Disable reportedly broken assembly of Sparc(64)

fixes #292

ChangeLog

@@ -21,6 +21,8 @@ Bugfix
      size/curve against the profile. Before that, there was no way to set a
      minimum key size for end-entity certificates with RSA keys. Found by
      Matthew Page of Scannex Electronics Ltd.
+   * Fix failures in MPI on Sparc(64) due to use of bad assembly code.
+     Found by Kurt Danielson. #292
 
 Changes
    * Improved performance of mbedtls_ecp_muladd() when one of the scalars is 1

include/mbedtls/bn_mul.h

@@ -412,10 +412,11 @@
 #endif /* PPC32 */
 
 /*
- * The Sparc64 assembly is reported to be broken.
+ * The Sparc(64) assembly is reported to be broken.
  * Disable it for now, until we're able to fix it.
  */
-#if 0 && defined(__sparc__) && defined(__sparc64__)
+#if 0 && defined(__sparc__)
+#if defined(__sparc64__)
 
 #define MULADDC_INIT                                    \
     asm(                                                \
@@ -446,9 +447,8 @@
         : "g1", "o0", "o1", "o2", "o3", "o4",   \
           "o5"                                  \
         );
-#endif /* SPARCv9 */
 
-#if defined(__sparc__) && !defined(__sparc64__)
+#else /* __sparc64__ */
 
 #define MULADDC_INIT                                    \
     asm(                                                \
@@ -480,7 +480,8 @@
           "o5"                                  \
         );
 
-#endif /* SPARCv8 */
+#endif /* __sparc64__ */
+#endif /* __sparc__ */
 
 #if defined(__microblaze__) || defined(microblaze)