ARM: Add ARM disassembler.

1 files changed, 538 insertions, 0 deletions

diff --git a/lib/dis_arm.lua b/lib/dis_arm.lua
new file mode 100644
index 00000000..d007f86c
--- /dev/null
+++ b/lib/dis_arm.lua
@@ -0,0 +1,538 @@
+----------------------------------------------------------------------------
+-- LuaJIT ARM disassembler module.
+--
+-- Copyright (C) 2005-2010 Mike Pall. All rights reserved.
+-- Released under the MIT/X license. See Copyright Notice in luajit.h
+----------------------------------------------------------------------------
+-- This is a helper module used by the LuaJIT machine code dumper module.
+--
+-- It disassembles most user-mode ARMv7 instructions
+-- NYI: Advanced SIMD and VFP instructions.
+------------------------------------------------------------------------------
+
+local type = type
+local sub, byte, format = string.sub, string.byte, string.format
+local match, gmatch, gsub = string.match, string.gmatch, string.gsub
+local concat = table.concat
+local bit = require("bit")
+local band, bor, ror, tohex = bit.band, bit.bor, bit.ror, bit.tohex
+local lshift, rshift, arshift = bit.lshift, bit.rshift, bit.arshift
+
+------------------------------------------------------------------------------
+-- Opcode maps
+------------------------------------------------------------------------------
+
+local map_loadc = {
+  shift = 9, mask = 7,
+  [5] = {
+    shift = 0, mask = 0 -- NYI VFP load/store.
+  },
+  _ = {
+    shift = 0, mask = 0 -- NYI ldc, mcrr, mrrc.
+  },
+}
+
+local map_datac = {
+  shift = 24, mask = 1,
+  [0] = {
+    shift = 9, mask = 7,
+    [5] = {
+      shift = 0, mask = 0 -- NYI VFP data.
+    },
+    _ = {
+      shift = 0, mask = 0 -- NYI cdp, mcr, mrc.
+    },
+  },
+  "svcT",
+}
+
+local map_loadcu = {
+  shift = 0, mask = 0, -- NYI unconditional CP load/store.
+}
+
+local map_datacu = {
+  shift = 0, mask = 0, -- NYI unconditional CP data.
+}
+
+local map_simddata = {
+  shift = 0, mask = 0, -- NYI SIMD data.
+}
+
+local map_simdload = {
+  shift = 0, mask = 0, -- NYI SIMD load/store, preload.
+}
+
+local map_preload = {
+  shift = 0, mask = 0, -- NYI preload.
+}
+
+local map_media = {
+  shift = 20, mask = 31,
+  [0] = false,
+  { --01
+    shift = 5, mask = 7,
+    [0] = "sadd16DNM", "sasxDNM", "ssaxDNM", "ssub16DNM",
+    "sadd8DNM", false, false, "ssub8DNM",
+  },
+  { --02
+    shift = 5, mask = 7,
+    [0] = "qadd16DNM", "qasxDNM", "qsaxDNM", "qsub16DNM",
+    "qadd8DNM", false, false, "qsub8DNM",
+  },
+  { --03
+    shift = 5, mask = 7,
+    [0] = "shadd16DNM", "shasxDNM", "shsaxDNM", "shsub16DNM",
+    "shadd8DNM", false, false, "shsub8DNM",
+  },
+  false,
+  { --05
+    shift = 5, mask = 7,
+    [0] = "uadd16DNM", "uasxDNM", "usaxDNM", "usub16DNM",
+    "uadd8DNM", false, false, "usub8DNM",
+  },
+  { --06
+    shift = 5, mask = 7,
+    [0] = "uqadd16DNM", "uqasxDNM", "uqsaxDNM", "uqsub16DNM",
+    "uqadd8DNM", false, false, "uqsub8DNM",
+  },
+  { --07
+    shift = 5, mask = 7,
+    [0] = "uhadd16DNM", "uhasxDNM", "uhsaxDNM", "uhsub16DNM",
+    "uhadd8DNM", false, false, "uhsub8DNM",
+  },
+  { --08
+    shift = 5, mask = 7,
+    [0] = "pkhbtDNMU", false, "pkhtbDNMU",
+    { shift = 16, mask = 15, [15] = "sxtb16DMU", _ = "sxtab16DNMU", },
+    "pkhbtDNMU", "selDNM", "pkhtbDNMU",
+  },
+  false,
+  { --0a
