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.pl 88 ZZZZZZZZZZZ MMMM MMMM ZZ MM MM MM MM ZZ MM MM MM MM ZZ MM MM MM MM ZZ MM MM MM MM ZZ MM MMMM MM ZZ MM MM MM ZZ MM MM ZZ MM MM ZZZZZZZZZZZ MM MM Copyright (c) 1983 Roger E. Donais If you have ant questions concerning ZM, contact the author: Roger E. Donais, USA Ret 7506 Republic Ct. #201 Alexandria, VA 22306 (703) 765-0615 C O N T E N T S INTRODUCTION .................................... 1 STATEMENT SYNTAX ................................ 4 OPCODES ......................................... 5 OPERANDS ........................................ 5 OPERATORS ....................................... 7 DIRECTIVES ...................................... 9 PREDEFINED USER SYMBOLS ......................... 13 TERMINAL ERRORS ................................. 14 FATAL ERRORS .................................... 16 WARNING MESSAGES ................................ 18 RUNTIME REQUIREMENTS ............................ 19 RESERVED SYMBOLS ................................ 20 Z80 SYNTAX SUMMARY .............................. 21 ALTERATION ...................................... 23 INDEX ........................................... 27 I N T R O D U C T I O N ZM translates symbolic language source files into machine executable code in either (.COM) or Intel loader (.HEX) format. It has been designed to be easily used by the novice, yet provide a variety of capabilities powerful enough for the expert. ZM can be used to assemble large files on relatively small systems. TO USE: Enter ZM drive:filename.type options Where "drive" is the CP/M drive which will receive the assembled object file, "filename.type" is any valid CP/M file, and "options" are one or more of the following: L to get an assembled Listing H to get a .HEX type object file C to get a .COM type object file 1 for printer setup #1 (see alteration notes) 2 for printer setup #2 (see alteration notes) = to enter subject text (see listing) All options, except "=", may be entered in any order. When used, the "=" option must always be entered last. Default settings are NO listing, NO object file and a blank subject line. ZM uses the same resources to produce both a .HEX and .COM Object file, therefore only one or the other may be requested. NOTE: ^C may be used to abort assembly from the keyboard. ^S may be used to pause and restart assembly. EXAMPLE: C>ZM B:JUNK.PDQ C Will cause ZM to create the object file B:JUNK.COM using the first JUNK.PDQ found on the designated drive, default drive, an internally defined drive or drive A:. If JUNK.PDQ cannot be found on any of these drives, ZM will prompt with the message: --Insert disk with JUNK.PDQ and press <RETURN> The disk may then be inserted in any of the previously mentioned drives, EXCEPT the drive destined to receive the object file (in this example B:). The process will repeat until JUNK.PDQ is found, or a ^C is entered in response to the prompt. PAGE 1 LISTING: A two line heading is printed on each page: SUBJECT: __________________________________________ SOURCE FILE: _______ PAGE - nn DATE: yy/mm/dd The source file is the name of the file currently being assembled (see INCL directive). The subject will contain the text immediately following an equal sign. Control characters may be entered to initialize specific printer options. Maximum text length is 63 characters. An assembly listing is printed only when the "L" option has been selected. The actual listing may then be disabled/enabled by LIST directive. A partial listing, consisting of all source statements containing warning and fatal assembly error messages, will be displayed whenever the "L" option has not been selected. The console is the default list device. Use options 1 or 2 to obtain printer output. Used by themselves, they will direct the error and warning messages to the printer. Used with the "L" option, they direct the entire assembly listing to the printer. If the printer is NOT ready when ZM begins to print, output will automatically be set to the console. ZM will wait indefinately if the printer goes off line, or otherwise becomes unavailable, once printer output has started. EXAMPLES: ZM JUNK error messages will be sent to the console. ZM JUNK 1 error messages will be sent to the printer using printer setup string #1. If the printer is not ready, messages will be sent to the console. ZM JUNK L listing will be sent to the console. ZM JUNK L2 listing will be sent to the printer using printer setup string #2. If the printer is not ready, listing will be sent to the console. PAGE 2 END OF ASSEMBLY: The following will be displayed: NEXT ADDRESS nnnnH NEXT DATA nnnnH FREE MEMORY nnnnH STACK SPACE nnnn ERROR COUNT nnnn/nnnn NEXT ADDRESS is the first hexadecimal address following the last item of assembled code. NEXT DATA is the hexadecimal value currently assigned to the predefined symbol DATA. (see directives and predefined symbols). Depending upon how the DATA directive/symbol was used, NEXT ADDRESS or NEXT DATA could be used as the origin for a co-resident or chained program or program overlay. FREE MEMORY is the hexadecimal amount of memory available for symbols and object file buffer (see RUNTIME requirements). STACK SPACE is the decimal amount of unused buffer/stack memory which is available for expression evaluation and source file inclusion (see RUNTIME requirements). ERROR COUNT is a two part decimal number corresponding to the number of statements tagged with fatal/warning messages. The sum of these numbers reflect the total number of statements, not the total number of error messages. PAGE 3 _ _ _ _ _ _ _ _ S T A T E M E N T S Y N T A X _ _ _ _ _ _ _ _ The general format of an assembly statement is: LABEL OPCODE OPERAND(s) COMMENT UNDERSCORE and COLON