sentence: gdb target processors ( as of 2003 ) include : alpha , arm , avr , h8/300 , altera nios/nios ii , system/370 , system 390 , x86 and its 64-bit extension x86-64 , ia-64 '' itanium '' , motorola 68000 , mips , pa-risc , powerpc , superh , sparc , and vax .