The Telemark Assembler (TASM) User Manual
Contents
1. Character constants are single characters surrounded by single quotes The ASCII value of the character in the quotes is returned No escape provision exists to represent non printable characters within the quotes but this is not necessary since these can be just as easily represented as numeric constants or using the TEXT directive which does allow escapes String Constants String constants are one or more characters surrounded by double quotes Note that string constants are not allowed in expressions They are only allowable following the TITLE BYTE DB and TEXT assembler directives The quoted strings may also contain escape sequences to put in unprintable values The following escape sequences are supported Escape Sequence Description n Line Feed r Carriage return b Backspace t Tab f Formfeed Backslash Quote 000 Octal value of character Location Counter Symbol The current value of the location counter PC can be used in expressions by placing a in the desired place The Location Counter Symbol is allowable anywhere a numeric constant is Note that if the is followed by a decimal digit then it is taken to be the hexadecimal radix indicator instead of the Location Counter symbol as mentioned above The may also be used to represent the location counter but is less preferred because of its ambiguity with the multiplicative operator Operators Expressions can optionally contain operators to pe2. l Label Table This option causes a label table to appear in the listing file Each label is shown with its corresponding value Macro labels as established via the DEFINE directives do not appear Two optional suffixes may follow the l option Suffix Description 1 Use long form listing a Show all labels including local labels The suffix should immediately follow the l Here are some examples 1 to show non local labels in the short form la to show all labels in the short form 11 to show non local labels in the long form lal to show all labels in the long form m MOS Technology Object Format This option causes the object file to be written in MOS Technology hex format rather than the default Intel hex format See section on OBJECT FILE FORMATS for a description of the format o Set Number of Bytes per Object Record When generating object code in either the MOS Technology format or the Intel hex format a default of 24 decimal bytes of object are defined on each record This can be altered by invoking the o option immediately followed by two hex digits defining the number of bytes per record desired For example if 32 bytes per record are desired one might invoke TASM as tasm 48 020 source asm p Page Listing File This option causes the listing file to have top of page headers and form feeds inserted at appropriate intervals every sixty lines of output To override the default of sixty
3. optional argument list for variable substitution in macro expansion macro_def string to replace the occurrences of macro_label in the source file The simplest form of the DEFINE directive might look like this DEFINE MLABEL Notice that no substitutionary string is specified The purpose of a statement like this would typically be to define a label for the purpose of controlling some subsequent conditional assembly IFDEF or IFNDEF 16 A more complicated example performing simple substitution might look like this DEFINE VAR1_LO VAR1 amp 255 This statement would cause all occurrences of the string VAR1_LO in the source to be substituted with VAR1 amp 255 As amore complicated example using the argument expansion capability consider this DEFINE ADD xx yy clc lda xx adc yy sta xx If the source file then contained a line like this ADD VARX VARY It would be expanded to clc lda VARX adc VARY sta VARX The above example shows the use of the backslash character as a multiple instruction statement delimiter This approach allows the definition of fairly powerful multiple statement macros The example shown generates 6502 instructions to add one memory location to another Some rules associated with the argument list 1 Use a maximum of 10 arguments 2 Each argument should be a maximum of 15 characters Note that macros can be defined on the TA
4. be generated this is applicable to IFDEF IFNDEF and IF IFNDEF The IFNDEF directive is the opposite of the IFDEF directive The block of code following is assembled only if the specified macro_label is undefined It has the following form IFNDEF macro label When invoked the list of macro labels established via DEFINE directives is searched If the label is not found the following lines of code are assembled If it is found the input file is skipped until an ENDIF or ELSE directive is found IF 19 The IF directive can be used to optionally assemble a block of code dependent on the value of a given expression The format is as follows 1F expr If the expression expr evaluates to non zero the following block of code is assembled until an ENDIF or ELSE is encountered INCLUDE The INCLUDE directive reads in and assembles the indicated source file INCLUDEs can be nested up to four levels This allows a convenient means to keep common definitions declarations or subroutines in files to be included as needed The format is as follows INCLUDE filename The filename must be enclosed in double quotes Here are some examples INCLUDE macros h include equates include subs asm LIST NOLIST The LIST and NOLIST directives can be used to alternately turn the output to the list file on LIST or off NOLIST The formats are LIST NOLIST LOCALLABELCHAR The LOCALLABELCHAR directive can be
5. define a title string that appears at the top of each page of the list file assuming the PAGE mode is on The format is label TITLE string The string should not exceed 80 characters Here are some examples TITLE Controller version 1 1 title This is the title of the assembly title 22 WORD The WORD directive allows a value assignment to the next two bytes pointed to by the current Instruction Pointer The format is label WORD expr expr The least significant byte of expr is put at the current Instruction Pointer with the most significant byte at the next sequential location unless the MSFIRST directive has been invoked Here are some examples data_table WORD data_table 1 word 1234 Word GEER GG eee Word 12 55 32 OBJECT FILE FORMATS TASM can generate object code in the formats indicated below Option Description g0 Intel hex default g1 MOS Technology hex same as m g2 Motorola hex g3 binary same as b g4 Intel hex with word addresses The m and b flags may also be used as indicated above If both are used the right most option on the command line will be obeyed Intel Hex Object Format This is the default object file format This format is line oriented and uses only printable ASCII characters except for the carriage return line feed at the end of each line The format is symbolically represented as NN AAAA RR HH CC CRLF Where Record Star