characters are ignored, except when used between quotes. An exaggerated example is _L_D_: and LD being equivalent. SPACES are used only to identify an item boundary, otherwise they may be used without restriction between any element, including parts of an expression. TABS (ascii 09h or ^I) are treated as spaces during assembly and expanded to every eighth print position within the listing. LINE FEED (ascii 0Ah or ^J) and CARRIAGE RETURN (ascii 0Dh or ^M) are always recognized as the end of a source statement and may NOT be embedded within a statement. FORM FEED (ascii 0Ch or ^L) will assemble when embedded in quotes, however, always cause the list driver to perform a page eject. CONTROL CHARACTERS (ascii 00h through 1Fh) are similiar to spaces in that they mark the boundary of an item, otherwise they may appear at any point within a statement. They are not processed during assembly, but sent to the printer "as is". Note that this applies to all control characters except tabs (ascii 09h or ^I), line feed (ascii 0Ah or ^J) and carriage returns (0Dh or ^M) which are explained above. BIT-7 is removed from all characters in the source file before processing. This eliminates the need to preprocess files that have been edited as a WordStar document. DECIMAL POINTS, entered as the first character in a statement, are assumed to be WordStar DOT COMMANDS. The statement is ignored and will not appear on the listing. LABELS or SYMBOLS are items, 1 to 31 character long whose first character is a letter (A thru Z) and subsequent characters are the letters A thru Z and numbers 0 thru 9. They used to represent an address or value. Embedded underscores and colons are ignored and do NOT count toward the 31 character limit. Upper and lower case may be used interchangeably. SYMBOL and S_y_m_b_o_l: are the same. Labels are optional for all statements except MARK an d DATA. When omited from an EQU statement, the value of the resolved expression wiil be printed, but will not be retained. Labels on a line by themselves are assigned the value of the current assembly address. NO reserved word (opcode, directive, operand or condition code) may be used as a label. Labels do not have to begin in the first character position, but must be the first item in a statement. PAGE 4 OPCODES are Z80 instruction mnemonics or assembler directives. (See Z80 instruction syntax for additional details) OPERANDS are numeric constants, reserved symbols, user defined labels or expressions. Their use is strictly dependent upon the OPCODE used in the source statement. ZM recognizes two special symbols in the operand field. $ The dollar sign is used in an expression to represent the current assembly address. It may be used alone or as part of an arithmetic expression. \ The backslash is used in place of any 8 or 16-bit immediate operand to "cut" the instruction. This allows a formal means of representing and documenting an advanced assembly language technique where the immediate operand for one instruction is itself an instruction. The practice is often used to create a one or two byte relative jump by using an 8 or 16 bit register to load the in-line code, or to flag the entry of a single routine that must later continue with separate procedures. EXAMPLE: ENTRY_1 OR \ ;OR 0AFh makes NZ ENTRY_2 XOR A ;Makes Z True PUSH AF ;Save entry flag (procedure common to both) POP AF ;Retrieve entry flag JP Z,PROC_2 ; (procedure unique to Entry_1) RET PROC_2 (procedure unique to Entry_2) RET EXAMPLE: ERROR_1 LD A,0 LD BC,\ ;Skip-2 ERROR_2 LD A,2 LD BC,\ ;Skip-2 ERROR_3 LD A,4 (Continue with common routine) PAGE 5 NUMERIC CONSTANTS are literal values 1 to 31 characters long whose first character is always a number (0 thru 9). Embedded underscores and colons are ignored and do NOT count toward the 31 character limit. Both upper and lower case may be used interchangeably. A suffix is used to indicate the desired base. Any overflow while evaluating a number is IGNORED, with only the lower 2 bytes being retained. BINARY CONSTANTS are a sequence of 0's and 1's followed by the letter B. OCTAL CONSTANTS are a sequence of the digits 0 through 7 followed by the letter O or the letter Q. DECIMAL CONSTANTS are a sequence of the digits 0 through 9 with no base designation suffix. ( 0d is NOT decimal zero, but an illegal number! ) HEXADECIMAL CONSTANTS are a sequence of the digits 0 through 9 and the letters A through F followed by the letter H. STRING CONSTANTS are a sequence of ANY ascii characters, except line feeds (ascii 0Ah) and carriage returns (ascii 0Dh), enclosed between apostrophes ('). Lower case letters are not converted to uppercase, nor are tab characters (ascii 09h) expanded within the assembled code. Tabs are, however, expanded on the printed listing. An apostrophe may be included within a string by immediately following it with a second one. To include an apostrophe at the end of a string requires three in a row (one to indicate end of string). A string constant containing a carriage return (ascii 0Dh) or line feed (ascii 0Ah) will generate a fatal error for that statement. String constants may NOT be used in an arithmetic expression. CHARACTER CONSTANTS are a SINGLE ascii character, except line feed and carriage return, enclosed between apostrophes ('). Lower case letters are not converted to upper case. An apostrophe may also be quoted ('''). Character constants may be used in an arithmetic expression (the assembler assigns a zero value to the most significant byte). EXPRESSIONS are a sequence of constants and user defined labels separated by arithmetic or logical operators. During assembly each expression is evaluated in a strict left to right sequence and reduced to a single word (two byte) value. Any overflow during