mirror of
https://github.com/superseriousbusiness/gotosocial
synced 2024-12-27 00:34:40 +01:00
387 lines
7.1 KiB
Go
387 lines
7.1 KiB
Go
// Copyright 2014 The Go Authors. All rights reserved.
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// Use of this source code is governed by a BSD-style
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// license that can be found in the LICENSE file.
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package x86asm
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import (
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"fmt"
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"strings"
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)
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type SymLookup func(uint64) (string, uint64)
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// GoSyntax returns the Go assembler syntax for the instruction.
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// The syntax was originally defined by Plan 9.
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// The pc is the program counter of the instruction, used for expanding
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// PC-relative addresses into absolute ones.
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// The symname function queries the symbol table for the program
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// being disassembled. Given a target address it returns the name and base
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// address of the symbol containing the target, if any; otherwise it returns "", 0.
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func GoSyntax(inst Inst, pc uint64, symname SymLookup) string {
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if symname == nil {
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symname = func(uint64) (string, uint64) { return "", 0 }
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}
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var args []string
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for i := len(inst.Args) - 1; i >= 0; i-- {
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a := inst.Args[i]
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if a == nil {
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continue
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}
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args = append(args, plan9Arg(&inst, pc, symname, a))
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}
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var rep string
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var last Prefix
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for _, p := range inst.Prefix {
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if p == 0 || p.IsREX() || p.IsVEX() {
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break
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}
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switch {
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// Don't show prefixes implied by the instruction text.
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case p&0xFF00 == PrefixImplicit:
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continue
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// Only REP and REPN are recognized repeaters. Plan 9 syntax
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// treats them as separate opcodes.
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case p&0xFF == PrefixREP:
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rep = "REP; "
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case p&0xFF == PrefixREPN:
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rep = "REPNE; "
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default:
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last = p
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}
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}
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prefix := ""
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switch last & 0xFF {
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case 0, 0x66, 0x67:
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// ignore
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default:
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prefix += last.String() + " "
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}
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op := inst.Op.String()
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if plan9Suffix[inst.Op] {
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s := inst.DataSize
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if inst.MemBytes != 0 {
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s = inst.MemBytes * 8
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} else if inst.Args[1] == nil { // look for register-only 64-bit instruction, like PUSHQ AX
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if r, ok := inst.Args[0].(Reg); ok && RAX <= r && r <= R15 {
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s = 64
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}
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}
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switch s {
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case 8:
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op += "B"
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case 16:
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op += "W"
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case 32:
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op += "L"
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case 64:
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op += "Q"
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}
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}
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if args != nil {
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op += " " + strings.Join(args, ", ")
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}
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return rep + prefix + op
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}
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func plan9Arg(inst *Inst, pc uint64, symname func(uint64) (string, uint64), arg Arg) string {
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switch a := arg.(type) {
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case Reg:
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return plan9Reg[a]
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case Rel:
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if pc == 0 {
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break
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}
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// If the absolute address is the start of a symbol, use the name.
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// Otherwise use the raw address, so that things like relative
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// jumps show up as JMP 0x123 instead of JMP f+10(SB).
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// It is usually easier to search for 0x123 than to do the mental
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// arithmetic to find f+10.
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addr := pc + uint64(inst.Len) + uint64(a)
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if s, base := symname(addr); s != "" && addr == base {
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return fmt.Sprintf("%s(SB)", s)
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}
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return fmt.Sprintf("%#x", addr)
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case Imm:
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if s, base := symname(uint64(a)); s != "" {
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suffix := ""
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if uint64(a) != base {
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suffix = fmt.Sprintf("%+d", uint64(a)-base)
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}
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return fmt.Sprintf("$%s%s(SB)", s, suffix)
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}
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if inst.Mode == 32 {
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return fmt.Sprintf("$%#x", uint32(a))
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}
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if Imm(int32(a)) == a {
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return fmt.Sprintf("$%#x", int64(a))
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}
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return fmt.Sprintf("$%#x", uint64(a))
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case Mem:
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if s, disp := memArgToSymbol(a, pc, inst.Len, symname); s != "" {
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suffix := ""
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if disp != 0 {
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suffix = fmt.Sprintf("%+d", disp)
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}
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return fmt.Sprintf("%s%s(SB)", s, suffix)
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}
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s := ""
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if a.Segment != 0 {
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s += fmt.Sprintf("%s:", plan9Reg[a.Segment])
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}
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if a.Disp != 0 {
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s += fmt.Sprintf("%#x", a.Disp)
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} else {
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s += "0"
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}
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if a.Base != 0 {
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s += fmt.Sprintf("(%s)", plan9Reg[a.Base])
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}
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if a.Index != 0 && a.Scale != 0 {
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s += fmt.Sprintf("(%s*%d)", plan9Reg[a.Index], a.Scale)
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}
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return s
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}
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return arg.String()
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}
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func memArgToSymbol(a Mem, pc uint64, instrLen int, symname SymLookup) (string, int64) {
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if a.Segment != 0 || a.Disp == 0 || a.Index != 0 || a.Scale != 0 {
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return "", 0
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}
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var disp uint64
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switch a.Base {
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case IP, EIP, RIP:
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disp = uint64(a.Disp + int64(pc) + int64(instrLen))
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case 0:
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disp = uint64(a.Disp)
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default:
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return "", 0
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}
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s, base := symname(disp)
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return s, int64(disp) - int64(base)
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}
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var plan9Suffix = [maxOp + 1]bool{
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ADC: true,
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ADD: true,
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AND: true,
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BSF: true,
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BSR: true,
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BT: true,
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BTC: true,
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BTR: true,
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BTS: true,
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CMP: true,
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CMPXCHG: true,
