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src/jit/dis_arm.lua - luajit-2.0-src

Functions defined

Source code

  1. ----------------------------------------------------------------------------
  2. -- LuaJIT ARM disassembler module.
  3. --
  4. -- Copyright (C) 2005-2015 Mike Pall. All rights reserved.
  5. -- Released under the MIT license. See Copyright Notice in luajit.h
  6. ----------------------------------------------------------------------------
  7. -- This is a helper module used by the LuaJIT machine code dumper module.
  8. --
  9. -- It disassembles most user-mode ARMv7 instructions
  10. -- NYI: Advanced SIMD and VFP instructions.
  11. ------------------------------------------------------------------------------

  13. local type = type
  14. local sub, byte, format = string.sub, string.byte, string.format
  15. local match, gmatch, gsub = string.match, string.gmatch, string.gsub
  16. local concat = table.concat
  17. local bit = require("bit")
  18. local band, bor, ror, tohex = bit.band, bit.bor, bit.ror, bit.tohex
  19. local lshift, rshift, arshift = bit.lshift, bit.rshift, bit.arshift

  21. ------------------------------------------------------------------------------
  22. -- Opcode maps
  23. ------------------------------------------------------------------------------

  25. local map_loadc = {
  26.   shift = 8, mask = 15,
  27.   [10] = {
  28.     shift = 20, mask = 1,
  29.     [0] = {
  30.       shift = 23, mask = 3,
  31.       [0] = "vmovFmDN", "vstmFNdr",
  32.       _ = {
  33.         shift = 21, mask = 1,
  34.         [0] = "vstrFdl",
  35.         { shift = 16, mask = 15, [13] = "vpushFdr", _ = "vstmdbFNdr", }
  36.       },
  37.     },
  38.     {
  39.       shift = 23, mask = 3,
  40.       [0] = "vmovFDNm",
  41.       { shift = 16, mask = 15, [13] = "vpopFdr", _ = "vldmFNdr", },
  42.       _ = {
  43.         shift = 21, mask = 1,
  44.         [0] = "vldrFdl", "vldmdbFNdr",
  45.       },
  46.     },
  47.   },
  48.   [11] = {
  49.     shift = 20, mask = 1,
  50.     [0] = {
  51.       shift = 23, mask = 3,
  52.       [0] = "vmovGmDN", "vstmGNdr",
  53.       _ = {
  54.         shift = 21, mask = 1,
  55.         [0] = "vstrGdl",
  56.         { shift = 16, mask = 15, [13] = "vpushGdr", _ = "vstmdbGNdr", }
  57.       },
  58.     },
  59.     {
  60.       shift = 23, mask = 3,
  61.       [0] = "vmovGDNm",
  62.       { shift = 16, mask = 15, [13] = "vpopGdr", _ = "vldmGNdr", },
  63.       _ = {
  64.         shift = 21, mask = 1,
  65.         [0] = "vldrGdl", "vldmdbGNdr",
  66.       },
  67.     },
  68.   },
  69.   _ = {
  70.     shift = 0, mask = 0 -- NYI ldc, mcrr, mrrc.
  71.   },
  72. }

  74. local map_vfps = {
  75.   shift = 6, mask = 0x2c001,
  76.   [0] = "vmlaF.dnm", "vmlsF.dnm",
  77.   [0x04000] = "vnmlsF.dnm", [0x04001] = "vnmlaF.dnm",
  78.   [0x08000] = "vmulF.dnm", [0x08001] = "vnmulF.dnm",
  79.   [0x0c000] = "vaddF.dnm", [0x0c001] = "vsubF.dnm",
  80.   [0x20000] = "vdivF.dnm",
  81.   [0x24000] = "vfnmsF.dnm", [0x24001] = "vfnmaF.dnm",
  82.   [0x28000] = "vfmaF.dnm", [0x28001] = "vfmsF.dnm",
  83.   [0x2c000] = "vmovF.dY",
  84.   [0x2c001] = {
  85.     shift = 7, mask = 0x1e01,
  86.     [0] = "vmovF.dm", "vabsF.dm",
  87.     [0x0200] = "vnegF.dm", [0x0201] = "vsqrtF.dm",
  88.     [0x0800] = "vcmpF.dm", [0x0801] = "vcmpeF.dm",
  89.     [0x0a00] = "vcmpzF.d", [0x0a01] = "vcmpzeF.d",
  90.     [0x0e01] = "vcvtG.dF.m",
  91.     [0x1000] = "vcvt.f32.u32Fdm", [0x1001] = "vcvt.f32.s32Fdm",
  92.     [0x1800] = "vcvtr.u32F.dm", [0x1801] = "vcvt.u32F.dm",
  93.     [0x1a00] = "vcvtr.s32F.dm", [0x1a01] = "vcvt.s32F.dm",
  94.   },
  95. }

