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Text File | 1992-08-20 | 17.3 KB | 493 lines

now accepts character constants of 'c and 'c' NAME DAsm SYNOPSIS SAsm [options] <srcfile> [options] DESCRIPTION SAsm is the assembler for the DEV11 system. It is a high level macro cross assembler for the Motorola 6803, 6805 and 68HC11 families and for the Hitachi 6303 family. It is a highly modified version of the publicly distributable DASM V2.12. (C)Copyright 1987,1988 Matthew Dillon, All Rights Reserved (C)Copyright 1992 Stan Burton, All Rights Reserved Publicly distributable for non-profit only. Must be distributed as is, with NO CHANGES to the documentation or code. -fast assembly -supports several common 8 bit processor models (NOT 8086, thank god!) -optionally takes as many passes as needed -generates relocatable object module output for use with SLink and SLib. -XREF and XDEF pseudo ops for external module references. -multiple segments, BSS segments (no generation). -expressions, as in C. (all expressions are computed with 32 bit integers) -no real limitation on label size, label values are 32 bits. -complex pseudo ops, repeat loops, macros, etc.... COMMAND LINE: asm [options] srcfile [options] srcfile: if no extension is specified in the name, .a is added options: -l[name] generate list file, if no name is specified extension-less srcfile with .lst extension is used -s[name] generate symbol file, if no name is specified extension-less srcfile with .sym extension is used -v# select verboseness 0-4 (default 0, see below) -p# select number of passes 2-9 (default 2) -d debug mode -DSYMBOL predefine a symbol, set to 0 -DSYMBOL=EXPRESSION predefine a symbol, set to exp outfile: the file generated is the extension-less srcfile with a .o extension Example: asm master.asm -lram:list -v3 -DVER=4 The options list can contain any of the following, separated by spaces: -v 0 (default) Only warnings and errors are generated 1 -Segment list information generated after each pass -Include file names are displayed -statistics on why the assembler is going to make another pass R1,R2 reason code: R3 where R1 is the number of times the assembler encountered something requiring another pass to resolve. R2 is the number of references to unknown symbols which occured in the pass (but only R1 determines the need for another pass). R3 is a BITMASK of the reasons why another pass is required. See the end of this document for bit designations. 2 mismatches between program labels and equates are displayed on every pass (usually none occur in the first pass unless you have re-declared a symbol name). displayed information for symbols: ???? = unknown value str = symbol is a string eqm = symbol is an eqm macro (r) = symbol has been referenced (s) = symbol created with SET or EQM pseudo-op 3 Unresolved and unreferenced symbols are displayed every pass (unsorted, sorry) 4 An entire symbol list is displayed every pass to STDOUT. (unsorted, sorry) PROCESSOR MODEL: The processor model is chosen with the PROCESSOR pseudo-op and should be the first thing you do in your assembly file. Only one PROCESSOR pseudo-op may be declared in the entire assembly, and should be the first thing encountered. -68HC11 -68705 -6803 -HD6303 -68HC16 SEGMENTS: The SEG pseudo-op creates/sets the current segment. Segments are used to separate the various parts of a program, for example CODE and BSS_DATA; later the linker could place the CODE at the EPROM address range and the data at the ram address range. The use of DS or RMB statements in a segment planned for ROM is not logical. As a result of the use of relocatable segments the ORG statement found in simpler assemblers is not used; its functionality is passed to the linker. 'Uninitialized' (.U) segments do not produce output. Therefore, output generating statements are not allowed in these segments. GENERAL: Most everything is recursive. You cannot have a macro DEFINITION within a macro definition, but can nest macro calls, repeat loops, and include files. ? The other major feature in this assembler is the SUBROUTINE pseudo-op, which logically separates local labels (starting with a dot). This allows you to reuse label names (for example, .1 .fail) rather than think up crazy combinations of the current subroutine to keep it all unique. By default the assembler will make 2 passes, if your file requires more passes you can set the number via an option. PSEUDOPS: INCLUDE "name" Include another assembly file. [label] SEG[.U] name [label] RSEG[.U] name This sets the current segment, creating it if neccessary. If