Appendix B

BNF Grammar

This appendix provides a complete description of symbols, operators, and directives for MASM 6.1. It uses the Backus-Naur Form (BNF) for grammar notation. You can use BNF grammar to determine the exact syntax for any language component and find all available options for any MASM command.

BNF definitions consist of "nonterminals" and "terminals." Nonterminals are placeholders within a BNF definition, defined elsewhere in the BNF grammar. Terminals are endpoints in a BNF definition, consisting of MASM 6.1 keywords. In this Appendix, all nonterminals appear in italics type and all terminals appear in bold type.

BNF Conventions

The conventions use different font attributes for different items in the BNF. The symbols and formats are as follows:

Attribute Description

nonterminal Italic type indicates nonterminals.

RESERVED Terminals in boldface type are literal reserved words and symbols that must be entered as shown. Characters in this context are always case insensitive.

[[ ]] Objects enclosed in double brackets ([[ ]]) are optional. The brackets do not actually appear in the source code.

| A vertical bar indicates a choice between the items on each side of the bar.

.8086 Underlined items indicate the default option if one is given.

default typeface Characters in the set described or listed can be used as terminals in MASM statements.

How to Use the BNF Grammar

To illustrate the use of the BNF, Figure B.1 diagrams the definition of the TYPEDEF directive, starting with the nonterminal typedefDir.

The entries under each horizontal brace in Figure B.1 are terminals (such as NEAR16, NEAR32, FAR16, and FAR32) or nonterminals (such as qualifier, qualifiedType, distance, and protoSpec) that can be further defined. Each italicized nonterminal in the typedefDir definition is also an entry in the BNF. Three vertical dots indicate a branching definition for a nonterminal that, for the sake of simplicity, this figure does not illustrate.

The BNF grammar allows recursive definitions. For example, the grammar uses qualifiedType as a possible definition for qualifiedType, which is also a component of the definition for qualifier.

Figure B.1 BNF Definition of the TYPEDEF Directive

Nonterminal Definition

;; endOfLine | comment

=Dir id = immExpr ;;

addOp + | -

aExpr term | aExpr && term

Nonterminal Definition

altId id

arbitraryText charList

asmInstruction mnemonic [[ exprList ]]

assumeDir ASSUME assumeList ;; | ASSUME NOTHING ;;

assumeList assumeRegister | assumeList , assumeRegister

assumeReg register : assumeVal

assumeRegister assumeSegReg | assumeReg

assumeSegReg segmentRegister : assumeSegVal

assumeSegVal frameExpr | NOTHING | ERROR

assumeVal qualifiedType | NOTHING | ERROR

bcdConst [[ sign ]] decNumber

binaryOp == | != | >= | <= | > | < | &

bitDef bitFieldId : bitFieldSize [[ = constExpr ]]

bitDefList bitDef | bitDefList , [[ ;; ]] bitDef

bitFieldId id

bitFieldSize constExpr

blockStatements directiveList | .CONTINUE [[ .IF cExpr ]] | .BREAK [[ .IF cExpr ]]

bool TRUE | FALSE

byteRegister AL | AH | BL | BH | CL | CH | DL | DH

cExpr aExpr | cExpr || aExpr

character Any character with ordinal in the range 0-255 except linefeed (10)

charList character | charList character

className string

commDecl [[ nearfar ]] [[ langType ]] id : commType [[ : constExpr ]]

commDir COMM commList ;;

comment ; text ;;

Nonterminal Definition

commentDir COMMENT delimiter text text delimiter text ;;

commList commDecl | commList , commDecl

commType type | constExpr

constant digits [[ radixOverride ]]

constExpr expr

contextDir PUSHCONTEXT contextItemList ;; | POPCONTEXT contextItemList ;;

contextItem ASSUMES | RADIX | LISTING | CPU | ALL

contextItemList contextItem | contextItemList , contextItem

controlBlock whileBlock | repeatBlock

controlDir controlIf | controlBlock

controlElseif .ELSEIF cExpr ;; directiveList [[ controlElseif ]]

controlIf .IF cExpr ;; directiveList [[ controlElseif ]] [[ .ELSE ;; directiveList ]] .ENDIF ;;

coprocessor .8087 | .287 | .387 | .NO87

crefDir crefOption ;;

crefOption .CREF | .XCREF [[ idList ]] | .NOCREF [[ idList ]]

cxzExpr expr | ! expr | expr == expr | expr != expr

dataDecl DB | DW | DD | DF | DQ | DT | dataType | typeId

dataDir [[ id ]] dataItem ;;

