Index: gas/config/tc-arm.c
===================================================================
RCS file: /cvs/src/src/gas/config/tc-arm.c,v
retrieving revision 1.250.2.15
diff -c -p -r1.250.2.15 tc-arm.c
*** gas/config/tc-arm.c	5 May 2006 18:31:28 -0000	1.250.2.15
--- gas/config/tc-arm.c	11 May 2006 21:13:09 -0000
*************** static const arm_feature_set fpu_neon_ex
*** 215,220 ****
--- 215,224 ----
  static const arm_feature_set fpu_vfp_v3_or_neon_ext =
    ARM_FEATURE (0, FPU_NEON_EXT_V1 | FPU_VFP_EXT_V3);
  
+ static const arm_feature_set arm_thumb_only = ARM_FEATURE (THUMB_ONLY, 0);
+ static const arm_feature_set arm_thumb_only_except =
+   ARM_FEATURE (THUMB_ONLY_EXCEPT, 0);
+ 
  static int mfloat_abi_opt = -1;
  /* Record user cpu selection for object attributes.  */
  static arm_feature_set selected_cpu = ARM_ARCH_NONE;
*************** md_assemble (char *str)
*** 13484,13490 ****
  	ARM_MERGE_FEATURE_SETS (thumb_arch_used, thumb_arch_used,
  				arm_ext_v6t2);
      }
!   else
      {
        /* Check that this instruction is supported for this CPU.  */
        if (!opcode->avariant ||
--- 13488,13495 ----
  	ARM_MERGE_FEATURE_SETS (thumb_arch_used, thumb_arch_used,
  				arm_ext_v6t2);
      }
!   else if (!ARM_CPU_HAS_FEATURE (cpu_variant, arm_thumb_only)
!            || ARM_CPU_HAS_FEATURE (cpu_variant, arm_thumb_only_except))
      {
        /* Check that this instruction is supported for this CPU.  */
        if (!opcode->avariant ||
*************** md_assemble (char *str)
*** 13517,13522 ****
--- 13522,13532 ----
  	ARM_MERGE_FEATURE_SETS (arm_arch_used, arm_arch_used,
  				*opcode->avariant);
      }
+   else
+     {
+       as_bad (_("attempt to use ARM instruction on Thumb-only core `%s'"), str);
+       return;
+     }
    output_inst (str);
  }
  
*************** set_constant_flonums (void)
*** 18296,18301 ****
--- 18306,18322 ----
        abort ();
  }
  
+ /* Auto-select Thumb mode if it's the only available instruction set for the
+    given architecture.  */
+ 
+ static void
+ autoselect_thumb_from_cpu_variant (void)
+ {
+   if (ARM_CPU_HAS_FEATURE (cpu_variant, arm_thumb_only)
+       && !ARM_CPU_HAS_FEATURE (cpu_variant, arm_thumb_only_except))
+     opcode_select (16);
+ }
+ 
  void
  md_begin (void)
  {
*************** md_begin (void)
*** 18396,18401 ****
--- 18417,18424 ----
  
    ARM_MERGE_FEATURE_SETS (cpu_variant, *mcpu_cpu_opt, *mfpu_opt);
  
+   autoselect_thumb_from_cpu_variant ();
+ 
    arm_arch_used = thumb_arch_used = arm_arch_none;
  
  #if defined OBJ_COFF || defined OBJ_ELF
*************** s_arm_cpu (int ignored ATTRIBUTE_UNUSED)
*** 19457,19462 ****
--- 19480,19486 ----
  	    selected_cpu_name[i] = 0;
  	  }
  	ARM_MERGE_FEATURE_SETS (cpu_variant, *mcpu_cpu_opt, *mfpu_opt);
+         autoselect_thumb_from_cpu_variant ();
  	*input_line_pointer = saved_char;
  	demand_empty_rest_of_line ();
  	return;
*************** s_arm_arch (int ignored ATTRIBUTE_UNUSED
*** 19490,19495 ****
--- 19514,19520 ----
  	selected_cpu = opt->value;
  	strcpy(selected_cpu_name, opt->name);
  	ARM_MERGE_FEATURE_SETS (cpu_variant, *mcpu_cpu_opt, *mfpu_opt);
+         autoselect_thumb_from_cpu_variant ();
  	*input_line_pointer = saved_char;
  	demand_empty_rest_of_line ();
  	return;
Index: gas/testsuite/gas/arm/noarm.d
===================================================================
RCS file: gas/testsuite/gas/arm/noarm.d
diff -N gas/testsuite/gas/arm/noarm.d
*** /dev/null	1 Jan 1970 00:00:00 -0000
--- gas/testsuite/gas/arm/noarm.d	11 May 2006 21:13:09 -0000
***************
*** 0 ****
--- 1,3 ----
+ # name: Disallow ARM instructions on V7M
+ # as: 
+ # error-output: noarm.l
Index: gas/testsuite/gas/arm/noarm.l
===================================================================
RCS file: gas/testsuite/gas/arm/noarm.l
diff -N gas/testsuite/gas/arm/noarm.l
*** /dev/null	1 Jan 1970 00:00:00 -0000
--- gas/testsuite/gas/arm/noarm.l	11 May 2006 21:13:09 -0000
***************
*** 0 ****
--- 1,3 ----
+ [^:]*: Assembler messages:
+ [^:]*:11: Error: selected processor does not support ARM opcodes
+ [^:]*:12: Error: attempt to use ARM instruction on Thumb-only core `nop'
Index: gas/testsuite/gas/arm/noarm.s
===================================================================
RCS file: gas/testsuite/gas/arm/noarm.s
diff -N gas/testsuite/gas/arm/noarm.s
*** /dev/null	1 Jan 1970 00:00:00 -0000
--- gas/testsuite/gas/arm/noarm.s	11 May 2006 21:13:09 -0000
***************
*** 0 ****
--- 1,12 ----
+         .arch armv7a
+         .syntax unified
+ 	.text
+ func:
+ 	nop
+ 	movw r0, #0
+ 
+ 	.arch armv7
+ 	nop
+ 	movw r0, #0
+ 	.arm
+ 	nop
Index: include/opcode/arm.h
===================================================================
RCS file: /cvs/src/src/include/opcode/arm.h,v
retrieving revision 1.9.2.1
diff -c -p -r1.9.2.1 arm.h
*** include/opcode/arm.h	3 Apr 2006 00:03:34 -0000	1.9.2.1
--- include/opcode/arm.h	11 May 2006 21:13:10 -0000
***************
*** 45,50 ****
--- 45,55 ----
  #define ARM_EXT_V7R	 0x00200000	/* Arm V7R.                */
  #define ARM_EXT_V7M	 0x00400000	/* Arm V7M.                */
  
+ /* A bitmask of architecture versions which support only Thumb instructions,
+    and exceptions containing bits which nullify that situation.  */
+ #define THUMB_ONLY	  (ARM_EXT_V7 | ARM_EXT_V7M)
+ #define THUMB_ONLY_EXCEPT (ARM_EXT_V7A | ARM_EXT_V7R)
+ 
  /* Co-processor space extensions.  */
  #define ARM_CEXT_XSCALE   0x00000001	/* Allow MIA etc.          */
  #define ARM_CEXT_MAVERICK 0x00000002	/* Use Cirrus/DSP coprocessor.  */