evaluation is ignored. PAGE 6 OPERATORS: [ ] Brackets are used in an expression to control the strict left to right evaluation process, or to make the expression easier to read. Remember that Z80 syntax uses parentheses "( )" to denote memory addressing and are therefore not an integral part of an expression. An expression contained in brackets is treated as a single item. + ADDS the next item to the current value (may also be used as a unary operator). - SUBTRACTS the next item from the current value (may also be used as a unary operator). * MULTIPLIES the current value by the next item. & Logically ANDs the current value with the next item. # Logically XORs the current value with the next item. < SHIFTS the current value left the amount of the next item. High order bits are discarded and low order bits are replaced with zeros. > SHIFTS the current value right the amount of the next item. Low order bits are discarded and high order bits are replaced with zeros. ! Compares the current value with the next item and keeps the LARGER of the two. = Sets the current value TRUE (-1, all bits set) if the current item and next item are equal, otherwise sets the current value equal to zero. ^ Is a unary operator used to create an ascii control character. It must exactly precede (no spaces) the unquoted character. (e.g. ^Z or ^z give a control Z) @ Is a unary operator designed to return the integer value from a memory location at assembly time. Its use should be restricted to very special occasions since the resulting code will function properly only if the same values exist at runtime. Its primary use is to create system specific extensions, or overlays. EXAMPLE: LD HL,(06) ; Runtime BDOS entry LD DE,@6 ; Assembly Time BDOS entry OR A SBC HL,DE ; test runtime compatibility JP NZ,IMPROPER PAGE 7 ? Is a kludged operator for use with MARK and IF directives to provide a primitive library capability that assembles only required functions. MARK symbol = ? will create symbol if it does not exist, otherwise it does nothing. IF? symbol is TRUE only if symbol has been previously defined. EXAMPLE: (main program) MARK CON_INP = ?, PRINT = ?, ...etc INCL B:LIBRARY.C13 (library source) IF? PRINT PRINT MARK CON_OUT = ? (code for print subroutine) ENDIF ; PRINT subroutine IF? CON_OUT CON_OUT (code for con_out subroutine) ENDIF ; CON_OUT subroutine ADDRESSING involves the Z80 registers, memory references and expressions used in the operand field of a assembly source statement and are covered in greater detail in the many books on Z80 assembly language programming. The main inconsistency amongst these texts is the form used to address 8-bit Z80 arithmetic and logic instructions. Some use only a single operand, omitting the A-register from the source statement entirely. Another uses two operands only for those instructions having a 16-bit counterpart and one operand for the remaining instructions. A third method requires two operands for all 8-bit arithmetic and logic instructions. Since chosing one of these technique depends upon personal preference, ZM will recognize and process both the first and third. This means you may chose to use two operands, or a single operand for all 8-bit arithmetic and logic instructions. A record is kept on the particular method used, and if not consistent, will generate a single warning message. NOTE: ZM also recognizes INTEL style port i/o instructions ( IN nn and OUT nn ) as well as their ZILOG counter parts ( IN A,(nn) and OUT (nn),A ) and includes their use when generating the 8-Bit mixed address warning. PAGE 8 DIRECTIVES are commands to direct the assembler during the assembly process and have no meaning to the Z80 processor. EQU assigns the value of an expression to a label. If there is no label, the value will appear on the listing without error, but the value is not retained. label EQU expression EQU expression DEFS and DS define storage by reserving the the number of bytes for storage represented by the expression. If the expression is not resolved, ZM will display an appropriate message and terminate assembly after completing the first pass. DS expression DEFS expression DEFB and DB assemble an expression a byte at a time. The expression may be arithmetic or string. Supports multiple expressions seperated by comas. DB expression, expression DEFB expression, expression DEFW and DW assemble an expression a word at a time (Z80 fashion with LSB first). Supports multiple expressions separated by comas. DW expression, expression DEFW expression, expression DEFM and DM assemble one or more expressions a byte at a time. The expressions may be arithmetic or string, or a combination of both. The length of the assembled code is placed at the current assembly address followed by the code itself. DM expression,expression DEFM expression,expression ORG initializes the assembly address to the value of the expression. A label on this line will be assigned this value. If the expression is not resolved, ZM will display an appropriate message and terminate assembly after completing the first pass. ORG expression PAGE 9 RUN accepts the value of an expression as the logical execution address. An offset is then determined and used to define all subsequent labels and in evaluating the assembly operand "$". This allows assembling code that will be moved from the current physical address to be executed at a different address. Uses include ROM resident code and bank switching requirements. A label on this line will be assigned the assembly address before the RUN evaluation. If the expression is not resolved, ZM will display an appropriate message and terminate assembly after completing the first pass. RUN expression ;execute at expression RUN $ ;execute at physical EXAMPLE: ORG 100h LD HL,LoMem LD DE,HiMem LD BC,CodeLength LDIR JP HiMem LoMem RUN 8000h HiMem ( code to execute at address 8000h) CodeLength equ $-HiMem INCL merges another source file with the current one. The file name can contain only the letters A to Z and numbers 0 to 9. An optional drive identifier may be given. If no file type is specified, a null type is assumed. Once the end of file or END directive is reached, assembly will resume with the statement following the INCL. The included file may also contain INCL directives. ZM will search for the included file on the designated drive, default drive, drive A: and internally defined drive. You will be allowed to change disks if the file cannot be found. Do NOT change the disk that is to receive the .COM or .HEX file as it will cause a CP/M disk write error when ZM attempts to write the file to disk. Prompting continues until the file is found, or a ^C is entered. INCL <drive:><filename><.type> END marks the logical end of a source file. Assembly will NOT proceed beyond that point. The END statement is optional. If not used, assembly will continue to the physical end of the file. END PAGE 10 LIST turns the listing ON or OFF only if the "L" option was requested. A non-zero expression enables the listing, and a zero disables the listing. Statements containing errors are always listed with their associated messages regardless of the LIST setting or "L" option. LIST expression IF, ELSE, and ENDIF provide conditional assembly. When the evaluated expression is NOT zero, all statements will be assembled until the corresponding ELSE or ENDIF is reached. The ELSE directive is optional. IF's may be nested seven deep. EXAMPLE: IF expression1 (following statements will assemble only if the expression1 is NOT zero) IF expression2 (following statements assemble only if expression1 is NOT zero AND expression2 is NOT zero) ENDIF (following statements assemble only if expression1 is NOT zero) ELSE (following statements assemble only if expression1 is ZERO) IF expression3 (following statements assemble only if expression1 is ZERO AND expression3 is NOT zero) ELSE (following statements assemble only if expression1 is ZERO AND expression3 is ZERO) ENDIF (following statements assemble only if expression1 is ZERO) ENDIF (assembly resumes in a normal manner) MARK sets a label to the current assembly address or to the value of an expression following an equal sign "=". If the label has been previously defined and not marked, an error will occur. MARK supports multiple labels seperated by commas. MARK'd labels may be used in any desired manner. They differ from normal labels in that they may be reused. The most recently defined value is used when a marked label appears in an expression (see ? operator). MARK label1,label2 = expression, ...etc PAGE 11 DATA exists both as a directive and as a predefined label. The directive assigns the current value of DATA to a label, then reassigns DATA = DATA + expression This allows defining internal data overlays or data areas outside the physical program. Using DATA without a label will cause a fatal error (missing data). (See user defined sysbols for additional information). label DATA expression MSG evaluates an expression similar to a DEFB and displays it on the console. The expression used must contain all necessary screen control characters, including carriage return and line feed. A dollar sign ($) is the only character that may not appear in the evaluated text. No text will appear afterward, and no error will be generated. GET Accepts 1 to 80 characters from the console and appends them to the end of the current statement. The statement is then assembled as usual. Remember to leave any necessary spaces or puntuation at the end of the incomplete statement. Use MSG to provide the necessary prompting. MSG 'ENTER PRINTER SELECTION:', cr, lf, lf MSG '1. Epson mx-80/100', cr, lf MSG '2. Okidata 82a', cr, lf MSG '3. Anderson Jacobson', tab GET MARK PRINTER = IF Printer =1 (epson code assembles here) ENDIF IF Printer =2 (okidata code assembles here) ENDIF IF Printer =3 (anderson code assembles here) ENDIF (normal program code continues here) PAGE 12 PREDEFINED USER SYMBOLS DATA is a progressive counter used with the DATA directive. It is NOT altered between passes, therefore it MUST be initialized with the MARK directive before it is used. EXAMPLE: ORG 100H MARK DATA, LOOP CALL INITIALIZE DB 'Initial Program signon message$' DB 'Additional text for "TYPE .COM"', 1AH FCB2 DATA 33 COUNT DATA 2 ORG DATA ! $ FCB2 overlays the beginning of the program at 100h and COUNT is assigned 121h. The assembly address is then adjusted to the larger value of "$" or "DATA". IX and IY are used to evaluate memory references using their respective index registers. They must always be defined using a negative value. EXAMPLE: FLAGS DEFB 0 ;One byte flag variable IX EQU -$ ;<--<< IX BASE ADDRESS <--<< TEMP DEFW 0 IX has been defined as the current assembly address. SET 0,(IX+FLAGS) will assemble correctly and is the same as SET 0,(IX+FLAGS-BASEX) used with the following: EXAMPLE: FLAGS DEFB 0 ;One byte flag variable BASEX EQU $ ;<--<< IX BASE ADDRESS <--<< TEMP DEFW 0 NOTE: Loading the index register must use the negative of these symbols. LD IX,-IX ;Initialize IX base position NOTE: Since the predefined symbols IX and IY are initially zero, NOT using them will cause assembly to take place in the usual manner. If you do use them, remember they are redefinable and affect only those expressions FORWARD of themselves. Also realize that the beginning of the file is AFTER its END during the second pass. If you plan on using ANY redefinable symbol, but expect them to be zero at the beginning, MARK THEM BEFORE YOU SET THE ORIGIN or EQUATE