add comment documenting hard-coded opcode for reading mips thread pointer
diff --git a/arch/mips/pthread_arch.h b/arch/mips/pthread_arch.h
index 904a248..93edbd4 100644
--- a/arch/mips/pthread_arch.h
+++ b/arch/mips/pthread_arch.h
@@ -5,6 +5,7 @@
__asm__ __volatile__ (".word 0x7c03e83b ; move %0, $3" : "=r" (tp) : : "$3" );
#else
register char *tp __asm__("$3");
+ /* rdhwr $3,$29 */
__asm__ __volatile__ (".word 0x7c03e83b" : "=r" (tp) );
#endif
return (pthread_t)(tp - 0x7000 - sizeof(struct pthread));