[rfa] Add new breakpoints for arm-linux Thumb

[Daniel Jacobowitz <drow@false.org>]

Just like for ARM mode, Linux uses different instructions for Thumb
breakpoints than other ARM targets.  These properly raise a SIGTRAP
rather than some other signal, which makes GDB much happier.

Committed to csl-arm-20050325-branch.  OK for HEAD?

-- 
Daniel Jacobowitz
CodeSourcery, LLC

2005-03-25  Daniel Jacobowitz  <dan@codesourcery.com>

	* arm-linux-tdep.c (arm_linux_thumb_be_breakpoint)
	(arm_linux_thumb_le_breakpoint): New.  Update comments.
	(arm_linux_init_abi): Set Thumb breakpoints also.

Index: gdb/gdb/arm-linux-tdep.c
===================================================================
--- gdb.orig/gdb/arm-linux-tdep.c	2005-03-24 11:47:34.557904020 -0500
+++ gdb/gdb/arm-linux-tdep.c	2005-03-24 11:54:16.014184011 -0500
@@ -39,13 +39,16 @@
    is to execute a particular software interrupt, rather than use a
    particular undefined instruction to provoke a trap.  Upon exection
    of the software interrupt the kernel stops the inferior with a
-   SIGTRAP, and wakes the debugger.  Since ARM GNU/Linux doesn't support
-   Thumb at the moment we only override the ARM breakpoints.  */
+   SIGTRAP, and wakes the debugger.  */
 
 static const char arm_linux_arm_le_breakpoint[] = { 0x01, 0x00, 0x9f, 0xef };
 
 static const char arm_linux_arm_be_breakpoint[] = { 0xef, 0x9f, 0x00, 0x01 };
 
+static const char arm_linux_thumb_be_breakpoint[] = {0xde, 0x01};
+
+static const char arm_linux_thumb_le_breakpoint[] = {0x01, 0xde};
+
 /* Description of the longjmp buffer.  */
 #define ARM_LINUX_JB_ELEMENT_SIZE	INT_REGISTER_SIZE
 #define ARM_LINUX_JB_PC			21
@@ -466,10 +469,17 @@ arm_linux_init_abi (struct gdbarch_info 
 
   tdep->lowest_pc = 0x8000;
   if (info.byte_order == BFD_ENDIAN_BIG)
-    tdep->arm_breakpoint = arm_linux_arm_be_breakpoint;
+    {
+      tdep->arm_breakpoint = arm_linux_arm_be_breakpoint;
+      tdep->thumb_breakpoint = arm_linux_thumb_be_breakpoint;
+    }
   else
-    tdep->arm_breakpoint = arm_linux_arm_le_breakpoint;
+    {
+      tdep->arm_breakpoint = arm_linux_arm_le_breakpoint;
+      tdep->thumb_breakpoint = arm_linux_thumb_le_breakpoint;
+    }
   tdep->arm_breakpoint_size = sizeof (arm_linux_arm_le_breakpoint);
+  tdep->thumb_breakpoint_size = sizeof (arm_linux_thumb_le_breakpoint);
 
   tdep->fp_model = ARM_FLOAT_FPA;