xnu-344.23.tar.gz

[apple/xnu.git] / osfmk / ddb / db_access.c

diff --git a/osfmk/ddb/db_access.c b/osfmk/ddb/db_access.c
index d803b7e549e51edfe7cad552422682d3e88871b8..75fe96d4dc1c4f5b4ac4c6d68e8ba036a386eb4d 100644 (file)
--- a/osfmk/ddb/db_access.c
+++ b/osfmk/ddb/db_access.c
@@ -3,22 +3,19 @@
  *
  * @APPLE_LICENSE_HEADER_START@
  * 
- * Copyright (c) 1999-2003 Apple Computer, Inc.  All Rights Reserved.
+ * The contents of this file constitute Original Code as defined in and
+ * are subject to the Apple Public Source License Version 1.1 (the
+ * "License").  You may not use this file except in compliance with the
+ * License.  Please obtain a copy of the License at
+ * http://www.apple.com/publicsource and read it before using this file.
  * 
- * This file contains Original Code and/or Modifications of Original Code
- * as defined in and that are subject to the Apple Public Source License
- * Version 2.0 (the 'License'). You may not use this file except in
- * compliance with the License. Please obtain a copy of the License at
- * http://www.opensource.apple.com/apsl/ and read it before using this
- * file.
- * 
- * The Original Code and all software distributed under the License are
- * distributed on an 'AS IS' basis, WITHOUT WARRANTY OF ANY KIND, EITHER
+ * This Original Code and all software distributed under the License are
+ * distributed on an "AS IS" basis, WITHOUT WARRANTY OF ANY KIND, EITHER
  * EXPRESS OR IMPLIED, AND APPLE HEREBY DISCLAIMS ALL SUCH WARRANTIES,
  * INCLUDING WITHOUT LIMITATION, ANY WARRANTIES OF MERCHANTABILITY,
- * FITNESS FOR A PARTICULAR PURPOSE, QUIET ENJOYMENT OR NON-INFRINGEMENT.
- * Please see the License for the specific language governing rights and
- * limitations under the License.
+ * FITNESS FOR A PARTICULAR PURPOSE OR NON-INFRINGEMENT.  Please see the
+ * License for the specific language governing rights and limitations
+ * under the License.
  * 
  * @APPLE_LICENSE_HEADER_END@
  */
@@ -72,6 +69,33 @@
 
 int db_access_level = DB_ACCESS_LEVEL;
 
+/*
+ * This table is for sign-extending things.
+ * Therefore its entries are signed, and yes
+ * they are in fact negative numbers.
+ * So don't put Us in it. Or Ls either.
+ * Otherwise there is no point having it, n'est pas ?
+ */
+static int db_extend[sizeof(long)+1] = { /* table for sign-extending */
+#if defined(__arch64__)
+       0,
+       0xFFFFFFFFFFFFFF80,
+       0xFFFFFFFFFFFF8000,
+       0xFFFFFFFFFF800000,
+       0xFFFFFFFF80000000,
+       0xFFFFFF8000000000,
+       0xFFFF800000000000,
+       0xFF80000000000000,
+       0x8000000000000000,
+#else /* !defined(__arch64__) */
+       0,
+       0xFFFFFF80,
+       0xFFFF8000,
+       0xFF800000,
+       0x80000000
+#endif /* defined(__arch64__) */
+};
+
 db_expr_t
 db_get_task_value(
        db_addr_t       addr,
@@ -82,9 +106,6 @@ db_get_task_value(
        char            data[sizeof(db_expr_t)];
        register db_expr_t value;
        register int    i;
-       uint64_t signx;
-
-       if(size == 0) return 0;
 
        db_read_bytes((vm_offset_t)addr, size, data, task);
 
@@ -97,13 +118,11 @@ db_get_task_value(
        {
            value = (value << 8) + (data[i] & 0xFF);
        }
-       
-       if(!is_signed) return value;
-       
-       signx = 0xFFFFFFFFFFFFFFFFULL << ((size << 3) - 1);
-        
-       if(value & signx) value |= signx;       /* Add 1s to front if sign bit is on */
-
+           
+       if (size <= sizeof(int)) {
+           if (is_signed && (value & db_extend[size]) != 0)
+               value |= db_extend[size];
+       }
        return (value);
 }