MacGames Sampler

home *** CD-ROM | disk | FTP | other *** search

/ MacGames Sampler / PHT MacGames Bundle.iso / MacSource Folder / Samples from the CD / Assembly / Mac68k / MANUAL / MAN3.DOC < prev next >

Wrap

Text File | 1985-08-20 | 13.4 KB | 468 lines | [TEXT/Anon]

MAC.68K II.11 ASCII Control Characters II.11 ASCII Control Characters II.11 ASCII Control Characters Any ASCII control characters found in the source input will be converted to # prior to processing except for: CR ($0D), LF ($0A), DLE ($10), and HT ($09) (see II.4). II.12 Numeric Data Representation II.12 Numeric Data Representation II.12 Numeric Data Representation Hex numbers begin with the symbol $, octal numbers use a postfix radix character of B or Q, and decimal numbers may optionally use a radix of D. Radix and hex alpha characters may be any mixture of upper and/or lower case. All numbers are represented internally as 32-bit integers. This places a range limit of +2**31 - 1 on the value of any _ number. Examples DECIMAL OCTAL HEX unsigned 18 7Q $1AF signed -123D -77Q -$30 +5 +03Q +$FF II.13 Character Data Representation II.13 Character Data Representation II.13 Character Data Representation Character data may be defined by placing the desired character string within single quotes. (Double quotes are used for STRING names.) MAC.68K also supports a variety of left and right justified character data types. Justification occurs when the specified character data is shorter than its field. For example one byte of data in a word field, or 21 bytes in a 6 long word field will be aligned to a left or right field boundary. Space and zero fill are available options. -7- MAC.68K MAC.68K The general form for justified character data is: n / type / string A special form available for DC operations only is: #type / d / string / d where n is the field size and d is any character type description A Right justified with blank fill H Left justified with blank fill L Left justified with zero fill R Right justified with zero fill Z Left justified with zero fill. For DC instructions, one trailing zero byte is guaranteed even if another byte, word, or long word must be allocated. Within an expression or constant, type Z is equivalent to type L. Each character data type may either have an explicit character length or may use delimiter characters to bracket the string. For example, 4LABCD and L*ABCD* each describe a string of length 4 characters. The delimiting character may be any character (other than & or ") that does not appear in the string itself. The type designation character must be upper case. Examples MOVE.L #'ABCD',D1 CMP.W #1R-,D2 Compare Right Justified Character Data DC.L 22H THIS IS A LONG STRING DC.B #Z*SAMPLE ZERO BYTE TERMINATED MESSAGE* DC.B 'The End' MAC.68K -8- MAC.68K II.14 Expression Evaluation II.14 Expression Evaluation II.14 Expression Evaluation Symbols and data values can be combined into expressions using normal algebraic notation. A single term expression takes on the value of the term involved. Multiple term expressions are reduced to a single value following the rules: Unary operator + - Binary operator + - * / 1. Parenthesized expressions are evaluated from the innermost outward. Parenthesis can be nested to six levels. 2. Arithmetic operators are evaluated left to right, with multiplication and division taking precedence over addition and subtraction. 3. Each term is evaluated as a 32-bit value. 4. Division yields a 32-bit integer with no remainder, and division by zero yields zero, but it is flagged as an error. -9- MAC.68K MAC.68K III. MACROS III. MACROS III. MACROS A macro definition contains a sequence of source lines that are saved, and then later inserted into the program text when referenced by using the macro name as an operation code. The first line of a macro definition contains the MACRO or MACROL operation code, the macro name, and any substitutable parameters used within the body of the macro. Reserved macro names are: END ENDM LOCAL ENDD. Next, a macro definition may optionally contain one or more LOCAL pseudo ops that identify symbols used within the body of the macro that are local to the macro definition. During macro expansion, local symbols are replaced with a symbol name of ..hhhh where hhhh is a hex number starting at 0000 and being incremented by one each time a local symbol is created. By generating unique symbol names, a macro may be expanded more than once without causing duplicate symbol definition errors. These generated symbol names are not listed in the symbol table and are not cross referenced. The body of the macro comes next. It consists of a sequence of source lines terminated by an ENDM operation code. The source lines may contain any combination of operation codes, comment lines, or macro calls except op code END. By using named ENDM op codes (see ENDM) a macro may even contain other macro definitions. Note that any macros contained within another macro are merely saved and not processed/defined until the outer level macro is called. The name of a substitutable parameter or local symbol can occur in any field in a macro body source line. The name is recognized if it is bracketed by two of the following macro delimiter characters: space + - * / ( ) & , = " A macro must be defined prior to its call. A macro defined by program source lines (including INCLUDE source lines) is considered a user macro. A macro defined thru inclusion of a preassembled macro file (see INCLUDES) is considered a system macro. By default MAC.68K does not list either user or system macro call expansions. See LIST for the appropriate macro list option. IV. (deleted) IV. IV. MAC.68K -10- MAC.68K V. PROGRAM LIST FORMATS AND LIST CONTROL V. PROGRAM LIST FORMATS AND LIST CONTROL V. PROGRAM LIST FORMATS AND LIST CONTROL MAC.68K does not automatically list every line of input to the output device. Each line is categorized by its origin type (e.g., a line from an included text file, a line generated by a macro, etc) and is listed only if the appropriate list options are currently enabled. Pseudo op LIST controls the active list options. Output is formatted either for an 80 column device or a 120 column device. The console is assumed to be 80 columns wide and everything else 120. This may be overridden by the PAGE initialization pseudo op. When going to an 80 column output device, any data characters beyond column 80 are by default truncated. When overridden by the OPTION WRAP, columns 81 thru 120 are printed on the next line beginning in column position 32. By default output is paged with a one line header, one blank line, and 58 source lines per page. An optional two line header format or no header at all may be selected by using OPTION. Lines per page may be reset using the PAGE pseudo op. The page line fields are: First header line columns 1 - 32 64 - 83 88 - 107 112 - 120 Title Version # Date/Time PAGE nnn Second header line columns 1 - 32 64 - 83 88 - 95 112 - 120 Subtitle Subheading QUAL Name Source line output columns 1 - 2 3 - 8 9 - 30 31 - 120 Error Flags Location Address Machine Code Source line In 80 column mode the first header line is compressed by dropping the date/time field and replacing it with the page number field. Two optional fields for the source line output are sequence numbers and sequence names. If selected via OPTION, these fields are inserted so they end in column 120. Sequence numbers are not always sequential with an assembler that can INCLUDE other text files or can generate source lines itself with MACRO or DUP. Each INCLUDE file or call to a macro generates a new block of code starting with sequence number 1. The old number sequence is resumed when the inserted block of code terminates. The optional sequence name reflects the source of the code. For source input or INCLUDE it is the file name, for macros it is the macro name, and for DUP it is DUP**. -11- MAC.68K MAC.68K When the console is used as the output device, MAC.68K will pause after a page is displayed on the screen and wait for a keyboard input character before advancing to the next page. The character *S* or a ctl/C character will immediately terminate the assembly. Any other character will cause MAC.68K to continue assembling until the next page is full or the assembly is complete. The OPTION NOPAWS will disable the pause feature and the output will scroll continuously until the assembly finishes. Note that the standard CPM-68K console control keys ctl/S and ctl/Q may also be used to stop and continue output. A printed symbol table must be explicitly requested via an OPTION. OPTION CROSSREF will generate symbol cross references and list these symbol references sorted by page and output line number when it lists the symbol table. OPTION SYMBOL will generate the same sorted symbol table that lists each symbol and its value, but not any cross references. VI. PROGRAM STRUCTURE VI. PROGRAM STRUCTURE VI. PROGRAM STRUCTURE The minimum executable program on the Macintosh is: ExitToShell ;RESTART THE FINDER APPLICATION .END MAC.68K requires all programs to end with an END card, and to optionally begin with an IDENT card. The IDENT/END pair brackets the program text and provides some guarantee of program completeness. Some of the MAC.68K pseudo ops are used only for initialization of assembly values, and must appear immediately following the IDENT card (if present) but prior to any non-initialization operation or pseudo operation code. These pseudo ops are: OPTION MODULE STEXT INCLUDES If they appear later in the program they are flagged with an error and are not processed. Pseudo op PAGE may be used anywhere in the program. When used to initialize page width and/or page length, it must appear as an initializtion pseudo op. MAC.68K -12- MAC.68K VII. FILE NAMES AND EXTENSIONS VII. FILE NAMES AND EXTENSIONS VII. FILE NAMES AND EXTENSIONS File names supported by MAC.68K are limited to 8 characters in length with an optional extension (a . followed by up to 3 characters). Imbedded spaces within a file name or extension are not supported. The input source file may have any file extension, although .S is recommended. The input file name, the object file name specified with the -O command, and the output file name specfied with the > command line parameter are the only file names that are not assigned explicit file name extensions by MAC.68K. If present, the program name from the IDENT card is used as the base file name for the generated object file. Based on whether it is a program, module, or definition table assembly the object file extension is .68K, .MOD, or .STX . File names used by the include pseudo ops may optionally specify device names and extension names. Included text files are assumed to have a blank extension. The extensions .MOD and .STX are assumed by INCLUDEH and INCLUDES. The console is referenced with file name CON: and the printer with name LST:. -13- MAC.68K -13-