Initial import, 0.1 + pk 0.2.4-B1

1 files changed, 248 insertions, 0 deletions

diff --git a/sys/ddb/db_expr.c b/sys/ddb/db_expr.c
new file mode 100644
index 0000000..062662c
--- /dev/null
+++ b/sys/ddb/db_expr.c
@@ -0,0 +1,248 @@
+/* 
+ * Mach Operating System
+ * Copyright (c) 1991,1990 Carnegie Mellon University
+ * All Rights Reserved.
+ * 
+ * Permission to use, copy, modify and distribute this software and its
+ * documentation is hereby granted, provided that both the copyright
+ * notice and this permission notice appear in all copies of the
+ * software, derivative works or modified versions, and any portions
+ * thereof, and that both notices appear in supporting documentation.
+ * 
+ * CARNEGIE MELLON ALLOWS FREE USE OF THIS SOFTWARE IN ITS 
+ * CONDITION.  CARNEGIE MELLON DISCLAIMS ANY LIABILITY OF ANY KIND FOR
+ * ANY DAMAGES WHATSOEVER RESULTING FROM THE USE OF THIS SOFTWARE.
+ * 
+ * Carnegie Mellon requests users of this software to return to
+ * 
+ *  Software Distribution Coordinator  or  Software.Distribution@CS.CMU.EDU
+ *  School of Computer Science
+ *  Carnegie Mellon University
+ *  Pittsburgh PA 15213-3890
+ * 
+ * any improvements or extensions that they make and grant Carnegie the
+ * rights to redistribute these changes.
+ */
+/*
+ * HISTORY
+ * $Log: db_expr.c,v $
+ * Revision 1.1  1992/03/25  21:45:09  pace
+ * Initial revision
+ *
+ * Revision 2.3  91/02/05  17:06:25  mrt
+ * 	Changed to new Mach copyright
+ * 	[91/01/31  16:17:46  mrt]
+ * 
+ * Revision 2.2  90/08/27  21:50:57  dbg
+ * 	Use '..' instead of '$$' for db_prev.
+ * 	Use '+' for db_next.
+ * 	[90/08/22            dbg]
+ * 
+ * 	Allow repeated unary operators.
+ * 	[90/08/20            dbg]
+ * 
+ * 	Reflected back rename of db_symbol_value->db_value_of_name
+ * 	[90/08/20            af]
+ * 	Reduce lint.
+ * 	[90/08/07            dbg]
+ * 	Created.
+ * 	[90/07/25            dbg]
+ * 
+ */
+/*
+ *	Author: David B. Golub, Carnegie Mellon University
+ *	Date:	7/90
+ */
+#include "param.h"
+#include "proc.h"
+#include <machine/db_machdep.h>
+#include <ddb/db_lex.h>
+#include <ddb/db_access.h>
+#include <ddb/db_command.h>
+
+boolean_t
+db_term(valuep)
+	db_expr_t *valuep;
+{
+	int	t;
+
+	t = db_read_token();
+	if (t == tIDENT) {
+	    if (!db_value_of_name(db_tok_string, valuep)) {
+		db_error("Symbol not found\n");
+		/*NOTREACHED*/
+	    }
+	    return (TRUE);
+	}
+	if (t == tNUMBER) {
+	    *valuep = (db_expr_t)db_tok_number;
+	    return (TRUE);
+	}
+	if (t == tDOT) {
+	    *valuep = (db_expr_t)db_dot;
+	    return (TRUE);
+	}
+	if (t == tDOTDOT) {
+	    *valuep = (db_expr_t)db_prev;
+	    return (TRUE);
+	}
+	if (t == tPLUS) {
+	    *valuep = (db_expr_t) db_next;
+	    return (TRUE);
+	}
+	if (t == tDITTO) {
+	    *valuep = (db_expr_t)db_last_addr;