a .U extension is specified on segment creation, the segment is an UNINITIALIZED segment. The .U is not needed when going back to an already created uninitialized segment, though it makes the code more readable. [label] DC[.BWL] exp,exp,exp ... [label] FDB exp,exp,exp ... [label] FCB exp,exp,exp ... Declare data in the current segment. The default size extension for DC is a byte. [label] DS[.BWL] exp[,filler] [label] RMB exp[,filler] Declare space (default filler is 0). Data is not generated if within an uninitialized segment. Note that the number of bytes generated is exp * entrysize (1,2, or 4) The default size extension for DS is a byte. Note that the default filler is always 0. [label] DV[.BWL] eqmlabel exp,exp,exp.... This is equivalent to DC, but each exp in the list is passed through the symbolic expression specified by the EQM label. The expression is held in a special symbol dotdot '..' on each call to the EQM label. See EQM below [label] HEX hh hh hh.. This sets down raw HEX data. Spaces are optional between bytes. NO EXPRESSIONS are allowed. Note that you do NOT place a $ in front of the digits. This is a short form for creating tables compactly. Data is always layed down on a byte-by-byte basis. Example: HEX 1A45 45 13254F 3E12 ERR Abort assembly. [label] XDEF symbol,symbol,symbol Defines which symbols/labels are available outside of this module. [label] XREF symbol,symbol,symbol Declares which symbols/labels from outside modules are used in this module. PROCESSOR model Do not quote. Model is one of: 6803,HD6303,68705,68HC11 Can only be executed once, and should be the first thing encountered by the assembler. ECHO exp,exp,exp The expressions (which may also be strings), are echod on the screen and into the list file [label] ALIGN N[,fill] Align the current PC to an N byte boundry. The default fill character is always 0, and has nothing to do with the default fill character specifiable in an ORG. [label] SUBROUTINE name This isn't really a subroutine, but a boundry between sets of temporary labels (which begin with a dot). Temporary label names are unique within segments of code bounded by SUBROUTINE: CHARLIE subroutine ldx #10 .1 dex bne .1 BEN subroutine ldx #20 .qq dex bne .qq Automatic temporary label boundries occur for each macro level. Usually temporary labels are used in macros and within actual subroutines (so you don't have to think up a thousand different names) symbol EQU exp The expression is evaluated and the result assigned to the symbol. symbol EQM exp The STRING representing the expression is assigned to the symbol. Occurances of the symbol in later expressions causes the string to be evaluated for each occurance. Also used in conjuction with the DV psuedo-op. symbol SET exp Same as EQU, but the symbol may be reassigned later. END [symbol] Optional. If used with a symbol name the value of that symbol will be entered into the output file as the starting address of the program. May only be used once and only at the end of the file. Be careful - if a symbol is not given and a comment without a preceding ';' is used the first word of the comment will be interpreted as the symbol. MAC name MACRO name Declare a macro. lines between MAC and ENDM are the macro. You cannot recursively declare a macro. You CAN recursively use a macro (reference a macro in a macro). No label is allowed to the left of MAC or ENDM. Arguments passed to macros are referenced with: {#}. The first argument passed to a macro would thus be {1}. You should always use LOCAL labels (.name) inside macros which you use more than once. {0} represents an EXACT substitution of the ENTIRE argument line. ENDM end of macro def. NO LABEL ALLOWED ON THE LEFT! MEXIT Used in conjuction with conditionals. Exits the current macro level. [label] IFCONST exp [label] IFD exp Is TRUE if the expression result is defined, FALSE otherwise and NO error is generated if the expression is undefined. [label] IFNCONST exp [label] IFND exp Is TRUE if the expression result is undefined, FALSE otherwise and NO error is generated if the expression is undefined. [label] IF exp Is TRUE if the expression result is defined AND non-zero. Is FALSE if the expression result is defined AND zero. Neither IF or ELSE will be executed if the expression result is undefined. If the expression is undefined, another assembly pass is automatically taken. [label] ELSE ELSE the current IF. [label] ENDIF [label] ENDC [label] EIF Terminate an IF. ENDIF and EIF are equivalent. [label] REPEAT exp [label] REPEND Repeat code between REPEAT/REPEND 'exp' times. if exp == 0, the code repeats forever. exp is evaluated once. Y SET 0 REPEAT 10 X SET 0 REPEAT 10 DC X,Y X SET X + 1 REPEND Y SET Y + 1 REPEND generates an output table: 0,0 1,0 2,0 ... 