not to assemble certain blocks of code based on the result of
an expression. Code that is not assembled is passed through to
11
the listing but otherwise ignored by the assembler. The IF
pseudo-op signals the beginning of a conditionally assembled
block. It requires one argument that may contain no forward
references. If the value of the argument is non-zero, the block
is assembled. Otherwise, the block is ignored. The ENDI pseudo-
op signals the end of the conditionally assembled block. For
example:
IF EXPRESSION ;This whole thing generates
FCB $01, $02, $03 ; no code whatsoever if
ENDI ; EXPRESSION is zero.
The ELSE pseudo-op allows the assembly of either one of two
blocks, but not both. The following two sequences are
equivalent:
IF EXPRESSION
... some stuff ...
ELSE
... some more stuff ...
ENDI
TEMP_LAB SET EXPRESSION
IF TEMP_LAB NE 0
... some stuff ...
ENDI
IF TEMP_LAB EQ 0
... some more stuff ...
ENDI
The pseudo-ops in this group do NOT permit labels to exist
on the same line as the status of the label (ignored or not)
would be ambiguous.
All IF statements (even those in ignored conditionally
assembled blocks) must have corresponding ENDI statements and all
ELSE and ENDI statements must have a corresponding IF statement.
IF blocks can be nested up to 16 levels deep before the
assembler dies of a fatal error. This should be adequate for any
conceivable job, but if you need more, change the constant
IFDEPTH in file A68.H and recompile the assembler.
4.8 Pseudo-ops -- INCL
The INCL pseudo-op is used to splice the contents of another
file into the current file at assembly time. The name of the
file to be INCLuded is specified as a normal string constant, so
the following line would splice the contents of file "const.def"
into the source code stream:
INCL "const.def"
12
INCLuded files may, in turn, INCLude other files until four
files are open simultaneously. This limit should be enough for
any conceivable job, but if you need more, change the constant
FILES in file A68.H and recompile the assembler.
4.9 Pseudo-ops -- ORG
The ORG pseudo-op is used to set the assembly program
counter to a particular value. The expression that defines this
value may contain no forward references. The default initial
value of the assembly program counter is $0000. The following
statement would change the assembly program counter to $F000:
ORG $F000
If a label is present on the same line as an ORG statement,
it is assigned the new value of the assembly program counter.
4.10 Pseudo-ops -- PAGE
The PAGE pseudo-op always causes an immediate page ejection
in the listing by inserting a form feed ('\f') character before
the next line. If an argument is specified, the argument
expression specifies the number of lines per page in the listing.
Legal values for the expression are any number except 1 and 2. A
value of 0 turns the listing pagination off. Thus, the following
statement cause a page ejection and would divide the listing into
60-line pages:
PAGE 60
4.11 Pseudo-ops -- RMB
The RMB (Reserve Memory Bytes) pseudo-op is used to reserve
a block of storage for program variables, or whatever. This
storage is not initialized in any way, so its value at run time
will usually be random. The argument expression (which may
contain no forward references) is added to the assembly program
counter. The following statement would reserve 10 bytes of
storage called "STORAGE":
STORAGE RMB 10
4.12 Pseudo-ops -- SET
The SET pseudo-op functions like the EQU pseudo-op except
that the SET statement can reassign the value of a label that has
already been assigned by another SET statement. Like the EQU
statement, the argument expression may contain no forward
references. A label defined by a SET statement cannot be
redefined by writing it in column 1 or with an EQU statement.
13
The following series of statements would set the value of label
"COUNT" to 1, 2, then 3:
COUNT SET 1
COUNT SET 2
COUNT SET 3
4.13 Pseudo-ops -- TITL
The TITL pseudo-op sets the running title for the listing.
The argument field is required and must be a string constant,
though the null string ("") is legal. This title is printed
after every page ejection in the listing, therefore, if page
ejections have not been forced by the PAGE pseudo-op, the title
will never be printed. The following statement would print the
title "Random Bug Generator -- Ver 3.14159" at the top of every
page of the listing:
TITL "Random Bug Generator -- Ver 3.14159"
5.0 Assembly Errors
When a source line contains an illegal construct, the line
is flagged in the listing with a single-letter code describing
the error. The meaning of each code is listed below. In
addition, a count of the number of lines with errors is kept and
printed on the C "stderr" device (by default, the console) after
the END statement is processed. If more than one error occurs in
a given line, only the first is reported. For example, the
illegal label "=$#*'(" would generate the following listing line:
L 0000 FF 00 00 =$#*'( CPX #0
5.1 Error * -- Illegal or Missing Statement
This error occurs when either:
1) the assembler reaches the end of the source file
without seeing an END statement, or
2) an END statement is encountered in an INCLude file.
If you are "sure" that the END statement is present when the
assembler thinks that it is missing, it probably is in the
ignored section of an IF block. If the END statement is missing,
supply it. If the END statement is in an INCLude file, delete
it.
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5.2 Error ( -- Parenthesis Imbalance
For every left parenthesis, there must be a right paren-
thesis. Count them.
5.3 Error " -- Missing Quotation Mark
Strings have to begin and end with either " or '. Remember
that " only matches " while ' only matches '.
5.4 Error A -- Illegal Addressing Mode
This error occurs if the index register designator X is used
with a machine opcode that does not permit indexed addressing or
if the immediate designator # is used with an opcode that does
not permit immediate addressing.
5.5 Error B -- Branch Target Too Distant
The 6800 relative branch instructions will only reach -126
to +129 bytes from the first byte of the branch instruction. If
this error occurs, the source code will have to be rearranged to
shorten the distance to the branch target address or a long
branch instruction that will reach anywhere (JMP or JSR) will
have to be used.
