const char *GetOpCodeString(unsigned int opcode) {
  switch (opcode) {
  case 0x0:
    return "AND";
  case 0x1:
    return "EOR";
  case 0x2:
    return "SUB";
  case 0x3:
    return "RSB";
  case 0x4:
    return "ADD";
  case 0x5:
    return "ADC";
  case 0x6:
    return "SBC";
  case 0x7:
    return "RSC";
  case 0x8:
    return "TST";
  case 0x9:
    return "TEQ";
  case 0xA:
    return "CMP";
  case 0xB:
    return "CMN";
  case 0xC:
    return "ORR";
  case 0xD:
    return "MOV";
  case 0xE:
    return "BIC";
  case 0xF:
    return "MVN";
  default:
    return "";
  }
}


x86 assembly (clang, -O0):
<GetOpCodeString>:
push   %rbp
mov    %rsp,%rbp
mov    %edi,-0xc(%rbp)
mov    -0xc(%rbp),%eax
mov    %rax,-0x18(%rbp)
sub    $0xf,%rax
ja     122c <GetOpCodeString+0x12c>
mov    -0x18(%rbp),%rax
lea    0xedd(%rip),%rcx
movslq (%rcx,%rax,4),%rax
add    %rcx,%rax
jmp    *%rax
lea    0xf0d(%rip),%rax
mov    %rax,-0x8(%rbp)
jmp    1237 <GetOpCodeString+0x137>
lea    0xf01(%rip),%rax
mov    %rax,-0x8(%rbp)
jmp    1237 <GetOpCodeString+0x137>
lea    0xef5(%rip),%rax
mov    %rax,-0x8(%rbp)
jmp    1237 <GetOpCodeString+0x137>
lea    0xee9(%rip),%rax
mov    %rax,-0x8(%rbp)
jmp    1237 <GetOpCodeString+0x137>
lea    0xedd(%rip),%rax
mov    %rax,-0x8(%rbp)
jmp    1237 <GetOpCodeString+0x137>
lea    0xed1(%rip),%rax
mov    %rax,-0x8(%rbp)
jmp    1237 <GetOpCodeString+0x137>
lea    0xec5(%rip),%rax
mov    %rax,-0x8(%rbp)
jmp    1237 <GetOpCodeString+0x137>
lea    0xeb9(%rip),%rax
mov    %rax,-0x8(%rbp)
jmp    1237 <GetOpCodeString+0x137>
lea    0xead(%rip),%rax
mov    %rax,-0x8(%rbp)
jmp    1237 <GetOpCodeString+0x137>
lea    0xea1(%rip),%rax
mov    %rax,-0x8(%rbp)
jmp    1237 <GetOpCodeString+0x137>
lea    0xe95(%rip),%rax
mov    %rax,-0x8(%rbp)
jmp    1237 <GetOpCodeString+0x137>
lea    0xe89(%rip),%rax
mov    %rax,-0x8(%rbp)
jmp    1237 <GetOpCodeString+0x137>
lea    0xe7d(%rip),%rax
mov    %rax,-0x8(%rbp)
jmp    1237 <GetOpCodeString+0x137>
lea    0xe71(%rip),%rax
mov    %rax,-0x8(%rbp)
jmp    1237 <GetOpCodeString+0x137>
lea    0xe65(%rip),%rax
mov    %rax,-0x8(%rbp)
jmp    1237 <GetOpCodeString+0x137>
lea    0xe59(%rip),%rax
mov    %rax,-0x8(%rbp)
jmp    1237 <GetOpCodeString+0x137>
lea    0xe1c(%rip),%rax
mov    %rax,-0x8(%rbp)
mov    -0x8(%rbp),%rax
pop    %rbp
ret

x86 assembly (clang, -O2):
<GetOpCodeString>:
cmp    $0xf,%edi
ja     1117 <GetOpCodeString+0x17>
movslq %edi,%rax
lea    0xf31(%rip),%rcx
movslq (%rcx,%rax,4),%rax
add    %rcx,%rax
ret
lea    0xef1(%rip),%rax
ret

LLVM IR (-O0):
@.str = [4 x i8] c"AND\00"
@.str.1 = [4 x i8] c"EOR\00"
@.str.2 = [4 x i8] c"SUB\00"
@.str.3 = [4 x i8] c"RSB\00"
@.str.4 = [4 x i8] c"ADD\00"
@.str.5 = [4 x i8] c"ADC\00"
@.str.6 = [4 x i8] c"SBC\00"
@.str.7 = [4 x i8] c"RSC\00"
@.str.8 = [4 x i8] c"TST\00"
@.str.9 = [4 x i8] c"TEQ\00"
@.str.10 = [4 x i8] c"CMP\00"
@.str.11 = [4 x i8] c"CMN\00"