Nonterminal Definition

dataItem dataDecl scalarInstList | structTag structInstList | typeId structInstList | unionTag structInstList | recordTag recordInstList

dataType BYTE | SBYTE | WORD | SWORD | DWORD | SDWORD | FWORD | QWORD | TBYTE | REAL4 | REAL8 | REAL10

decdigit 0 | 1 | 2 | 3 | 4 | 5 | 6 | 7 | 8 | 9

decNumber decdigit | decNumber decdigit

delimiter Any character except whiteSpaceCharacter

digits decdigit | digits decdigit | digits hexdigit

directive generalDir | segmentDef

directiveList directive | directiveList directive

distance nearfar | NEAR16 | NEAR32 | FAR16 | FAR32

e01 e01 orOp e02 | e02

e02 e02 AND e03 | e03

e03 NOT e04 | e04

e04 e04 relOp e05 | e05

e05 e05 addOp e06 | e06

e06 e06 mulOp e07 | e06 shiftOp e07 | e07

e07 e07 addOp e08 | e08

e08 HIGH e09 | LOW e09 | HIGHWORD e09 | LOWWORD e09 | e09

Nonterminal Definition

e09 OFFSET e10 | SEG e10 | LROFFSET e10 | TYPE e10 | THIS e10 | e09 PTR e10 | e09 : e10 | e10

e10 e10 . e11 | e10 [[ expr ]] | e11

e11 ( expr ) | [[ expr ]] | WIDTH id | MASK id | SIZE sizeArg | SIZEOF sizeArg | LENGTH id | LENGTHOF id | recordConst | string | constant | type | id | $ | segmentRegister | register | ST | ST ( expr )

echoDir ECHO arbitraryText ;; %OUT arbitraryText ;;

elseifBlock elseifStatement ;; directiveList [[ elseifBlock ]]

elseifStatement ELSEIF constExpr | ELSEIFE constExpr | ELSEIFB textItem | ELSEIFNB textItem | ELSEIFDEF id | ELSEIFNDEF id | ELSEIFDIF textItem , textItem | ELSEIFDIFI textItem , textItem | ELSEIFIDN textItem , textItem | ELSEIFIDNI textItem , textItem | ELSEIF1 | ELSEIF2

Nonterminal Definition

endDir END [[ immExpr ]] ;;

endpDir procId ENDP ;;

endsDir id ENDS ;;

equDir textMacroId EQU equType ;;

equType immExpr | textLiteral

errorDir errorOpt ;;

errorOpt .ERR [[ textItem ]] | .ERRE constExpr [[ optText ]] | .ERRNZ constExpr [[ optText ]] | .ERRB textItem [[ optText ]] | .ERRNB textItem [[ optText ]] | .ERRDEF id [[ optText ]] | .ERRNDEF id [[ optText ]] | .ERRDIF textItem , textItem [[ optText ]] | .ERRDIFI textItem , textItem [[ optText ]] | .ERRIDN textItem , textItem [[ optText ]] | .ERRIDNI textItem , textItem [[ optText ]] | .ERR1 [[ textItem ]] | .ERR2 [[ textItem ]]

exitDir .EXIT [[ expr ]] ;;

exitmDir: EXITM | EXITM textItem

exponent E [[ sign ]] decNumber

expr SHORT e05 | .TYPE e01 | OPATTR e01 | e01

exprList expr | exprList , expr

externDef [[ langType ]] id [[ ( altId ) ]] : externType

externDir externKey externList ;;

externKey EXTRN | EXTERN | EXTERNDEF

externList externDef | externList , [[ ;; ]] externDef

externType ABS | qualifiedType

fieldAlign constExpr

fieldInit [[ initValue ]] | structInstance

Nonterminal Definition

fieldInitList fieldInit | fieldInitList , [[ ;; ]] fieldInit

fileChar delimiter

fileCharList fileChar | fileCharList fileChar

fileSpec fileCharList | textLiteral

flagName ZERO? | CARRY? | OVERFLOW? |SIGN? | PARITY?

floatNumber [[ sign ]] decNumber . [[ decNumber ]] [[ exponent ]] | digits R | digits r

forcDir FORC | IRPC

forDir FOR |IRP

forParm id [[ : forParmType ]]

forParmType REQ | = textLiteral

frameExpr SEG id | DGROUP : id | segmentRegister : id | id

generalDir modelDir | segOrderDir | nameDir | includeLibDir | commentDir | groupDir | assumeDir | structDir | recordDir | typedefDir | externDir | publicDir | commDir | protoTypeDir | equDir | =Dir | textDir | contextDir | optionDir | processorDir | radixDir | titleDir | pageDir | listDir | crefDir | echoDir | ifDir | errorDir | includeDir | macroDir | macroCall | macroRepeat | purgeDir | macroWhile | macroFor | macroForc | aliasDir

gpRegister AX | EAX | BX | EBX | CX | ECX | DX | EDX | BP | EBP | SP | ESP | DI | EDI | SI | ESI

groupDir groupId GROUP segIdList

groupId id

hexdigit a | b | c | d | e | f | A | B | C | D | E | F

Nonterminal Definition

id alpha | id alpha | id decdigit

idList id | idList , id

ifDir ifStatement ;; directiveList [[ elseifBlock ]] [[ ELSE ;; directiveList ]] ENDIF ;;

ifStatement IF constExpr | IFE constExpr | IFB textItem | IFNB textItem | IFDEF id | IFNDEF id | IFDIF textItem , textItem | IFDIFI textItem , textItem | IFIDN textItem , textItem | IFIDNI textItem , textItem | IF1 | IF2

immExpr expr

includeDir INCLUDE fileSpec ;;

includeLibDir INCLUDELIB fileSpec ;;

initValue immExpr | string | ? | constExpr DUP ( scalarInstList ) | floatNumber | bcdConst

inSegDir [[ labelDef ]] inSegmentDir

inSegDirList inSegDir | inSegDirList inSegDir

Nonterminal Definition

inSegmentDir instruction | dataDir | controlDir | startupDir | exitDir | offsetDir | labelDir | procDir [[ localDirList ]] [[ inSegDirList ]] endpDir | invokeDir | generalDir

instrPrefix REP | REPE | REPZ | REPNE | REPNZ | LOCK

instruction [[ instrPrefix ]] asmInstruction

invokeArg register :: register | expr | ADDR expr

invokeDir INVOKE expr [[ , [[ ;; ]] invokeList ]] ;;

invokeList invokeArg | invokeList , [[ ;; ]] invokeArg

keyword Any reserved word

keywordList keyword | keyword keywordList

labelDef id : | id :: | @@:

labelDir id LABEL qualifiedType ;;

langType C | PASCAL | FORTRAN |BASIC | SYSCALL | STDCALL

listDir listOption ;;

listOption .LIST | .NOLIST | .XLIST | .LISTALL | .LISTIF | .LFCOND | .NOLISTIF | .SFCOND | .TFCOND | .LISTMACROALL | .LALL | .NOLISTMACRO | .SALL | .LISTMACRO | .XALL

localDef LOCAL idList ;;

localDir LOCAL parmList ;;

localDirList localDir | localDirList localDir

Nonterminal Definition

localList localDef | localList localDef

macroArg % constExpr | % textMacroId | % macroFuncId ( macroArgList ) | string | arbitraryText | < arbitraryText >

macroArgList macroArg | macroArgList , macroArg

macroBody [[ localList ]] macroStmtList

macroCall id macroArgList ;; | id ( macroArgList )

macroDir id MACRO [[ macroParmList ]] ;; macroBody ENDM ;;

macroFor forDir forParm , < macroArgList > ;; macroBody ENDM ;;

macroForc forcDir id , textLiteral ;; macroBody ENDM ;;

macroFuncId id

macroId macroProcId | macroFuncId

macroIdList macroId | macroIdList , macroId

macroLabel id

macroParm id [[ : parmType ]]

macroParmList macroParm | macroParmList , [[ ;; ]] macroParm

macroProcId id

macroRepeat repeatDir constExpr ;; macroBody ENDM ;;

macroStmt directive | exitmDir | : macroLabel | GOTO macroLabel

Nonterminal Definition

macroStmtList macroStmt ;; | macroStmtList macroStmt ;;

macroWhile WHILE constExpr ;; macroBody ENDM ;;

mapType ALL | NONE | NOTPUBLIC

memOption TINY | SMALL | MEDIUM | COMPACT | LARGE | HUGE | FLAT

mnemonic Instruction name

modelDir .MODEL memOption [[ , modelOptlist ]] ;;

modelOpt langType | stackOption

modelOptlist modelOpt | modelOptlist , modelOpt

module [[ directiveList ]] endDir

mulOp * | / | MOD

nameDir NAME id ;;

nearfar NEAR | FAR

nestedStruct structHdr [[ id ]] ;; structBody ENDS ;;

offsetDir offsetDirType ;;

offsetDirType EVEN | ORG immExpr | ALIGN [[ constExpr ]]

offsetType GROUP | SEGMENT | FLAT

oldRecordFieldList [[ constExpr ]] | oldRecordFieldList , [[ constExpr ]]

optionDir OPTION optionList ;;

Nonterminal Definition

optionItem CASEMAP : mapType | DOTNAME | NODOTNAME | EMULATOR | NOEMULATOR | EPILOGUE : macroId | EXPR16 | EXPR32 | LANGUAGE : langType | LJMP | NOLJMP | M510 | NOM510 | NOKEYWORD : < keywordList > | NOSIGNEXTEND | OFFSET : offsetType | OLDMACROS | NOOLDMACROS | OLDSTRUCTS | NOOLDSTRUCTS | PROC : oVisibility | PROLOGUE : macroId | READONLY | NOREADONLY | SCOPED | NOSCOPED | SEGMENT : segSize | SETIF2 : bool

optionList optionItem | optionList , [[ ;; ]] optionItem

optText , textItem

orOp OR | XOR

oVisibility PUBLIC |PRIVATE |EXPORT

pageDir PAGE [[ pageExpr ]] ;;

pageExpr + | [[ pageLength ]] [[ , pageWidth ]]

pageLength constExpr

pageWidth constExpr

parm parmId [[ : qualifiedType ]] | parmId [[ constExpr ]] [[ : qualifiedType ]]

parmId id

parmList parm | parmList , [[ ;; ]] parm

parmType REQ | = textLiteral | VARARG

pOptions [[ distance ]] [[ langType ]] [[ oVisibility ]]

primary expr binaryOp expr | flagName | expr

Nonterminal Definition

procDir procId PROC [[ pOptions ]] [[ < macroArgList > ]] [[ usesRegs ]] [[ procParmList ]]

processor .8086 | .186 | .286 | .286C | .286P | .386 | .386C | .386P | .486 | .486P

processorDir processor ;; | coprocessor ;;

procId id

procParmList [[ , [[ ;; ]] parmList ]] [[ , [[ ;; ]] parmId :VARARG]]

protoArg [[ id ]] : qualifiedType

protoArgList [[ , [[ ;; ]] protoList ]] [[ , [[ ;; ]] [[ id ]] :VARARG ]]

protoList protoArg | protoList , [[ ;; ]] protoArg

protoSpec [[ distance ]] [[ langType ]] [[ protoArgList ]] | typeId

protoTypeDir id PROTO protoSpec

pubDef [[ langType ]] id

publicDir PUBLIC pubList ;;

pubList pubDef | pubList , [[ ;; ]] pubDef

purgeDir PURGE macroIdList

qualifiedType type | [[ distance ]] PTR [[ qualifiedType ]]

qualifier qualifiedType | PROTO protoSpec

quote " | ‘

radixDir .RADIX constExpr ;;

radixOverride h | o | q | t | y | H | O | Q | T | Y

recordConst recordTag { oldRecordFieldList } | recordTag < oldRecordFieldList >

recordDir recordTag RECORD bitDefList ;;

recordFieldList [[ constExpr ]] | recordFieldList , [[ ;; ]] [[ constExpr ]]

