C/C++ Interactive Reference Guide

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.pl 70 .op .he TMS9900/99105 Cross-assembler Rev. 1.0 Page # TMS9900/99105 Cross-assembler Rev. 1.0 Derived from the original William C. Colley, III. M6800 Cross Assembler by Alexander Cameron Written and modified during June 1984. The Manual Such As It Is. .pa .pn 1 .op ...COLUMNWIDTH 65 ...MARGINWIDTH 6 ...T1 1.1 Format of Cross-assembler Commands ...T2 1.1.1 Command Strings To run the 9900 cross-assembler, type the following command line: A>a99 filename options filename: The name of the source input file is filename.a99, the list can go to filename.l99, and the hex file can go to filename.h99. options: See next section. ...T2 1.1.2 Options The source file comes from the currently logged disk drive unless it is redirected by putting the string "sd" in the options field. s specifies the source file and d is a device code from the following list: a, b, c, d Disk drives. - The currently logged in disk drive. Lines of input containing errors will always be output to the console device. If the full listing is desired, it must be called for by putting the string "ld" in the options field. l specifies list file and d is a device code as per the source file, or one of the following: x Console device. y List device. The hex file will not be output unless called for as per the list file. Options must be run together into a single string with no embedded blanks. ...T2 1.1.3 Examples A>a99 barf source -- a:barf.a99 list -- none. hex -- none. A>a99 barf sblxha source -- b:barf.a99 list -- con: hex -- a:barf.h99 A>a99 barf ly source -- a:barf.a99 list -- lst: hex -- none. A>b:a99 barf sbh- source -- b:barf.a99 list -- none. hex -- a:barf.h99 ...T1 1.2 Format of TMS9900 Cross-assembler Source Files Lines of source input are terminated with CR/LF pairs. Internally, the character before the LF is discarded, so if the CR is missing, the last character of the line will be eaten up. The internal line buffer will hold a 120 character line. This may be changed by altering the "#define LINLEN 120" statement in xasm99.gbl and recompiling the cross-assembler. Excess characters in the line are thrown out. Lower case letters are converted to upper case in as few places as possible. They are: 1) In opcodes, 2) In checking for keywords such as NOT, and 3) In command strings. This means that "not", "NOT", "Not", etc. are all possible spellings of the logical inversion operator. This also means that "foo" and "FOO" are different symbols. Watch this if you start encountering U errors of symbols that you "know" you defined. ...T2 1.2.1 Statements Source files input to the 9900 Cross-assembler consist of statements of the form: [label] [opcode] [arguments] [;comments.] Labels are recognized by their beginning in column 1. If it doesn't begin there, it is assumed to be an opcode. Labels are assigned the current program counter value unless the line's opcode is "EQU" or "SET". Opcodes may be either 9900 instruction mnemonics or pseudo-ops. The arguments following the opcode will vary with the opcode. In the case of opcodes such as "NOP", they may be absent entirely. Lines terminate with either a CR/LF pair or a semicolon that is not embedded in a quoted string. Anything after a semicolon is ignored by the assembler, but will appear in the listing. Note that a semicolon in column 1 will make the entire line a comment. ...T2 1.2.2 Symbols Symbols may be of any length, but only the first 8 characters are significant. This may be changed by changing the "#define SYMLEN 8" statement in a68.gbl and recompiling the assembler. Note that this increases the storage required by the symbol table as each entry in the symbol table is SYMLEN+2 bytes in length. The following characters are legal in a symbol: A-Z a-z ! & . : ? [ \ ] ^ _ ` { | } ~ 0-9 Note that symbols may not begin with 0-9 as this would make them impossible to distinguish from Intel format numbers. A special symbol $ is always equal to the address of the first byte of code generated by a given line. ...T2 1.2.3 Numeric Constants Numbers begin with 0-9,%. % leading base designator represent binary. If the number begins with 0-9, the assembler looks for one of the trailing base designators B, O, Q, D, or H. If the number does not end with