6. lines per page indicate the desired number of lines per page as a decimal number immediately following the p Here is an example tasm 48 p56 source asm q Disable Listing File This option causes all output to the listing file to be suppressed unless a LIST directive is encountered in the source file see LIST NOLIST directives s Enable Symbol File Generation If this flag is set a symbol file is generated at the end of the assembly The format of the file is one line per label each label starts in the first column and is followed by white space and then four hexadecimal digits representing the value of the label The following illustrates the format labell FFFE label2 FFEF label3 1000 The symbol file name can be provided as the fifth file name on the command line or the name will be generated from the source file name with a SYM extension The symbol table file can also be generated by invoking the SYM directive The AVSYM directive also generates the symbol file but in a different format see section on ASSEMBLER DIRECTIVES t Table Name As an alternative to specifying the instruction set table as two decimal digits the table indication may be proceeded by the t option This is useful if the desired table name starts with a non numeric Thus a table for an F8 might be selected as tasm tf8 source asm TASM would expect to read the instruction set definition tables from a file named TASMF8 TAB
7. not yet been defined Heap overflow on label definition TASM was unable to allocate memory to store the label Imbalanced conditional An end of file was encountered at which time the level of descent in conditional directives was different from when the file was entered Conditional directives include IF IFDEF and IFNDEF Invalid Object file type An object file type was requested by the g command line option that is not valid See section on Option g Object File Format Invalid operand No indirection for this instruction The first character of an operand was a left parenthesis for an instruction that does not explicitly specify that as the format Some micros use the parenthesis as an indicator of indirection but putting a layer of parenthesis around an expression is always a valid thing to do as far as the expression evaluator is concerned The test for this case is only done if the a4 option is selected See section on ASSEMBLY CONTROL Invalid token where value expected Two binary operators in a row are not allowed Label too long Labels are limited to 31 characters Label value misaligned The value of a label appears to have a different value on the second pass then it was computed to have on the first pass This is generally due to Zero Page Addressing mode problems with the 6502 version of TASM Labels that are used in operands for statements that could utilize Zero Page addressing mode should always be defined before used a
8. the following could be done start ORG 1000H The expression expr may contain references to the current Instruction Pointer thus allowing various manipulations to be done For example to align the Instruction Pointer on the next 256 byte boundary the following could be done ORG OFFH amp OFFOOH ORG can also be used to reserve space without assigning values ORG 8 An alternate form of ORG is or Thus the following two examples are exactly equivalent to the previous example 8 8 PAGE NOPAGE The PAGE NOPAGE directives can be used to alternately turn the paging mode on PAGE or off NOPAGE If paging is in effect then every sixty lines of output will be followed by a Top of Form character and a two line header containing page number filename and the title The format is PAGE NOPAGE The number of lines per page can be set with the p command line option SET The SET directive allows the value of an existing label to be changed The format is label SET expr The use of the SET directive should be avoided since changing the value of a label can sometimes cause phase errors between pass 1 and pass 2 of the assembly SYM AVSYM These directives can be used to cause a symbol table file to be generated The format is SYM symbol filename AVSYM symbol_filename For example SYM symbol map SYM AVSYM prog sym AVSYM 21 The two directives are simi
9. used to override the default _ as the label prefix indicating a local label For example to change the prefix to do this label LOCALLABELCHAR Be careful to use only characters that are not operators for expression evaluation To do so causes ambiguity for the expression evaluator Some safe characters are and See Labels for an example of local label usage LSFIRST MSFIRST The LSFIRST and MSFIRST directives determine the byte order rule to be employed for the WORD directive The default whether correct or not for all TASM versions is the least significant byte first LSFIRST The following illustrates its effect 0000 34 12 word 1234 0002 msfirst 0002 12 34 word 1234 0004 lsfirst 0004 34 12 word 1234 MODULE The MODULE directive defines the scope of local labels The format is label MODULE label Here is an example MODULE module x lda regx jne _skip dec _skip rts 20 MODULE module y lda regy jne _skip dec _skip rts In the above example the local label _skip is reused without harm since the two usages are in separate modules See also section LOCALLABELCHAR directive ORG The ORG directive provides the means to set the Instruction Pointer a k a Program Counter to the desired value The format is label ORG expr The label is optional The Instruction pointer is assigned the value of the expr For example to generate code starting at address 1000H
10. your editor or IDE use the TASMERRFORMAT environment variable to alter the error message format When using automatic invocation of TASM from within an editor or IDE it may be useful to use the TASMOPTS environment variable to set other command line options For example to cause TASM to perform 6502 assemblies set TASMOPTS like this SET TASMOPTS 65 ERROR MESSAGE DESCRIPTIONS Binary operator where value expected Two binary operators in a row indicate a missing value Branch off of current 2K page An instruction is attempting to branch to a location not within the current 2K byte page Branch off of current page An instruction is attempting to branch to a location not within the current 256 byte page Cannot malloc for label storage Insufficient memory to store more labels See LIMITATIONS Duplicate label 27 The label for the current line has already been assigned a value Duplicate label checks are optionally enabled by the a option File name too short A file name on the command line is fewer than 3 characters A two character file name may be valid of course but it is detected as an error to prevent a garbled option flag from being taken as a source file which in turn can result in the true source file being taken as the object file Since the object file is truncated at startup time the source file could be clobbered Forward reference in equate An EQU directive is using a label on the right hand side that has