+    shift = 5, mask = 7,
+    [0] = "ssatDxMu", "ssat16DxM", "ssatDxMu",
+    { shift = 16, mask = 15, [15] = "sxtbDMU", _ = "sxtabDNMU", },
+    "ssatDxMu", false, "ssatDxMu",
+  },
+  { --0b
+    shift = 5, mask = 7,
+    [0] = "ssatDxMu", "revDM", "ssatDxMu",
+    { shift = 16, mask = 15, [15] = "sxthDMU", _ = "sxtahDNMU", },
+    "ssatDxMu", "rev16DM", "ssatDxMu",
+  },
+  { --0c
+    shift = 5, mask = 7,
+    [3] = { shift = 16, mask = 15, [15] = "uxtb16DMU", _ = "uxtab16DNMU", },
+  },
+  false,
+  { --0e
+    shift = 5, mask = 7,
+    [0] = "usatDwMu", "usat16DwM", "usatDwMu",
+    { shift = 16, mask = 15, [15] = "uxtbDMU", _ = "uxtabDNMU", },
+    "usatDwMu", false, "usatDwMu",
+  },
+  { --0f
+    shift = 5, mask = 7,
+    [0] = "usatDwMu", "rbitDM", "usatDwMu",
+    { shift = 16, mask = 15, [15] = "uxthDMU", _ = "uxtahDNMU", },
+    "usatDwMu", "revshDM", "usatDwMu",
+  },
+  { --10
+    shift = 12, mask = 15,
+    [15] = {
+      shift = 5, mask = 7,
+      "smuadNMS", "smuadxNMS", "smusdNMS", "smusdxNMS",
+    },
+    _ = {
+      shift = 5, mask = 7,
+      [0] = "smladNMSD", "smladxNMSD", "smlsdNMSD", "smlsdxNMSD",
+    },
+  },
+  false, false, false,
+  { --14
+    shift = 5, mask = 7,
+    [0] = "smlaldDNMS", "smlaldxDNMS", "smlsldDNMS", "smlsldxDNMS",
+  },
+  { --15
+    shift = 5, mask = 7,
+    [0] = { shift = 12, mask = 15, [15] = "smmulNMS", _ = "smmlaNMSD", },
+    { shift = 12, mask = 15, [15] = "smmulrNMS", _ = "smmlarNMSD", },
+    false, false, false, false,
+    "smmlsNMSD", "smmlsrNMSD",
+  },
+  false, false,
+  { --18
+    shift = 5, mask = 7,
+    [0] = { shift = 12, mask = 15, [15] = "usad8NMS", _ = "usada8NMSD", },
+  },
+  false,
+  { --1a
+    shift = 5, mask = 3, [2] = "sbfxDMvw",
+  },
+  { --1b
+    shift = 5, mask = 3, [2] = "sbfxDMvw",
+  },
+  { --1c
+    shift = 5, mask = 3,
+    [0] = { shift = 0, mask = 15, [15] = "bfcDvX", _ = "bfiDMvX", },
+  },
+  { --1d
+    shift = 5, mask = 3,
+    [0] = { shift = 0, mask = 15, [15] = "bfcDvX", _ = "bfiDMvX", },
+  },
+  { --1e
+    shift = 5, mask = 3, [2] = "ubfxDMvw",
+  },
+  { --1f
+    shift = 5, mask = 3, [2] = "ubfxDMvw",
+  },
+}
+
+local map_load = {
+  shift = 21, mask = 9,
+  {
+    shift = 20, mask = 5,
+    [0] = "strtDL", "ldrtDL", [4] = "strbtDL", [5] = "ldrbtDL",
+  },
+  _ = {
+    shift = 20, mask = 5,
+    [0] = "strDL", "ldrDL", [4] = "strbDL", [5] = "ldrbDL",
+  }
+}
+
+local map_load1 = {
+  shift = 4, mask = 1,
+  [0] = map_load, map_media,
+}
+
+local map_loadm = {
+  shift = 20, mask = 1,
+  [0] = {
+    shift = 23, mask = 3,
+    [0] = "stmdaNR", "stmNR",
+    { shift = 16, mask = 63, [45] = "pushR", _ = "stmdbNR", }, "stmibNR",
+  },
+  {
+    shift = 23, mask = 3,
+    [0] = "ldmdaNR", { shift = 16, mask = 63, [61] = "popR", _ = "ldmNR", },
+    "ldmdbNR", "ldmibNR",
+  },
+}
+
+local map_data = {
+  shift = 21, mask = 15,
+  [0] = "andDNPs", "eorDNPs", "subDNPs", "rsbDNPs",
+  "addDNPs", "adcDNPs", "sbcDNPs", "rscDNPs",
+  "tstNP", "teqNP", "cmpNP", "cmnNP",
+  "orrDNPs", "movDPs", "bicDNPs", "mvnDPs",
+}
+
+local map_mul = {
+  shift = 21, mask = 7,
+  [0] = "mulNMSs", "mlaNMSDs", "umaalDNMS", "mlsDNMS",
+  "umullDNMSs", "umlalDNMSs", "smullDNMSs", "smlalDNMSs",
+}
+
+local map_sync = {
+  shift = 20, mask = 15, -- NYI: brackets around N. R(D+1) for ldrexd/strexd.
