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- /*
- * (c) copyright 1987 by the Vrije Universiteit, Amsterdam, The Netherlands.
- * See the copyright notice in the ACK home directory, in the file "Copyright".
- */
- /* $Id$ */
- /* EXPRESSION DESCRIPTOR */
- /* What we want to define is the struct expr, but since it contains
- a union of various goodies, we define them first; so be patient.
- */
- #include "nofloat.h"
- /* classes of value */
- #define Const 1
- #define Name 2
- #define Label 3
- struct value {
- int vl_class; /* Const, Name or Label */
- arith vl_value; /* constant value or offset */
- union {
- struct idf *vl_idf; /* external name */
- label vl_lbl; /* compiler-generated label */
- } vl_data;
- };
- struct string {
- char *sg_value; /* row of bytes repr. the constant */
- int sg_len; /* length of the row */
- label sg_datlab; /* global data-label */
- };
- #ifndef NOFLOAT
- struct floating {
- char *fl_value; /* pointer to string repr. the fp const. */
- label fl_datlab; /* global data_label */
- };
- #endif /* NOFLOAT */
- struct oper {
- struct type *op_type; /* resulting type of the operation */
- struct expr *op_left;
- int op_oper; /* the symbol of the operator */
- struct expr *op_right;
- };
- /* The following constants indicate the class of the expression: */
- #define Value 0 /* it is a value known at load time */
- #define String 1 /* it is a string constant */
- #ifndef NOFLOAT
- #define Float 2 /* it is a floating point constant */
- #endif /* NOFLOAT */
- #define Oper 3 /* it is a run-time expression */
- #define Type 4 /* only its type is relevant */
- struct expr {
- struct expr *next;
- char *ex_file; /* the file it (probably) comes from */
- unsigned int ex_line; /* the line it (probably) comes from */
- struct type *ex_type;
- char ex_lvalue;
- char ex_flags;
- int ex_class;
- int ex_depth;
- union {
- struct value ex_value;
- struct string ex_string;
- #ifndef NOFLOAT
- struct floating ex_float;
- #endif /* NOFLOAT */
- struct oper ex_oper;
- } ex_object;
- };
- /* some abbreviated selections */
- #define EX_VALUE ex_object.ex_value
- #define VL_CLASS EX_VALUE.vl_class
- #define VL_VALUE EX_VALUE.vl_value
- #define VL_IDF EX_VALUE.vl_data.vl_idf
- #define VL_LBL EX_VALUE.vl_data.vl_lbl
- #define SG_VALUE ex_object.ex_string.sg_value
- #define SG_LEN ex_object.ex_string.sg_len
- #define SG_DATLAB ex_object.ex_string.sg_datlab
- #ifndef NOFLOAT
- #define FL_VALUE ex_object.ex_float.fl_value
- #define FL_DATLAB ex_object.ex_float.fl_datlab
- #endif /* NOFLOAT */
- #define OP_TYPE ex_object.ex_oper.op_type
- #define OP_LEFT ex_object.ex_oper.op_left
- #define OP_OPER ex_object.ex_oper.op_oper
- #define OP_RIGHT ex_object.ex_oper.op_right
- /* some bits for the ex_flag field, to keep track of various
- interesting properties of an expression.
- */
- #define EX_SIZEOF 0001 /* contains sizeof operator */
- #define EX_CAST 0002 /* contains cast */
- #define EX_LOGICAL 0004 /* contains logical operator */
- #define EX_COMMA 0010 /* contains expression comma */
- #define EX_PARENS 0020 /* the top level is parenthesized */
- #define EX_SIDEEFFECTS 0040 /* expression has side effects */
- #define EX_ERROR 0200 /* the expression is wrong */
- #define NILEXPR ((struct expr *)0)
- /* some useful tests */
- #define ISNAME(e) ((e)->ex_class == Value && (e)->VL_CLASS == Name)
- #define ISCOMMA(e) ((e)->ex_class == Oper && (e)->OP_OPER == INITCOMMA)
- extern struct expr *intexpr(), *new_oper();
- /* ALLOCDEF "expr" 20 */
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