  97. local map_vfpd = {
  98.   shift = 6, mask = 0x2c001,
  99.   [0] = "vmlaG.dnm", "vmlsG.dnm",
  100.   [0x04000] = "vnmlsG.dnm", [0x04001] = "vnmlaG.dnm",
  101.   [0x08000] = "vmulG.dnm", [0x08001] = "vnmulG.dnm",
  102.   [0x0c000] = "vaddG.dnm", [0x0c001] = "vsubG.dnm",
  103.   [0x20000] = "vdivG.dnm",
  104.   [0x24000] = "vfnmsG.dnm", [0x24001] = "vfnmaG.dnm",
  105.   [0x28000] = "vfmaG.dnm", [0x28001] = "vfmsG.dnm",
  106.   [0x2c000] = "vmovG.dY",
  107.   [0x2c001] = {
  108.     shift = 7, mask = 0x1e01,
  109.     [0] = "vmovG.dm", "vabsG.dm",
  110.     [0x0200] = "vnegG.dm", [0x0201] = "vsqrtG.dm",
  111.     [0x0800] = "vcmpG.dm", [0x0801] = "vcmpeG.dm",
  112.     [0x0a00] = "vcmpzG.d", [0x0a01] = "vcmpzeG.d",
  113.     [0x0e01] = "vcvtF.dG.m",
  114.     [0x1000] = "vcvt.f64.u32GdFm", [0x1001] = "vcvt.f64.s32GdFm",
  115.     [0x1800] = "vcvtr.u32FdG.m", [0x1801] = "vcvt.u32FdG.m",
  116.     [0x1a00] = "vcvtr.s32FdG.m", [0x1a01] = "vcvt.s32FdG.m",
  117.   },
  118. }

  120. local map_datac = {
  121.   shift = 24, mask = 1,
  122.   [0] = {
  123.     shift = 4, mask = 1,
  124.     [0] = {
  125.       shift = 8, mask = 15,
  126.       [10] = map_vfps,
  127.       [11] = map_vfpd,
  128.       -- NYI cdp, mcr, mrc.
  129.     },
  130.     {
  131.       shift = 8, mask = 15,
  132.       [10] = {
  133.         shift = 20, mask = 15,
  134.         [0] = "vmovFnD", "vmovFDn",
  135.         [14] = "vmsrD",
  136.         [15] = { shift = 12, mask = 15, [15] = "vmrs", _ = "vmrsD", },
  137.       },
  138.     },
  139.   },
  140.   "svcT",
  141. }

  143. local map_loadcu = {
  144.   shift = 0, mask = 0, -- NYI unconditional CP load/store.
  145. }

  147. local map_datacu = {
  148.   shift = 0, mask = 0, -- NYI unconditional CP data.
  149. }

  151. local map_simddata = {
  152.   shift = 0, mask = 0, -- NYI SIMD data.
  153. }

  155. local map_simdload = {
  156.   shift = 0, mask = 0, -- NYI SIMD load/store, preload.
  157. }

  159. local map_preload = {
  160.   shift = 0, mask = 0, -- NYI preload.
  161. }

