1------------------------------------------------------------------------------
2--                                                                          --
3--                         GNAT COMPILER COMPONENTS                         --
4--                                                                          --
5--                     SYSTEM.MACHINE_STATE_OPERATIONS                      --
6--                                                                          --
7--                                 B o d y                                  --
8--                         (Version for Alpha/Dec Unix)                     --
9--                                                                          --
10--           Copyright (C) 1999-2003 Ada Core Technologies, Inc.            --
11--                                                                          --
12-- GNAT is free software;  you can  redistribute it  and/or modify it under --
13-- terms of the  GNU General Public License as published  by the Free Soft- --
14-- ware  Foundation;  either version 2,  or (at your option) any later ver- --
15-- sion.  GNAT is distributed in the hope that it will be useful, but WITH- --
16-- OUT ANY WARRANTY;  without even the  implied warranty of MERCHANTABILITY --
17-- or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License --
18-- for  more details.  You should have  received  a copy of the GNU General --
19-- Public License  distributed with GNAT;  see file COPYING.  If not, write --
20-- to  the Free Software Foundation,  59 Temple Place - Suite 330,  Boston, --
21-- MA 02111-1307, USA.                                                      --
22--                                                                          --
23-- As a special exception,  if other files  instantiate  generics from this --
24-- unit, or you link  this unit with other files  to produce an executable, --
25-- this  unit  does not  by itself cause  the resulting  executable  to  be --
26-- covered  by the  GNU  General  Public  License.  This exception does not --
27-- however invalidate  any other reasons why  the executable file  might be --
28-- covered by the  GNU Public License.                                      --
29--                                                                          --
30-- GNAT was originally developed  by the GNAT team at  New York University. --
31-- Extensive contributions were provided by Ada Core Technologies Inc.      --
32--                                                                          --
33------------------------------------------------------------------------------
34
35--  This version of System.Machine_State_Operations is for use on
36--  Alpha systems running DEC Unix.
37
38with System.Memory;
39
40package body System.Machine_State_Operations is
41
42   use System.Exceptions;
43
44   pragma Linker_Options ("-lexc");
45   --  Needed for definitions of exc_capture_context and exc_virtual_unwind
46
47   ----------------------------
48   -- Allocate_Machine_State --
49   ----------------------------
50
51   function Allocate_Machine_State return Machine_State is
52      use System.Storage_Elements;
53
54      function c_machine_state_length return Storage_Offset;
55      pragma Import (C, c_machine_state_length, "__gnat_machine_state_length");
56
57   begin
58      return Machine_State
59        (Memory.Alloc (Memory.size_t (c_machine_state_length)));
60   end Allocate_Machine_State;
61
62   -------------------
63   -- Enter_Handler --
64   -------------------
65
66   procedure Enter_Handler (M : Machine_State; Handler : Handler_Loc) is
67      procedure c_enter_handler (M : Machine_State; Handler : Handler_Loc);
68      pragma Import (C, c_enter_handler, "__gnat_enter_handler");
69
70   begin
71      c_enter_handler (M, Handler);
72   end Enter_Handler;
73
74   ----------------
75   -- Fetch_Code --
76   ----------------
77
78   function Fetch_Code (Loc : Code_Loc) return Code_Loc is
79   begin
80      return Loc;
81   end Fetch_Code;
82
83   ------------------------
84   -- Free_Machine_State --
85   ------------------------
86
87   procedure Free_Machine_State (M : in out Machine_State) is
88   begin
89      Memory.Free (Address (M));
90      M := Machine_State (Null_Address);
91   end Free_Machine_State;
92
93   ------------------
94   -- Get_Code_Loc --
95   ------------------
96
97   function Get_Code_Loc (M : Machine_State) return Code_Loc is
98      Asm_Call_Size : constant := 4;
99
100      function c_get_code_loc (M : Machine_State) return Code_Loc;
101      pragma Import (C, c_get_code_loc, "__gnat_get_code_loc");
102
103      --  Code_Loc returned by c_get_code_loc is the return point but here we
104      --  want Get_Code_Loc to return the call point. Under DEC Unix a call
105      --  asm instruction takes 4 bytes. So we must remove this value from
106      --  c_get_code_loc to have the call point.
107
108      Loc : constant Code_Loc := c_get_code_loc (M);
109
110   begin
111      if Loc = 0 then
112         return 0;
113      else
114         return Loc - Asm_Call_Size;
115      end if;
116   end Get_Code_Loc;
117
118   --------------------------
119   -- Machine_State_Length --
120   --------------------------
121
122   function Machine_State_Length
123     return System.Storage_Elements.Storage_Offset
124   is
125      use System.Storage_Elements;
126
127      function c_machine_state_length return Storage_Offset;
128      pragma Import (C, c_machine_state_length, "__gnat_machine_state_length");
129
130   begin
131      return c_machine_state_length;
132   end Machine_State_Length;
133
134   ---------------
135   -- Pop_Frame --
136   ---------------
137
138   procedure Pop_Frame
139     (M    : Machine_State;
140      Info : Subprogram_Info_Type)
141   is
142      pragma Warnings (Off, Info);
143
144      procedure exc_virtual_unwind
145        (Fcn  : System.Address;
146         M    : Machine_State);
147      pragma Import (C, exc_virtual_unwind, "exc_virtual_unwind");
148
149   begin
150      exc_virtual_unwind (System.Null_Address, M);
151   end Pop_Frame;
152
153   -----------------------
154   -- Set_Machine_State --
155   -----------------------
156
157   procedure Set_Machine_State (M : Machine_State) is
158      procedure c_capture_context (M : Machine_State);
159      pragma Import (C, c_capture_context, "exc_capture_context");
160
161   begin
162      c_capture_context (M);
163      Pop_Frame (M, System.Null_Address);
164   end Set_Machine_State;
165
166   ------------------------------
167   -- Set_Signal_Machine_State --
168   ------------------------------
169
170   procedure Set_Signal_Machine_State
171     (M       : Machine_State;
172      Context : System.Address)
173   is
174      pragma Warnings (Off, M);
175      pragma Warnings (Off, Context);
176
177   begin
178      null;
179   end Set_Signal_Machine_State;
180
181end System.Machine_State_Operations;
182