2007-09-12 H.J. Lu <hongjiu.lu@intel.com>

[deliverable/binutils-gdb.git] / gdb / mep-tdep.c

diff --git a/gdb/mep-tdep.c b/gdb/mep-tdep.c
index 0f1ec474fcc25d0db3257f86d575bbeebb8c8aff..3a639a80b9a07f14dc69a830f4f6edb54d58f623 100644 (file)
--- a/gdb/mep-tdep.c
+++ b/gdb/mep-tdep.c
@@ -9,7 +9,7 @@
 
    This program is free software; you can redistribute it and/or modify
    it under the terms of the GNU General Public License as published by
-   the Free Software Foundation; either version 2 of the License, or
+   the Free Software Foundation; either version 3 of the License, or
    (at your option) any later version.
 
    This program is distributed in the hope that it will be useful,
@@ -18,9 +18,7 @@
    GNU General Public License for more details.
 
    You should have received a copy of the GNU General Public License
-   along with this program; if not, write to the Free Software
-   Foundation, Inc., 59 Temple Place - Suite 330,
-   Boston, MA 02111-1307, USA.  */
+   along with this program.  If not, see <http://www.gnu.org/licenses/>.  */
 
 #include "defs.h"
 #include "frame.h"
@@ -852,7 +850,7 @@ current_me_module ()
   if (target_has_registers)
     {
       ULONGEST regval;
-      regcache_cooked_read_unsigned (current_regcache,
+      regcache_cooked_read_unsigned (get_current_regcache (),
                                     MEP_MODULE_REGNUM, &regval);
       return regval;
     }
@@ -875,7 +873,7 @@ current_options ()
   if (target_has_registers)
     {
       ULONGEST regval;
-      regcache_cooked_read_unsigned (current_regcache,
+      regcache_cooked_read_unsigned (get_current_regcache (),
                                     MEP_OPT_REGNUM, &regval);
       return regval;
     }
@@ -1121,31 +1119,17 @@ mep_register_type (struct gdbarch *gdbarch, int reg_nr)
 
 
 static CORE_ADDR
-mep_read_pc (ptid_t ptid)
+mep_read_pc (struct regcache *regcache)
 {
-  ptid_t saved_ptid;
-  CORE_ADDR pc;
-
-  saved_ptid = inferior_ptid;
-  inferior_ptid = ptid;
-
-  pc = read_register (MEP_PC_REGNUM);
-
-  inferior_ptid = saved_ptid;
+  ULONGEST pc;
+  regcache_cooked_read_unsigned (regcache, MEP_PC_REGNUM, &pc);
   return pc;
 }
 
 static void
-mep_write_pc (CORE_ADDR pc, ptid_t ptid)
+mep_write_pc (struct regcache *regcache, CORE_ADDR pc)
 {
-  ptid_t saved_ptid;
-
-  saved_ptid = inferior_ptid;
-  inferior_ptid = ptid;
-
-  write_register (MEP_PC_REGNUM, pc);
-
-  inferior_ptid = saved_ptid;
+  regcache_cooked_write_unsigned (regcache, MEP_PC_REGNUM, pc);
 }
 
 
@@ -1592,6 +1576,10 @@ mep_get_insn (CORE_ADDR pc, long *insn)
 #define MOV_TARGET(i)        (FIELD (i, 24, 4))
 #define MOV_SOURCE(i)        (FIELD (i, 20, 4))
 
+/* BRA disp12.align2         1011_dddd_dddd_ddd0 xxxx_xxxx_xxxx_xxxx */
+#define IS_BRA(i)            (((i) & 0xf0010000) == 0xb0000000)
+#define BRA_DISP(i)           (SFIELD (i, 17, 11) << 1)
+
 
 /* This structure holds the results of a prologue analysis.  */
 struct mep_prologue
@@ -1820,6 +1808,30 @@ mep_analyze_prologue (CORE_ADDR start_pc, CORE_ADDR limit_pc,
 
           reg[rn] = pv_area_fetch (stack, addr, 4);
         }
+      else if (IS_BRA (insn) && BRA_DISP (insn) > 0)
+       {
+         /* When a loop appears as the first statement of a function
+            body, gcc 4.x will use a BRA instruction to branch to the
+            loop condition checking code.  This BRA instruction is
+            marked as part of the prologue.  We therefore set next_pc
+            to this branch target and also stop the prologue scan. 
+            The instructions at and beyond the branch target should
+            no longer be associated with the prologue.
+            
+            Note that we only consider forward branches here.  We
+            presume that a forward branch is being used to skip over
+            a loop body.
+            
+            A backwards branch is covered by the default case below.
+            If we were to encounter a backwards branch, that would
+            most likely mean that we've scanned through a loop body.
+            We definitely want to stop the prologue scan when this
+            happens and that is precisely what is done by the default
+            case below.  */
+         next_pc = pc + BRA_DISP (insn);
+         after_last_frame_setup_insn = next_pc;
+         break;
+       }
       else
         /* We've hit some instruction we don't know how to simulate.
            Strictly speaking, we should set every value we're