5.6 Error D -- Illegal Digit
This error occurs if a digit greater than or equal to the
base of a numeric constant is found. For example, a 2 in a
binary number would cause a D error. Especially, watch for 8 or
9 in an octal number.
5.7 Error E -- Illegal Expression
This error occurs because of:
1) a missing expression where one is required
2) a unary operator used as a binary operator or vice-
versa
3) a missing binary operator
4) a SHL or SHR count that is not 0 thru 15
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5.8 Error I -- IF-ENDI Imbalance
For every IF there must be a corresponding ENDI. If this
error occurs on an ELSE or ENDI statement, the corresponding IF
is missing. If this error occurs on an END statement, one or
more ENDI statements are missing.
5.9 Error L -- Illegal Label
This error occurs because of:
1) a non-alphabetic in column 1
2) a reserved word used as a label
3) a missing label on an EQU or SET statement
4) a label on an IF, ELSE, or ENDI statement
5.10 Error M -- Multiply Defined Label
This error occurs because of:
1) a label defined in column 1 or with the EQU statement
being redefined
2) a label defined by a SET statement being redefined
either in column 1 or with the EQU statement
3) the value of the label changing between assembly passes
5.11 Error O -- Illegal Opcode
The opcode field of a source line may contain only a valid
machine opcode, a valid pseudo-op, or nothing at all. Anything
else causes this error. Note that the unique 6801 opcodes are
not valid until they are enabled with the CPU statement.
5.12 Error P -- Phasing Error
This error occurs because of:
1) a forward reference in a CPU, EQU, ORG, RMB, or SET
statement
2) a label disappearing between assembly passes
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5.13 Error R -- Illegal Register
This error occurs either when the register designator A or B
is used with a machine opcode that does not permit it, or when
the register designator is missing with a machine opcode that
requires it.
5.14 Error S -- Illegal Syntax
This error means that an argument field is scrambled. Sort
the mess out and reassemble.
5.15 Error T -- Too Many Arguments
This error occurs if there are more items (expressions,
register designators, etc.) in the argument field than the opcode
or pseudo-op requires. The assembler ignores the extra items but
issues this error in case something is really mangled.
5.16 Error U -- Undefined Label
This error occurs if a label is referenced in an expression
but not defined anywhere in the source program. If you are
"sure" you have defined the label, note that upper and lower case
letters in labels are different. Defining "LABEL" does not
define "Label."
5.17 Error V -- Illegal Value
This error occurs because:
1) an index offset is not 0 thru 255, or
2) an 8-bit immediate value is not -128 thru 255, or
3) an FCB argument is not -128 thru 255, or
4) a CPU argument is not 6800 and not 6801, or
5) an INCL argument refers to a file that does not exist.
6.0 Warning Messages
Some errors that occur during the parsing of the cross-
assembler command line are non-fatal. The cross-assembler flags
these with a message on the C "stdout" device (by default, the
console) beginning with the word "Warning." The messages are
listed below:
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6.1 Warning -- Illegal Option Ignored
The only options that the cross-assembler knows are -l and
-o. Any other command line argument beginning with - will draw
this error.
6.2 Warning -- -l Option Ignored -- No File Name
6.3 Warning -- -o Option Ignored -- No File Name
The -l and -o options require a file name to tell the
assembler where to put the listing file or object file. If this
file name is missing, the option is ignored.
6.4 Warning -- Extra Source File Ignored
The cross-assembler will only assemble one file at a time,
so source file names after the first are ignored. To assemble a
second file, invoke the assembler again. Note that under CP/M-
80, the old trick of reexecuting a core image will NOT work as
the initialized data areas are not reinitialized prior to the
second run.
6.5 Warning -- Extra Listing File Ignored
6.6 Warning -- Extra Object File Ignored
The cross-assembler will only generate one listing and one
object file per assembly run, so -l and -o options after the
first are ignored.
7.0 Fatal Error Messages
Several errors that occur during the parsing of the cross-
assembler command line or during the assembly run are fatal. The
cross-assembler flags these with a message on the C "stdout"
device (by default, the console) beginning with the words "Fatal
Error." The messages are explained below:
7.1 Fatal Error -- No Source File Specified
This one is self-explanatory. The assembler does not know
what to assemble.
7.2 Fatal Error -- Source File Did Not Open
The assembler could not open the source file. The most
likely cause is that the source file as specified on the command
line does not exist. On larger systems, there could also be
priviledge violations. Rarely, a read error in the disk
directory could cause this error.
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7.3 Fatal Error -- Listing File Did Not Open
7.4 Fatal Error -- Object File Did Not Open
This error indicates either a defective listing or object
file name or a full disk directory. Correct the file name or
make more room on the disk.
7.5 Fatal Error -- Error Reading Source File
This error generally indicates a read error in the disk data
space. Use your backup copy of the source file (You do have one,
don't you?) to recreate the mangled file and reassemble.
7.6 Fatal Error -- Disk or Directory Full
This one is self-explanatory. Some more space must be found
either by deleting files or by using a disk with more room on it.
7.7 Fatal Error -- File Stack Overflow
This error occurs if you exceed the INCLude file limit of
four files open simultaneously. This limit can be increased by
increasing the constant FILES in file A68.H and recompiling the
cross-assembler.
7.8 Fatal Error -- If Stack Overflow
This error occurs if you exceed the nesting limit of 16 IF
blocks. This limit can be increased by increasing the constant
IFDEPTH in file A68.H and recompiling the cross-assembler.
7.9 Fatal Error -- Too Many Symbols
Congratulations! You have run out of memory. The space for
the cross-assembler's symbol table is allocated at run-time using
the C library function alloc(), so the cross-assembler will use
all available memory. The only solutions to this problem are to
lessen the number of labels in the source program, to use a
larger memory model (MSDOS/PCDOS systems only), or to add more
memory to your machine.
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