+  [0] = "swpDMN", false, false, false,
+  "swpbDMN", false, false, false,
+  "strexDMN", "ldrexDN", "strexdDN", "ldrexdDN",
+  "strexbDMN", "ldrexbDN", "strexhDN", "ldrexhDN",
+}
+
+local map_mulh = {
+  shift = 21, mask = 3,
+  [0] = { shift = 5, mask = 3,
+    [0] = "smlabbNMSD", "smlatbNMSD", "smlabtNMSD", "smlattNMSD", },
+  { shift = 5, mask = 3,
+    [0] = "smlawbNMSD", "smulwbNMS", "smlawtNMSD", "smulwtNMS", },
+  { shift = 5, mask = 3,
+    [0] = "smlalbbDNMS", "smlaltbDNMS", "smlalbtDNMS", "smlalttDNMS", },
+  { shift = 5, mask = 3,
+    [0] = "smulbbNMS", "smultbNMS", "smulbtNMS", "smulttNMS", },
+}
+
+local map_misc = {
+  shift = 4, mask = 7,
+  -- NYI: decode PSR bits of msr.
+  [0] = { shift = 21, mask = 1, [0] = "mrsD", "msrM", },
+  { shift = 21, mask = 3, "bxM", false, "clzDM", },
+  { shift = 21, mask = 3, "bxjM", },
+  { shift = 21, mask = 3, "blxM", },
+  false,
+  { shift = 21, mask = 3, [0] = "qaddDMN", "qsubDMN", "qdaddDMN", "qdsubDMN", },
+  false,
+  { shift = 21, mask = 3, "bkptK", },
+}
+
+local map_datar = {
+  shift = 4, mask = 9,
+  [9] = {
+    shift = 5, mask = 3,
+    [0] = { shift = 24, mask = 1, [0] = map_mul, map_sync, },
+    { shift = 20, mask = 1, [0] = "strhDL", "ldrhDL", },
+    { shift = 20, mask = 1, [0] = "ldrdDL", "ldrsbDL", },
+    { shift = 20, mask = 1, [0] = "strdDL", "ldrshDL", },
+  },
+  _ = {
+    shift = 20, mask = 25,
+    [16] = { shift = 7, mask = 1, [0] = map_misc, map_mulh, },
+    _ = {
+      shift = 0, mask = 0xffffffff,
+      [bor(0xe1a00000)] = "nop",
+      _ = map_data,
+    }
+  },
+}
+
+local map_datai = {
+  shift = 20, mask = 31, -- NYI: decode PSR bits of msr. Decode imm12.
+  [16] = "movwDW", [20] = "movtDW",
+  [18] = { shift = 0, mask = 0xf00ff, [0] = "nopv6", _ = "msrNW", },
+  [22] = "msrNW",
+  _ = map_data,
+}
+
+local map_branch = {
+  shift = 24, mask = 1,
+  [0] = "bB", "blB"
+}
+
+local map_condins = {
+  [0] = map_datar, map_datai, map_load, map_load1,
+  map_loadm, map_branch, map_loadc, map_datac
+}
+
+-- NYI: setend.
