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7shi/disasm.fsx

Last active August 29, 2015 14:03
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[F#]逆アセンブラ（途中）
Raw
disasm.fsx
let bin = System.IO.File.ReadAllBytes "../../cc"
let mutable i = 0
let show len asm =
printf "%08X " i
for j = 0 to len - 1 do
printf "%02X" bin.[i + j]
for j = len to 8 do
printf " "
printfn "%s" asm
i <- i + len
let reg16 = [| "ax"; "cx"; "dx"; "bx"; "sp"; "bp"; "si"; "di" |]
let reg8 = [| "al"; "cl"; "dl"; "bl"; "ah"; "ch"; "dh"; "bh" |]
let sreg = [| "es"; "cs"; "ss"; "ds" |]
let regm = [| "bx+si"; "bx+di"; "bp+si"; "bp+di"
"si"; "di"; "bp"; "bx" |]
// team3
let team3_accum = [| "al"; "ax" |]
let team3_regw = [| reg8; reg16 |]
let team3_word() =
int bin.[i] &&& 0b1
let team3_dispword () =
if team3_word() = 0 then
"byte"
elif team3_word() = 1 then
"word"
else
"???"
let team3_dispdata d =
if team3_word() = 0 then
sprintf "0x%02x" bin.[i+d]
elif team3_word() = 1 then
sprintf "0x%02x%02x" bin.[i+d+1] bin.[i+d]
else
sprintf "???"
// 最下位ビットからbyte or wordを判定
let team3_dispsize d =
if d &&& 0b00000001 = 0 then
sprintf "byte"
else
sprintf "word"
// 7番目のビットからcountの値を判定
let team3_dispcount d =
if d &&& 0b00000010 = 0 then
sprintf "1"
else
sprintf "cl"
let getregstr w (bin: byte) =
let reg = (int bin >>> 3) &&& 0b111
if w = 0b0 then reg8.[reg]
else reg16.[reg]
let dispstr d =
if d < 0 then
sprintf "-0x%x" (abs d)
else
sprintf "+0x%x" d
let modrm() =
let mode = int bin.[i+1] >>> 6
let rm = int bin.[i+1] &&& 0b111
match mode, rm with
| 0b00, 0b110 ->
2, sprintf "[0x%02x%02x]" bin.[i+3] bin.[i+2]
| 0b00, _ ->
0, sprintf "[%s]" regm.[rm]
| 0b01, _ ->
let d = bin.[i+2] |> sbyte
1, sprintf "[%s%s]" regm.[rm] (dispstr (int d))
| 0b10, _ ->
let d = (int16 bin.[i+2]) ||| ((int16 bin.[i+3]) <<< 8)
2, sprintf "[%s%s]" regm.[rm] (dispstr (int d))
| 0b11, _ ->
0, reg16.[rm]
| _ ->
0, "???"
while i < bin.Length do
match int bin.[i] with
// MOV: R/M to/from Register
| b when b &&& 0b11111100 = 0b10001000 ->
let dat = bin.[i]
let d = (int dat >>> 1) &&& 0b1 // to or from
let w = int dat &&& 0b1 // word or byte
let reg = (if w > 0 then reg16 else reg8).[((int bin.[i+1] >>> 3) &&& 0b111)]
let len, opr = modrm()
show (2 + len) <| if d > 0 then sprintf "mov %s,%s" reg opr else sprintf "mov %s,%s" opr reg
// MOV: Immediate to R/M (word)
| 0b11000111 ->
let len, opr = modrm()
show (4 + len) <| sprintf "mov word %s,0x%02x%02x" opr bin.[i+3+len] bin.[i+2+len]
// MOV: Immediate to R/M (byte)
| 0b11000110 ->
let len, opr = modrm()
show (3 + len) <| sprintf "mov byte %s,0x%02x" opr bin.[i+2+len]
// POP: R/M
| 0b10001111 ->
let len, opr = modrm()
show (2 + len) <| sprintf "pop %s%s" (if (int bin.[i+1] &&& 0b11000000) = 0b11000000 then "" else "word ") opr
// POP: Register
| b when b &&& 0b11111000 = 0b01011000 ->
show 1 <| sprintf "pop %s" (reg16.[int bin.[i] &&& 0b111])
// POP: Segment Register
