> PathSize = 64 BufferSize = 20 WordSize = 32 MaxIdentifierSize = 30 .include dos.i .include symtab.i Reg8 = 1 Reg16 = 2 SegReg = 3 Immediate = 4 AddMode = 5 Disp = 6 |AddDisp = 7 |Isn't ever used! CR = 13 LF = 10 call GetFileName |Get the name of the file to be |assembled into PresentFilename call InitSymbolTable call AssembleOneFile jmp ExitToDos |Get back to DOS CloseInputFile: movb ah,#CloseFileFunction |Close the input file mov bx,InputFileHandle int #DosInterrupt ret CloseOutputFiles: movb ah,#CloseFileFunction mov bx,OutputFileHandle int #DosInterrupt movb ah,#CloseFileFunction mov bx,ListFileHandle int #DosInterrupt ret GetFileName: mov si,#CommandLineStart |Get the start of the command line lodsb |first byte is length of command line orb al,al |If there is no command line then jnz SkipCommandLineSpaces |show the ReportNoName: mov bx,#HelpMessage | call Panic |help screen to the nosey user. SkipCommandLineSpaces: | lodsb |Get more chars from the command line cmpb al,#' ' |Skip spaces at start of name jz SkipCommandLineSpaces |Any number of them cmpb al,#' ' |Also skip tabs jz SkipCommandLineSpaces | cmpb al,#CR jz ReportNoName mov di,StringSpace |Copy the name into the StringSpace mov PresentFileNameOffset,di | stosb |done by string insts. mov bx,si |To display of the filename. dec bx |Actually si is pointing at one |past the start of the filename. xorb cl,cl |cl is whether the filename |given had an extension or not. |If there was no extension then we |have to put a .s after it. | We assume that there is |enough space to do such a thing |in the command line. FindCommandLineCR: |white spaces after the name of the lodsb |should be removed stosb |Keep Storing the name cmpb al,#' ' |it means that that was the end of jz FoundFilenameEnd |the filename cmpb al,#' ' |This is true for tabs too jz FoundFilenameEnd| |If a '.' is found, it means that cmpb al,#'.' |an extension need not be added to jnz NotTheDotInFilename |to the filename incb cl |record the fact in cl that a dot |has been seen in the input name NotTheDotInFilename: cmpb al,#'/' |reset the dot if a path separator jnz NotSlashinFilename |is found xorb cl,cl NotSlashinFilename: cmpb al,#'\' jnz NotBackSlashInFilename xorb cl,cl NotBackSlashInFilename: |We have to check whether we cmpb al,#CR |crash into the tail of the command jnz FindCommandLineCR |line. Check for carriage return FoundFilenameEnd: |Here we are at the end of the name dec di |Adjust, 'cos even the carriage retn orb cl,cl |or white space is in. If there was jnz NoNeedToPutExtension |an extension don't put another mov ax,#'s'!'.' |store an extension after the name stosw |'.s' NoNeedToPutExtension: |Terminate the name with a zero movb al,#0 |character, C and DOS style stosb |store the zero call CheckStringTableOverflow mov StringSpace,di ret |return to main routine. .include symtab.s AssembleOneFile: call OpenInputFile jc InputFileOpenError call ConstructOutputFileNames mov dx,OutputFileNameOffset call OpenOutputFile mov OutputFileHandle,ax mov dx,ListFileNameOffset call OpenOutputFile mov ListFileHandle,ax call Assemble call FixUnknowns call PatchCode call WriteOutputFile call CloseInputFile call WriteListFile call CloseOutputFiles ret InputFileOpenError: mov bx,#NoInputFileMessage |There was an error - so quit. call Panic OpenInputFile: mov ax,#OpenFileFunction!ReadOnly mov dx,PresentFileNameOffset int #DosInterrupt jc CouldNotOpenFile mov InputFileHandle,ax |Preserving Carry dangerous stuff mov InputLineNumber,#1 mov ax,#0 mov InputBufferReadPtr,ax |Both Should be the same mov InputBufferEndPtr,ax CouldNotOpenFile: ret ConstructOutputFileNames: mov di,PresentFileNameOffset movb al,#0 mov cx,#PathSize repnz scasb dec di std mov cx,#PathSize movb al,#'.' repnz scasb cld inc di mov si,PresentFileNameOffset mov cx,di sub cx,si mov dx,cx |save offset for list file opening mov di,StringSpace mov OutputFileNameOffset,di rep movsb mov ax,#'c'!'.' stosw mov ax,#'m'!'o' stosw xorb al,al stosb mov si,PresentFileNameOffset mov cx,dx mov ListFileNameOffset,di rep movsb mov ax,#'l'!'.' stosw mov ax,#'t'!'s' stosw xorb al,al stosb call CheckStringTableOverflow mov StringSpace,di ret OpenOutputFile: movb ah,#60 mov cx,#0 int #DosInterrupt jnc OutputFileWasOpened mov bx,#OutputFileMessage call Panic OutputFileWasOpened: ret RemoveOutputFile: movb ah,#DeleteFileFunction mov dx,OutputFileNameOffset int #DosInterrupt ret |Assemble |The main procedure for processing a file |On input, the variable, | InputFileHandle - is a valid handle of an opened file. | | | Assemble: mov SavedStackPointer,sp AssembleLabelTail: xor ax,ax mov bp,1 call GetEndOfLine1 jc AssembleEnd Assemble1: call GetWord jc AssembleEnd movb al,InputWord cmpb al,#'|' jnz NotAComment call GetEndOfLine jc AssembleEnd jmps Assemble1 NotAComment: mov si,#Directives call MatchKeyword jc NotDirective call [si] call GetEndOfLine jc AssembleEnd jmps Assemble1 NotDirective: call GetInstruction jc EquateOrLabel call GetEndOfLine jc AssembleEnd jmps Assemble1 EquateOrLabel: call DefineNewSymbol or bx,#IsEquate jz AssembleLabelTail call GetEndOfLine jc AssembleEnd jmps Assemble1 AssembleEnd: ret NotImplemented: ret CheckStringTableOverflow: cmp di,#StringTableEnd jc NoStringOverflow mov bx,#StrTblOverflowMessage call Panic NoStringOverflow: ret .include input.s .include symbols.s .include message.s .include display.s .include support.s .include equ.s .include expr.s .include direct.s .include output.s EndOfCode: