Z80 ASM BNF结构...我在正确的轨道上吗？

我想学习BNF并试图组装一些Z80 ASM代码。由于我对这两个领域都很陌生，我的问题是，我是否在正确的轨道上？我正在尝试将Z80 ASM的格式编写为EBNF，以便我可以确定从哪里开始从源代码创建机器代码。目前我有以下几种：Z80 ASM BNF结构...我在正确的轨道上吗？

Assignment = Identifier, ":" ; 

Instruction = Opcode, [ Operand ], [ Operand ] ; 

Operand = Identifier | Something* ; 

Something* = "(" , Identifier, ")" ; 

Identifier = Alpha, { Numeric | Alpha } ; 

Opcode = Alpha, Alpha ; 

Int = [ "-" ], Numeric, { Numeric } ; 

Alpha = "A" | "B" | "C" | "D" | "E" | "F" | 
     "G" | "H" | "I" | "J" | "K" | "L" | 
     "M" | "N" | "O" | "P" | "Q" | "R" | 
     "S" | "T" | "U" | "V" | "W" | "X" | 
     "Y" | "Z" ; 

Numeric = "0" | "1" | "2" | "3"| "4" | 
      "5" | "6" | "7" | "8" | "9" ;

任何方向性反馈，如果我错了会很好。

来源

2009-08-22 Gary Paluk

http://stackoverflow.com/questions/1305091/writing-an-z80-assembler-lexi的杜佩ng-asm-and-building-a-parse-tree-using-composition由同一用户 – 2009-08-23 20:10:03

@Butterworth：不重复。另一个问题是关于他可能使用语法构造的树来传递信息。这个问题与他是否应该使用语法有关，如果是的话，它会是什么样子。这个问题的答案是其他人感兴趣的前提条件。 – 2009-08-23 20:19:01

老派装配是典型的手工编码的汇编器和用于自组织解析技术来处理组件的源极线，以产生实际的汇编代码。当汇编程序语法很简单时（例如总是OPCODE REG，OPERAND），这种方法运行得很好。

现代机器具有杂乱的，讨厌的指令集与许多指令的变化和操作数，其可以与复杂的语法允许多个索引寄存器参加操作数式表示。允许具有固定和可重定位常量的复杂组装时表达式以及各种类型的加法运算符使这变得复杂。先进的汇编程序允许条件编译，宏，结构化数据声明等都对语法提出了新的要求。通过临时方法处理所有这些语法非常困难，并且是发明分析器发生器的原因。

使用BNF和解析器发电机是建立一个现代化的组装非常合理的方式，即使是作为Z80的传统处理器，。我为摩托罗拉8位机器（如6800/6809）构建了这样的组装器，并且准备为现代x86做同样的工作。我认为你正走向正确的道路。

**********编辑**************** OP要求例如词法分析器和分析器定义。我在这里提供了这两个。

这些是从一个6809 asssembler真正规范的摘录。完整的定义是这里样本大小的2-3倍。为了保持空间不足，我编辑了大部分的暗角复杂度，这是这些定义的要点。人们可能会因为表现复杂而感到沮丧; 要点是，用这样的定义，你试图描述形状的语言，而不是程序上的代码。如果您以临时的方式对所有这些代码进行编码，那么您将支付更高的复杂性，并且它将远远低于可维护性的。

这也将有一定的帮助要知道，这些定义与该有词法/分析工具作为子系统高端项目分析系统中使用，称为 The DMS Software Reengineering Toolkit。 DMS将自动在解析器规范中从
语法规则中构建AST，这使得构建解析工具变得更容易。最后，解析器规范包含所谓的“prettyprinter”声明，它允许DMS从AST重新创建源文本。（一本语法的真正目的是为了让我们能够建立代表汇编指令的AST，然后将它们吐出馈送到一个真正的汇编！）注意

一两件事：语意和语法规则是如何规定（metasyntxax！）在不同的词法分析器/解析器生成器系统之间有所不同。基于DMS的规范的语法不例外。 DMS有自己的相对复杂的语法规则，在这里可用的空间中真的不太实际。你必须理解其他系统使用类似符号的想法， EBNF适用于规则，而正则表达式适用于词位。

鉴于OP的利益，他可以实现类似的词法分析器/解析器任何词法分析器/解析器生成工具，例如，FLEX/YACC，的JavaCC，ANTLR，...

******* *** LEXER **************

-- M6809.lex: Lexical Description for M6809 
-- Copyright (C) 1989,1999-2002 Ira D. Baxter 

%% 
#mainmode Label 

#macro digit "[0-9]" 
#macro hexadecimaldigit "<digit>|[a-fA-F]" 

#macro comment_body_character "[\u0009 \u0020-\u007E]" -- does not include NEWLINE 

#macro blank "[\u0000 \ \u0009]" 

#macro hblanks "<blank>+" 

#macro newline "\u000d \u000a? \u000c? | \u000a \u000c?" -- form feed allowed only after newline 

#macro bare_semicolon_comment "\; <comment_body_character>* " 

#macro bare_asterisk_comment "\* <comment_body_character>* " 

...[snip] 

#macro hexadecimal_digit "<digit> | [a-fA-F]" 

#macro binary_digit "[01]" 

#macro squoted_character "\' [\u0021-\u007E]" 

#macro string_character "[\u0009 \u0020-\u007E]" 

%%Label -- (First mode) processes left hand side of line: labels, opcodes, etc. 

#skip "(<blank>*<newline>)+" 
#skip "(<blank>*<newline>)*<blank>+" 
    << (GotoOpcodeField ?) >> 

#precomment "<comment_line><newline>" 

#preskip "(<blank>*<newline>)+" 
#preskip "(<blank>*<newline>)*<blank>+" 
    << (GotoOpcodeField ?) >> 

-- Note that an apparant register name is accepted as a label in this mode 
#token LABEL [STRING] "<identifier>" 
    << (local (;; (= [TokenScan natural] 1) ; process all string characters 
     (= [TokenLength natural] ?:TokenCharacterCount)= 
     (= [TokenString (reference TokenBodyT)] (. ?:TokenCharacters)) 
     (= [Result (reference string)] (. ?:Lexeme:Literal:String:Value)) 
     [ThisCharacterCode natural] 
     (define Ordinala #61) 
     (define Ordinalf #66) 
     (define OrdinalA #41) 
     (define OrdinalF #46) 
    );; 
    (;; (= (@ Result) `') ; start with empty string 
    (while (<= TokenScan TokenLength) 
     (;; (= ThisCharacterCode (coerce natural TokenString:TokenScan)) 
     (+= TokenScan) ; bump past character 
     (ifthen (>= ThisCharacterCode Ordinala) 
      (-= ThisCharacterCode #20) ; fold to upper case 
     )ifthen 
     (= (@ Result) (append (@ Result) (coerce character ThisCharacterCode)))= 

     );; 
    )while 
    );; 
)local 
    (= ?:Lexeme:Literal:String:Format (LiteralFormat:MakeCompactStringLiteralFormat 0)) ; nothing interesting in string 
    (GotoLabelList ?) 
    >> 

%%OpcodeField 

#skip "<hblanks>" 
    << (GotoEOLComment ?) >> 
#ifnotoken 
    << (GotoEOLComment ?) >> 

-- Opcode field tokens 
#token 'ABA'  "[aA][bB][aA]" 
    << (GotoEOLComment ?) >> 
#token 'ABX'  "[aA][bB][xX]" 
    << (GotoEOLComment ?) >> 
#token 'ADC'  "[aA][dD][cC]" 
    << (GotoABregister ?) >> 
#token 'ADCA'  "[aA][dD][cC][aA]" 
    << (GotoOperand ?) >> 
#token 'ADCB'  "[aA][dD][cC][bB]" 
    << (GotoOperand ?) >> 
#token 'ADCD'  "[aA][dD][cC][dD]" 
    << (GotoOperand ?) >> 
#token 'ADD'  "[aA][dD][dD]" 
    << (GotoABregister ?) >> 
#token 'ADDA'  "[aA][dD][dD][aA]" 
    << (GotoOperand ?) >> 
#token 'ADDB'  "[aA][dD][dD][bB]" 
    << (GotoOperand ?) >> 
#token 'ADDD'  "[aA][dD][dD][dD]" 
    << (GotoOperand ?) >> 
#token 'AND'  "[aA][nN][dD]" 
    << (GotoABregister ?) >> 
#token 'ANDA'  "[aA][nN][dD][aA]" 
    << (GotoOperand ?) >> 
#token 'ANDB'  "[aA][nN][dD][bB]" 
    << (GotoOperand ?) >> 
#token 'ANDCC'  "[aA][nN][dD][cC][cC]" 
    << (GotoRegister ?) >> 
...[long list of opcodes snipped] 

#token IDENTIFIER [STRING] "<identifier>" 
    << (local (;; (= [TokenScan natural] 1) ; process all string characters 
     (= [TokenLength natural] ?:TokenCharacterCount)= 
     (= [TokenString (reference TokenBodyT)] (. ?:TokenCharacters)) 
     (= [Result (reference string)] (. ?:Lexeme:Literal:String:Value)) 
     [ThisCharacterCode natural] 
     (define Ordinala #61) 
     (define Ordinalf #66) 
     (define OrdinalA #41) 
     (define OrdinalF #46) 
    );; 
    (;; (= (@ Result) `') ; start with empty string 
    (while (<= TokenScan TokenLength) 
     (;; (= ThisCharacterCode (coerce natural TokenString:TokenScan)) 
     (+= TokenScan) ; bump past character 
     (ifthen (>= ThisCharacterCode Ordinala) 
      (-= ThisCharacterCode #20) ; fold to upper case 
     )ifthen 
     (= (@ Result) (append (@ Result) (coerce character ThisCharacterCode)))= 

     );; 
    )while 
    );; 
)local 
    (= ?:Lexeme:Literal:String:Format (LiteralFormat:MakeCompactStringLiteralFormat 0)) ; nothing interesting in string 
    (GotoOperandField ?) 
    >> 

#token '#' "\#" -- special constant introduction (FDB) 
    << (GotoDataField ?) >> 

#token NUMBER [NATURAL] "<decimal_number>" 
    << (local [format LiteralFormat:NaturalLiteralFormat] 
    (;; (= ?:Lexeme:Literal:Natural:Value (ConvertDecimalTokenStringToNatural (. format) ? 0 0)) 
    (= ?:Lexeme:Literal:Natural:Format (LiteralFormat:MakeCompactNaturalLiteralFormat format)) 
    );; 
)local 
(GotoOperandField ?) 
    >> 

#token NUMBER [NATURAL] "\$ <hexadecimal_digit>+" 
    << (local [format LiteralFormat:NaturalLiteralFormat] 
    (;; (= ?:Lexeme:Literal:Natural:Value (ConvertHexadecimalTokenStringToNatural (. format) ? 1 0)) 
    (= ?:Lexeme:Literal:Natural:Format (LiteralFormat:MakeCompactNaturalLiteralFormat format)) 
    );; 
)local 
(GotoOperandField ?) 
    >> 

#token NUMBER [NATURAL] "\% <binary_digit>+" 
    << (local [format LiteralFormat:NaturalLiteralFormat] 
    (;; (= ?:Lexeme:Literal:Natural:Value (ConvertBinaryTokenStringToNatural (. format) ? 1 0)) 
    (= ?:Lexeme:Literal:Natural:Format (LiteralFormat:MakeCompactNaturalLiteralFormat format)) 
    );; 
)local 
(GotoOperandField ?) 
    >> 

#token CHARACTER [CHARACTER] "<squoted_character>" 
    << (= ?:Lexeme:Literal:Character:Value (TokenStringCharacter ? 2)) 
    (= ?:Lexeme:Literal:Character:Format (LiteralFormat:MakeCompactCharacterLiteralFormat 0 0)) ; nothing special about character 
    (GotoOperandField ?) 
    >> 


%%OperandField 

#skip "<hblanks>" 
    << (GotoEOLComment ?) >> 
#ifnotoken 
    << (GotoEOLComment ?) >> 

-- Tokens signalling switch to index register modes 
#token ',' "\," 
    <<(GotoRegisterField ?)>> 
#token '[' "\[" 
    <<(GotoRegisterField ?)>> 

-- Operators for arithmetic syntax 
#token '!!' "\!\!" 
#token '!' "\!" 
#token '##' "\#\#" 
#token '#' "\#" 
#token '&' "\&" 
#token '(' "\(" 
#token ')' "\)" 
#token '*' "\*" 
#token '+' "\+" 
#token '-' "\-" 
#token '/' "\/" 
#token '//' "\/\/" 
#token '<' "\<" 
#token '<' "\<" 
#token '<<' "\<\<" 
#token '<=' "\<\=" 
#token '</' "\<\/" 
#token '=' "\=" 
#token '>' "\>" 
#token '>' "\>" 
#token '>=' "\>\=" 
#token '>>' "\>\>" 
#token '>/' "\>\/" 
#token '\\' "\\" 
#token '|' "\|" 
#token '||' "\|\|" 

#token NUMBER [NATURAL] "<decimal_number>" 
    << (local [format LiteralFormat:NaturalLiteralFormat] 
    (;; (= ?:Lexeme:Literal:Natural:Value (ConvertDecimalTokenStringToNatural (. format) ? 0 0)) 
    (= ?:Lexeme:Literal:Natural:Format (LiteralFormat:MakeCompactNaturalLiteralFormat format)) 
    );; 
)local 
    >> 

#token NUMBER [NATURAL] "\$ <hexadecimal_digit>+" 
    << (local [format LiteralFormat:NaturalLiteralFormat] 
    (;; (= ?:Lexeme:Literal:Natural:Value (ConvertHexadecimalTokenStringToNatural (. format) ? 1 0)) 
    (= ?:Lexeme:Literal:Natural:Format (LiteralFormat:MakeCompactNaturalLiteralFormat format)) 
    );; 
)local 
    >> 

#token NUMBER [NATURAL] "\% <binary_digit>+" 
    << (local [format LiteralFormat:NaturalLiteralFormat] 
    (;; (= ?:Lexeme:Literal:Natural:Value (ConvertBinaryTokenStringToNatural (. format) ? 1 0)) 
    (= ?:Lexeme:Literal:Natural:Format (LiteralFormat:MakeCompactNaturalLiteralFormat format)) 
    );; 
)local 
    >> 

-- Notice that an apparent register is accepted as a label in this mode 
#token IDENTIFIER [STRING] "<identifier>" 
    << (local (;; (= [TokenScan natural] 1) ; process all string characters 
     (= [TokenLength natural] ?:TokenCharacterCount)= 
     (= [TokenString (reference TokenBodyT)] (. ?:TokenCharacters)) 
     (= [Result (reference string)] (. ?:Lexeme:Literal:String:Value)) 
     [ThisCharacterCode natural] 
     (define Ordinala #61) 
     (define Ordinalf #66) 
     (define OrdinalA #41) 
     (define OrdinalF #46) 
    );; 
    (;; (= (@ Result) `') ; start with empty string 
    (while (<= TokenScan TokenLength) 
     (;; (= ThisCharacterCode (coerce natural TokenString:TokenScan)) 
     (+= TokenScan) ; bump past character 
     (ifthen (>= ThisCharacterCode Ordinala) 
      (-= ThisCharacterCode #20) ; fold to upper case 
     )ifthen 
     (= (@ Result) (append (@ Result) (coerce character ThisCharacterCode)))= 

     );; 
    )while 
    );; 
)local 
    (= ?:Lexeme:Literal:String:Format (LiteralFormat:MakeCompactStringLiteralFormat 0)) ; nothing interesting in string 
    >> 

%%Register -- operand field for TFR, ANDCC, ORCC, EXG opcodes 

#skip "<hblanks>" 
#ifnotoken << (GotoRegisterField ?) >> 

%%RegisterField -- handles registers and indexing mode syntax 
-- In this mode, names that look like registers are recognized as registers 

#skip "<hblanks>" 
    << (GotoEOLComment ?) >> 
#ifnotoken 
    << (GotoEOLComment ?) >> 

#token '[' "\[" 
#token ']' "\]" 
#token '--' "\-\-" 
#token '++' "\+\+" 

#token 'A'  "[aA]" 
#token 'B'  "[bB]" 
#token 'CC'  "[cC][cC]" 
#token 'DP'  "[dD][pP] | [dD][pP][rR]" -- DPR shouldnt be needed, but found one instance 
#token 'D'  "[dD]" 
#token 'Z'  "[zZ]" 

-- Index register designations 
#token 'X'  "[xX]" 
#token 'Y'  "[yY]" 
#token 'U'  "[uU]" 
#token 'S'  "[sS]" 
#token 'PCR' "[pP][cC][rR]" 
#token 'PC'  "[pP][cC]" 

#token ',' "\," 

-- Operators for arithmetic syntax 
#token '!!' "\!\!" 
#token '!' "\!" 
#token '##' "\#\#" 
#token '#' "\#" 
#token '&' "\&" 
#token '(' "\(" 
#token ')' "\)" 
#token '*' "\*" 
#token '+' "\+" 
#token '-' "\-" 
#token '/' "\/" 
#token '<' "\<" 
#token '<' "\<" 
#token '<<' "\<\<" 
#token '<=' "\<\=" 
#token '<|' "\<\|" 
#token '=' "\=" 
#token '>' "\>" 
#token '>' "\>" 
#token '>=' "\>\=" 
#token '>>' "\>\>" 
#token '>|' "\>\|" 
#token '\\' "\\" 
#token '|' "\|" 
#token '||' "\|\|" 

#token NUMBER [NATURAL] "<decimal_number>" 
    << (local [format LiteralFormat:NaturalLiteralFormat] 
    (;; (= ?:Lexeme:Literal:Natural:Value (ConvertDecimalTokenStringToNatural (. format) ? 0 0)) 
    (= ?:Lexeme:Literal:Natural:Format (LiteralFormat:MakeCompactNaturalLiteralFormat format)) 
    );; 
)local 
    >> 

... [snip] 

%% -- end M6809.lex

**************** PARSER ******** ******

-- M6809.ATG: Motorola 6809 assembly code parser 
-- (C) Copyright 1989;1999-2002 Ira D. Baxter; All Rights Reserved 

m6809 = sourcelines ; 

sourcelines = ; 
sourcelines = sourcelines sourceline EOL ; 
    <<PrettyPrinter>>: { V(CV(sourcelines[1]),H(sourceline,A<eol>(EOL))); } 

-- leading opcode field symbol should be treated as keyword. 

sourceline = ; 
sourceline = labels ; 
sourceline = optional_labels 'EQU' expression ; 
    <<PrettyPrinter>>: { H(optional_labels,A<opcode>('EQU'),A<operand>(expression)); } 
sourceline = LABEL 'SET' expression ; 
    <<PrettyPrinter>>: { H(A<firstlabel>(LABEL),A<opcode>('SET'),A<operand>(expression)); } 
sourceline = optional_label instruction ; 
    <<PrettyPrinter>>: { H(optional_label,instruction); } 
sourceline = optional_label optlabelleddirective ; 
    <<PrettyPrinter>>: { H(optional_label,optlabelleddirective); } 
sourceline = optional_label implicitdatadirective ; 
    <<PrettyPrinter>>: { H(optional_label,implicitdatadirective); } 
sourceline = unlabelleddirective ; 
sourceline = '?ERROR' ; 
    <<PrettyPrinter>>: { A<opcode>('?ERROR'); } 

optional_label = labels ; 
optional_label = LABEL ':' ; 
    <<PrettyPrinter>>: { H(A<firstlabel>(LABEL),':'); } 
optional_label = ; 

optional_labels = ; 
optional_labels = labels ; 
labels = LABEL ; 
    <<PrettyPrinter>>: { A<firstlabel>(LABEL); } 
labels = labels ',' LABEL ; 
    <<PrettyPrinter>>: { H(labels[1],',',A<otherlabels>(LABEL)); } 

unlabelleddirective = 'END' ; 
    <<PrettyPrinter>>: { A<opcode>('END'); } 
unlabelleddirective = 'END' expression ; 
    <<PrettyPrinter>>: { H(A<opcode>('END'),A<operand>(expression)); } 
unlabelleddirective = 'IF' expression EOL conditional ; 
    <<PrettyPrinter>>: { V(H(A<opcode>('IF'),H(A<operand>(expression),A<eol>(EOL))),CV(conditional)); } 
unlabelleddirective = 'IFDEF' IDENTIFIER EOL conditional ; 
    <<PrettyPrinter>>: { V(H(A<opcode>('IFDEF'),H(A<operand>(IDENTIFIER),A<eol>(EOL))),CV(conditional)); } 
unlabelleddirective = 'IFUND' IDENTIFIER EOL conditional ; 
    <<PrettyPrinter>>: { V(H(A<opcode>('IFUND'),H(A<operand>(IDENTIFIER),A<eol>(EOL))),CV(conditional)); } 
unlabelleddirective = 'INCLUDE' FILENAME ; 
    <<PrettyPrinter>>: { H(A<opcode>('INCLUDE'),A<operand>(FILENAME)); } 
unlabelleddirective = 'LIST' expression ; 
    <<PrettyPrinter>>: { H(A<opcode>('LIST'),A<operand>(expression)); } 
unlabelleddirective = 'NAME' IDENTIFIER ; 
    <<PrettyPrinter>>: { H(A<opcode>('NAME'),A<operand>(IDENTIFIER)); } 
unlabelleddirective = 'ORG' expression ; 
    <<PrettyPrinter>>: { H(A<opcode>('ORG'),A<operand>(expression)); } 
unlabelleddirective = 'PAGE' ; 
    <<PrettyPrinter>>: { A<opcode>('PAGE'); } 
unlabelleddirective = 'PAGE' HEADING ; 
    <<PrettyPrinter>>: { H(A<opcode>('PAGE'),A<operand>(HEADING)); } 
unlabelleddirective = 'PCA' expression ; 
    <<PrettyPrinter>>: { H(A<opcode>('PCA'),A<operand>(expression)); } 
unlabelleddirective = 'PCC' expression ; 
    <<PrettyPrinter>>: { H(A<opcode>('PCC'),A<operand>(expression)); } 
unlabelleddirective = 'PSR' expression ; 
    <<PrettyPrinter>>: { H(A<opcode>('PSR'),A<operand>(expression)); } 
unlabelleddirective = 'TABS' numberlist ; 
    <<PrettyPrinter>>: { H(A<opcode>('TABS'),A<operand>(numberlist)); } 
unlabelleddirective = 'TITLE' HEADING ; 
    <<PrettyPrinter>>: { H(A<opcode>('TITLE'),A<operand>(HEADING)); } 
unlabelleddirective = 'WITH' settings ; 
    <<PrettyPrinter>>: { H(A<opcode>('WITH'),A<operand>(settings)); } 

settings = setting ; 
settings = settings ',' setting ; 
    <<PrettyPrinter>>: { H*; } 
setting = 'WI' '=' NUMBER ; 
    <<PrettyPrinter>>: { H*; } 
setting = 'DE' '=' NUMBER ; 
    <<PrettyPrinter>>: { H*; } 
setting = 'M6800' ; 
setting = 'M6801' ; 
setting = 'M6809' ; 
setting = 'M6811' ; 

-- collects lines of conditional code into blocks 
conditional = 'ELSEIF' expression EOL conditional ; 
    <<PrettyPrinter>>: { V(H(A<opcode>('ELSEIF'),H(A<operand>(expression),A<eol>(EOL))),CV(conditional[1])); } 
conditional = 'ELSE' EOL else ; 
    <<PrettyPrinter>>: { V(H(A<opcode>('ELSE'),A<eol>(EOL)),CV(else)); } 
conditional = 'FIN' ; 
    <<PrettyPrinter>>: { A<opcode>('FIN'); } 
conditional = sourceline EOL conditional ; 
    <<PrettyPrinter>>: { V(H(sourceline,A<eol>(EOL)),CV(conditional[1])); } 

else = 'FIN' ; 
    <<PrettyPrinter>>: { A<opcode>('FIN'); } 
else = sourceline EOL else ; 
    <<PrettyPrinter>>: { V(H(sourceline,A<eol>(EOL)),CV(else[1])); } 

-- keyword-less directive, generates data tables 

implicitdatadirective = implicitdatadirective ',' implicitdataitem ; 
    <<PrettyPrinter>>: { H*; } 
implicitdatadirective = implicitdataitem ; 

implicitdataitem = '#' expression ; 
    <<PrettyPrinter>>: { A<operand>(H('#',expression)); } 
implicitdataitem = '+' expression ; 
    <<PrettyPrinter>>: { A<operand>(H('+',expression)); } 
implicitdataitem = '-' expression ; 
    <<PrettyPrinter>>: { A<operand>(H('-',expression)); } 
implicitdataitem = expression ; 
    <<PrettyPrinter>>: { A<operand>(expression); } 
implicitdataitem = STRING ; 
    <<PrettyPrinter>>: { A<operand>(STRING); } 

-- instructions valid for m680C (see Software Dynamics ASM manual) 
instruction = 'ABA' ; 
    <<PrettyPrinter>>: { A<opcode>('ABA'); } 
instruction = 'ABX' ; 
    <<PrettyPrinter>>: { A<opcode>('ABX'); } 

instruction = 'ADC' 'A' operandfetch ; 
    <<PrettyPrinter>>: { H(A<opcode>(H('ADC','A')),A<operand>(operandfetch)); } 
instruction = 'ADC' 'B' operandfetch ; 
    <<PrettyPrinter>>: { H(A<opcode>(H('ADC','B')),A<operand>(operandfetch)); } 
instruction = 'ADCA' operandfetch ; 
    <<PrettyPrinter>>: { H(A<opcode>('ADCA'),A<operand>(operandfetch)); } 
instruction = 'ADCB' operandfetch ; 
    <<PrettyPrinter>>: { H(A<opcode>('ADCB'),A<operand>(operandfetch)); } 
instruction = 'ADCD' operandfetch ; 
    <<PrettyPrinter>>: { H(A<opcode>('ADCD'),A<operand>(operandfetch)); } 

instruction = 'ADD' 'A' operandfetch ; 
    <<PrettyPrinter>>: { H(A<opcode>(H('ADD','A')),A<operand>(operandfetch)); } 
instruction = 'ADD' 'B' operandfetch ; 
    <<PrettyPrinter>>: { H(A<opcode>(H('ADD','B')),A<operand>(operandfetch)); } 
instruction = 'ADDA' operandfetch ; 
    <<PrettyPrinter>>: { H(A<opcode>('ADDA'),A<operand>(operandfetch)); } 

[..snip...] 

-- condition code mask for ANDCC and ORCC 
conditionmask = '#' expression ; 
    <<PrettyPrinter>>: { H*; } 
conditionmask = expression ; 

target = expression ; 

operandfetch = '#' expression ; --immediate 
    <<PrettyPrinter>>: { H*; } 

operandfetch = memoryreference ; 

operandstore = memoryreference ; 

memoryreference = '[' indexedreference ']' ; 
    <<PrettyPrinter>>: { H*; } 
memoryreference = indexedreference ; 

indexedreference = offset ; 
indexedreference = offset ',' indexregister ; 
    <<PrettyPrinter>>: { H*; } 
indexedreference = ',' indexregister ; 
    <<PrettyPrinter>>: { H*; } 
indexedreference = ',' '--' indexregister ; 
    <<PrettyPrinter>>: { H*; } 
indexedreference = ',' '-' indexregister ; 
    <<PrettyPrinter>>: { H*; } 
indexedreference = ',' indexregister '++' ; 
    <<PrettyPrinter>>: { H*; } 
indexedreference = ',' indexregister '+' ; 
    <<PrettyPrinter>>: { H*; } 

offset = '>' expression ; -- page zero ref 
    <<PrettyPrinter>>: { H*; } 
offset = '<' expression ; -- long reference 
    <<PrettyPrinter>>: { H*; } 
offset = expression ; 
offset = 'A' ; 
offset = 'B' ; 
offset = 'D' ; 

registerlist = registername ; 
registerlist = registerlist ',' registername ; 
    <<PrettyPrinter>>: { H*; } 

registername = 'A' ; 
registername = 'B' ; 
registername = 'CC' ; 
registername = 'DP' ; 
registername = 'D' ; 
registername = 'Z' ; 
registername = indexregister ; 

indexregister = 'X' ; 
indexregister = 'Y' ; 
indexregister = 'U' ; -- not legal on M6811 
indexregister = 'S' ; 
indexregister = 'PCR' ; 
indexregister = 'PC' ; 

expression = sum '=' sum ; 
    <<PrettyPrinter>>: { H*; } 
expression = sum '<<' sum ; 
    <<PrettyPrinter>>: { H*; } 
expression = sum '</' sum ; 
    <<PrettyPrinter>>: { H*; } 
expression = sum '<=' sum ; 
    <<PrettyPrinter>>: { H*; } 
expression = sum '<' sum ; 
    <<PrettyPrinter>>: { H*; } 
expression = sum '>>' sum ; 
    <<PrettyPrinter>>: { H*; } 
expression = sum '>/' sum ; 
    <<PrettyPrinter>>: { H*; } 
expression = sum '>=' sum ; 
    <<PrettyPrinter>>: { H*; } 
expression = sum '>' sum ; 
    <<PrettyPrinter>>: { H*; } 
expression = sum '#' sum ; 
    <<PrettyPrinter>>: { H*; } 
expression = sum ; 

sum = product ; 
sum = sum '+' product ; 
    <<PrettyPrinter>>: { H*; } 
sum = sum '-' product ; 
    <<PrettyPrinter>>: { H*; } 
sum = sum '!' product ; 
    <<PrettyPrinter>>: { H*; } 
sum = sum '!!' product ; 
    <<PrettyPrinter>>: { H*; } 

product = term '*' product ; 
    <<PrettyPrinter>>: { H*; } 
product = term '||' product ; -- wrong? 
    <<PrettyPrinter>>: { H*; } 
product = term '/' product ; 
    <<PrettyPrinter>>: { H*; } 
product = term '//' product ; 
    <<PrettyPrinter>>: { H*; } 
product = term '&' product ; 
    <<PrettyPrinter>>: { H*; } 
product = term '##' product ; 
    <<PrettyPrinter>>: { H*; } 
product = term ; 

term = '+' term ; 
    <<PrettyPrinter>>: { H*; } 
term = '-' term ; 
    <<PrettyPrinter>>: { H*; } 
term = '\\' term ; -- complement 
    <<PrettyPrinter>>: { H*; } 
term = '&' term ; -- not 

term = IDENTIFIER ; 
term = NUMBER ; 
term = CHARACTER ; 
term = '*' ; 
term = '(' expression ')' ; 
    <<PrettyPrinter>>: { H*; } 

numberlist = NUMBER ; 
numberlist = numberlist ',' NUMBER ; 
    <<PrettyPrinter>>: { H*; }

来源

2009-08-23 04:39:08

艾拉，谢谢你的好评（我试图排名这个，但我没有经历足够的大声笑）。我想知道你是否有一个使用这种方法的词法分析器和/或解析器的例子，这样我就可以看一看，如果没有，一些伪代码的任何机会让我向前移动:)。最好的问候 – 2009-08-23 09:40:47

@Gary：当心你的要求：}请参阅编辑我的小答案把它变成一个巨大的。 – 2009-08-23 17:44:29

@Gary：PS，为了“排名靠前”，只需点击答案开头旁边分数上方的三角形即可。： - } – 2009-08-23 17:46:07

BNF更一般地用于例如Pascal，C++，或从Algo1系列（其包括现代语言如C＃）衍生真的什么结构，嵌套的语言。如果我正在实现汇编程序，我可能会使用一些简单的正则表达式来对操作码和操作数进行模式匹配。它是因为我已经用Z80汇编语言一段时间，但你可能会使用类似：

/\s*(\w{2,3})\s+((\w+)(,\w+)?)?/

这将匹配它由两个或三个字母的操作码，然后分开的一个或两个操作数的任何线以逗号分隔。在提取像这样的汇编器行后，您可以查看操作码并为指令生成正确的字节，包括操作数的值（如果适用）。

上面使用正则表达式概述的解析器类型将被称为“ad hoc”解析器，它基本上意味着您在某种块的基础上拆分和检查输入（在汇编语言的情况下，通过文本行）。

来源

2009-08-22 23:05:15

我不认为你需要过时。当你可以直接将整个事件（模块大小写和空白字符串）匹配到一个操作码时，将解析器分解为“LD A，A”到加载操作，目标寄存器和源寄存器是毫无意义的。

有没有那么多的操作码，和他们没有安排在这样一种方式，你真的从解析和理解IMO汇编得到多少好处。显然你需要一个解析器来处理字节/地址/索引参数，但除此之外，我只需要进行一对一的查找。

来源

2009-08-22 23:55:56 bobince

感谢您的反馈......我同意走下更简单的道路，但也有兴趣将此扩展为更复杂的语言，并且我想从一开始就利用这些功能......还有在ASM的一些其他部分（如equ，.db，.ds，.dw，#include，（））方面存在差异，然后我们开始进入简单的case语句IF ELSE。此外，这也是学习BNF概念的练习，并将其用于更简单的实现。 – 2009-08-23 01:51:54

Z80 ASM BNF结构...我在正确的轨道上吗？

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