| b when b &&& 0b11100111 = 0b00000111 ->
show 1 <| sprintf "pop %s" (sreg.[int bin.[i] >>> 3 &&& 0b11])
// <<<<<<<<<<<<<<<<<<<<<<
// IN: Fixed Port w=1
| 0b11100101 ->
show 2 <| sprintf "in ax,0x%x" bin.[i+1]
// IN: Fixed Port w=0
| 0b11100100 ->
show 2 <| sprintf "in al,0x%x" bin.[i+1]
// IN: Variable Port w=1
| 0b11101101 ->
show 1 <| sprintf "in ax,dx"
// IN: Variable Port w=0
| 0b11101100 ->
show 1 <| sprintf "in al,dx"
// XLAT
| 0b11010111 ->
show 1 <| sprintf "xlatb"
// LDS
| 0b11000101 ->
let len, opr = modrm()
let reg = (int bin.[i+1] >>> 3) &&& 0b111
show (2 + len) <| sprintf "lds %s,%s" reg16.[reg] opr
// LAHF
| 0b10011111 ->
show 1 <| "lahf"
// PUSHF
| 0b10011100 ->
show 1 <| "pushfw"
// <<<<<<<<<<<<<<<<<<<<<<
// ----------------------
// MOV Memory to Accumulator
| b when b &&& 0b11111110 = 0b10100000 ->
show 3 <| sprintf "mov %s, [0x%02x%02x]"
(if b &&& 0b1 = 0 then "al"; else "ax")
bin.[i+2] bin.[i+1]
// MOV Accumulator to Memory
| b when b &&& 0b11111110 = 0b10100010 ->
show 3 <| sprintf "mov [0x%02x%02x], %s"
bin.[i+2] bin.[i+1]
(if b &&& 0b1 = 0 then "al"; else "ax")
// OUT Fixed value
| b when b &&& 0b11111110 = 0b11100110 ->
show 2 <| sprintf "out 0x%x, %s"
bin.[i+1]
(if b &&& 0b1 = 0 then "al"; else "ax")
// OUT Variable port
| b when b &&& 0b11111110 = 0b11101110 ->
show 1 <| sprintf "out dx, %s"
(if b &&& 0b1 = 0 then "al"; else "ax")
// LEA
| 0b10001101 ->
let reg = (int bin.[i+1] >>> 3) &&& 0b111
let len, opr = modrm()
show (2 + len) <| sprintf "lea %s, %s"
reg16.[reg] opr
// LES
| 0b11000100 ->
let reg = (int bin.[i+1] >>> 3) &&& 0b111
let len, opr = modrm()
show (2 + len) <| sprintf "les %s, %s"
reg16.[reg] opr
// PUSH Register/Memory
| 0b11111111 ->
let mode = int bin.[i+1] >>> 6
let len, opr = modrm()
show (2 + len) <| sprintf "push %s%s"
(if mode = 0b11 then "" else "word ")
opr
// PUSH Register
| b when b &&& 0b11111000 = 0b01010000 ->
show 1 <| sprintf "push %s"
reg16.[b &&& 0b111]
// PUSH Segment Register
| b when b &&& 0b11100111 = 0b00000110 ->
let reg = (int b >>> 3) &&& 0b11
show 1 <| sprintf "push %s"
sreg.[reg]
// XCHG Register/Memory with Register
| b when b &&& 0b11111110 = 0b10000110 ->
let mode = int bin.[i+1] >>> 6
let reg = (int bin.[i+1] >>> 3) &&& 0b111
let len, opr = modrm()
let w = if (int b &&& 0b1 = 1) then true else false
show (2 + len) <| sprintf "xchg %s, %s"
(if w then reg16 else reg8).[reg]
(if (w || (mode <> 0b11)) then
opr
else
reg8.[int bin.[i+1] &&& 0b111])
| 0b10000111 -> // w = 1
let reg = (int bin.[i+1] >>> 3) &&& 0b111
let len, opr = modrm()
show (2 + len) <| sprintf "xchg %s, %s"
reg16.[reg] opr
// NOP
| 0b10010000 ->
show (1) <| sprintf "nop"
// XCHG Register with Accumulator
| b when b &&& 0b11111000 = 0b10010000 ->
show 1 <| sprintf "xchg ax, %s"
reg16.[b &&& 0b111]
// SAHF
| 0b10011110 ->
show 1 <| sprintf "sahf"
//POPFW
| 0b10011101 ->
show 1 <| sprintf "popfw"
// ----------------------
// AND Reg./Memory and Register to Either
| b when b &&& 0b11111100 = 0b00100000 ->
let reg = (int bin.[i+1] >>> 3) &&& 0b111
let len, opr = modrm()
if b &&& 0b10 = 0b00 then
show (2 + len) <| sprintf "and %s, %s"
opr team3_regw.[team3_word()].[reg]
if b &&& 0b10 = 0b10 then
show (2 + len) <| sprintf "and %s, %s"
team3_regw.[team3_word()].[reg] opr
// OR Reg./Memory and Register to Either
| b when b &&& 0b11111100 = 0b00001000 ->
let reg = (int bin.[i+1] >>> 3) &&& 0b111
let len, opr = modrm()
if b &&& 0b10 = 0b00 then
show (2 + len) <| sprintf "or %s, %s"
opr team3_regw.[team3_word()].[reg]
if b &&& 0b10 = 0b10 then
show (2 + len) <| sprintf "or %s, %s"
team3_regw.[team3_word()].[reg] opr
// XOR Reg./Memory and Register to Either
| b when b &&& 0b11111100 = 0b00110000 ->
let reg = (int bin.[i+1] >>> 3) &&& 0b111
let len, opr = modrm()
if b &&& 0b10 = 0b00 then
show (2 + len) <| sprintf "xor %s, %s"
opr team3_regw.[team3_word()].[reg]
if b &&& 0b10 = 0b10 then
show (2 + len) <| sprintf "xor %s, %s"
team3_regw.[team3_word()].[reg] opr
// TEST Register/Memory and Register
| b when b &&& 0b11111110 = 0b10000100 ->
let reg = (int bin.[i+1] >>> 3) &&& 0b111
let len, opr = modrm()
show (2 + len) <| sprintf "test %s, %s"
opr team3_regw.[team3_word()].[reg]
// AND Immediate to Register/Memory
// OR Immediate to Register/Memory
// XOR Immediate to Register/Memory
| b when b &&& 0b11111110 = 0b10000000 ->
let reg = (int bin.[i+1] >>> 3) &&& 0b111
let len, opr = modrm()
let data = team3_dispdata 2
let team3_w = team3_dispword()
if reg = 4 then
show (3 + len + team3_word()) <| sprintf "and %s %s, %s"
team3_w opr data
elif reg = 1 then
show (3 + len + team3_word()) <| sprintf "or %s %s, %s"
team3_w opr data
elif reg = 6 then
show (3 + len + team3_word()) <| sprintf "xor %s %s, %s"
team3_w opr data
elif reg = 0b000 then
show (3 + len + team3_word()) <| sprintf "add %s %s, %s" team3_w opr data
elif reg = 0b000 then
show (3 + len + team3_word()) <| sprintf "adc %s %s, %s" team3_w opr data
elif reg = 0b000 then
show (3 + len + team3_word()) <| sprintf "sub %s %s, %s" team3_w opr data
elif reg = 0b000 then
show (3 + len + team3_word()) <| sprintf "sbb %s %s, %s" team3_w opr data
elif reg = 0b111 then
show (3 + len + team3_word()) <| sprintf "cmp %s %s, %s" team3_w opr data
else
show 1 <| sprintf "db 0x%02x" bin.[i]
// TEST Immediate Data and Register/Memory
| b when b &&& 0b11111110 = 0b11110110 ->
let reg = (int bin.[i+1] >>> 3) &&& 0b111
let len, opr = modrm()
let data = team3_dispdata 2
let team3_w = team3_dispword()
let size = team3_dispsize (int bin.[i])
if reg = 0 then
show (3 + len + team3_word()) <| sprintf "test %s %s, %s"
team3_w opr data
// NOTの分岐
elif reg = 0b010 then
show (2 + len) <| sprintf "not %s %s" size opr
else
show 1 <| sprintf "db 0x%02x" bin.[i]
// AND Immediate to Accumulator
| b when b &&& 0b11111110 = 0b00100100 ->