  163. local map_media = {
  164.   shift = 20, mask = 31,
  165.   [0] = false,
  166.   { --01
  167.     shift = 5, mask = 7,
  168.     [0] = "sadd16DNM", "sasxDNM", "ssaxDNM", "ssub16DNM",
  169.     "sadd8DNM", false, false, "ssub8DNM",
  170.   },
  171.   { --02
  172.     shift = 5, mask = 7,
  173.     [0] = "qadd16DNM", "qasxDNM", "qsaxDNM", "qsub16DNM",
  174.     "qadd8DNM", false, false, "qsub8DNM",
  175.   },
  176.   { --03
  177.     shift = 5, mask = 7,
  178.     [0] = "shadd16DNM", "shasxDNM", "shsaxDNM", "shsub16DNM",
  179.     "shadd8DNM", false, false, "shsub8DNM",
  180.   },
  181.   false,
  182.   { --05
  183.     shift = 5, mask = 7,
  184.     [0] = "uadd16DNM", "uasxDNM", "usaxDNM", "usub16DNM",
  185.     "uadd8DNM", false, false, "usub8DNM",
  186.   },
  187.   { --06
  188.     shift = 5, mask = 7,
  189.     [0] = "uqadd16DNM", "uqasxDNM", "uqsaxDNM", "uqsub16DNM",
  190.     "uqadd8DNM", false, false, "uqsub8DNM",
  191.   },
  192.   { --07
  193.     shift = 5, mask = 7,
  194.     [0] = "uhadd16DNM", "uhasxDNM", "uhsaxDNM", "uhsub16DNM",
  195.     "uhadd8DNM", false, false, "uhsub8DNM",
  196.   },
  197.   { --08
  198.     shift = 5, mask = 7,
  199.     [0] = "pkhbtDNMU", false, "pkhtbDNMU",
  200.     { shift = 16, mask = 15, [15] = "sxtb16DMU", _ = "sxtab16DNMU", },
  201.     "pkhbtDNMU", "selDNM", "pkhtbDNMU",
  202.   },
  203.   false,
  204.   { --0a
  205.     shift = 5, mask = 7,
  206.     [0] = "ssatDxMu", "ssat16DxM", "ssatDxMu",
  207.     { shift = 16, mask = 15, [15] = "sxtbDMU", _ = "sxtabDNMU", },
  208.     "ssatDxMu", false, "ssatDxMu",
  209.   },
  210.   { --0b
  211.     shift = 5, mask = 7,
  212.     [0] = "ssatDxMu", "revDM", "ssatDxMu",
  213.     { shift = 16, mask = 15, [15] = "sxthDMU", _ = "sxtahDNMU", },
  214.     "ssatDxMu", "rev16DM", "ssatDxMu",
  215.   },
  216.   { --0c
  217.     shift = 5, mask = 7,
  218.     [3] = { shift = 16, mask = 15, [15] = "uxtb16DMU", _ = "uxtab16DNMU", },
  219.   },
  220.   false,
  221.   { --0e
  222.     shift = 5, mask = 7,
  223.     [0] = "usatDwMu", "usat16DwM", "usatDwMu",
  224.     { shift = 16, mask = 15, [15] = "uxtbDMU", _ = "uxtabDNMU", },
  225.     "usatDwMu", false, "usatDwMu",
  226.   },
  227.   { --0f
  228.     shift = 5, mask = 7,
  229.     [0] = "usatDwMu", "rbitDM", "usatDwMu",
  230.     { shift = 16, mask = 15, [15] = "uxthDMU", _ = "uxtahDNMU", },
  231.     "usatDwMu", "revshDM", "usatDwMu",
  232.   },
  233.   { --10
  234.     shift = 12, mask = 15,
  235.     [15] = {
  236.       shift = 5, mask = 7,
  237.       "smuadNMS", "smuadxNMS", "smusdNMS", "smusdxNMS",
  238.     },
  239.     _ = {
  240.       shift = 5, mask = 7,
  241.       [0] = "smladNMSD", "smladxNMSD", "smlsdNMSD", "smlsdxNMSD",
  242.     },
  243.   },
  244.   false, false, false,
  245.   { --14
  246.     shift = 5, mask = 7,
  247.     [0] = "smlaldDNMS", "smlaldxDNMS", "smlsldDNMS", "smlsldxDNMS",
  248.   },
  249.   { --15
  250.     shift = 5, mask = 7,
  251.     [0] = { shift = 12, mask = 15, [15] = "smmulNMS", _ = "smmlaNMSD", },
  252.     { shift = 12, mask = 15, [15] = "smmulrNMS", _ = "smmlarNMSD", },
  253.     false, false, false, false,
  254.     "smmlsNMSD", "smmlsrNMSD",
  255.   },
  256.   false, false,
  257.   { --18
  258.     shift = 5, mask = 7,
  259.     [0] = { shift = 12, mask = 15, [15] = "usad8NMS", _ = "usada8NMSD", },
  260.   },
  261.   false,
  262.   { --1a
  263.     shift = 5, mask = 3, [2] = "sbfxDMvw",
  264.   },
  265.   { --1b
  266.     shift = 5, mask = 3, [2] = "sbfxDMvw",
  267.   },
  268.   { --1c
  269.     shift = 5, mask = 3,
  270.     [0] = { shift = 0, mask = 15, [15] = "bfcDvX", _ = "bfiDMvX", },
  271.   },
  272.   { --1d
  273.     shift = 5, mask = 3,
  274.     [0] = { shift = 0, mask = 15, [15] = "bfcDvX", _ = "bfiDMvX", },
  275.   },
  276.   { --1e
  277.     shift = 5, mask = 3, [2] = "ubfxDMvw",
  278.   },
  279.   { --1f
  280.     shift = 5, mask = 3, [2] = "ubfxDMvw",
  281.   },
  282. }