@.str.12 = [4 x i8] c"ORR\00"
@.str.13 = [4 x i8] c"MOV\00"
@.str.14 = [4 x i8] c"BIC\00"
@.str.15 = [4 x i8] c"MVN\00"
@.str.16 = [1 x i8] zeroinitializer
define i8* @GetOpCodeString(i32 %0) {
%2 = alloca i8*
%3 = alloca i32
store i32 %0, i32* %3
%4 = load i32, i32* %3
switch i32 %4, label %21 [
i32 0, label %5
i32 1, label %6
i32 2, label %7
i32 3, label %8
i32 4, label %9
i32 5, label %10
i32 6, label %11
i32 7, label %12
i32 8, label %13
i32 9, label %14
i32 10, label %15
i32 11, label %16
i32 12, label %17
i32 13, label %18
i32 14, label %19
i32 15, label %20
]
5: ; preds = %1
store i8* getelementptr inbounds ([4 x i8], [4 x i8]* @.str, i64 0, i64 0), i8** %2
br label %22
6: ; preds = %1
store i8* getelementptr inbounds ([4 x i8], [4 x i8]* @.str.1, i64 0, i64 0), i8** %2
br label %22
7: ; preds = %1
store i8* getelementptr inbounds ([4 x i8], [4 x i8]* @.str.2, i64 0, i64 0), i8** %2
br label %22
8: ; preds = %1
store i8* getelementptr inbounds ([4 x i8], [4 x i8]* @.str.3, i64 0, i64 0), i8** %2
br label %22
9: ; preds = %1
store i8* getelementptr inbounds ([4 x i8], [4 x i8]* @.str.4, i64 0, i64 0), i8** %2
br label %22
10: ; preds = %1
store i8* getelementptr inbounds ([4 x i8], [4 x i8]* @.str.5, i64 0, i64 0), i8** %2
br label %22
11: ; preds = %1
store i8* getelementptr inbounds ([4 x i8], [4 x i8]* @.str.6, i64 0, i64 0), i8** %2
br label %22
12: ; preds = %1
store i8* getelementptr inbounds ([4 x i8], [4 x i8]* @.str.7, i64 0, i64 0), i8** %2
br label %22
13: ; preds = %1
store i8* getelementptr inbounds ([4 x i8], [4 x i8]* @.str.8, i64 0, i64 0), i8** %2
br label %22
14: ; preds = %1
store i8* getelementptr inbounds ([4 x i8], [4 x i8]* @.str.9, i64 0, i64 0), i8** %2
br label %22
15: ; preds = %1
store i8* getelementptr inbounds ([4 x i8], [4 x i8]* @.str.10, i64 0, i64 0), i8** %2
br label %22
16: ; preds = %1
store i8* getelementptr inbounds ([4 x i8], [4 x i8]* @.str.11, i64 0, i64 0), i8** %2
br label %22
17: ; preds = %1
store i8* getelementptr inbounds ([4 x i8], [4 x i8]* @.str.12, i64 0, i64 0), i8** %2
br label %22
18: ; preds = %1
store i8* getelementptr inbounds ([4 x i8], [4 x i8]* @.str.13, i64 0, i64 0), i8** %2
br label %22
19: ; preds = %1
store i8* getelementptr inbounds ([4 x i8], [4 x i8]* @.str.14, i64 0, i64 0), i8** %2
br label %22
20: ; preds = %1
store i8* getelementptr inbounds ([4 x i8], [4 x i8]* @.str.15, i64 0, i64 0), i8** %2
br label %22
21: ; preds = %1
store i8* getelementptr inbounds ([1 x i8], [1 x i8]* @.str.16, i64 0, i64 0), i8** %2
br label %22
22: ; preds = %21, %20, %19, %18, %17, %16, %15, %14, %13, %12, %11, %10, %9, %8, %7, %6, %5
%23 = load i8*, i8** %2
ret i8* %23
}

LLVM IR (-O2):
@.str = [4 x i8] c"AND\00"
@.str.1 = [4 x i8] c"EOR\00"
@.str.2 = [4 x i8] c"SUB\00"
@.str.3 = [4 x i8] c"RSB\00"
@.str.4 = [4 x i8] c"ADD\00"
@.str.5 = [4 x i8] c"ADC\00"