let data = team3_dispdata 1
show (2 + team3_word()) <| sprintf "and %s, %s"
team3_accum.[team3_word()] data
// TEST Immediate Data and Accumulator
| b when b &&& 0b11111110 = 0b10101000 ->
let data = team3_dispdata 1
show (2 + team3_word()) <| sprintf "test %s, %s"
team3_accum.[team3_word()] data
// OR Immediate to Accumulator
| b when b &&& 0b11111110 = 0b00001100 ->
let data = team3_dispdata 1
show (2 + team3_word()) <| sprintf "or %s, %s"
team3_accum.[team3_word()] data
// XOR Immediate to Accumulator
| b when b &&& 0b11111110 = 0b00110100 ->
let data = team3_dispdata 1
show (2 + team3_word()) <| sprintf "xor %s, %s"
team3_accum.[team3_word()] data
// Shift/Rotate系の分岐
| b when b &&& 0b11111100 = 0b11010000 ->
let reg = (int bin.[i+1] >>> 3) &&& 0b111
let len, opr = modrm()
let count = team3_dispcount (int bin.[i])
let size = team3_dispsize (int bin.[i])
match reg with
// Shift Logical/Arithmetic Left
| 0b100 ->
show (2 + len) <| sprintf "shl %s %s,%s"
size opr count
// Shift Logical Right
| 0b101 ->
show (2 + len) <| sprintf "shr %s %s,%s"
size opr count
// Shift Arithmetic Rigth
| 0b111 ->
show (2 + len) <| sprintf "sar %s %s,%s"
size opr count
// Rotate Right
| 0b000 ->
show (2 + len) <| sprintf "rol %s %s,%s"
size opr count
// Rotate Left
| 0b001 ->
show (2 + len) <| sprintf "ror %s %s,%s"
size opr count
// Rotate Through Carry Flag Left
| 0b010 ->
show (2 + len) <| sprintf "rcl %s %s,%s"
size opr count
// Rotate Through Carry Right
| 0b011 ->
show (2 + len) <| sprintf "rcr %s %s,%s"
size opr count
| _ ->
show 1 <| sprintf "db 0x%02x" bin.[i]
// REP系の分岐
| b when b &&& 0b11111110 = 0b11110010 ->
let opr = if b &&& 0b1 = 0 then "repne" else "rep"
if i = bin.Length - 1 then
show 1 <| sprintf "%s" opr
elif bin.[i] = bin.[i+1] then
i <- i + 1
else
match (int bin.[i+1]) &&& 0b11111110 with
// REP MOVS
| 0b10100100 ->
show 2 <| sprintf "%s movs%c" opr (team3_dispsize(int bin.[i+1])).[0]
// REP CMPS
| 0b10100110 ->
if opr = "rep" then
show 2 <| sprintf "%se cmps%c" opr (team3_dispsize(int bin.[i+1])).[0]
else
show 2 <| sprintf "%s cmps%c" opr (team3_dispsize(int bin.[i+1])).[0]
// REP SCAS
| 0b10101110 ->
if opr = "rep" then
show 2 <| sprintf "%se scas%c" opr (team3_dispsize(int bin.[i+1])).[0]
else
show 2 <| sprintf "%s scas%c" opr (team3_dispsize(int bin.[i+1])).[0]
// REP LODS
| 0b10101100 ->
show 2 <| sprintf "%s lods%c" opr (team3_dispsize(int bin.[i+1])).[0]
// REP STOS
| 0b10101010 ->
show 2 <| sprintf "%s stos%c" opr (team3_dispsize(int bin.[i+1])).[0]
| _ ->
show 1 <| sprintf "%s" opr
// MOVSの分岐
| b when b &&& 0b11111110 = 0b10100100 ->
show 1 <| sprintf "%s%c" "movs" (team3_dispsize b).[0]
// CMPSの分岐
| b when b &&& 0b11111110 = 0b10100110 ->
show 1 <| sprintf "%s%c" "cmps" (team3_dispsize b).[0]
// SCASの分岐
| b when b &&& 0b11111110 = 0b10101110 ->
show 1 <| sprintf "%s%c" "scas" (team3_dispsize b).[0]
// LODSの分岐