9,0 0,1 1,1 2,1 ... 9,1, etc... Labels within a REPEAT/REPEND should be temporary labels with a SUBROUTINE pseudoop to keep them unique. The Label to the left of REPEND is assigned AFTER the loop FINISHES. [label] XXX[.force] operand XXX is some mnemonic, not necessarily three characters long. The .FORCE optional extension is used to force specific addressing modes (see below). GENERAL: The label will be set to the current segment counter either before or after a pseudo-op is executed. Most of the time, the label is set before the pseudo-op is executed. The following pseudo-op's labels are created AFTER execution of the pseudo-op: SEG, ALIGN EXTENSIONS: FORCE extensions are used to force an addressing mode. Force extensions are also used with DS,DC, and DV to determine the element size. NOT ALL EXTENSIONS APPLY TO ALL PROCESSORS! example: lda.z charlie i -implied ind -indirect word 0 -implied 0x -implied indexing (0,x) 0y -implied indexing (0,y) b -byte address bx -byte address indexed x by -byte address indexed y w -word address wx -word address indexed x wy -word address indexed y l -longword (4 bytes) (DS/DC/DV) r -relative u -uninitialized (SEG) First character equivalent substitutions: b z d (byte, zeropage, direct) w e a (word, extended, absolute) EXPRESSIONS: Some operators, such as ||, can return a resolved value even if one of the expressions is not resolved. Operators are as follows: NOTE WELL! Some operations will result in non-byte values when a byte value was wanted. For example: ~1 is NOT $FF, but $FFFFFFFF. Preceding it with a < (take LSB of) will solve the problem. ALL ARITHMETIC IS CARRIED OUT IN 32 BITS. The final Result will be automatically truncated to the maximum handleable by the particular machine language (usually a word) when applied to standard mnemonics. prec UNARY 20 ~exp one's complement. 20 -exp negation 20 !exp not expression (returns 0 if exp non-zero, 1 if exp zero) 20 <exp take LSB byte of a 16 bit expression 20 >exp take MSB byte of an expression BINARY 19 * multiplication 19 / division 19 % mod 18 + addition 18 - subtraction 17 >>,<< shift right, shift left 16 >,>= greater, greater equal 16 <,<= smaller, smaller equal 15 == equal to. Try to use this instead of = 15 = exactly the same as == (exists compatibility) 15 != not equal to 14 & logical and 13 ^ logical xor 12 | logical or 11 && left expression is true AND right expression is true 10 || left expression is true OR right expression is true 9 ? if left expression is true, result is right expression, else result is 0. [10 ? 20] returns 20 8 [] group expressions 7 , separate expressions in list (also used in addressing mode resolution, BE CAREFUL! Constants: nnn decimal 0nnn octal %nnn binary $nnn hex 'c character 'c' character "cc.." string (NOT zero terminated if in DC/DS/DV) [exp]d the constant expressions is evaluated and it's decimal result turned into an ascii string. Symbols: .. -holds evaluated value in DV pseudo op .name -represents a temporary symbol name. Temporary symbols may be reused inside MACROS and between SUBROUTINES, but may not be referenced across macros or across SUBROUTINEs. . -current program counter (as of the beginning of the instruction). name -beginning with an alpha character and containing letters, numbers, or '_'. Represents some global symbol name. WHY codes: Each bit in the WHY word (verbose option 1) is a reason (why the assembler needs to do another pass), as follows: bit 0 expression in mnemonic not resolved 1 - 2 expression in a DC not resolved 3 expression in a DV not resolved (probably in DV's EQM symbol) 4 expression in a DV not resolved (could be in DV's EQM symbol) 5 expression in a DS not resolved 6 expression in an ALIGN not resolved 7 ALIGN: Relocatable origin not known (impossible -Stan) 8 ALIGN: Normal origin not known (if in ORG at the time) 9 EQU: expression not resolved 10 EQU: value mismatch from previous pass (phase error) 11 IF: expression not resolved 12 REPEAT: expression not resolved 13 a program label has been defined after it has been referenced (forward reference) and thus we need another pass 14 a program label's value is different from that of the previous pass (phase error) Certain errors will cause the assembly to abort immediately, others will wait until the current pass is over. The remaining allow another pass to occur in the hopes the error will fix itself. VERSIONS: