grammar

grammar Lab1;

fragment E: 'E' | 'e';
fragment X: 'X' | 'x';
fragment A: 'A' | 'a';
fragment B: 'B' | 'b';
fragment C: 'C' | 'c';
fragment D: 'D' | 'd';

REGISTER: ('%'E A X | '%'E B X | '%'E C X | '%'E D X);

ADD: '+';
SUB: '-';
MUL: '*';
DIV: '/';
LBRA: '(';
RBRA: ')';
NUMBER: [0-9]+;
WHITESPACE: [ \r\n\t]+ -> skip;

MOV: 'mov';
PUSH: 'push';
INT: 'int 0x80';
XOR: 'xor';
COMMANDS: MOV | PUSH | INT | XOR;

start: commands;

commands
    : MOV expression ',' registers      #Mov
    | PUSH expression                   #Push
    | XOR expression ',' expression     #Xor
    | INT '0x80'                        #Int
    ;

expression
    : NUMBER                        #Number
    | registers                     #ExpRegi
    | LBRA expression RBRA          #BRexp
    | expression MUL expression     #Multiply
    | expression DIV expression     #Divide
    | expression ADD expression     #Add
    | expression SUB expression     #Subtract
    ;

registers
    : REGISTER #Register
    ;