| b when b &&& 0b11111110 = 0b10101100 ->
show 1 <| sprintf "%s%c" "lods" (team3_dispsize b).[0]
// STOSの分岐
| b when b &&& 0b11111110 = 0b10101010 ->
show 1 <| sprintf "%s%c" "stos" (team3_dispsize b).[0]
// CALLの分岐その1(Direct within Segment)
| 0b11101000 ->
let d = (int16 bin.[i+1]) ||| ((int16 bin.[i+2]) <<< 8)
show 3 <| sprintf "call word 0x%x" (d + int16 (i + 3))
// CALLの分岐その2(Direct Intersegment)
| 0b10011010 ->
let off = (int16 bin.[i+1]) ||| ((int16 bin.[i+2]) <<< 8)
let seg = (int16 bin.[i+3]) ||| ((int16 bin.[i+4]) <<< 8)
show 5 <| sprintf "call word 0x%x:0x%x" (int16 seg) (int16 off)
// CALLの分岐その3(Indirect within Segment or Indirect Intersegment)
| 0b11111111 ->
let reg = (int bin.[i+1] >>> 3) &&& 0b111
let len, opr = modrm()
match reg with
// Indirect within Segment
| 0b010 ->
show (2 + len) <| sprintf "call word %s" opr
// Indirect Intersegment
| 0b011 ->
show (2 + len) <| sprintf "call word far %s" opr
| _ ->
show 1 <| sprintf "db 0x%02x" bin.[i]
| 0b10001110 ->
let reg = (int bin.[i+1] >>> 3) &&& 0b11
let len, opr = modrm()
show (2 + len) <| sprintf "mov %s, %s"
sreg.[reg] opr
| 0b10001100 ->
let reg = (int bin.[i+1] >>> 3) &&& 0b11
let len, opr = modrm()
show (2 + len) <| sprintf "mov %s, %s"
opr sreg.[reg]
| b when b &&& 0b11111000 = 0b10110000 ->
show 2 <| sprintf "mov %s, 0x%02x"
reg8.[b &&& 0b111] bin.[i+1]
| b when b &&& 0b11111000 = 0b10111000 ->
show 3 <| sprintf "mov %s, 0x%02x%02x"
reg16.[b &&& 0b111] bin.[i+2] bin.[i+1]
// Add: R/M with R to Either
| b when (b >>> 2) = 0b000000 ->
let d = (int bin.[i] >>> 1) &&& 0b1
let w = (int bin.[i]) &&& 0b1
let len, op = modrm()
let reg = (int bin.[i+1] >>> 3) &&& 0b111
let fromreg = if d = 0 then (getregstr w bin.[i+1]) else op
let toreg = if d = 1 then (getregstr w bin.[i+1]) else op
show (2 + len) <| sprintf "add %s, %s" toreg fromreg
// Add with Carry: R/M with R to Either
| b when (b >>> 2) = 0b000100 ->
let d = (int bin.[i] >>> 1) &&& 0b1
let w = (int bin.[i]) &&& 0b1
let len, op = modrm()
let reg = (int bin.[i+1] >>> 3) &&& 0b111
let fromreg = if d = 0 then (getregstr w bin.[i+1]) else op
let toreg = if d = 1 then (getregstr w bin.[i+1]) else op
show (2 + len) <| sprintf "adc %s, %s" toreg fromreg
// Subtract: R/M with R to Either dw=00
| b when (b >>> 2) = 0b001010 ->
let d = (int bin.[i] >>> 1) &&& 0b1
let w = (int bin.[i]) &&& 0b1
let len, op = modrm()
let reg = (int bin.[i+1] >>> 3) &&& 0b111
let fromreg = if d = 0 then (getregstr w bin.[i+1]) else op
let toreg = if d = 1 then (getregstr w bin.[i+1]) else op
show (2 + len) <| sprintf "sub %s, %s" toreg fromreg
// Add: Immediate to R/M sw=00
// Add with Carry: Immediate to R/M sw=00
// Subtract: Immediate to R/M sw=00
| 0b10000000 ->
let reg = (int bin.[i+1] >>> 3) &&& 0b111
let len, op = modrm()
// 異常な命令は弾く
if reg <> 0b000 && reg <> 0b010 && reg <> 0b101 && reg <> 0b011 && reg <> 0b111
then show 1 <| sprintf "db 0x%02x" bin.[i]