one of these, it is assumed to be decimal. B is the base designator for binary, O and Q are for octal, D is for decimal, and H is for hexidecimal. Trailing base designators and the hex digits A-F can be in either upper or lower case. Note that hex numbers that start with A-F and are specified with the designator H must have a leading zero added to keep them from being mistaken for symbols. For example: 0ff80h evaluate to ff80 hex. 128 and 128d evaluate to 80 hex. 35o, and 35q evaluate to 1d hex. %0111000 and 0111000b evaluate to 39 hex. A character constant is a string composed of zero, one, or two ASCII characters, delimited by either single or double quotes (' or "). Note that single quotes only balance single quotes, and double quotes only balance double quotes. Thus a character constant of 22 hex can be specified by '"'. For example: "ab" evaluates to 6162 hex. "" evaluates to 0000 hex. "'" evaluates to 0027 hex. 'A' evaluates to 0041 hex. Note that in the two-character character constant, the left-hand character will appear in the upper-order byte and the right-hand character will appear in the lower-order byte. ...T2 1.2.4 Strings Strings are formed in the same way as character constants except that they may be of any length up to and including 255 characters. The first character will be placed in the lowest-order memory byte. A line-feed character may not be embedded in a string as it terminates the line and will yield a quote imbalance error. Note that strings are only valid in the arguement field of an "TEXT" pseudo-op. ...T1 1.3 Expression Evaluation The following operators are allowed in expressions. The operators are listed in order of precedence. Unary Plus, Unary Minus *, /, MOD, SHL, SHR +, - >, >=, <, <=, <>, = (These can also be written as GT, GE, LT, LE, NE, EQ.) NOT (1's complement) AND (Bitwise logical AND) OR, XOR (Bitwise logical OR and Exclusive OR) HIGH, LOW Parentheses are used to change the order of precedence. During evaluation of an expression, as soon as a new operator is encountered that has precedence less than or equal to the last operator encountered, all operations up to the new operator are performed. That is, subexpressions involving operators of higher precedence are computed first. All operators except +, -, *, /, =, <>, >=, <=, >, < must be separated from their operands by at least one space or tab. The "HIGH mumble" is equivalent to "mumble SHR 8" and "LOW mumble" is equivalent to "mumble AND 0ffH". The relational operators (=, >, etc.) evaluate to 0ffffh if the relationship is true, 0 if it is false. Expressions are terminated by commas, semicolons, or CR/LF pairs. ...T1 1.4 990 Family Instructions The instructions of the 9900/99105 microprocessor fall into several catagories. Each requires a certain set of arguments and disallows other arguments. Arguments may be specified in any order and are separated by commas Blanks may be used freely throughout the argument field (except within symbols or operators such as NOT) to enhance the readability of the source code. The basic syntax is as follows: [label] LI R1,expression ;The expression ;is evaluated ;from left to ;right. The type of addressing each instruction is allowed along with the number of operands the assembler expects the instruction to have, is carried in the ATTRIB byte which is returned by the GETOPC function. The ATTRIB byte is is made up of two 4 bit nibbles the least significat describing operand 1 and the most significant describing operand 2. (See the heading comments of GETOPC which is part of the file A99TBLS.CSM). The ATTRIB byte will also tell the assembler which one of the 7 basic instruction formats a particulare instruction falls into. Thes formats/groups are discussed in the following sections. ...T2 1.4.1 Addressing Modes The 9900/99105 instruction set allows 5 basic addressing modes. These are: Mode Example ---- ------- Workspace register MOV R1,R3 Workspace register indirect A *R1,R2 Symbolic CLR @expr Indexed A @expr(R1),R2 Workspace register indirect DEC *R7+ (auto increment) These modes will in general be written in the form: R, *R, *R+, @X, @X(R) where R refers to a Register and X to an address. ...T2 1.4.2 Instruction Formats The assembler will properly evaluate 7 basic instrucion formats; these are: Format 0 - No operands