  284. local map_load = {
  285.   shift = 21, mask = 9,
  286.   {
  287.     shift = 20, mask = 5,
  288.     [0] = "strtDL", "ldrtDL", [4] = "strbtDL", [5] = "ldrbtDL",
  289.   },
  290.   _ = {
  291.     shift = 20, mask = 5,
  292.     [0] = "strDL", "ldrDL", [4] = "strbDL", [5] = "ldrbDL",
  293.   }
  294. }

  296. local map_load1 = {
  297.   shift = 4, mask = 1,
  298.   [0] = map_load, map_media,
  299. }

  301. local map_loadm = {
  302.   shift = 20, mask = 1,
  303.   [0] = {
  304.     shift = 23, mask = 3,
  305.     [0] = "stmdaNR", "stmNR",
  306.     { shift = 16, mask = 63, [45] = "pushR", _ = "stmdbNR", }, "stmibNR",
  307.   },
  308.   {
  309.     shift = 23, mask = 3,
  310.     [0] = "ldmdaNR", { shift = 16, mask = 63, [61] = "popR", _ = "ldmNR", },
  311.     "ldmdbNR", "ldmibNR",
  312.   },
  313. }

  315. local map_data = {
  316.   shift = 21, mask = 15,
  317.   [0] = "andDNPs", "eorDNPs", "subDNPs", "rsbDNPs",
  318.   "addDNPs", "adcDNPs", "sbcDNPs", "rscDNPs",
  319.   "tstNP", "teqNP", "cmpNP", "cmnNP",
  320.   "orrDNPs", "movDPs", "bicDNPs", "mvnDPs",
  321. }

  323. local map_mul = {
  324.   shift = 21, mask = 7,
  325.   [0] = "mulNMSs", "mlaNMSDs", "umaalDNMS", "mlsDNMS",
  326.   "umullDNMSs", "umlalDNMSs", "smullDNMSs", "smlalDNMSs",
  327. }

  329. local map_sync = {
  330.   shift = 20, mask = 15, -- NYI: brackets around N. R(D+1) for ldrexd/strexd.
  331.   [0] = "swpDMN", false, false, false,
  332.   "swpbDMN", false, false, false,
  333.   "strexDMN", "ldrexDN", "strexdDN", "ldrexdDN",
  334.   "strexbDMN", "ldrexbDN", "strexhDN", "ldrexhDN",
  335. }