// コマンド名を選択
let cmd =
if reg = 0b000 then "add"
elif reg = 0b010 then "adc"
elif reg = 0b101 then "sub"
elif reg = 0b011 then "sbb"
else "cmp"
// 表示
show (3 + len) <| sprintf "%s byte %s, 0x%02x" cmd op bin.[i+2]
// Add: Immediate to R/M sw=01
// Add with Carry: Immediate to R/M sw=01
// Subtract: Immediate to R/M sw=01
| 0b10000001 ->
let w = (int bin.[i]) &&& 0b1
let reg = (int bin.[i+1] >>> 3) &&& 0b111
let len, op = modrm()
// 異常な命令は弾く
if reg <> 0b000 && reg <> 0b010 && reg <> 0b101 && reg <> 0b011 && reg <> 0b111
then show 1 <| sprintf "db 0x%02x" bin.[i]
// コマンド名を選択
let cmd =
if reg = 0b000 then "add"
elif reg = 0b010 then "adc"
elif reg = 0b101 then "sub"
elif reg = 0b011 then "sbb"
else "cmp"
// 表示
show (3 + len + w) <| sprintf "%s word %s, 0x%02x%02x" cmd op bin.[i+3] bin.[i+2]
// Add: Immediate to R/M sw=11
// Add with Carry: Immediate to R/M sw=11
// Subtract: Immediate to R/M sw=11
| 0b10000011 ->
let reg = (int bin.[i+1] >>> 3) &&& 0b111
let len, op = modrm()
// Add
if reg = 0b000 then
show (3 + len) <| sprintf "add word %s, byte %s" op (dispstr (int (sbyte bin.[i+2])))
// Add with Carry
elif reg = 0b010 then
show (3 + len) <| sprintf "adc word %s, byte %s" op (dispstr (int (sbyte bin.[i+2])))
// Subtract
elif reg = 0b101 then
show (3 + len) <| sprintf "sub word %s, byte %s" op (dispstr (int (sbyte bin.[i+2])))
elif reg = 0b011 then
show (3 + len) <| sprintf "sbb word %s, byte %s" op (dispstr (int (sbyte bin.[i+2])))
elif reg = 0b111 then
show (3 + len) <| sprintf "cmp word %s, byte %s" op (dispstr (int (sbyte bin.[i+2])))
else show 1 <| sprintf "db 0x%02x" bin.[i]
// Add: Immediate to Accumulator w=0
| 0b00000100 ->
show 2 <| sprintf "add al, 0x%02x" bin.[i+1]
// Add: Immediate to Accumulator w=1
| 0b00000101 ->
show 3 <| sprintf "add ax, 0x%02x%02x" bin.[i+2] bin.[i+1]
// Add with Carry: Immediate to Accumulator w=0
| 0b00010100 ->
show 2 <| sprintf "adc al, 0x%02x" bin.[i+1]
// Add with Carry: Immediate to Accumulator w=1
| 0b00010101 ->
show 3 <| sprintf "adc ax, 0x%02x%02x" bin.[i+2] bin.[i+1]
// Increment: Register
| b when (b >>> 3) = 0b01000 ->
let reg = (int b) &&& 0b111
show 1 <| sprintf "inc %s" reg16.[reg]
// Increment: R/M w=0
| 0b11111110 ->
let reg = (int bin.[i + 1] >>> 3) &&& 0b111
let len, op = modrm()
if reg = 0b000 then
show (2 + len) <| sprintf "inc byte %s" op
elif reg = 0b001 then
show (2 + len) <| sprintf "dec byte %s" op
else show 1 <| sprintf "db 0x%02x" bin.[i]
// Increment: R/M w=1
| 0b11111111 ->
let len, op = modrm()
let reg = (int bin.[i + 1] >>> 3) &&& 0b111
if reg = 0b000 then
show (2 + len) <| sprintf "inc word %s" op
elif reg = 0b001 then
show (2 + len) <| sprintf "dec word %s" op
else show 1 <| sprintf "db 0x%02x" bin.[i]
// AAA: ASCII Adjust for Add
| 0b00110111 -> show 1 <| sprintf "aaa"
// DAA: Decimal Adjust for Add
| 0b00100111 -> show 1 <| sprintf "daa"
