+/* This routine is provided two arch_infos and works out which AVR
+ machine which would be compatible with both and returns a pointer
+ to its info structure. */
+
+static const bfd_arch_info_type *
+compatible (const bfd_arch_info_type * a,
+ const bfd_arch_info_type * b)
+{
+ /* If a & b are for different architectures we can do nothing. */
+ if (a->arch != b->arch)
+ return NULL;
+
+ if (a->mach == b->mach)
+ return a;
+
+ /* avr-6 is compatible only with itself as its call convention is not
+ compatible with other avr (the mcu saves the return address on 3 bytes
+ instead of 2). */
+ if (a->mach == bfd_mach_avr6 || b->mach == bfd_mach_avr6)
+ return NULL;
+
+ if (a->mach < bfd_mach_avr6 && b->mach < bfd_mach_avr6)
+ {
+ /* Special case for ATmega[16]03 (avr:3) and ATmega83 (avr:4). */
+ if ((a->mach == bfd_mach_avr3 && b->mach == bfd_mach_avr4)
+ || (a->mach == bfd_mach_avr4 && b->mach == bfd_mach_avr3))
+ return NULL;
+
+ if (a->mach <= b->mach)
+ return b;
+
+ if (a->mach >= b->mach)
+ return a;
+ }
+
+ if (a->mach == bfd_mach_avr2 && b->mach == bfd_mach_avr25)
+ return a;
+ if (a->mach == bfd_mach_avr25 && b->mach == bfd_mach_avr2)
+ return b;
+
+ if (a->mach == bfd_mach_avr3 && b->mach == bfd_mach_avr31)
+ return a;
+ if (a->mach == bfd_mach_avr31 && b->mach == bfd_mach_avr3)
+ return b;
+ if (a->mach == bfd_mach_avr3 && b->mach == bfd_mach_avr35)
+ return a;
+ if (a->mach == bfd_mach_avr35 && b->mach == bfd_mach_avr3)
+ return b;
+
+ if (a->mach == bfd_mach_avr5 && b->mach == bfd_mach_avr51)
+ return a;
+ if (a->mach == bfd_mach_avr51 && b->mach == bfd_mach_avr5)
+ return b;
+
+ return NULL;
+}