11. 2 3 4 13 Typical rules of precedence would cause the 2 3 to be evaluated first such as 1 2 3 4 4h To make sure you get the desired order of evaluation use parenthesis liberally Here are some examples of valid expressions O 800H tab label 2 gt gt 8 label 3 lt lt 8 amp f000 S 4 010010000100100b a base label 4 gt gt 5 amp mask lt lt 2 ASSEMBLER DIRECTIVES 14 Most of the assembler directives have a format similar to the machine instruction format However instead of specifying operations for the processor to carry out the directives cause the assembler to perform some function related to the assembly process TASM has two types of assembler directives those that mimic the C preprocessor functions and those that resemble the more traditional assembler directive functions Each of these will be discussed The ANSI C preprocessor style directives are invoked with a as the first character of the line followed by the appropriate directive just as in C Thus these directives cannot have a label preceding them on the same line Note that in the examples directives are shown in upper case however either upper or lower case is acceptable ADDINSTR The ADDINSTR directive can be used to define additional instructions for TASM to use in this assembly The format iS label ADDINSTR inst args opcode nbytes rule class shift binor The fields are separated by white spa
12. 405060708090A0BOCODOE0F101112131415161718A8 S 1051018191A9F S9030000FC The last line of the file will be a record with a byte count of zero and a tag of S9 The address field will be 0000 unless and address was provided with the END directive in which case it will appear in the address field Binary Object Format This file format is essentially a memory image of the object code without address checksum or format description information Note that when this object format is selected b option the c option is forced This is done so that no ambiguity results from the lack of address information in the file Without the c option discontinuous blocks of object code would appear contiguous LISTING FILE FORMAT Each line of source code generates one or more lines of output in the listing file The fields of the output line are as follows 1 Current source file line number 4 decimal digits 2 An optional appears if this is an INCLUDE file One for each level of INCLUDE invoked 3 Current Instruction Pointer 4 hex digits An optional follows the Instruction Pointer if the line of source code is not being assembled because of an IFDEF IFNDEF or IF directive 4 Resulting code data generated from this source line two hex digits per byte each byte separated by a space up to six bytes per line 5 The source line exactly as it appears in the source file If paging is enabled by either the p option fla
13. EQU directive so that the resulting file can be included in a subsequent assembly This feature can help overcome some of the deficiencies of TASM due to its lack of a relocating linker The format is label EXPORT label label The following example illustrates the use of the EXPORT directive and the format of the resulting export file Source file EXPORT read byte EXPORT write byte open fil Resulting export file read _ byte EQU 1243 write byte EQU S12AF open file EQU 1301 FILL The FILL directive can be used to fill a selected number of object bytes with a fixed value Object memory is filled from the current program counter forward The format is as follows label FILL number of bytes fill_ value The number_of_bytes value can be provided as any valid expression The optional fill_value can also be any valid expression If fill_value is not provided a default value of 255 FF is used IFDEF The IFDEF directive can be used to optionally assemble a block of code It has the following form IFDEF macro label When invoked the list of macro labels established via DEFINE directives is searched If the label is found the following lines of code are assembled If not found the input file is skipped until an ENDIF or ELSE directive is found Lines that are skipped over still appear in the listing file but a will appear immediately after the current PC and no object code will
14. F labell lda bytel sta byte2 ENDIF ifdef label1 lda bytel else lda byte2 endif ifndef label1 lda byte2 else lda bytel endif if gt 1000h generate an invalid statement to cause an error when we go over the 4K boundary PROM bounds exceeded endif END The END directive should follow all code data generating statements in the source file It forces the last record to be written to the object file The format is label END addr The optional addr will appear in the last object record Motorola S9 record type if the object format is Motorola hex The addr field is ignored for all other object formats ENDIF The ENDIF directive must always follow an IFDEF IFNDFF or IF directive and signifies the end of the conditional block EQU The EQU directive can be used to assign values to labels The labels can then be used in expressions in place of the literal constant The format is label EQU expr Here is an example MASK EQU OFOH r lda IN BYTE and MASK sta OUT BYTE An alternate form of the EQU directive is The previous example is equivalent to any of the following MASK OFOH MASK 0F0H MASK SFO0 18 White space must exist after the label but none is required after the EXPORT The EXPORT directive can be used to define labels symbols that are to be written to the export symbol file The symbols are written as equates using the
15. SM command line also with the d option flag DEFCONT The DEFCONT directive can be used to add to the last macro started with a DEFINE directive This provides a convenient way to define long macros without running off the edge of the page The ADD macro shown above could be defined as follows DEFINE ADD xx yy cle DEFCONT lda xx DEFCONT adc yy DEFCONT sta xx ECHO The ECHO directive can be used to send output to the console stderr It can accept either a quoted text string with the standard escape sequences allowed or a valid expression It can accept only one or the other however Multiple instances of the directive may be used to create output that contains both Consider the following example ECHO The size of the table is ECHO table end table start ECHO bytes long n This would result in a single line of output something like this The size of the table is 196 bytes long EJECT The EJECT directive can be used to force a top of form and the generation of a page header on the list file It has no effect if the paging mode is off see PAGE NOPAGE The format is label EJECT ELSE 17 The ELSE directive can optionally be used with IFDEF IFNDEF and IF to delineate an alternate block of code to be assembled if the block immediately following the IFDEF IFNDEF or IF is not assembled Here are some examples of the use of IFDEF IFNDEF IF ELSE and ENDIF IFDE
16. The Telemark Assembler TASM User Manual Version 3 2 Thomas N Anderson Squak Valley Software 837 Front Street South Issaquah WA 98027 email tnetherly comcast net http www tasmhome com Copyright C 1985 2002 by Thomas N Anderson All rights reserved TABLE OF CONTENTS INTRODUCTION SHAREWARE INVOCATION ENVIRONMENT VARIABLES EXIT CODES SOURCE FILE FORMAT EXPRESSIONS ASSEMBLER DIRECTIVES OBJECT FILE FORMATS LISTING FILE FORMAT PROM PROGRAMMING ERROR MESSAGES LIMITATIONS INTRODUCTION The Telemark Assembler TASM is a table driven cross assembler for the MS DOS and LINUX environments Assembly source code written in the appropriate dialect generally very close to the manufacturers assembly language can be assembled with TASM and the resulting object code transferred to the target microprocessor system via PROM or other mechanisms The microprocessor families supported by TASM are 6502 6800 6801 68HC11 6805 8048 8051 8080 8085 Z80 e TMS32010 TMS320C25 e TS7000 e 8096 80196 The user so inclined may build tables for other microprocessors The descriptions of the various existing tables and instructions on building new tables are not in this document but can be found in the TASMTABS HTM file on the TASM distribution disk TASM characteristics include Powerful expression parsing 17 operators Supports a subset of the C preprocessor commands Macro capability through use o
17. aracter immediately following it should be considered the first character of a new line and thus must either be a start of a label or white space not an instruction As the examples show a space is put between the backslash and the start of the next instruction Sample Source Listing Some examples of valid source statements follow 6502 mnemonics shown labl lda bytel get the first byte dec bytel jne labell lab2 sta byte2 X a multiple statement line follows lda bytel sta bytel 4 lda byte2 sta byte2 4 EXPRESSIONS Expressions are made up of various syntactic elements combined according to a set of syntactical rules Expressions can be comprised of the following elements e Labels e Constants e Location Counter Symbol 11 e Operators e Parenthesis Labels Labels are strings of characters that have a numeric value associated with them generally representing an address Labels can contain upper and lower case letters digits underscores and periods The first character must be a letter or the local label prefix default _ The value of a label is limited to 32 bit precision Labels can contain up to 32 characters all of which are significant none are ignored when looking at a label s value as in some assemblers Case is significant unless the 1 command line option is invoked Local labels must only be unique within the scope of the current module Modules are defined with the MODULE directive Here is an exam
18. aracters Maximum address space 64 Kbytes 65536 bytes Maximum number of nested INCLUDES 4 29 Maximum length of TITLE string 79 characters Maximum source line length 511 characters Maximum length after macro expansion 511 characters Maximum length of expressions 511 characters Maximum length of pathnames 79 characters Maximum length of command line 127 characters Maximum number of instructions per table 1200 Maximum number of macros 1000 Maximum number of macro arguments 10 Maximum length of macro argument 16 characters Memory requirements 512K Other Limitations The 8048 version of TASM does not check for use of memory beyond any reasonable bounds e g an 8048 has a maximum address space of 4 Kbytes but TASM will let you pretend that you have 64 Kbytes Expression evaluation has no operator precedence in effect which can make for unexpected results if not explicitly grouped with parenthesis First page of listing file will not show a user defined title defined via TITLE directive
19. assign the specified value to all bytes before the assembly begins so that when the object file is written all bytes not assigned a value in the source code will have a known value As an example the following command line will generate object code in the default Intel Hex format with all bytes not assigned a value in the source set to EA hex 6502 NOP instruction 26 tasm 65 c fEA test asm CONTIGUOUS BLOCKS To ensure that TASM generates object code to cover the full address range of the target PROM put a ORG statement at the end of the source file set to the last address desired For example to generate code to be put in a 2716 EPROM 2 Kbytes from hex address 1000 to 17ff do something like this in the source file start of the file ORG 1000 rest of the source code follows source code 7 end of the source code ORG STIFTE BYTE 0 END Now to invoke TASM to generate the code in the binary format with all unassigned bytes set to 00 6502 BRK instruction do the following tasm 65 b f 00 test asm Note b forces the c option ERROR MESSAGES Error Message Format TASM error messages take the following general form filename line line number error message For example main asm line 0032 Duplicate label start Many editors and IDE s can run assemblies from within and parse the error messages to make it convenient to jump to each error and correct If the above format is not satisfactory for
20. ce just as they would appear in an instruction definition file See the TASMTABS HTM file on the TASM distribution disk for more detail AVSYM See SYM AVSYM BLOCK The BLOCK directive causes the Instruction Pointer to advance the specified number of bytes without assigning values to the skipped over locations The format is label BLOCK expr Some valid examples are wordl BLOCK 2 bytel block 1 buffer block 80 BSEG CSEG DSEG NSEG XSEG These directives can be invoked to indicate the appropriate address space for symbols and labels defined in the subsequent code The invocation of these directives in no way affects the code generated only provides more information in the symbol table file if the AVSYM directive is employed Segment control directives such as these are generally supported by assemblers that generate relocatable object code TASM does not generate relocatable object code and does not support a link phase so these directives have no direct effect on the resulting object code The segments are defined as follows Directive Segment Description BSEG _ Bit address CSEG Code address DSEG _ Data address internal RAM NSEG Number or constant EQU XSEG External data address external RAM BYTE 15 The BYTE directive allows a value assignment to the byte pointed to by the current Instruction Pointer The format is label BYTE expr expr Only the lower eight bits of expr are used Multiple byt
21. cept for the carriage return line feed at the end of each line Each line in the file is of the following format NN AAAA HH CC CRLF Where Fs Record Start Character semicolon NN _ Byte Count 2 hex digits AAAA Address of first byte 4 hex digits HH Data Bytes a pair of hex digits for each byte of data in the record CCCC Check Sum 4 hex digits CRLF Line Terminator CR LF for DOS LF for LINUX The last line of the file will be a record conforming to the above format with a byte count of zero The checksum is defined as 24 sum byte_count address_hit address_lo record_type sum of all data bytes checksum sum amp ffffh Here is a sample object file 71810000102030405060708090A0B0OCODOEOF1011121314151617180154 7021018191A005D 700 Motorola Hex Object Format This format is line oriented and uses only printable ASCII characters except for the carriage return line feed at the end of each line The format is symbolically represented as S1 NN AAAA HH CCCC CRLF Where SI Record Start tag NN _ Byte Count 2 hex digits data byte count 3 AAAA Address of first byte 4 hex digits HH Data Bytes a pair of hex digits for each byte of data in the record CC Check Sum 2 hex digits CRLF Line Terminator CR LF for DOS LF for LINUX The checksum is defined as sum byte_count address_hit address_lo sum of all data bytes checksum sum amp ffh Here is a sample file S11B10000102030
22. done If a digit follows then it is used as a mask to determine the error checks to be made The bits of the mask are defined as follows Bit Option Default Description 0 al OFF Check for apparent illegal use of indirection 1 a2 ON Check for unused data in the arguments 2 a4 ON Check for duplicate labels 3 a8 OFF Check for non unary operators at start of expression Combinations of the above bits can also be used For example a5 would enable the checking for illegal indirection and duplicate labels Illegal indirection applies to micros that use parenthesis around an argument to indicate indirection Since it is always legal to put an extra pair of parenthesis around any expression as far as the expression parser is concerned the user may think that he she is indicating indirection for an instruction that has no indirection and TASM would not complain Enabling this checking will result in an error message warning whenever an outer pair of parenthesis is used and the instruction set definition table does not explicitly indicate that to be a valid form of addressing Unused data in arguments applies to cases where a single byte of data is needed from an argument but the argument contains more than one byte of data If a full sixteen bit address is used in a Load Immediate type instruction that needs only a single byte for example an error message would be generated Here is an example 6502 code 0001 1234 org 1234 test as
23. es may be assigned by separating them with commas or for printable strings enclosed in double quotes Here are some examples labell BYTE 10010110B byte a byte 0 byte 100010110b a 0 byte Hello 10 13 World CHK The CHK directive causes a checksum to be computed and deposited at the current location The starting point of the checksum calculation is indicated as an argument Here is the format label CHK starting addr Here is an example start NOP LDA 1 CHK start The checksum is calculated as the simple arithmetic sum of all bytes starting at the starting_addr up to but not including the address of the CHK directive The least significant byte is all that is used CODES NOCODES The CODES NOCODES directives can be used to alternately turn on or off the generation of formatted listing output with line numbers opcodes data etc With NOCODES in effect the source lines are sent to the listing file untouched This is useful around blocks of comments that need a full 80 columns of width for clarity DB This is alternate form of the BYTE directive DW This is alternate form of the WORD directive DEFINE The DEFINE directive is one of the most powerful of the directives and allows string substitution with optional arguments macros The format is as follows DEFINE macro label arg list macro definition Where macro_label character string to be expanded when found in the source file arg_list
24. f DEFINE directive Multiple statements per line Four object file formats Intel hex MOS Technology hex Motorola hex binary Absolute code generation only Source code available in C Uniform syntax across versions for different target machines Features in support of PROM programming preset memory contiguous block Supports extended instructions for many of the supported microprocessor families Tables read at run time single TASM executable for all table versions Symbol table export for inclusion in subsequent assemblies Symbol table export file for import with some simulator products SO ONY NS ee WNrR SHAREWARE TASM is distributed as shareware TASM is not in the public domain The TASM distribution files may be freely copied excluding the source code files and freely used for the purpose of evaluating the suitability of TASM for a given purpose Use of TASM beyond a reasonable evaluation period requires registration Prolonged use without registration is unethical INVOCATION TASM can be invoked as follows optional fields shown in brackets symbolic fields in italics tasm pn options src file obj file lst file exp file sym file Where options can be one or more of the following table Specify version table table designation ttable Table alternate form of above aamask Assembly control optional error checking b Produce object in binary COM format C Object fi
25. files are read at run time TASM determines which table to use based on the table field shown above For example to assemble the code in a file called source asm one would enter tasm 48 source asm for an 8048 assembly tasm 65 source asm for a 6502 assembly tasm 51 source asm for an 8051 assembly tasm 85 source asm for an 8085 assembly tasm 80 source asm for a Z80 assembly tasm 05 source asm for a 6805 assembly tasm 68 source asm for a 6800 6801 68HC11 assembly tasm 70 source asm for a TMS7000 assembly tasm 3210 source asm fora TMS32010 assembly tasm 3225 source asm fora TMS320C25 assembly tasm 96 source asm for a 8096 80196 assembly Tables are read from a file named by taking the digits specified after the and appending it to TASM then appending the TAB extension Thus the 48 flag would cause the tables to be read from the file TASM48 TAB It is possible to designate tables by non numeric part numbers if the t flag is used For example if a user built a table called TASMF8 TAB then TASM could be invoked as follows tasm tf8 source asm Each option flag must be preceded by a dash Options need not precede the file names The various options are described in the sections that follow a Assembly Control TASM can provide additional error checking by specifying the a option at the time of execution If the a is provided without a digit following then all the available error checking is