// Subtract: Immediate to Accumulator w=0
| 0b00101100 ->
show 2 <| sprintf "sub al, 0x%02x" bin.[i+1]
// Subtract: Immediate to Accumulator w=1
| 0b00101101 ->
show 3 <| sprintf "sub ax, 0x%02x%02x" bin.[i+2] bin.[i+1]
// sbb
| 0b00011000 ->
let reg = (int bin.[i+1] >>> 3) &&& 0b111
let len, opr = modrm()
show 2 <| sprintf "sbb %s, %s" opr reg8.[reg]
| 0b00011001 ->
let reg = (int bin.[i+1] >>> 3) &&& 0b111
let len, opr = modrm()
show 2 <| sprintf "sbb %s, %s" opr reg16.[reg]
| 0b00011010 ->
let reg = (int bin.[i+1] >>> 3) &&& 0b111
let len, opr = modrm()
show 2 <| sprintf "sbb %s, %s" reg8.[reg] opr
| 0b00011011 ->
let reg = (int bin.[i+1] >>> 3) &&& 0b111
let len, opr = modrm()
show 2 <| sprintf "sbb %s, %s" reg16.[reg] opr
| 0b00011100 ->
let len, opr = modrm()
show (2 + len) <| sprintf "sbb al, 0x%02x" bin.[i+1]
| 0b00011101 ->
let len, opr = modrm()
show (3 + len) <| sprintf "sbb ax, 0x%02x%02x" bin.[i+2] bin.[i+1]
// dec
| b when (b >>> 3) = 0b01001 ->
let reg = b &&& 0b111
show 1 <| sprintf "dec %s" reg16.[reg]
// cmp, sbb
| 0b00111000 ->
let reg = (int bin.[i+1] >>> 3) &&& 0b111
let len, opr = modrm()
show 2 <| sprintf "cmp %s, %s"
opr reg8.[reg]
| 0b00111001 ->
let reg = (int bin.[i+1] >>> 3) &&& 0b111
let len, opr = modrm()
show 4 <| sprintf "cmp %s, %s"
opr reg16.[reg]
| 0b00111100 ->
show 2 <| sprintf "cmp al, 0x%02x" bin.[i+1]
| 0b00111101 ->
show 3 <| sprintf "cmp ax, 0x%02x%02x" bin.[i+2] bin.[i+1]
| 0b00111010 ->
let len, opr = modrm()
show 2 <| sprintf "cmp al, %s"
opr
| 0b00111011 ->
let len, opr = modrm()
show 2 <| sprintf "cmp ax, %s"
opr
// aas
| 0b00111111 ->
show 1 <| sprintf "aas"
// das
| 0b00101111 ->
show 1 <| sprintf "das"
// aam
| 0b11010100 ->
show 2 <| sprintf "aam"
// mul,imul, div, idiv,neg
| 0b11110110 ->
let reg = (int bin.[i+1] >>> 3) &&& 0b111
let len, opr = modrm()
if reg = 0b100
then show (2 + len) <| sprintf "mul byte %s" opr
elif reg = 0b101
then show (2 + len) <| sprintf "imul byte %s" opr
elif reg = 0b110
then show (2 + len) <| sprintf "div byte %s" opr
elif reg = 0b111
then show (2 + len) <| sprintf "idiv byte %s" opr
elif reg = 0b011
then show (2 + len) <| sprintf "neg byte %s" opr
else
show 1 <| sprintf "db 0x%02x" bin.[i]
| 0b11110111 ->
let reg = (int bin.[i+1] >>> 3) &&& 0b111
let len, opr = modrm()
if reg = 0b100
then show (2 + len) <| sprintf "mul word %s" opr
elif reg = 0b101
then show (2 + len) <| sprintf "imul word %s" opr
elif reg = 0b110
then show (2 + len) <| sprintf "div word %s" opr
elif reg = 0b111
then show (2 + len) <| sprintf "idiv word %s" opr
elif reg = 0b011
then show (2 + len) <| sprintf "neg word %s" opr
else
show 1 <| sprintf "db 0x%02x" bin.[i]
// aad
| 0b11010101 ->
show 2 <| sprintf "aad 0xb"
// cbw
| 0b10011000 ->
show 1 <| sprintf "cbw"
// cwd
| 0b10011001 ->
show 1 <| sprintf "cwd"
| _ ->
show 1 <| sprintf "db 0x%02x" bin.[i]
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