THEM TO ZERO ! PAGE 13 _ _ _ _ _ _ _ _ _ _ _ _ _ E R R O R S _ _ _ _ _ _ _ _ _ _ _ _ _ There are three types of errors: Terminal, Fatal and Warning: TERMINAL errors terminate the program! All Terminal errors are displayed on the console and control is immediately returned to CP/M. Fatal errors result in the offending source statement not being processed. NO CODE IS GENERATED! WARNINGS are provided when the integrity of the assembled code is questionable. In other words, what you got, might not be what you wanted! Warning and Fatal error messages are always displayed with the offending source statement, even if the "L" option was not selected. The format includes the current file name if it has not yet been displayed. The offending statement is then printed, followed by a line of carats (^) to indicate those points that caused ZM to choke. The appropriate warning and fatal error messages are then lsited. Finally, the current statement number, which matches WordStar's FL number, or ED.COM's line number, is printed. Any relationship between the carats and the ordering of error messages is purely coincidental. EXAMPLE: SOURCE FILE: JUNK.PDQ db tab,'LINE OF TEXT',0D,0Ah, ^ ^ ^ -- WARNING -- 17: BAD NUMBER 15: UNDEFINED LABEL *** FATAL *** 1: MISSING INFORMATION - Line No 1263 - _______________________________________________________________ TERMINAL ERRORS: Assembly stops and control is returned to CP/M. USE: ZM <file> <option> WHERE <option> is one or more of the following: L = Listing H = Hex object file C = Com object file 1 = 10 lpi x 10 cpi 2 = 8 lpi x 17 cpi Cause: No file was provided, or an unrecognized option was given. Solution: Examine and reenter the command line. Remember the the "=" must be the last option. PAGE 14 ** CANNOT HAVE BOTH ".HEX" & ".COM" OUTPUTS ** Cause: Both the H and C options were requested. Solution: Reenter the command line with an H option, then use CP/M's LOAD.COM utility to provide the .COM file. ** CANNOT CREATE/OPEN OBJECT FILE ** Cause: This will most likely result from a FULL Directory. Solution: Erase a few files to make room. ** DISK or DIRECTORY FULL ** Cause: The system reported it could NOT write the object file. Solution: Erase a few file to make room. ** SYMBOL TABLE OVERFLOW ** Cause: Symbol and GET storage have collided! Solution: Shorten Symbol names, use more MARK'd symbols, or separate the source file into two or more smaller ones and assemble them separately. NOTE: See RUNTIME requirements for additional information. ** STACK OVERFLOW ** Cause: The hardware stack and source statements have collided. Solution: Reduce the INCL nest level, simplify complex expressions, use shorter source statements. NOTE: See RUNTIME requirements for additional information. ** CANNOT CLOSE OBJECT FILE ** Cause: Something prevented CP/M from closing the output file. Solution: Read the CP/M manual for causes and solutions. ** INVALID OBJECT (.COM) FILE ABANDONED ** Cause: The initial ORG was not 100h, or was less than the current assembly address. Solution: Reorganize or Rewrite the assembly source file. NOTE: This error is not terminal. Assembly will continue, providing a listing and/or additional error messages. ** NESTING TOO DEEP ** Cause: The current statement brings the IF/ELSE/ENDIF to more than 7-levels. Solution: Rewrite the file using fewer IF/ELSE/ENDIF levels. PAGE 15 ________________________________________________________________ FATAL ERRORS: No code is generated for the statement containing the error. Assembly continues with the next statement. 0: BAD/UNRESOLVED EXPRESSION Cause: An INCL statement contained a bad filename, or an ORG RUN, or DS/DEFS statement contained an unresolved expression NOTE: Assembly will terminate at the end of the first pass. 1: MISSING INFORMATION Cause: The expression was missing an operand, a comma, or a parenthesis; or a statement ended with a comma. 2: ILLEGAL ADDRESSING Cause: The operand(s) violate Z80 addressing options for the opcode used. 4: ILLEGAL OPCODE Cause: The item being processed was not a recognized opcode or assembler directive. (This relates to the second item, the first was processed as a symbol). This usually occurs when a reserved symbol (opcode, register, condition code or directive) was used as a label, or an opcode or directive was misspelled. 5: EXPRESSION TOO LONG Cause: A statement generated more than 82 bytes of code. 6: ITEM TOO LONG Cause: A single item (symbol or number) exceeded 31 characters. 7: EXPRESSION ERROR Cause: An expression had two successive operators, two successive items, a missing operator, a missing item, a missing right parentheses, included extraneous characters, or contained unbalanced braces. PAGE 16 _______________________________________________________________ WARNINGS: The assembled code may NOT be what was intended. 8: MIXED 8-Bit ADDRESSING MODES Cause: The source file contains a mixture of one and two operand address for 8-bit arithmetic or logic instructions. Result: Since ZM handles both methods, the code was properly assembled. However, had the intention been to use only one of the two addressing methods, then one or more statements are not what was intended. 10: ORIGIN NOT IN SEQUENCE Cause: The expression for an ORG resolved to an address smaller than the current assembly address. Result: Any .COM file is abandoned, but assembly resumes. 11: BRANCH (origin - target) OUT OF RANGE Cause: The target for a relative jump (JR or DJNZ) was not in the range -128 to +127 Result: The target for the jump becomes the instruction itself. 12: ILLEGAL LABEL Cause: The symbol being defined is a reserved operand. (See #4) Result: The symbol is ignored. 