+ /*op2<uint16_t, uint16_t, uint32_t> o(0xfff0);
+ uint32_t p = 0xfffffef;
+ o = o + p;
+ */
+ opcvt cvt(u64_u64_cvt, u64_u64_cvt, sext32);
+ uint64_t o = 0xff00;
+ uint64_t s1 = 0x1ff01;
+ uint64_t s2 = 0x2ff01;
+ cvt.add(o, s1, s2);
+ printf("hello %lx\n", o);