Nonterminal Definition

recordInstance { [[ ;; ]] recordFieldList [[ ;; ]] } | < oldRecordFieldList > | constExpr DUP ( recordInstance )

recordInstList recordInstance | recordInstList , [[ ;; ]] recordInstance

recordTag id

register specialRegister | gpRegister | byteRegister

regList register | regList register

relOp EQ | NE | LT | LE | GT | GE

repeatBlock .REPEAT ;; blockStatements ;; untilDir ;;

repeatDir REPEAT | REPT

scalarInstList initValue | scalarInstList , [[ ;; ]] initValue

segAlign BYTE | WORD | DWORD | PARA | PAGE

segAttrib PUBLIC | STACK | COMMON | MEMORY | AT constExpr | PRIVATE

segDir .CODE [[ segId ]] | .DATA | .DATA? | .CONST | .FARDATA [[ segId ]] | .FARDATA? [[ segId ]] | .STACK [[ constExpr ]]

segId id

segIdList segId | segIdList , segId

segmentDef segmentDir [[ inSegDirList ]] endsDir | simpleSegDir [[ inSegDirList ]] [[ endsDir ]]

segmentDir segId SEGMENT [[ segOptionList ]] ;;

segmentRegister CS | DS | ES | FS | GS | SS

Nonterminal Definition

segOption segAlign | segRO | segAttrib | segSize | className

segOptionList segOption | segOptionList segOption

segOrderDir .ALPHA | .SEQ | .DOSSEG | DOSSEG

segRO READONLY

segSize USE16 | USE32 |FLAT

shiftOp SHR | SHL

sign - | +

simpleExpr ( cExpr ) | primary

simpleSegDir segDir ;;

sizeArg id | type | e10

specialChars : | . | [[ | ]] | ( | ) | < | > | { | } | + | - | / | * | & | % | ! | ’ | \ | = | ; | , | " | whiteSpaceCharacter | endOfLine

specialRegister CR0 | CR2 | CR3 | DR0 | DR1 | DR2 | DR3 | DR6 | DR7 | TR3 | TR4 | TR5 | TR6 | TR7

stackOption NEARSTACK | FARSTACK

startupDir .STARTUP ;;

stext stringChar | stext stringChar

string quote [[ stext ]] quote

stringChar quote quote | Any character except quote

structBody structItem ;; | structBody structItem ;;

structDir structTag structHdr [[ fieldAlign ]] [[, NONUNIQUE ]] ;; structBody structTag ENDS ;;

structHdr STRUC | STRUCT | UNION

Nonterminal Definition

structInstance < [[ fieldInitList ]] > | { [[ ;; ]] [[ fieldInitList ]] [[ ;; ]] } | constExpr DUP ( structInstList )

structInstList structInstance | structInstList , [[ ;; ]] structInstance

structItem dataDir | generalDir | offsetDir | nestedStruct

structTag id

term simpleExpr | ! simpleExpr

text textLiteral | text character | ! character text | character | ! character

textDir id textMacroDir ;;

textItem textLiteral | textMacroId | % constExpr

textLen constExpr

textList textItem | textList , [[ ;; ]] textItem

textLiteral < text >;;

textMacroDir CATSTR [[ textList ]] |TEXTEQU [[ textList ]] | SIZESTR textItem | SUBSTR textItem , textStart [[ , textLen ]] | INSTR [[ textStart , ]] textItem , textItem

textMacroId id

textStart constExpr

titleDir titleType arbitraryText ;;

titleType TITLE | SUBTITLE | SUBTTL

type structTag | unionTag | recordTag | distance | dataType | typeId

typedefDir typeId TYPEDEF qualifier

Nonterminal Definition

typeId id

unionTag id

untilDir .UNTIL cExpr ;; .UNTILCXZ [[ cxzExpr ]] ;;

usesRegs USES regList

whileBlock .WHILE cExpr ;; blockStatements ;; .ENDW

whiteSpaceCharacter ASCII 8, 9, 11-13, 26, 32

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