26. g or the PAGE directive some additional fields will be inserted into the listing file every 60 lines These fields are Top of Form form feed Assembler identifier e g TASM 6502 Assembler Initial source file name Page number Title Ae whe If errors are encountered then error messages will be interspersed in the listing TASM outputs error messages proceeding the offending line The following example illustrates the format 0001 0000 labell equ 40h 0002 0000 label2 equ 44h 0003 0000 0004 1000 start org 1000h 0005 1000 E6 40 inc label1 0006 1002 E6 44 inc label2 tt asm line 0007 Label not found label3 0007 1004 EE 00 00 inc label3 0008 1007 4C 00 10 jmp start 0009 100A end 0010 100A tasm Number of errors 1 PROM PROGRAMMING A wide variety of PROM programming equipment is available that can use object code in one or more of the formats supported by TASM Here are some notes concerning the generation of code to be programmed into PROMs PRESET MEMORY It is often desirable to have all bytes in the PROM programmed even if not explicitly assigned a value in the source code e g the bytes are skipped over with a ORG statement This can be accomplished by using the c contiguous block and the f fill command line option flags The c will ensure that every byte from the lowest byte assigned a value to the highest byte assigned a value will be in the object file with no gaps The f flag will
27. he path to be searched for TASM instruction set definition tables If it is not defined then the table s must exist in the current working directory The following examples illustrate possible usage For MSDOS set TASMTABS C TASM For LINUX TASMTABS tasm TASMOPTS This variable specifies TASM command line options that are to be invoked every time TASM is executed For example if TASM is being used for 8048 assemblies with binary object file output desired the following statement would be appropriate in the AUTOEXEC BAT file set TASMOPTS 48 b TASMERRFORMAT The TASMERRFORMAT variable provides user control of the format of error messages The format string must be a valid printf format string for ANSI C The default value is Ss line 04d s s Which provides error messages like this Main asm line 1234 No such label Start The four fields associated with an error message are Field Description Associated Data Type ANSI C File name char Line number within file lint Error description char Error data optional char No user control of the order of the error message fields is provided Here are sample usages For MSDOS set TASMERRFORMAT 3s d s s For LINUX TASMERRFORMAT s 3d 38 s EXIT CODES When TASM terminates it will return to the OS the following exit codes Exit Code Definition Normal completion no assembly errors Normal completion with assembly errors Abnormal comp
28. icros use as an indirection operator Since it is also a legitimate operator in an expression some ambiguity can arise If a particular instruction addressing mode does not allow indirection and a is placed in front of the associated expression the assembler will assume this error See the a8 option of ASSEMBLY CONTROL Object file open error TASM was not able to open the specified object file Range of argument exceeded The value of an argument exceeds the valid range for the current instruction and addressing mode Range of relative branch exceeded A branch instruction exceeds the maximum range Source file open error TASM was not able to open the specified source file Unrecognized directive A statement starting with a or has a mnemonic that is not defined as a directive Unrecognized instruction A statement has an opcode mnemonic that is not defined Unrecognized argument A statement has an operand format that is not defined Unknown token Unexpected characters were encountered while parsing an expression Unused data in MS byte of argument An instruction or directive used the least significant byte of an argument and left the most significant byte unused but it was non zero Unknown option Flag Invalid option flag has been specified on the command line invoke TASM with nothing on the command line to see a list of valid options LIMITATIONS Maximum number of labels 15000 Maximum length of labels 32 ch
29. lar but result in a different format of the symbol table file The format of the SYM file is one line per symbol each symbol starts in the first column and is followed by white space and then four hexadecimal digits representing the value of the symbol The following illustrates the format labell FFFE label2 FFFF label13 1000 The AVSYM directive is provided to generate symbol tables compatible with the Avocet 8051 simulator The format is similar but each line is prefixed by an AS and each symbol value is prefixed by a segment indicator AS start C 1000 AS read byte C 1245 AS write byte C 1280 AS low_nib mask N 000F AS buffer X 0080 The segment prefixes are determined by the most recent segment directive invoked see BSEG CSEG DSEG NSEG XSEG directives TEXT This directive allows an ASCII string to be used to assign values to a sequence of locations starting at the current Instruction Pointer The format is label TEXT Wstring The ASCII value of each character in string is taken and assigned to the next sequential location Some escape sequences are supported as follows Escape Sequence Description n Line Feed r Carriage return b Backspace t Tab f Formfeed Backslash Ae Quote 000 Octal value of character Here are some examples messagel TEXT Disk I O error message2 text Enter file name text abcdefg n r text T said No TITLE The TITLE directive allows the user to