  337. local map_mulh = {
  338.   shift = 21, mask = 3,
  339.   [0] = { shift = 5, mask = 3,
  340.     [0] = "smlabbNMSD", "smlatbNMSD", "smlabtNMSD", "smlattNMSD", },
  341.   { shift = 5, mask = 3,
  342.     [0] = "smlawbNMSD", "smulwbNMS", "smlawtNMSD", "smulwtNMS", },
  343.   { shift = 5, mask = 3,
  344.     [0] = "smlalbbDNMS", "smlaltbDNMS", "smlalbtDNMS", "smlalttDNMS", },
  345.   { shift = 5, mask = 3,
  346.     [0] = "smulbbNMS", "smultbNMS", "smulbtNMS", "smulttNMS", },
  347. }

  349. local map_misc = {
  350.   shift = 4, mask = 7,
  351.   -- NYI: decode PSR bits of msr.
  352.   [0] = { shift = 21, mask = 1, [0] = "mrsD", "msrM", },
  353.   { shift = 21, mask = 3, "bxM", false, "clzDM", },
  354.   { shift = 21, mask = 3, "bxjM", },
  355.   { shift = 21, mask = 3, "blxM", },
  356.   false,
  357.   { shift = 21, mask = 3, [0] = "qaddDMN", "qsubDMN", "qdaddDMN", "qdsubDMN", },
  358.   false,
  359.   { shift = 21, mask = 3, "bkptK", },
  360. }

  362. local map_datar = {
  363.   shift = 4, mask = 9,
  364.   [9] = {
  365.     shift = 5, mask = 3,
  366.     [0] = { shift = 24, mask = 1, [0] = map_mul, map_sync, },
  367.     { shift = 20, mask = 1, [0] = "strhDL", "ldrhDL", },
  368.     { shift = 20, mask = 1, [0] = "ldrdDL", "ldrsbDL", },
  369.     { shift = 20, mask = 1, [0] = "strdDL", "ldrshDL", },
  370.   },
  371.   _ = {
  372.     shift = 20, mask = 25,
  373.     [16] = { shift = 7, mask = 1, [0] = map_misc, map_mulh, },
  374.     _ = {
  375.       shift = 0, mask = 0xffffffff,
  376.       [bor(0xe1a00000)] = "nop",
  377.       _ = map_data,
  378.     }
  379.   },
  380. }

  382. local map_datai = {
  383.   shift = 20, mask = 31, -- NYI: decode PSR bits of msr. Decode imm12.
  384.   [16] = "movwDW", [20] = "movtDW",
  385.   [18] = { shift = 0, mask = 0xf00ff, [0] = "nopv6", _ = "msrNW", },
  386.   [22] = "msrNW",
  387.   _ = map_data,
  388. }

  390. local map_branch = {
  391.   shift = 24, mask = 1,
  392.   [0] = "bB", "blB"
  393. }

  395. local map_condins = {
  396.   [0] = map_datar, map_datai, map_load, map_load1,
  397.   map_loadm, map_branch, map_loadc, map_datac
  398. }

  400. -- NYI: setend.
  401. local map_uncondins = {
  402.   [0] = false, map_simddata, map_simdload, map_preload,
  403.   false, "blxB", map_loadcu, map_datacu,
  404. }

  406. ------------------------------------------------------------------------------

  408. local map_gpr = {
  409.   [0] = "r0", "r1", "r2", "r3", "r4", "r5", "r6", "r7",
  410.   "r8", "r9", "r10", "r11", "r12", "sp", "lr", "pc",
  411. }

  413. local map_cond = {
  414.   [0] = "eq", "ne", "hs", "lo", "mi", "pl", "vs", "vc",
  415.   "hi", "ls", "ge", "lt", "gt", "le", "al",
  416. }