at all (N) Format 1 - R,*R,*R+,@X,@X(R) Format 2 - Displacement (Disp) Format 3 - Destination Field only (D) Format 4 - Signed Displacement (SD) Format 5 - Workspace Register (W or C) Format 6 - Immediate Operands (IOP) Format 7 - Bit Manipulation Instrucions (TMS99105 only) Depending on the instruction these formats may lie within either the source or destination fields. ...T2 1.4.3 Group 1 Instructions This group contains the following opcodes: NOP RSET IDLE CKOF CKON LREX RTWP These opcodes permit no arguments, and hence are of format 0. ...T2 1.4.4 Group 2 Instructions This group of instructions are of Format type 1 and are Dual Operand Instructions with Multiple Addressing Modes for Source and Destination Operand. This group contains the following opcodes: A AB C CB S SB SOC SOCB SZC SZCB MOV MOVB Instruction format: [opcode|format1|format1] Example: A *R1+,R2 ...T2 1.4.5 Group 3 Instructions This group of instructions are Dual Operand Instructions with Multiple Addressing Modes for the Source Operand and Workspace Register Addressifng for the Destination. This group contains the following opcodes: COC CZC XOR MPY DIV XOP LDCR STCR Instruction format: [opcode|format3|format1] Example: XOP @LABEL,3 ...T2 1.4.6 Group 4 Instructions This group of instructions allow Multiple Addressing modes for the source Operand, and thus a single operand instructions. This following instructions belong to this group: B BL BLWP CLR SETO INV NEG ABS SWPB INC INCT DEC DECT X BIND(a TMS99105 instruction) Instruction format: [opcode|format1] Example: INC @LABEL(R3) ...T2 1.4.7 Group 5 Instructions This group of instructions are CRU Single-Bit Instructions. The following instructions belong to this group: SBO SBZ TB Instruction format: [opcode|format4] Example: SBO 25 1.4.8 Group 6 Instructions This group covers the Conditional Jump instrucions. Note that the maximum displacement range is +127 to -128 words. The following instructions belong to this group: JEQ JGT JH JHE JL JLE JLT JMP JNC JNE JNO JOC JOP Instruction format: [opcode|format2] Example: JEQ LABEL ...T2 1.4.9 Group 7 Instructions This group have an Immediate Source Operand with an Workspace Register as the Destination Operand. The following instructions belong to this group: AI ANDI CI LI ORI BLSK (a TMS99105 instruction) Instruction format: [opcode|format5] [ format6 ] Example: AI R3,128 ...T2 1.4.10 Group 8 Instructions This group covers the Internal Register Load Immediate Instructions and have an Immediate Source Operand only. The following instructions belong to this group: LWPI LIMI Instruction format: [ opcode ] [ format6 ] Example: LIMI 3 ...T2 1.4.11 Group 9 Instructions This group covers the Internal Register Store Instructions and have Destination Workspace Register Addressing only. The following instructions belong to this group: STST STWP LST LWP ( TMS99105 instructions ) Instruction format: [opcode|format5] Example: STST R3 ...T2 1.4.12 Group 10 (TMS99105 only) This group covers the Bit-Manipulation instruc- tions peculiar to the TMS99105. This group has a different instruction format than the basic 9900 set insofar as the format fields lie in the 2nd word. The instructions in this group are: TMB TCMB TSMC Instruction format: [ opcode ] [ format3|format1] Example: TMB @BITMAP(R3),8 ...T1 1.5 Pseudo-operations ...T2 1.5.1 END When this statement is encountered, the assembler decides that the end of the source file has been reached. If this statement is missing or in a conditional assembly block that is not being assembled, the assembler will encounter end-of-file on the source file. In this case, the assembler will attach an END statement and will flag an error. The syntax is as follows: [label] END If any IF statement is not closed with an ENDI at this point, an error will be flagged. This statement permits no arguments. ...T2 1.5.2 EQU This statement is used to assign a permenant value to a symbol. This value may not be subsequently changed by a SET, another EQU, or by writing the symbol in column 1 as a label. The syntax is as follows: label EQU expression A phasing (P) error will result if any forward references are encountered in the evaluation of the expression. ...T2 1.5.3 BYTE This statement is used to place bytes in memory. Each byte is defined by an expression. Multiple