projects / unix-history / blame
| Commit | Line | Data |
|---|---|---|
| 629188b5 JR |
1 | /* |
| 2 | * Definitions to parse tokens | |
| 3 | */ | |
| 4 | ||
| 5 | #define ERROR(string) yyerror(string); goto errorfix | |
| 6 | ||
| 7 | #define peekahead (*tokptr) | |
| 8 | ||
| 9 | #define shift val = yylex() | |
| 10 | #define advance shift | |
| 11 | ||
| 12 | #define shiftover(token) if (val != token) { \ | |
| 13 | yyerror("token expected"); \ | |
| 14 | goto errorfix; \ | |
| 15 | } \ | |
| 16 | shift | |
| 17 | ||
| 18 | #define advanceover shiftover | |
| 19 | ||
| 20 | /* | |
| 21 | * To speed up the expression processing, we class the input tokens | |
| 22 | * into various sets. | |
| 23 | * | |
| 24 | * We don't call the recursive descent expression analyzer if we can | |
| 25 | * determine by looking at the next token after the first token in | |
| 26 | * an expression that the expression is simple (name, integer or floating | |
| 27 | * point value). Expressions with operators are parsed using the recursive | |
| 28 | * descent method. | |
| 29 | */ | |
| 30 | ||
| 31 | /* | |
| 32 | * Functional forwards for expression utility routines | |
| 33 | */ | |
| 34 | struct exp *combine(); | |
| 35 | struct exp *boolterm(); | |
| 36 | struct exp *term(); | |
| 37 | struct exp *factor(); | |
| 38 | struct exp *yukkyexpr(); | |
| 39 | ||
| 40 | /* | |
| 41 | * The set definitions | |
| 42 | */ | |
| 43 | ||
| 44 | char tokensets[(LASTTOKEN) - (FIRSTTOKEN) + 1]; | |
| 45 | ||
| 46 | #define LINSTBEGIN 01 /*SEMI, NL, NAME*/ | |
| 47 | #define EBEGOPS 02 /*LP, MINUS, TILDE*/ | |
| 48 | #define YUKKYEXPRBEG 04 /*NAME, INSTn, INST0, REG, DOT*/ | |
| 49 | #define SAFEEXPRBEG 010 /*INT, FLTNUM*/ | |
| 50 | #define ADDOPS 020 /*PLUS, MINUS*/ | |
| 51 | #define BOOLOPS 040 /*IOR, XOR, AND*/ | |
| 52 | #define MULOPS 0100 /*LSH, RSH, MUL, DIV, TILDE*/ | |
| 53 | ||
| 54 | #define INTOKSET(val, set) (tokensets[(val)] & (set) ) | |
| 55 | ||
| 56 | #define expr(xp, val) { \ | |
| 57 | if ( (!INTOKSET(val, EBEGOPS)) && (!INTOKSET(peekahead, ADDOPS+BOOLOPS+MULOPS))) { \ | |
| 58 | if (INTOKSET(val, YUKKYEXPRBEG)) xp = yukkyexpr(val, yylval); \ | |
| 59 | else xp = (struct exp *) yylval; \ | |
| 60 | shift; \ | |
| 61 | } else { \ | |
| 62 | val = exprparse(val, ptrloc1xp); \ | |
| 63 | xp = loc1xp; \ | |
| 64 | } \ | |
| 65 | } | |
| 66 | ||
| 67 | /* | |
| 68 | * Registers can be either of the form r0...pc, or | |
| 69 | * of the form % <expression> | |
| 70 | * NOTE: Reizers documentation on the assembler says that it | |
| 71 | * can be of the form r0 + <expression>.. That's not true. | |
| 72 | * | |
| 73 | * NOTE: Reizer's yacc grammar would seem to allow an expression | |
| 74 | * to be: (This is undocumented) | |
| 75 | * a) a register | |
| 76 | * b) an Instruction (INSTn or INST0) | |
| 77 | */ | |
| 78 | ||
| 79 | #define findreg(regno) \ | |
| 80 | if (val == REG) { \ | |
| 81 | regno = yylval; \ | |
| 82 | shift; \ | |
| 83 | } else \ | |
| 84 | if (val == REGOP) { \ | |
| 85 | shift; /*over the REGOP*/ \ | |
| 86 | val = funnyreg(val, ptrregno); \ | |
| 87 | } \ | |
| 88 | else { ERROR ("register expected"); } |