  418. local map_shift = { [0] = "lsl", "lsr", "asr", "ror", }

  420. ------------------------------------------------------------------------------

  422. -- Output a nicely formatted line with an opcode and operands.
  423. ‌local function putop(ctx, text, operands)
  424.   local pos = ctx.pos
  425.   local extra = ""
  426.   if ctx.rel then
  427.     local sym = ctx.symtab[ctx.rel]
  428.     if sym then
  429.       extra = "\t->"..sym
  430.     elseif band(ctx.op, 0x0e000000) ~= 0x0a000000 then
  431.       extra = "\t; 0x"..tohex(ctx.rel)
  432.     end
  433.   end
  434.   if ctx.hexdump > 0 then
  435.     ctx.out(format("%08x  %s  %-5s %s%s\n",
  436.             ctx.addr+pos, tohex(ctx.op), text, concat(operands, ", "), extra))
  437.   else
  438.     ctx.out(format("%08x  %-5s %s%s\n",
  439.             ctx.addr+pos, text, concat(operands, ", "), extra))
  440.   end
  441.   ctx.pos = pos + 4
  442. end

  444. -- Fallback for unknown opcodes.
  445. ‌local function unknown(ctx)
  446.   return putop(ctx, ".long", { "0x"..tohex(ctx.op) })
  447. end

  449. -- Format operand 2 of load/store opcodes.
  450. ‌local function fmtload(ctx, op, pos)
  451.   local base = map_gpr[band(rshift(op, 16), 15)]
  452.   local x, ofs
  453.   local ext = (band(op, 0x04000000) == 0)
  454.   if not ext and band(op, 0x02000000) == 0 then
  455.     ofs = band(op, 4095)
  456.     if band(op, 0x00800000) == 0 then ofs = -ofs end
  457.     if base == "pc" then ctx.rel = ctx.addr + pos + 8 + ofs end
  458.     ofs = "#"..ofs
  459.   elseif ext and band(op, 0x00400000) ~= 0 then
  460.     ofs = band(op, 15) + band(rshift(op, 4), 0xf0)
  461.     if band(op, 0x00800000) == 0 then ofs = -ofs end
  462.     if base == "pc" then ctx.rel = ctx.addr + pos + 8 + ofs end
  463.     ofs = "#"..ofs
  464.   else
  465.     ofs = map_gpr[band(op, 15)]
  466.     if ext or band(op, 0xfe0) == 0 then
  467.     elseif band(op, 0xfe0) == 0x60 then
  468.       ofs = format("%s, rrx", ofs)
  469.     else
  470.       local sh = band(rshift(op, 7), 31)
  471.       if sh == 0 then sh = 32 end
  472.       ofs = format("%s, %s #%d", ofs, map_shift[band(rshift(op, 5), 3)], sh)
  473.     end
  474.     if band(op, 0x00800000) == 0 then ofs = "-"..ofs end
  475.   end
  476.   if ofs == "#0" then
  477.     x = format("[%s]", base)
  478.   elseif band(op, 0x01000000) == 0 then
  479.     x = format("[%s], %s", base, ofs)
  480.   else
  481.     x = format("[%s, %s]", base, ofs)
  482.   end
  483.   if band(op, 0x01200000) == 0x01200000 then x = x.."!" end
  484.   return x
  485. end

  487. -- Format operand 2 of vector load/store opcodes.
  488. ‌local function fmtvload(ctx, op, pos)
  489.   local base = map_gpr[band(rshift(op, 16), 15)]
  490.   local ofs = band(op, 255)*4
  491.   if band(op, 0x00800000) == 0 then ofs = -ofs end
  492.   if base == "pc" then ctx.rel = ctx.addr + pos + 8 + ofs end
  493.   if ofs == 0 then
  494.     return format("[%s]", base)
  495.   else
  496.     return format("[%s, #%d]", base, ofs)
  497.   end
  498. end