+local map_uncondins = {
+  [0] = false, map_simddata, map_simdload, map_preload,
+  false, "blxB", map_loadcu, map_datacu,
+}
+
+------------------------------------------------------------------------------
+
+local map_gpr = {
+  [0] = "r0", "r1", "r2", "r3", "r4", "r5", "r6", "r7",
+  "r8", "r9", "r10", "r11", "r12", "sp", "lr", "pc",
+}
+
+local map_cond = {
+  [0] = "eq", "ne", "hs", "lo", "mi", "pl", "vs", "vc",
+  "hi", "ls", "ge", "lt", "gt", "le", "al",
+}
+
+local map_shift = { [0] = "lsl", "lsr", "asr", "ror", }
+
+------------------------------------------------------------------------------
+
+-- Output a nicely formatted line with an opcode and operands.
+local function putop(ctx, text, operands)
+  local pos = ctx.pos
+  local extra = ""
+  if ctx.rel then
+    local sym = ctx.symtab[ctx.rel]
+    if sym then
+      extra = "\t->"..sym
+    elseif band(ctx.op, 0x0e000000) ~= 0x0a000000 then
+      extra = "\t; 0x"..tohex(ctx.rel)
+    end
+  end
+  if ctx.hexdump > 0 then
+    ctx.out(format("%08x  %s  %-5s %s%s\n",
+            ctx.addr+pos, tohex(ctx.op), text, concat(operands, ", "), extra))
+  else
+    ctx.out(format("%08x  %-5s %s%s\n",
+            ctx.addr+pos, text, concat(operands, ", "), extra))
+  end
+  ctx.pos = pos + 4
+end
+
+-- Fallback for unknown opcodes.
+local function unknown(ctx)
+  return putop(ctx, ".long", { "0x"..tohex(ctx.op) })
+end
+
+-- Format operand 2 of load/store opcodes.
+local function fmtload(ctx, op, pos)
+  local base = map_gpr[band(rshift(op, 16), 15)]
+  local x, ofs
+  local ext = (band(op, 0x04000000) == 0)
+  if not ext and band(op, 0x02000000) == 0 then
+    ofs = band(op, 4095)
+    if band(op, 0x00800000) == 0 then ofs = -ofs end
+    if base == "pc" then ctx.rel = ctx.addr + pos + 8 + ofs end
+    ofs = "#"..ofs
+  elseif ext and band(op, 0x00400000) ~= 0 then
+    ofs = band(op, 15) + band(rshift(op, 4), 0xf0)
+    if band(op, 0x00800000) == 0 then ofs = -ofs end
+    if base == "pc" then ctx.rel = ctx.addr + pos + 8 + ofs end
+    ofs = "#"..ofs
+  else
+    ofs = map_gpr[band(op, 15)]
+    if ext or band(op, 0xfe0) == 0 then
+    elseif band(op, 0xfe0) == 0x60 then
+      ofs = format("%s, rrx", ofs)
+    else
+      local sh = band(rshift(op, 7), 31)
+      if sh == 0 then sh = 32 end
+      ofs = format("%s, %s #%d", ofs, map_shift[band(rshift(op, 5), 3)], sh)
+    end
+    if band(op, 0x00800000) == 0 then ofs = "-"..ofs end
+  end
+  if ofs == "#0" then
+    x = format("[%s]", base)
+  elseif band(op, 0x01000000) == 0 then
+    x = format("[%s], %s", base, ofs)
+  else
+    x = format("[%s, %s]", base, ofs)
+  end
+  if band(op, 0x01200000) == 0x01200000 then x = x.."!" end
+  return x
+end
+
+-- Disassemble a single instruction.