bytes can be defined by expressions separated by commas. If an expression evaluates to a quantity outside the range -128 to 255, an error is flagged. The syntax is as follows: [label] BYTE [expr1][,epxr2]..... ...T2 1.5.4 TEXT This statement is used to place strings in memory. Its arguments may only be strings. Multiple strings may be placed in memory if the strings are separated by commas. The syntax is as follows: [label] TEXT [string][,string]..... ...T2 1.5.5 WORD This statement is used to place words in memory. Each word is defined by an expression. Multiple words may be defined by expressions separated by commas. Words are placed in memory with their high-order byte in the low-order memory location and the low-order byte in the high-order memory location. The syntax is as follows: [label] WORD [expr1][,expr2]..... ...T2 1.5.6 BSS (Block Starting with Symbol) This statement is used to reserve a block of memory for working storage, etc. It requires one argument that gives the number of bytes of storage to reserve. The syntax is as follows: [label] BSS expression ...T2 1.5.7 EVEN This statement is used to force the assembler to align code on an even word boundary if the present programme counter is odd. If the programme counter is odd a zero byte is output if even the statement is ignored. The assembler will also flag an error is an attempt is made to output code to an odd address. The syntax is as follows: [label] EVEN ...T2 1.5.8 DXOP This statement allows the programmer to define their own macro instructions around the Extended Operation Instruction (XOP). The assemble will substitute the XOP code for a given instruction in place of the name assigned to the XOP. The syntax is as follows: DXOP PUSH,3 ;assign the name PUSH to ;XOP number 3 For example if PUSH is a previously coded XOP which pushes registers onto the stack then instead of coding this XOP instruction as XOP R3,3 you can code PUSH R3 - this will produce the same code as XOP R3,3 but will generally make the programme far more easy to follow. The 990 CPU's allow up to 15 XOP's. ...T2 1.5.9 Conditional Assembly Blocks of code can be assembled or not assembled based on the value of some expression. The basic syntax is as follows: IF expression (lines of code) ENDI If the expression evaluates to 0, the code will not be assembled. The source lines will be transfered to the listing, but no hex output will be generated. It is recommended that a value of $ffff be used for a true value since it turns into a false value under bitwise inversion. In addition, the ELSE directive is supported as follows: IF expression (lines of code) ELSE (more lines of code) ENDI This is equivalent to: IF expression (lines of code) ENDI IF NOT expression (more lines of code) ENDI Note that labels are not permitted on conditional assembly directives. Also note that an END statement can fail to be recognized if it is in a conditional assembly block with a false expression. A phasing (P) error will be flagged if there are any forward references in the expression. ...T2 1.5.10 AORG This statement is used to load a value into the assembly program counter. The value is obtained from the expression. If the expression contains forward references, a phasing (P) error will result. If a label is present, it will be EQUed to the new program counter value. The syntax is: [label] AORG expression ...T2 1.5.11 SET This statement is used to assign a temporary value to a symbol. The symbol may not be redefined by an EQU or by writing it in column 1 as a label, but it may be redefined by another SET statement. The value for the symbol is obtained from the expression. If it contains forward references, a phasing (P) error will result. The syntax is: label SET expression ...T1 1.6 Error Messages Error messages are flagged with a single letter in column 1 of the offending line in the listing. The meaning of each letter follows. A Presently not implemented. B Distance on a branch instruction is too great. Use a jump instruction with a branch around it, or rearrange your code to shorten the distance. D Digit too large for the base was encountered. In particular, watch for 8 or 9 in an octal number and a- f in a decimal number. E Expression ill-formed. Look for non arithmetic characters in indexed addressing modes. I If stack