initial import of NetBSD tree

1 files changed, 97 insertions, 0 deletions

diff --git a/sys/ddb/db_access.c b/sys/ddb/db_access.c
new file mode 100644
index 00000000000..4914f1e02fd
--- /dev/null
+++ b/sys/ddb/db_access.c
@@ -0,0 +1,97 @@
+/*	$NetBSD: db_access.c,v 1.8 1994/10/09 08:37:35 mycroft Exp $	*/
+
+/* 
+ * 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.
+ *
+ *	Author: David B. Golub, Carnegie Mellon University
+ *	Date:	7/90
+ */
+
+#include <sys/param.h>
+#include <sys/proc.h>
+
+#include <machine/db_machdep.h>		/* type definitions */
+#include <machine/endian.h>
+
+#include <ddb/db_access.h>
+
+/*
+ * Access unaligned data items on aligned (longword)
+ * boundaries.
+ */
+
+int db_extend[] = {	/* table for sign-extending */
+	0,
+	0xFFFFFF80,
+	0xFFFF8000,
+	0xFF800000
+};
+
+db_expr_t
+db_get_value(addr, size, is_signed)
+	db_addr_t addr;
+	register size_t size;
+	boolean_t is_signed;
+{
+	char data[sizeof(int)];
+	register db_expr_t value;
+	register int i;
+
+	db_read_bytes(addr, size, data);
+
+	value = 0;
+#if BYTE_ORDER == LITTLE_ENDIAN
+	for (i = size - 1; i >= 0; i--)
+#else /* BYTE_ORDER == BIG_ENDIAN */
+	for (i = 0; i < size; i++)
+#endif /* BYTE_ORDER */
+		value = (value << 8) + (data[i] & 0xFF);
+	    
+	if (size < 4 && is_signed && (value & db_extend[size]) != 0)
+		value |= db_extend[size];
+	return (value);
+}
+
+void
+db_put_value(addr, size, value)
+	db_addr_t addr;
+	register size_t size;
+	register db_expr_t value;
+{
+	char data[sizeof(int)];
+	register int i;
+
+#if BYTE_ORDER == LITTLE_ENDIAN
+	for (i = 0; i < size; i++)
+#else /* BYTE_ORDER == BIG_ENDIAN */
+	for (i = size - 1; i >= 0; i--)
+#endif /* BYTE_ORDER */
+	{
+		data[i] = value & 0xFF;
+		value >>= 8;
+	}
+
+	db_write_bytes(addr, size, data);
+}