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<h4 class="subsection">9.21.3 M32R Warnings</h4>

<p><a name="index-warnings_002c-M32R-1395"></a><a name="index-M32R-warnings-1396"></a>
There are several warning and error messages that can be produced by
<code>as</code> which are specific to the M32R:

     <dl>
<dt><code>output of 1st instruction is the same as an input to 2nd instruction - is this intentional ?</code><dd>This message is only produced if warnings for explicit parallel
conflicts have been enabled.  It indicates that the assembler has
encountered a parallel instruction in which the destination register of
the left hand instruction is used as an input register in the right hand
instruction.  For example in this code fragment
&lsquo;<samp><span class="samp">mv r1, r2 || neg r3, r1</span></samp>&rsquo; register r1 is the destination of the
move instruction and the input to the neg instruction.

     <br><dt><code>output of 2nd instruction is the same as an input to 1st instruction - is this intentional ?</code><dd>This message is only produced if warnings for explicit parallel
conflicts have been enabled.  It indicates that the assembler has
encountered a parallel instruction in which the destination register of
the right hand instruction is used as an input register in the left hand
instruction.  For example in this code fragment
&lsquo;<samp><span class="samp">mv r1, r2 || neg r2, r3</span></samp>&rsquo; register r2 is the destination of the
neg instruction and the input to the move instruction.

     <br><dt><code>instruction &lsquo;</code><samp><span class="samp">...</span></samp><code>&rsquo; is for the M32RX only</code><dd>This message is produced when the assembler encounters an instruction
which is only supported by the M32Rx processor, and the &lsquo;<samp><span class="samp">-m32rx</span></samp>&rsquo;
command-line flag has not been specified to allow assembly of such
instructions.

     <br><dt><code>unknown instruction &lsquo;</code><samp><span class="samp">...</span></samp><code>&rsquo;</code><dd>This message is produced when the assembler encounters an instruction
which it does not recognize.

     <br><dt><code>only the NOP instruction can be issued in parallel on the m32r</code><dd>This message is produced when the assembler encounters a parallel
instruction which does not involve a NOP instruction and the
&lsquo;<samp><span class="samp">-m32rx</span></samp>&rsquo; command-line flag has not been specified.  Only the M32Rx
processor is able to execute two instructions in parallel.

     <br><dt><code>instruction &lsquo;</code><samp><span class="samp">...</span></samp><code>&rsquo; cannot be executed in parallel.</code><dd>This message is produced when the assembler encounters a parallel
instruction which is made up of one or two instructions which cannot be
executed in parallel.

     <br><dt><code>Instructions share the same execution pipeline</code><dd>This message is produced when the assembler encounters a parallel
instruction whose components both use the same execution pipeline.

     <br><dt><code>Instructions write to the same destination register.</code><dd>This message is produced when the assembler encounters a parallel
instruction where both components attempt to modify the same register. 
For example these code fragments will produce this message:
&lsquo;<samp><span class="samp">mv r1, r2 || neg r1, r3</span></samp>&rsquo;
&lsquo;<samp><span class="samp">jl r0 || mv r14, r1</span></samp>&rsquo;
&lsquo;<samp><span class="samp">st r2, @-r1 || mv r1, r3</span></samp>&rsquo;
&lsquo;<samp><span class="samp">mv r1, r2 || ld r0, @r1+</span></samp>&rsquo;
&lsquo;<samp><span class="samp">cmp r1, r2 || addx r3, r4</span></samp>&rsquo; (Both write to the condition bit)

   </dl>

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