RSP:  "RSP",
	RBP:  "RBP",
	RSI:  "RSI",
	RDI:  "RDI",
	R8:   "R8",
	R9:   "R9",
	R10:  "R10",
	R11:  "R11",
	R12:  "R12",
	R13:  "R13",
	R14:  "R14",
	R15:  "R15",
	IP:   "IP",
	EIP:  "EIP",
	RIP:  "RIP",
	F0:   "F0",
	F1:   "F1",
	F2:   "F2",
	F3:   "F3",
	F4:   "F4",
	F5:   "F5",
	F6:   "F6",
	F7:   "F7",
	M0:   "M0",
	M1:   "M1",
	M2:   "M2",
	M3:   "M3",

	if e != 0 {
		err = e
	}
	return
}

func (r *PtraceRegs) PC() uint64 { return uint64(uint32(r.Eip)) }

func (r *PtraceRegs) SetPC(pc uint64) { r.Eip = int32(pc) }

func (iov *Iovec) SetLen(length int) {
	iov.Len = uint32(length)
}

func (msghdr *Msghdr) SetControllen(length int) {
	msghdr.Controllen = uint32(length)
}

		if inst.Mode == 32 {
			return fmt.Sprintf("%#x", uint32(a))
		}
		if Imm(int32(a)) == a {
			return fmt.Sprintf("%#x", int64(a))
		}
		return fmt.Sprintf("%#x", uint64(a))
	case Mem:
		if a.Base == EIP {
			a.Base = RIP
		}
		prefix := ""
		switch inst.MemBytes {
		case 1:
			prefix = "byte "
		case 2:
			prefix = "word "
		case 4:
			prefix = "dword "
		case 8:
			prefix = "qword "

	RBP:  "%rbp",
	RSI:  "%rsi",
	RDI:  "%rdi",
	R8:   "%r8",
	R9:   "%r9",
	R10:  "%r10",
	R11:  "%r11",
	R12:  "%r12",
	R13:  "%r13",
	R14:  "%r14",
	R15:  "%r15",
	IP:   "%ip",
	EIP:  "%eip",
	RIP:  "%rip",
	F0:   "%st",
	F1:   "%st(1)",
	F2:   "%st(2)",
	F3:   "%st(3)",
	F4:   "%st(4)",
	F5:   "%st(5)",
	F6:   "%st(6)",
	F7:   "%st(7)",
	M0:   "%mm0",
	M1:   "%mm1",

	Ecx      int32
	Edx      int32
	Esi      int32
	Edi      int32
	Ebp      int32
	Eax      int32
	Xds      int32
	Xes      int32
	Xfs      int32
	Xgs      int32
	Orig_eax int32
	Eip      int32
	Xcs      int32
	Eflags   int32
	Esp      int32
	Xss      int32
}

type FdSet struct {
	Bits [32]int32
}

type Sysinfo_t struct {
	Uptime    int32
	Loads     [3]uint32

	Ecx      int32
	Edx      int32
	Esi      int32
	Edi      int32
	Ebp      int32
	Eax      int32
	Xds      int32
	Xes      int32
	Xfs      int32
	Xgs      int32
	Orig_eax int32
	Eip      int32
	Xcs      int32
	Eflags   int32
	Esp      int32
	Xss      int32
}

type FdSet struct {
	Bits [32]int32
}

type Sysinfo_t struct {
	Uptime    int32
	Loads     [3]uint32

					pos++
				}

				// In 64-bit, mod=0 rm=5 is PC-relative instead of just disp.
				// See Vol 2A. Table 2-7.
				if mode == 64 && mod == 0 && rm&7 == 5 {
					if addrMode == 32 {
						mem.Base = EIP
					} else {
						mem.Base = RIP
					}
				}
			}

			if segIndex >= 0 {
				mem.Segment = prefixToSegment(inst.Prefix[segIndex])
			}
		}

		// Execute single opcode.