30. le written as a contiguous block dmacro Define a macro or just a macro label e Show source lines after macro expansion ffillbyte Fill entire memory space with fillbyte hex gobjtype Object file O Intel Hex 1 MOS Tech 2 Motorola 3 binary 4 Intel Hex Word h Produce hex table of the assembled code in list file i Ignore case for labels l al Produce a label table in the listing m Produce object in MOS Technology format oobytes Bytes per object record for hex obj formats p lines Page the listing file lines per page default 60 q Quiet disable the listing file S Write a symbol table file x xmask Enable extended instruction set if any y Time the assembly The filename parameters are defined as follows src_file Source file name obj_file Object code file name Ist_file Listing file name exp_file Symbol export file only if the EXPORT directive is used sym_file Symbol table file only if the s option or the SYM AVSYM directives are used The source file must be specified If not some usage information is displayed Default file names for all the other files are generated if they are not explicitly provided The filename is formed by taking the source filename and changing the extension to one of the following Extension File type OBJ Object file LST Listing file EXP Symbol export file SYM Symbol table file TASM has no built in instruction set tables Instruction set definition
31. letion insufficient memory Abnormal completion file access error BREW NN e Oo Abnormal completion general error Exit codes 2 and above will also be accompanied by messages to the console concerning the error SOURCE FILE FORMAT Statements in the source file must conform to a format as follows except for assembler directive statements which are described in a subsequent section label operation operand comment All of the fields are optional under appropriate circumstances An arbitrary amount of white space space and tabs can separate each field as long as the maximum line length of 255 characters is not exceeded Each of the fields are described in the following sections Label Field If the first character of the line is alphabetic it is assumed to be the start of a label Subsequent characters are accepted as part of that label until a space tab or is encountered The assembler assigns a value to the label corresponding to the current location counter Labels can be a maximum of 32 characters long Labels can contain upper and lower case letters digits underscores and periods the first character must be alphabetic Labels are case sensitive the label START is a different label from start unless the i ignore case option is enabled 10 Operation Field The operation field contains an instruction mnemonic which specifies the action to be carried out by the target processor when this instructio
32. m line 0002 Unused data in MS byte of argument 0002 1234 A9 34 start lda start To make the above checks occur whenever you do an assembly add a line like this to your AUTOEXEC BAT file SET TASMOPTS a b Binary Object Format This option causes the object file to be written in binary one byte for each byte of code data Note that no address information is included in the object file in this format The contiguous block c output mode is forced when this option is invoked This flag is equivalent to g3 c Contiguous Block Output If this option is specified then all bytes in the range from the lowest used byte to the highest will be defined in the object file Normally with the default Intel Hex object format enabled if the Program Counter PC jumps forward because of an ORG directive the bytes skipped over will not have any value assigned them in the object file With this option enabled no output to the object file occurs until the end of the assembly at which time the whole block is written This is useful when using TASM to generate code that will be put into a PROM so that all locations will have a known value This option is often used in conjunction with the f option to ensure all unused bytes will have a known value d Define a Macro Macros are defined on the command line generally to control the assembly of various IFDEF s that are in the source file This is a convenient way to generate various versions of objec
33. n is executed The interpretation of each mnemonic is dependent on the target microprocessor as indicated by the selected TASM table The operation field may begin in any column except the first The operation field is case insensitive Operand Field The operand field specifies the data to be operated on by the instruction It may include expressions and or special symbols describing the addressing mode to be used The actual format and interpretation is dependent on the target processor For a description of the format for currently supported processors see the TASMTABS DOC file on the TASM distribution disk Comment Field The comment field always begins with a semicolon The rest of the line from the semicolon to the end of the line is ignored by TASM but passed on to the listing file for annotation purposes The comment field must be the last field on a line but it may be the only field starting in column one if desired Multiple Statement Lines If the backslash character is encountered on a source line it is treated as a newline The remainder of the line following the backslash will be processed as an independent line of source code This allows one to put multiple statements on a line This facility is not so useful of itself but when coupled with the capability of the DEFINE directive powerful multiple statement macros can be constructed see section on ASSEMBLER DIRECTIVES Note that when using the statement separator the ch
34. ple MODULE xxx lda regx jne _skip dec _skip rts MODULE yyy lda regy jne _skip dec _skip rts In the above example the _skip label is reused without harm As a default local labels are not shown in the label table listing resulting from the l command line option See also sections on MODULE and LOCALLABELCHAR directives Numeric Constants Numeric constants must always begin with a decimal digit thus hexadecimal constants that start with a letter must be prefixed by a 0 unless the prefix is used The radix is determined by a letter immediately following the digit string according to the following table Radix Suffix Prefix 2 Borb 8 Ooro 10 D ord or nothing 16 Horh Decimal is the default radix so decimal constants need no suffix or prefix The following representations are equivalent 1234H or 1234 100d or 100 1774000 or 177400 01011000b or 01011000 The prefixes are provided for compatibility with some other source code formats but introduce a problem of ambiguity Both and have alternate uses for modulo for location counter symbol The ambiguity is resolved by examining the context The character is interpreted as the modulo operator only if it is in a position 12 suitable for a binary operator Similarly if the first character following a is a valid hexadecimal digit it is assumed to be a radix specifier and not the location counter Character Constants