+	    return (TRUE);
+	}
+	if (t == tDOLLAR) {
+	    if (!db_get_variable(valuep))
+		return (FALSE);
+	    return (TRUE);
+	}
+	if (t == tLPAREN) {
+	    if (!db_expression(valuep)) {
+		db_error("Syntax error\n");
+		/*NOTREACHED*/
+	    }
+	    t = db_read_token();
+	    if (t != tRPAREN) {
+		db_error("Syntax error\n");
+		/*NOTREACHED*/
+	    }
+	    return (TRUE);
+	}
+	db_unread_token(t);
+	return (FALSE);
+}
+
+boolean_t
+db_unary(valuep)
+	db_expr_t *valuep;
+{
+	int	t;
+
+	t = db_read_token();
+	if (t == tMINUS) {
+	    if (!db_unary(valuep)) {
+		db_error("Syntax error\n");
+		/*NOTREACHED*/
+	    }
+	    *valuep = -*valuep;
+	    return (TRUE);
+	}
+	if (t == tSTAR) {
+	    /* indirection */
+	    if (!db_unary(valuep)) {
+		db_error("Syntax error\n");
+		/*NOTREACHED*/
+	    }
+	    *valuep = db_get_value((db_addr_t)*valuep, sizeof(int), FALSE);
+	    return (TRUE);
+	}
+	db_unread_token(t);
+	return (db_term(valuep));
+}
+
+boolean_t
+db_mult_expr(valuep)
+	db_expr_t *valuep;
+{
+	db_expr_t	lhs, rhs;
+	int		t;
+
+	if (!db_unary(&lhs))
+	    return (FALSE);
+
+	t = db_read_token();
+	while (t == tSTAR || t == tSLASH || t == tPCT || t == tHASH) {
+	    if (!db_term(&rhs)) {
+		db_error("Syntax error\n");
+		/*NOTREACHED*/
+	    }
+	    if (t == tSTAR)
+		lhs *= rhs;
+	    else {
+		if (rhs == 0) {
+		    db_error("Divide by 0\n");
+		    /*NOTREACHED*/
+		}
+		if (t == tSLASH)
+		    lhs /= rhs;
+		else if (t == tPCT)
+		    lhs %= rhs;
+		else
+		    lhs = ((lhs+rhs-1)/rhs)*rhs;
+	    }
+	    t = db_read_token();
+	}
+	db_unread_token(t);
+	*valuep = lhs;
+	return (TRUE);
+}
+
+boolean_t
+db_add_expr(valuep)
+	db_expr_t *valuep;
+{
+	db_expr_t	lhs, rhs;
+	int		t;
+
+	if (!db_mult_expr(&lhs))
+	    return (FALSE);
+
+	t = db_read_token();
+	while (t == tPLUS || t == tMINUS) {
+	    if (!db_mult_expr(&rhs)) {
+		db_error("Syntax error\n");
+		/*NOTREACHED*/
+	    }
+	    if (t == tPLUS)
+		lhs += rhs;
+	    else
+		lhs -= rhs;
+	    t = db_read_token();
+	}
+	db_unread_token(t);
+	*valuep = lhs;
+	return (TRUE);
+}
+
+boolean_t
+db_shift_expr(valuep)
+	db_expr_t *valuep;
+{
+	db_expr_t	lhs, rhs;
+	int		t;
+
+	if (!db_add_expr(&lhs))
+	    return (FALSE);
+
+	t = db_read_token();
+	while (t == tSHIFT_L || t == tSHIFT_R) {
+	    if (!db_add_expr(&rhs)) {
+		db_error("Syntax error\n");
+		/*NOTREACHED*/
+	    }
+	    if (rhs < 0) {
+		db_error("Negative shift amount\n");
+		/*NOTREACHED*/
+	    }
+	    if (t == tSHIFT_L)
+		lhs <<= rhs;
+	    else {
+		/* Shift right is unsigned */
+		lhs = (unsigned) lhs >> rhs;
+	    }
+	    t = db_read_token();
+	}
+	db_unread_token(t);
+	*valuep = lhs;
+	return (TRUE);
+}
+
+int
+db_expression(valuep)
+	db_expr_t *valuep;
+{
+	return (db_shift_expr(valuep));
+}