13: LABEL NOT MARKED Cause: The symbol has been defined more than once. Result: The first assigned value is used. Hint: Use the MARK directive to define symbols you wish to use more than once. 14: UNPROCESSED CHARACTERS Cause: After the statement was assembled the end of the line had not been reached. Result: The assembled code may/may not be appropriate. 15: UNDEFINED LABEL Cause: An expression contains a symbol that has not been defined. Result: The symbol defaults to a value of zero. 16: MULTIPLY DEFINED Cause: An expression contains a symbol that was defined more than once. Result: The original symbol's value is used. PAGE 17 17: BAD NUMBER Cause: A item beginning with 0 thru 9 contained a character not appropriate for the assigned base. Result: The number defaults to a value of zero. 20: UNBALANCED IF/ENDIF Cause: An END directive, or the end of a file was reached without enough ENDIF's to complete all IF directives. Result: If the unbalance occurred while processing an included file, the previous file's IF/ENDIF stack was restored. Assembly will terminate at the end of the first pass. 22: NO ASSOCIATED "IF" STATEMENT Cause: An ENDIF statement was processed without first having processed an "IF" statement. Result: The statement was ignored. Assembly will terminate at the end of the first pass. 23: STATEMENT TRUNCATED Cause: A source statement was longer than 215 characters. Result: The excess was discarded. May cause additional errors if the discarded portion was not a comment. 24: INVERTED ORIGIN Cause: Source file contained no ORG statement or an ORG has an expression that is less than 100H Result: A .COM file will be abandoned, but assembly continues. 25: LABEL ADDRESS CHANGES Cause: The Label had a different address on the second pass than it had on the first pass. Result: Very dubious code! Hint: Look for a previous statement that adjusts the assembly address using a MARK'd symbol that is later redefined, or a previous IF/ENDIF that generated code on one pass, but was FALSE on the other pass. 26: FIELD OVERFLOW Cause: The evaluated expression exceeded the size limits for the opcode. (Example. IM n where 'n' is not 0, 1 or 2). Result: A "mask" is used to force a legal value. 27: BYTE VALUE OVERFLOW Cause: All expressions are reduced to an unsigned 16-bit integer. The least significant byte is used for instructions requiring an 8-bit value, however, the original value was neither 0 to 255 nor -128 to +127 Result: The least significant byte was used, "as is". PAGE 18 ------------------------------------------------------------ R U N T I M E R E Q U I R E M E N T S PROGRAM MEMORY MAP 100h ______________________________________________________ BDOS | | | | < ? > | | fixed | src stk | program | get wrk obj symbol | Pass1 => | 216 100 | | >>--> 31 xxx <---<< | Pass2 => | 216 100 | | ????? 31 128 ?????? | A substantial portion of the program (initialization section) is reclaimed and used for runtime data storage. All memory beyond ZM's original size, is used for symbol table and output file buffer. A fixed 216 byte buffer is allocated for the source statement. No statement may exceed 215 characters. A 100 byte (50 level) stack is provided. The stack, however, is not rigid. It is allowed to wander into the unused portion of the source statement buffer, but is NOT allowed to overwrite a statement. Should the program attempt to overwrite a statement, ** STACK OVERFLOW ** occurs and control is imediately returuned to CP/M. Minimum runtime requirement is approximately 15 levels. Each recurssive INCL consumes 22 bytes. Evaluation recursion (brackets) consumes 6 bytes. A typical source file containing 80 character lines can contain 8-Levels of INCL nesting and 5-Levels of brackets. STACK SPACE reported at the end of assembly is the minimum distance reached between any source statement and the stack. In other words, a stack crash barometer! GET responses begin at the end of the program and expand toward high memory and are stored as entered, with a byte count preceding each entry. Symbols are stored just below BDOS and expand toward low memory. Each symbol requires three bytes in addition to the actual symbol length. A 31 byte work space continually relocates at the end of the GET storage area during pass1. During pass2, all tables are fixed and this work space becomes stationary. All remaining space between the end of the 31 byte work space and the bottom of the symbol table is used to buffer the object file output. More space means less disk access, providing faster assembly. If at any time this space should become less than 128 bytes (one file sector) ** TABLE OVERFLOW ** occurs and assembly ceases. FREE MEMORY displayed at the end of assembly is the amount of memory available to expand the object file buffer beyond a single 128 byte sector. When less than 128, the object file buffering is limited to this one sector. Assembly may be slow, but still running. Less than zero, and it's dead. PAGE 19 ____________________________________________________________ R E S E R V E D S Y M B O L S ________________________Z80 Opcodes_________________________ EXX LDI LDIR LDD LDDR CPI CPIR CPD CPDR DAA CPL NEG CCF SCF NOP HALT DI EI IM RLCA RLA RRCA RRA RETI RETN INI INIR IND INDR OUTI OTIR OUTD OTDR LD RLC RL RRC RR SLA SRA SRL RLD RRD PUSH POP EX ADD ADC SBC SUB AND OR XOR CP INC DEC BIT SET RES JP CALL JR DJNZ RET RST IN OUT __________________Assembler Directives______________________ DS DEFS DB DEFB DW DEFW DM DEFM ORG RUN END INCL MARK EQU DATA LIST IF ELSE ENDIF MSG GET _________________________Operands________________________ Z NZ C NC PO PE P M A B C D E H L BC DE HL IX IY SP AF I R $ \ ? _______________Predefined User Symbols_______________________ DATA IX IY _____________________Operators___________________________________ + - * & # < > ! ? @ = [ ] ^ PAGE 20 _________________________________________________________________ _______________________ Z80 SYNTAX SUMMARY ______________________ _ _ _ _ _ _ _ _ _ _ D A T A T R A N S F E R _ _ _ _ _ _ _ _ _ 8 Bit Transfers 16 bit transfers Block Transfers LD r,r' LD ss,nnnn LDI LD r,nn LD ss,(nnnn) LDIR LD (nnnn),ss LD r,(m) LDD LD (m),r LD SP,HL LDDR LD (m),nn LD SP,IX LD SP,IY LD A,(BC) LD A,(DE) PUSH qq LD A,(nnnn) POP qq LD (nnnn),A LD (DE),A EX DE,HL NOTE: ZM is NOT sensitive LD (BC),A EX (SP),HL to the sequence of EX (SP),IX exchange operands. LD A,I EX (SP),IY EX HL,DE LD I,A EX AF,AF' is equivilent to LD A,R EXX EX DE,HL LD R,A _ _ _ _ _ _ _ _ _ _ _ _ A R I T H M E T I C _ _ _ _ _ _ _ _ _ _ _ 8 Bit Arithmetic 16 Bit Arithmetic Misc ADD r ADD A,r ADD HL,ss DAA ADD (m) ADD A,(m) ADD IX,xx CPL ADD nn ADD A,nn ADD IY,yy NEG SCF ADC r ADC A,r ADC HL,ss CCF ADC (m) ADC A,(m) ADC nn ADC A,nn SUB r SUB A,r SUB (m) SUB A,(m) SUB nn SUB A,nn SBC r SBC A,r SBC HL,ss SBC (m) SBC A,(m) SBC nn SBC A,nn INC r INC pp INC (m) DEC r DEC pp DEC (m) r = A, B, C, D, E, H, d ss = BC, DE, HL, IX, IY or SP nn = any 8-Bit expression qq = AF, BC, DE, HL, IX or IY nnnn = any 16-Bit expression xx = BC, DE, SP, IX (m) = (HL), (IX+d) or (IY+d) yy = BC, DE, SP, IY d = displacement (-128 to +127) PAGE 21 _________________________________________________________________ _ _ _ _ _ _ _ _ _ _ _ _ L O G I C _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ 8-Bit Logic Block Operations AND r AND A,r CPI AND (m) AND A,(m) CPIR AND nn AND nn OR r OR A,r CPD OR (m) OR A,(m) CPDR OR nn OR A,nn XOR r XOR A,r XOR (m) XOR A,(m) XOR nn XOR A,nn CP r CP A,r CP (m) CP A,(m) CP nn CP A,nn _ _ _ _ _ _ _ SHIFT, ROTATE and BIT INSTRUCTIONS _ _ _ _ _ _ _ _ RLCA RLC r RLC (m) BIT n,r RLA RL r RL (m) BIT n,(m) RRCA RRC r RRC (m) RRA RR r RR (m) SET n,r SLA r SLA (m) SET n,(m) SRA r SRA (m) RLD SRL r SRL (m) RES n,r RRD RES n,(m) _ _ _ _ _ _ _ _ I/O I N S T R U C T I O N S _ _ _ _ _ _ _ _ IN nn OUT nn INI OUTI IN A,(nn) OUT (nn),A INIR OTIR IN r,(C) OUT (C),A IND OUTD INDR OTDR _ _ _ _ _ _ _ _ _ G E N E R A L P U R P O S E _ _ _ _ _ _ _ _ DAA CCF NOP DI CPL SCF HALT EI NEG IM 0 IM 1 IM 2 _ _ _ _ _ _ _ _ _ _ _ _ C O N T R O L _ _ _ _ _ _ _ _ _ _ _ _ _ _ JR e JP nnnn JP (HL) CALL nnnn JR c,e JP cc,nnnn JP (IX) CALL cc,nnnn DJNZ e JP (IY) r = A, B, C, D, E, H, d c = NC, C, NZ, Z nn = any 8-Bit expression e = Relative Addree (-128 to +127) nnnn = any 16-Bit expression cc = NC, C, NZ, Z, M, P, PO, PE (m) = (HL), (IX+d) or (IY+d) d = displacement (-128 to +127) PAGE 22 A L T E R A T I O N S ZM does not require special installation to run on a CP/M system. It may, however, be modified to take advantage of special system features. The method is to create the necessary source file, then use DDT to overlay ZM with the assembled .HEX file. This may seem a little too much to install an assembler, but the rewards are that ZM will not only setup and restore your printer, but automatically search for files on a drive of your choice, and date program listings. Using the following source listing as a guide, create a source file containing the assembly instructions necessary to alter ZM to meet your printer requirements. Then use ZM to assemble the file into an Intel hex format and DDT to overlay ZM. The following dialog assumes the source is B:ZM/SETUP.Z80 and that a copies of ZM and DDT reside on drive A: A>B: B>A:ZM3P ZM-SETUP.Z80 H ZM v 1.3p - Z80 Assembler (c) 1984 NEXT ADDRESS xxxx NEXT DATA xxxx FREE MEMORY xxxx STACK SPACE xxxx ERROR COUNT None/None B>A:DDT A:ZM3P.COM DDT VERS 2.2 NEXT PC xxxx 0100 -IZM-SETUP.HEX -R NEXT PC xxxx 0000 -G0 B>SAVE xx B:ZM.COM B> et viola, ZM has been configured for your printer. PAGE 23 The INCL directive is programmed to search the specified drive (if given), the default drive, an internally defined drive, and finally drive A:. This four step search is repeated until the file is found or a ^C is entered. The internal drive may be defined by adjusting the value at 061Ch. Any CP/M drive may be specified using the convention that 0=default, 1=A, 2=B, etc. ZM contains three printer setup strings. The first two are concerned with printer initialization and listing format, and the third is used to restore the printer to its normal configuration. The number of lines per page is given as the first byte in the initialization strings followed by the number of characters in the string that follows. The first byte of the third string contains the number of characters that follow. There are two 32 character lines in 'USAGE MESSAGE' which should reflect the respective performance of the first two printer initialization strings. During initialization, ZM loads the 'DE' register pair to point to the date field in the header and calls 1D21h. The called routine is expected to fill the 8-character field pointed to by the 'DE' register pair with the current date. The routine may alter all registers (except IX) and can extend almost to the BDOS. IT MUST NOT ALTER MEMORY BELOW ITS ORIGIN! Look at the stack pointer (SP) if you are really concerned about the actual limit. Once the date has been obtained, the space occupied by the routine is reclaimed for runtime storage. If your system cannot provide the current date, or you do not wish to have dated listings, simply use a RET as the first instruction of the date routine. The following listing provides an example for creating an overlay to configure ZM for your particular requirements. The statements "ORG TIC + 18" and "ORG TIC + 17" are used to not only to adjust the current assebbly address, but to generate a warning (e.g. 10: ORIGIN NOT IN SEQUENCE) in the event the predefined size constraints are exceeded. ;ZM (Version 1.3p) Custom Setup for MX-100 printer MARK TIC Message1 