  500. ‌local function fmtvr(op, vr, sh0, sh1)
  501.   if vr == "s" then
  502.     return format("s%d", 2*band(rshift(op, sh0), 15)+band(rshift(op, sh1), 1))
  503.   else
  504.     return format("d%d", band(rshift(op, sh0), 15)+band(rshift(op, sh1-4), 16))
  505.   end
  506. end

  508. -- Disassemble a single instruction.
  509. ‌local function disass_ins(ctx)
  510.   local pos = ctx.pos
  511.   local b0, b1, b2, b3 = byte(ctx.code, pos+1, pos+4)
  512.   local op = bor(lshift(b3, 24), lshift(b2, 16), lshift(b1, 8), b0)
  513.   local operands = {}
  514.   local suffix = ""
  515.   local last, name, pat
  516.   local vr
  517.   ctx.op = op
  518.   ctx.rel = nil

  520.   local cond = rshift(op, 28)
  521.   local opat
  522.   if cond == 15 then
  523.     opat = map_uncondins[band(rshift(op, 25), 7)]
  524.   else
  525.     if cond ~= 14 then suffix = map_cond[cond] end
  526.     opat = map_condins[band(rshift(op, 25), 7)]
  527.   end
  528.   while type(opat) ~= "string" do
  529.     if not opat then return unknown(ctx) end
  530.     opat = opat[band(rshift(op, opat.shift), opat.mask)] or opat._
  531.   end
  532.   name, pat = match(opat, "^([a-z0-9]*)(.*)")
  533.   if sub(pat, 1, 1) == "." then
  534.     local s2, p2 = match(pat, "^([a-z0-9.]*)(.*)")
  535.     suffix = suffix..s2
  536.     pat = p2
  537.   end