@.str.6 = [4 x i8] c"SBC\00"
@.str.7 = [4 x i8] c"RSC\00"
@.str.8 = [4 x i8] c"TST\00"
@.str.9 = [4 x i8] c"TEQ\00"
@.str.10 = [4 x i8] c"CMP\00"
@.str.11 = [4 x i8] c"CMN\00"
@.str.12 = [4 x i8] c"ORR\00"
@.str.13 = [4 x i8] c"MOV\00"
@.str.14 = [4 x i8] c"BIC\00"
@.str.15 = [4 x i8] c"MVN\00"
@.str.16 = [1 x i8] zeroinitializer
@reltable.GetOpCodeString = [16 x i32] [i32 trunc (i64 sub (i64 ptrtoint ([4 x i8]* @.str to i64), i64 ptrtoint ([16 x i32]* @reltable.GetOpCodeString to i64)) to i32), i32 trunc (i64 sub (i64 ptrtoint ([4 x i8]* @.str.1 to i64), i64 ptrtoint ([16 x i32]* @reltable.GetOpCodeString to i64)) to i32), i32 trunc (i64 sub (i64 ptrtoint ([4 x i8]* @.str.2 to i64), i64 ptrtoint ([16 x i32]* @reltable.GetOpCodeString to i64)) to i32), i32 trunc (i64 sub (i64 ptrtoint ([4 x i8]* @.str.3 to i64), i64 ptrtoint ([16 x i32]* @reltable.GetOpCodeString to i64)) to i32), i32 trunc (i64 sub (i64 ptrtoint ([4 x i8]* @.str.4 to i64), i64 ptrtoint ([16 x i32]* @reltable.GetOpCodeString to i64)) to i32), i32 trunc (i64 sub (i64 ptrtoint ([4 x i8]* @.str.5 to i64), i64 ptrtoint ([16 x i32]* @reltable.GetOpCodeString to i64)) to i32), i32 trunc (i64 sub (i64 ptrtoint ([4 x i8]* @.str.6 to i64), i64 ptrtoint ([16 x i32]* @reltable.GetOpCodeString to i64)) to i32), i32 trunc (i64 sub (i64 ptrtoint ([4 x i8]* @.str.7 to i64), i64 ptrtoint ([16 x i32]* @reltable.GetOpCodeString to i64)) to i32), i32 trunc (i64 sub (i64 ptrtoint ([4 x i8]* @.str.8 to i64), i64 ptrtoint ([16 x i32]* @reltable.GetOpCodeString to i64)) to i32), i32 trunc (i64 sub (i64 ptrtoint ([4 x i8]* @.str.9 to i64), i64 ptrtoint ([16 x i32]* @reltable.GetOpCodeString to i64)) to i32), i32 trunc (i64 sub (i64 ptrtoint ([4 x i8]* @.str.10 to i64), i64 ptrtoint ([16 x i32]* @reltable.GetOpCodeString to i64)) to i32), i32 trunc (i64 sub (i64 ptrtoint ([4 x i8]* @.str.11 to i64), i64 ptrtoint ([16 x i32]* @reltable.GetOpCodeString to i64)) to i32), i32 trunc (i64 sub (i64 ptrtoint ([4 x i8]* @.str.12 to i64), i64 ptrtoint ([16 x i32]* @reltable.GetOpCodeString to i64)) to i32), i32 trunc (i64 sub (i64 ptrtoint ([4 x i8]* @.str.13 to i64), i64 ptrtoint ([16 x i32]* @reltable.GetOpCodeString to i64)) to i32), i32 trunc (i64 sub (i64 ptrtoint ([4 x i8]* @.str.14 to i64), i64 ptrtoint ([16 x i32]* @reltable.GetOpCodeString to i64)) to i32), i32 trunc (i64 sub (i64 ptrtoint ([4 x i8]* @.str.15 to i64), i64 ptrtoint ([16 x i32]* @reltable.GetOpCodeString to i64)) to i32)]
define i8* @GetOpCodeString(i32 %0) {
%2 = icmp ult i32 %0, 16
br i1 %2, label %3, label %7
3: ; preds = %1
%4 = sext i32 %0 to i64
%5 = shl i64 %4, 2
%6 = call i8* @llvm.load.relative.i64(i8* bitcast ([16 x i32]* @reltable.GetOpCodeString to i8*), i64 %5)
br label %7
7: ; preds = %1, %3
%8 = phi i8* [ %6, %3 ], [ getelementptr inbounds ([1 x i8], [1 x i8]* @.str.16, i64 0, i64 0), %1 ]
ret i8* %8
}