+local function disass_ins(ctx)
+  local pos = ctx.pos
+  local b0, b1, b2, b3 = byte(ctx.code, pos+1, pos+4)
+  local op = bor(lshift(b3, 24), lshift(b2, 16), lshift(b1, 8), b0)
+  local operands = {}
+  local suffix = ""
+  local last, name, pat
+  ctx.op = op
+  ctx.rel = nil
+
+  local cond = rshift(op, 28)
+  local opat
+  if cond == 15 then
+    opat = map_uncondins[band(rshift(op, 25), 7)]
+  else
+    if cond ~= 14 then suffix = map_cond[cond] end
+    opat = map_condins[band(rshift(op, 25), 7)]
+  end
+  while type(opat) ~= "string" do
+    if not opat then return unknown(ctx) end
+    opat = opat[band(rshift(op, opat.shift), opat.mask)] or opat._
+  end
+  name, pat = match(opat, "^([a-z0-9]*)(.*)")
+
+  for p in gmatch(pat, ".") do
+    local x = nil
+    if p == "D" then
+      x = map_gpr[band(rshift(op, 12), 15)]
+    elseif p == "N" then
+      x = map_gpr[band(rshift(op, 16), 15)]
+    elseif p == "S" then
+      x = map_gpr[band(rshift(op, 8), 15)]
+    elseif p == "M" then
+      x = map_gpr[band(op, 15)]
+    elseif p == "P" then
+      if band(op, 0x02000000) ~= 0 then
+        x = ror(band(op, 255), 2*band(rshift(op, 8), 15))
+      else
+        x = map_gpr[band(op, 15)]
+        if band(op, 0xff0) ~= 0 then
+          operands[#operands+1] = x
+          local s = map_shift[band(rshift(op, 5), 3)]
+          local r = nil
+          if band(op, 0xf90) == 0 then
+            if s == "ror" then s = "rrx" else r = "#32" end
+          elseif band(op, 0x10) == 0 then
+            r = "#"..band(rshift(op, 7), 31)
+          else
+            r = map_gpr[band(rshift(op, 8), 15)]
+          end
+          if name == "mov" then name = s; x = r
+          elseif r then x = format("%s %s", s, r)
+          else x = s end
+        end
+      end
+    elseif p == "L" then
+      x = fmtload(ctx, op, pos, false)
+    elseif p == "B" then
+      local addr = ctx.addr + pos + 8 + arshift(lshift(op, 8), 6)
+      if cond == 15 then addr = addr + band(rshift(op, 23), 2) end
+      ctx.rel = addr
+      x = "0x"..tohex(addr)
+    elseif p == "R" then
+      if band(op, 0x00200000) ~= 0 and #operands == 1 then
+        operands[1] = operands[1].."!"
+      end
+      local t = {}
+      for i=0,15 do
+        if band(rshift(op, i), 1) == 1 then t[#t+1] = map_gpr[i] end
+      end
+      x = "{"..concat(t, ", ").."}"
+    elseif p == "W" then
+      x = band(op, 0x0fff) + band(rshift(op, 4), 0xf000)
+    elseif p == "T" then
+      x = "#0x"..tohex(band(op, 0x00ffffff), 6)
+    elseif p == "U" then
+      x = band(rshift(op, 7), 31)
+      if x == 0 then x = nil end
+    elseif p == "u" then
+      x = band(rshift(op, 7), 31)
+      if band(op, 0x40) == 0 then
+        if x == 0 then x = nil else x = "lsl #"..x end
+      else
+        if x == 0 then x = "asr #32" else x = "asr #"..x end
+      end
+    elseif p == "v" then
+      x = band(rshift(op, 7), 31)
+    elseif p == "w" then
+      x = band(rshift(op, 16), 31)
+    elseif p == "x" then
+      x = band(rshift(op, 16), 31) + 1
+    elseif p == "X" then
+      x = band(rshift(op, 16), 31) - last + 1
+    elseif p == "K" then
+      x = "#0x"..tohex(band(rshift(op, 4), 0x0000fff0) + band(op, 15), 4)
+    elseif p == "s" then
+      if band(op, 0x00100000) ~= 0 then suffix = "s"..suffix end
+    else
+      assert(false)
+    end
+    if x then
+      last = x
+      if type(x) == "number" then x = "#"..x end
+      operands[#operands+1] = x
+    end
+  end
+
+  return putop(ctx, name..suffix, operands)
+end
+
+------------------------------------------------------------------------------
+
+-- Disassemble a block of code.
+local function disass_block(ctx, ofs, len)
+  if not ofs then ofs = 0 end
+  local stop = len and ofs+len or #ctx.code
+  ctx.pos = ofs
+  ctx.rel = nil
+  while ctx.pos < stop do disass_ins(ctx) end
+end
+
+-- Extended API: create a disassembler context. Then call ctx:disass(ofs, len).
+local function create_(code, addr, out)
+  local ctx = {}
+  ctx.code = code
+  ctx.addr = addr or 0
+  ctx.out = out or io.write
+  ctx.symtab = {}
+  ctx.disass = disass_block
+  ctx.hexdump = 8
+  return ctx
+end
+
+-- Simple API: disassemble code (a string) at address and output via out.
+local function disass_(code, addr, out)
+  create_(code, addr, out):disass()
+end
+
+
+-- Public module functions.
+module(...)
+
+create = create_
+disass = disass_
+