equ 0300h ;Option 1 Usage Message Message2 equ 0324h ;Option 2 Usage Message Drive equ 0548h ;Drive & Print Parameters Date equ 1D20h ;Date Initialization Routine ORG Message_1 ; !12345678901234567890123456789012! <--32 byte ruler DB '2 = 57 Lines (10 cpi at 6 lpi) ' ORG Message_2 ; !12345678901234567890123456789012! <--32 byte ruler DB '1 = 80 Lines (16.5 cpi at 8 lpi)' PAGE 24 ORG Drive DB 2 ;Add Drive B: to the search path TIC DB 57 ;57 lines per page DM ^[, ^F, ^R, ^[, 2 ;Emphasized OFF, condensed OFF, 6 lpi ORG tic + 18 ; <--<< ERROR IF SPACE EXCEEDED TIC DB 80 ;80 lines per page DM ^[, 'F', ^O, ^[, 0 ;Emphasized OFF, condensed ON, 8 lpi ORG tic + 18 ; <--<< ERROR IF SPACE EXCEEDED TIC DM ^R, ^[, 'N', 6 ;Condensed OFF, Skip 6 at perf ORG tic + 17 ; <--<< ERROR IF SPACE EXCEEDED ORG DATE ; PROMPT OPERATOR FOR DATE PUSH IX ;Preserve IX PUSH DE ; and date field pointer LD DE,DatePrompt ;Prompt operator for date LD C,9 CALL 5 LD DE,Buffer ;Accept date from console LD C,10 CALL 5 LD E,^j ;Punch line feed LD C,2 CALL 5 POP DE ;Restore registers now that POP IX ; we're done with system calls LD HL,BUFFER+1 ;Point to console input LD A,(HL) ; get length OR A RET Z ;Exit on null input DEC A ;Force length to range (1 to 8) AND 7 INC A LD C,A ;Move string to header date field LD B,0 INC HL LDIR RET DatePrompt db ^m,^j,^j,'ENTER LISTING DATE as (yy/mm/dd): $' Buffer db 40 END PAGE 26 I N D E X ! ............................................. 7 # ............................................. 7 $ ............................................. 4, 9,11 & ............................................. 7 ( ) ........................................... 7 * ............................................. 7 + ............................................. 7 - ............................................. 7 < ............................................. 7 = ............................................. 7 > ............................................. 7 ? ............................................. 8 @ ............................................. 7 ABORT ......................................... 1 ADDRESSING .................................... 8 ALTERATION .................................... 23 BINARY CONSTANTS .............................. 6 BIT-7 ......................................... 4 CARRIAGE RETURNS .............................. 4 CHARACTER CONSTANTS ........................... 6 COLON ......................................... 4, 6 CONTROL CHARACTERS ............................ 2, 4, 7, 12 DATA .......................................... 12,13 DB ............................................ 9 DECIMAL CONSTANTS ............................. 6 DECIMAL POINTS ................................ 4 DEFB .......................................... 9 DEFM .......................................... 9 DEFS .......................................... 9 DEFW .......................................... 9 DIRECTIVES .................................... 9,20 DM ............................................ 9 DS ............................................ 9 DW ............................................ 9 ELSE .......................................... 11 END ........................................... 10 ENDIF ......................................... 11 EQU ........................................... 9 ERROR COUNT ................................... 3 ERRORS ........................................ 14 EXPRESSIONS ................................... 6 FATAL ERRORS .................................. 15,16 FREE MEMORY ................................... 3,19 GET ........................................... 12,19 HEADING ....................................... 2 HEXADECIMAL CONSTANTS ......................... 6 IF ............................................ 8 INCL .......................................... 10,19 IX ............................................ 13 IY ............................................ 13 LABELS ........................................ 4 LINE FEED ..................................... 4 PAGE 27 LIST .......................................... 11 LISTING ....................................... 2, 3 MARK .......................................... 11 MSG ........................................... 12 NEXT ADDRESS .................................. 3 NEXT DATA ..................................... 3 NUMERIC CONSTANTS ............................. 6 OCTAL CONTSTANTS .............................. 6 OPCODES ....................................... 5,20 OPERANDS ...................................... 5,20 OPERATORS ..................................... 7,20 OPTIONS ....................................... 2 ORG ........................................... 9 PREDEFINED USER SYMBOLS ....................... 13,20 PROGRAM MEMORY MAP ............................ 16 RESERVED SYMBOLS .............................. 20 RUNTIME REQUIREMENTS .......................... 19 RUN ........................................... 10 SPACES ........................................ 4 STACK SPACE ................................... 3,19 STRING CONSTANTS .............................. 6 SYMBOLS ....................................... 4,13 SYNTAX ........................................ 7,21 TABS .......................................... 4, 6 TERMINAL ERRORS ............................... 14,15 UNDERSCORE .................................... 4, 6 WARNING MESSAGES .............................. 17,18 WORDSTAR DOT COMMANDS ......................... 4 Z80 OPCODES ................................... 20 Z80 SYNTAX SUMMARY ............................ 21 [ ] ........................................... 7 \ ............................................. 5 ^ ............................................. 7 PAGE 28