abnativeelf: test EF_MIPS_* flags against themselves

- Instead of testing non-zero, make sure the flags are equal after
  testing to avoid ambiguity (64R2 and 64R6 will have common bits set on
  their values).
- Test for EF_MIPS_ARCH_R6 first, since its value is greater than
  EF_MIPS_ARCH_64R2 and EF_MIPS_ARCH_3.

Author: Cyanoxygen

native/abnativeelf.cpp

@@ -352,12 +352,15 @@ const AOSCArch detect_architecture(Elf *elf_file, GElf_Ehdr &elf_ehdr,
       return AOSCArch::NONE;
     }
     // e_flags-based detection
-    if (elf_ehdr.e_flags & elf_flags_loongson2f) {
-      return AOSCArch::LOONGSON2F;
-    } else if (elf_ehdr.e_flags & elf_flags_loongson3) {
-      return AOSCArch::LOONGSON3;
-    } else if (elf_ehdr.e_flags & elf_flags_mips64r6el) {
+    // WARN: Never test the result with non-zero! For MIPS R2 and MIPS R6,
+    //       this causes ambiguity, since it will be true in both tests if
+    //       they are testing with non-zeroes after the AND operation.
+    if ((elf_ehdr.e_flags & elf_flags_mips64r6el) == elf_flags_mips64r6el) {
       return AOSCArch::MIPS64R6EL;
+    } else if ((elf_ehdr.e_flags & elf_flags_loongson3) == elf_flags_loongson3) {
+      return AOSCArch::LOONGSON3;
+    } else if ((elf_ehdr.e_flags & elf_flags_loongson2f) == elf_flags_loongson2f) {
+      return AOSCArch::LOONGSON2F;
     } else {
       return AOSCArch::NONE;
     }