projects / unix-history / blame
| Commit | Line | Data |
|---|---|---|
| ac675cfd | 1 | /* Copyright (c) 1980 Regents of the University of California */ |
| 31cef89c | 2 | /* "@(#)asexpr.h 4.2 8/15/80" */ |
| ac675cfd BJ |
3 | /* |
| 4 | * Definitions to parse tokens | |
| 5 | */ | |
| 6 | ||
| 7 | #define ERROR(string) yyerror(string); goto errorfix | |
| 8 | ||
| 9 | #define peekahead (*tokptr) | |
| 10 | ||
| 11 | #define shift val = yylex() | |
| 12 | #define advance shift | |
| 13 | ||
| 14 | #define shiftover(token) if (val != token) { \ | |
| 15 | yyerror("token expected"); \ | |
| 16 | goto errorfix; \ | |
| 17 | } \ | |
| 18 | shift | |
| 19 | ||
| 20 | #define advanceover shiftover | |
| 21 | ||
| 22 | /* | |
| 23 | * To speed up the expression processing, we class the input tokens | |
| 24 | * into various sets. | |
| 25 | * | |
| 26 | * We don't call the recursive descent expression analyzer if we can | |
| 27 | * determine by looking at the next token after the first token in | |
| 28 | * an expression that the expression is simple (name, integer or floating | |
| 29 | * point value). Expressions with operators are parsed using the recursive | |
| 30 | * descent method. | |
| 31 | */ | |
| 32 | ||
| 33 | /* | |
| 34 | * Functional forwards for expression utility routines | |
| 35 | */ | |
| 36 | struct exp *combine(); | |
| 37 | struct exp *boolterm(); | |
| 38 | struct exp *term(); | |
| 39 | struct exp *factor(); | |
| 40 | struct exp *yukkyexpr(); | |
| 41 | ||
| 42 | /* | |
| 43 | * The set definitions | |
| 44 | */ | |
| 45 | ||
| 46 | extern char tokensets[(LASTTOKEN) - (FIRSTTOKEN) + 1]; | |
| 47 | ||
| 451260e7 | 48 | #define LINSTBEGIN 01 /*SEMI, NL, NAME*/ |
| ac675cfd | 49 | #define EBEGOPS 02 /*LP, MINUS, TILDE*/ |
| 451260e7 | 50 | #define YUKKYEXPRBEG 04 /*NAME, INSTn, INST0, REG, BFINT*/ |
| ac675cfd | 51 | #define SAFEEXPRBEG 010 /*INT, FLTNUM*/ |
| 451260e7 | 52 | #define ADDOPS 020 /*PLUS, MINUS*/ |
| ac675cfd | 53 | #define BOOLOPS 040 /*IOR, XOR, AND*/ |
| 451260e7 | 54 | #define MULOPS 0100 /*LSH, RSH, MUL, DIV, TILDE*/ |
| ac675cfd BJ |
55 | |
| 56 | #define INTOKSET(val, set) (tokensets[(val)] & (set) ) | |
| 57 | ||
| 58 | #define expr(xp, val) { \ | |
| 59 | if ( (!INTOKSET(val, EBEGOPS)) && (!INTOKSET(peekahead, ADDOPS+BOOLOPS+MULOPS))) { \ | |
| 60 | if (INTOKSET(val, YUKKYEXPRBEG)) xp = yukkyexpr(val, yylval); \ | |
| 61 | else xp = (struct exp *) yylval; \ | |
| 62 | shift; \ | |
| 63 | } else { \ | |
| 64 | val = exprparse(val, ptrloc1xp); \ | |
| 65 | xp = loc1xp; \ | |
| 66 | } \ | |
| 67 | } | |
| 68 | ||
| 69 | /* | |
| 70 | * Registers can be either of the form r0...pc, or | |
| 71 | * of the form % <expression> | |
| 72 | * NOTE: Reizers documentation on the assembler says that it | |
| 73 | * can be of the form r0 + <expression>.. That's not true. | |
| 74 | * | |
| 75 | * NOTE: Reizer's yacc grammar would seem to allow an expression | |
| 76 | * to be: (This is undocumented) | |
| 77 | * a) a register | |
| 78 | * b) an Instruction (INSTn or INST0) | |
| 79 | */ | |
| 80 | ||
| 81 | #define findreg(regno) \ | |
| 82 | if (val == REG) { \ | |
| 83 | regno = yylval; \ | |
| 84 | shift; \ | |
| 85 | } else \ | |
| 86 | if (val == REGOP) { \ | |
| 87 | shift; /*over the REGOP*/ \ | |
| 88 | val = funnyreg(val, ptrregno); \ | |
| 89 | } \ | |
| 90 | else { ERROR ("register expected"); } |