imbalance. Look for ELSE or ENDI without an IF or an IF still open at the end of the file. L Invalid label. Label may contain invalid characters or be equal to a reserved word like NOT. Label may be present on a conditional assembly directive. M Label multiply defined. Label defined more than once and all definitions are not SET statements. O Invalid opcode. Look for misspellings, missing semicolons, or opcodes in column 1. P Phasing error. Look for expressions in ORG, EQU, SET, or IF directives that contain forward references. If none exist, something wierd is going on as a label that was defined in pass 1 mysteriously vanished in pass 2. R Register value too large. Registers values between 0 and 15 only are allowed. This error will most likely occur if a register value is being evaluated from an expression which overflows. S Syntax error. Check your syntax against my samples. T Too many arguments on this line. WORD directives may only define 127 words, while TEXT and BYTE directives may only define 255 bytes. On other statements, you put superfluous arguments on the line. U Undefined symbol encountered during expression evaluation. V Value out of bounds. In particular, FCB expressions and 8- bit immediate values must evaluate to -128 to 255, while index values must evaluate to 0 to 255. * This statement generated by the assembler. Right now, this only happens if you drop an END statement or remove it through conditional assembly. " Quote imbalance error. Bear in mind that ' will not terminate a string started with " and vice- versa. ( Parenthesis imbalance error. Count them! ...T1 1.7 Assembler Abort Conditions Under certain circumstances, this assembler will just give up and quit in the middle of an assembly. If you don't get the error count diagnostic on the console, read your screen for sure! The following messages occur: 1) Can't open source. The source file does not exist on the specified disk drive. 2) Can't open list. Can't open hex. No directory entries left on the disk drive in question. 3) Illegal command line. Bone up on command lines. 4) No file info supplied. Bone up on command lines. 5) If stack overflow. IF directives may only be nested 16 deep. Rebuild your source code to reduce your nesting depth, or change the "#define IFDEPTH 16" statement in xasm99.gbl and recompile the assembler. 6) Disk read error. Source file has a bad CRC or some other difficulty. 7) Disk write error. Out of disk or directory space on the list or hex file. 8) Error closing file. Problem closing list or hex file. You shouldn't get this one. 9) Symbol Table Overflow. Your source program defines too many symbols. The current limit is 500. If you have more memory than I do, you can change the "#define SYMBOLS 500" line in a99.gbl and recompile the assembler. Otherwise, you must work on your source code. ...T1 1.8 Compiling the Assembler To compile the assembler as it stands, you will need the following items: 1) 40K of RAM. 2) The BDS C Compiler Version 1.5 (good box, Leor!!). 3) Digital Research's ASM or MAC assembler. (Note: Only needed if you want to play with the functions in a99tbls.mac as they exist in a form digestible by CLINK in the file xasm99.crl.) To get a99tbls.crl up from scratch, you do the following. I assume all files including ASM or MAC live on drive A. A>casm a99tbls ;source a99tbls.csm This should yield a file a99tbls.asm on drive A. A>mac a99tbls $pz -s ;may use asm fn.aaz A>cload a99tbls ;produce CRL file You should now have a99tbls.crl on drive A. Now you are ready to compile the rest of the beast. A>cc a99 A>cc a99asmlnc A>cc a99evalc A>cc a99getc A>cc a99putc A>cc a99symbc Now you can link it all together. A>clink a99 -s *a99asmln *a99eval *a99get *a99put *a99symb *a99tbls And, as if by magic, you've got a99.com! Note that the linkage can all be done on one line, but my paper isn't wide enough here to do it that way. Note that if you have more than 40K of RAM, you may want to increase your symbol table size. Symbols are 10 bytes each, so plan accordingly. ...T1 1.9 Final Comments Happy assembling! If you have questions or note any bugs, I'd appreciate a shout at (617)258-1204, (617)266-3179 or on the Boston CBBS at (617)963-8310. The questions will point up weaknesses in the manual, and the bugs need to be stamped upon unmercifully.