35. rform some alterations or calculations on particular values The operators are summarized as follows Operator Type Description Additive addition subtraction Multiplicative multiplication division modulo 13 lt lt logical shift left gt gt logical shift right Unary bit inversion one s complement unary negation Relational equal equal not equal less than gt greater than lt less than or equal gt greater than or equal amp Binary binary and binary or A binary exclusive or The syntax is much the same as in ANSI C with the following notes 1 No operator precedence is in effect Evaluation is from left to right unless grouped by parenthesis see example below 2 All evaluations are done with 32 bit signed precision 3 Both and are allowable equality checkers This is allowed since the syntax does not provide assignment capability as would normally imply The relational operators return a value of 1 if the relation is true and 0 if it is false Thirty two bit signed arithmetic is used It is always a good idea to explicitly indicate the desired order of evaluation with parenthesis especially to maintain portability since TASM does not evaluate expressions in the same manner as many other assemblers To understand how it does arrive at the values for expressions consider the following example 1 2 3 4 TASM would evaluate this as COCR 40
36. s an operand Label not found A label used in an expression was not found in the current label table Label must pre exist for SET The SET directive can only be applied to an existing label Label table overflow To many labels have been encountered List file open error TASM was not able to open the specified list file Macro expansion too long The expansion of a macro resulted in a line that exceeded the maximum length Max number of nested conditionals exceeded Too many levels of IF IFDEF or IFNDEF Maximum number of args exceeded Too many macro arguments Maximum number of macros exceeded Too many macros DEFINEs have been encountered No END directive before EOF 28 The source file did not have an END directive in it This is not fatal but may cause the last object file record to be lost No files specified TASM was invoked with no source file specified No such label A SET directive was encountered for a label not yet defined The value of labels that are modified by the SET directive must already exist No terminating quote A double quote was used at the start of a a text string but was not used at the end of the string No indirection for this instruction A parenthesis was found around the operand expression This may indicate an attempt to use indirection where it is Inappropriate Non unary operator at start of expression A binary operator such as was found at the beginning of an expression Some m
37. t Character colon NN _ Byte Count 2 hex digits AAAA Address of first byte 4 hex digits RR Record Type 00 except for last record which is 01 HH Data Bytes a pair of hex digits for each byte of data in the record CC Check Sum 2 hex digits CRLF Line Terminator CR LF for DOS LF for LINUX The last line of the file will be a record conforming to the above format with a byte count of zero 23 The checksum is defined as sum byte_count address_hit address_lot record_type sum of all data bytes checksum sum amp ffh Here is a sample listing file followed by the resulting object file 0001 0000 0002 1000 Org 1000 0003 1000 010203040506 spyte ly 2 3 4p Dy 67 Ty 8 0003 1006 0708 0004 1008 O90AD0BOCODOE byte 9 10 11 12 13 14 15 16 0004 100E OF10 0005 1010 111213141516 byte 17 18 19 20 21 22 23 24 25 26 0005 1016 1718191A 0006 101A end 181000000102030405060708090A0BOCODOEOF101112131415161718AC 02101800191AA3 00000001FF Intel Hex Word Address Object Format This format is identical to the Intel Hex Object Format except that the address for each line of object code is divided by two thus converting it to a word address 16 bit word All other fields are identical Here is an example 180800000102030405060708090A0BOCOD0E0F101112131415161718AC 02080C00191A43 00000001FF MOS Technology Hex Object Format This format is line oriented and uses only printable ASCII characters ex
38. t code from a single source file e Expand Source Normally TASM shows lines in the listing file just as they are in the source file If macros are in use via the DEFINE directive it is sometimes desirable to see the source lines after expansion Use the e flag to accomplish this f Fill Memory This option causes the memory image that TASM maintains to be initialized to the value specified by the two hex characters immediately following the f TASM maintains a memory image that is a full 64K bytes in size even if the target processor cannot utilize that memory space Invocation of this option introduces a delay at start up time g Object File Format TASM can generate object code in the formats indicated below Option Description g0 Intel hex default g1 MOS Technology hex same as m g2 Motorola hex g3 binary same as b g4 Intel hex with word addresses The m and b flags may also be used as indicated above If both are used the right most option on the command line will be obeyed See the section on OBJECT FILE FORMATS for descriptions of each of the above h Hex Object Code Table This option causes a hex table of the produced object code to appear in the listing file Each line of the table shows sixteen bytes of code i Ignore Case in Labels TASM is normally case sensitive when dealing with labels For those that prefer case insensitivity the 1 command line option can be employed
39. x Enable Extended Instruction Set If a processor family has instructions that are valid for only certain members this option can be used to enable those beyond the basic standard instruction set A hex digit may follow the x to indicate a mask value used in selecting the appropriate instruction set Bit 0 of the mask selects the basic instruction set thus a x1 would have no effect A x3 would enable the basic set plus whatever instructions have bit set in their class mask A x without a digit following is equivalent to a xf which sets all four of the mask bits The following table indicates the current extended instruction sets available in the TASM tables Base Table Base Family Ext 1 x3 Ext 2 x7 Ext 3 x5 Ext 4 x9 48 8048 8041A 8022 8021 65 6502 R65C02 R65C00 21 05 6805 M146805 CMOS HC05C4 80 Z80 HD64180 68 6800 6801 6803 68HC11 51 8051 85 8080 3210 TMS32010 3225 TMS320C25 TMS320C26 70 TMS7000 The above table does not attempt to show the many microprocessor family members that may apply under a given column See the TASMTABS HTM on line document for details on each specific table y Enable Assembly Timing If this option is enabled TASM will generate a statement of elapsed time and assembled lines per second at the end of the assembly ENVIRONMENT VARIABLES The TASM environment can be customized by using the environment variables listed below TASMTABS The TASMTABS variable specifies t
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