title: Error: lo register required when build libunwind in android ndk
body: <p>I want to build libunwind from Android source at eclipse using ndk r10d.
  But I fail at compiling "Gresume.c" , and it fail at the asm code .
  I can't understand asm code and I searched any place can't found people who has the same problem ,so I hope somebody can help me .</p>
  
  <p><strong>the error line of code is:</strong></p>
  
  <pre><code>  asm __volatile__ (
  "ldmia %0, {r4-r12, lr}\n"
  "mov sp, r12\n"
  "bx lr\n"
  : : "r" (regs) ,
      "m" (*(struct regs_overlay *)regs)
    );
  </code></pre>
  
  <p><strong>the error output:</strong></p>
  
  <blockquote>
    <p>[armeabi] Compile thumb  : MyBacktrace &lt;= Gresume.c
    /var/folders/g7/9gd3cwy96z12qt3vlf7sc5q80000gn/T//cc6jsBSj.s: Assembler messages:
    /var/folders/g7/9gd3cwy96z12qt3vlf7sc5q80000gn/T//cc6jsBSj.s:88: Error: lo register required -- `ldmia r2,{r4-r12,lr}'
    make: *** [obj/local/armeabi/objs/MyBacktrace/libunwind/src/arm/Gresume.o] Error 1</p>
  </blockquote>
  
  <p><strong>the full code can found at the link bellow.</strong></p>
  
  <p><a href="https://android.googlesource.com/platform/external/libunwind/+/master/src/arm/Gresume.c" rel="nofollow"></a></p>