  539.   for p in gmatch(pat, ".") do
  540.     local x = nil
  541.     if p == "D" then
  542.       x = map_gpr[band(rshift(op, 12), 15)]
  543.     elseif p == "N" then
  544.       x = map_gpr[band(rshift(op, 16), 15)]
  545.     elseif p == "S" then
  546.       x = map_gpr[band(rshift(op, 8), 15)]
  547.     elseif p == "M" then
  548.       x = map_gpr[band(op, 15)]
  549.     elseif p == "d" then
  550.       x = fmtvr(op, vr, 12, 22)
  551.     elseif p == "n" then
  552.       x = fmtvr(op, vr, 16, 7)
  553.     elseif p == "m" then
  554.       x = fmtvr(op, vr, 0, 5)
  555.     elseif p == "P" then
  556.       if band(op, 0x02000000) ~= 0 then
  557.         x = ror(band(op, 255), 2*band(rshift(op, 8), 15))
  558.       else
  559.         x = map_gpr[band(op, 15)]
  560.         if band(op, 0xff0) ~= 0 then
  561.           operands[#operands+1] = x
  562.           local s = map_shift[band(rshift(op, 5), 3)]
  563.           local r = nil
  564.           if band(op, 0xf90) == 0 then
  565.             if s == "ror" then s = "rrx" else r = "#32" end
  566.           elseif band(op, 0x10) == 0 then
  567.             r = "#"..band(rshift(op, 7), 31)
  568.           else
  569.             r = map_gpr[band(rshift(op, 8), 15)]
  570.           end
  571.           if name == "mov" then name = s; x = r
  572.           elseif r then x = format("%s %s", s, r)
  573.           else x = s end
  574.         end
  575.       end
  576.     elseif p == "L" then
  577.       x = fmtload(ctx, op, pos)
  578.     elseif p == "l" then
  579.       x = fmtvload(ctx, op, pos)
  580.     elseif p == "B" then
  581.       local addr = ctx.addr + pos + 8 + arshift(lshift(op, 8), 6)
  582.       if cond == 15 then addr = addr + band(rshift(op, 23), 2) end
  583.       ctx.rel = addr
  584.       x = "0x"..tohex(addr)
  585.     elseif p == "F" then
  586.       vr = "s"
  587.     elseif p == "G" then
  588.       vr = "d"
  589.     elseif p == "." then
  590.       suffix = suffix..(vr == "s" and ".f32" or ".f64")
  591.     elseif p == "R" then
  592.       if band(op, 0x00200000) ~= 0 and #operands == 1 then
  593.         operands[1] = operands[1].."!"
  594.       end
  595.       local t = {}
  596.       for i=0,15 do
  597.         if band(rshift(op, i), 1) == 1 then t[#t+1] = map_gpr[i] end
  598.       end
  599.       x = "{"..concat(t, ", ").."}"
  600.     elseif p == "r" then
  601.       if band(op, 0x00200000) ~= 0 and #operands == 2 then
  602.         operands[1] = operands[1].."!"
  603.       end
  604.       local s = tonumber(sub(last, 2))
  605.       local n = band(op, 255)
  606.       if vr == "d" then n = rshift(n, 1) end
  607.       operands[#operands] = format("{%s-%s%d}", last, vr, s+n-1)
  608.     elseif p == "W" then
  609.       x = band(op, 0x0fff) + band(rshift(op, 4), 0xf000)
  610.     elseif p == "T" then
  611.       x = "#0x"..tohex(band(op, 0x00ffffff), 6)
  612.     elseif p == "U" then
  613.       x = band(rshift(op, 7), 31)
  614.       if x == 0 then x = nil end
  615.     elseif p == "u" then
  616.       x = band(rshift(op, 7), 31)
  617.       if band(op, 0x40) == 0 then
  618.         if x == 0 then x = nil else x = "lsl #"..x end
  619.       else
  620.         if x == 0 then x = "asr #32" else x = "asr #"..x end
  621.       end
  622.     elseif p == "v" then
  623.       x = band(rshift(op, 7), 31)
  624.     elseif p == "w" then
  625.       x = band(rshift(op, 16), 31)
  626.     elseif p == "x" then
  627.       x = band(rshift(op, 16), 31) + 1
  628.     elseif p == "X" then
  629.       x = band(rshift(op, 16), 31) - last + 1
  630.     elseif p == "Y" then
  631.       x = band(rshift(op, 12), 0xf0) + band(op, 0x0f)
  632.     elseif p == "K" then
  633.       x = "#0x"..tohex(band(rshift(op, 4), 0x0000fff0) + band(op, 15), 4)
  634.     elseif p == "s" then
  635.       if band(op, 0x00100000) ~= 0 then suffix = "s"..suffix end
  636.     else
  637.       assert(false)
  638.     end
  639.     if x then
  640.       last = x
  641.       if type(x) == "number" then x = "#"..x end
  642.       operands[#operands+1] = x
  643.     end
  644.   end

  646.   return putop(ctx, name..suffix, operands)
  647. end

  649. ------------------------------------------------------------------------------

  651. -- Disassemble a block of code.
  652. ‌local function disass_block(ctx, ofs, len)
  653.   if not ofs then ofs = 0 end
  654.   local stop = len and ofs+len or #ctx.code
  655.   ctx.pos = ofs
  656.   ctx.rel = nil
  657.   while ctx.pos < stop do disass_ins(ctx) end
  658. end

  660. -- Extended API: create a disassembler context. Then call ctx:disass(ofs, len).
  661. ‌local function create(code, addr, out)
  662.   local ctx = {}
  663.   ctx.code = code
  664.   ctx.addr = addr or 0
  665.   ctx.out = out or io.write
  666.   ctx.symtab = {}
  667.   ctx.disass = disass_block
  668.   ctx.hexdump = 8
  669.   return ctx
  670. end

  672. -- Simple API: disassemble code (a string) at address and output via out.
  673. ‌local function disass(code, addr, out)
  674.   create(code, addr, out):disass()
  675. end

  677. -- Return register name for RID.
  678. ‌local function regname(r)
  679.   if r < 16 then return map_gpr[r] end
  680.   return "d"..(r-16)
  681. end

  683. -- Public module functions.
  684. return {
  685.   create = create,
  686.   disass = disass,
  687.   regname = regname
  688. }

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