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CVTSI2SD: true,
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CVTSI2SS: true,
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CVTSD2SI: true,
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CVTSS2SI: true,
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CVTTSD2SI: true,
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CVTTSS2SI: true,
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DEC: true,
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DIV: true,
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FLDENV: true,
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FRSTOR: true,
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IDIV: true,
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IMUL: true,
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IN: true,
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INC: true,
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LEA: true,
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MOV: true,
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MOVNTI: true,
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MUL: true,
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NEG: true,
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NOP: true,
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NOT: true,
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OR: true,
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OUT: true,
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POP: true,
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POPA: true,
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POPCNT: true,
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PUSH: true,
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PUSHA: true,
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RCL: true,
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RCR: true,
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ROL: true,
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ROR: true,
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SAR: true,
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SBB: true,
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SHL: true,
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SHLD: true,
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SHR: true,
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SHRD: true,
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SUB: true,
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TEST: true,
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XADD: true,
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XCHG: true,
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XOR: true,
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}
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var plan9Reg = [...]string{
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AL: "AL",
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CL: "CL",
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BL: "BL",
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DL: "DL",
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AH: "AH",
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CH: "CH",
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BH: "BH",
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DH: "DH",
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SPB: "SP",
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BPB: "BP",
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SIB: "SI",
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DIB: "DI",
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R8B: "R8",
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R9B: "R9",
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R10B: "R10",
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R11B: "R11",
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R12B: "R12",
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R13B: "R13",
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R14B: "R14",
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R15B: "R15",
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AX: "AX",
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CX: "CX",
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BX: "BX",
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DX: "DX",
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SP: "SP",
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BP: "BP",
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SI: "SI",
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DI: "DI",
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R8W: "R8",
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R9W: "R9",
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R10W: "R10",
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R11W: "R11",
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R12W: "R12",
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R13W: "R13",
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R14W: "R14",
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R15W: "R15",
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EAX: "AX",
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ECX: "CX",
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EDX: "DX",
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EBX: "BX",
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ESP: "SP",
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EBP: "BP",
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ESI: "SI",
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EDI: "DI",
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R8L: "R8",
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R9L: "R9",
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R10L: "R10",
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R11L: "R11",
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R12L: "R12",
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R13L: "R13",
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R14L: "R14",
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R15L: "R15",
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RAX: "AX",
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RCX: "CX",
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RDX: "DX",
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RBX: "BX",
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RSP: "SP",
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RBP: "BP",
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RSI: "SI",
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RDI: "DI",
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R8: "R8",
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R9: "R9",
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R10: "R10",
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R11: "R11",
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R12: "R12",
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R13: "R13",
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R14: "R14",
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R15: "R15",
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IP: "IP",
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EIP: "IP",
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RIP: "IP",
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F0: "F0",
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F1: "F1",
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F2: "F2",
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F3: "F3",
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F4: "F4",
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F5: "F5",
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F6: "F6",
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F7: "F7",
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M0: "M0",
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M1: "M1",
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M2: "M2",
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M3: "M3",
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M4: "M4",
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M5: "M5",
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M6: "M6",
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M7: "M7",
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X0: "X0",
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X1: "X1",
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X2: "X2",
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X3: "X3",
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X4: "X4",
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X5: "X5",
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X6: "X6",
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X7: "X7",
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X8: "X8",
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X9: "X9",
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X10: "X10",
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X11: "X11",
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X12: "X12",
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X13: "X13",
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X14: "X14",
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X15: "X15",
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CS: "CS",
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SS: "SS",
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DS: "DS",
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ES: "ES",
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FS: "FS",
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GS: "GS",
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GDTR: "GDTR",
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IDTR: "IDTR",
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LDTR: "LDTR",
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MSW: "MSW",
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TASK: "TASK",
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CR0: "CR0",
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CR1: "CR1",
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CR2: "CR2",
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CR3: "CR3",
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CR4: "CR4",
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CR5: "CR5",
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CR6: "CR6",
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CR7: "CR7",
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CR8: "CR8",
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CR9: "CR9",
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CR10: "CR10",
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CR11: "CR11",
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CR12: "CR12",
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CR13: "CR13",
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CR14: "CR14",
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CR15: "CR15",
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DR0: "DR0",
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DR1: "DR1",
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DR2: "DR2",
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DR3: "DR3",
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DR4: "DR4",
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DR5: "DR5",
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DR6: "DR6",
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DR7: "DR7",
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DR8: "DR8",
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DR9: "DR9",
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DR10: "DR10",
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DR11: "DR11",
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DR12: "DR12",
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DR13: "DR13",
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DR14: "DR14",
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DR15: "DR15",
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TR0: "TR0",
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TR1: "TR1",
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TR2: "TR2",
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TR3: "TR3",
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TR4: "TR4",
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TR5: "TR5",
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TR6: "TR6",
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TR7: "TR7",
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}
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