lib/dis_ppc.lua

   1 ----------------------------------------------------------------------------
   2 -- LuaJIT PPC disassembler module.
   3 --
   4 -- Copyright (C) 2005-2010 Mike Pall. All rights reserved.
   5 -- Released under the MIT/X 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 all common, non-privileged 32/64 bit PowerPC instructions
  10 -- plus the e500 SPE instructions and some Cell/Xenon extensions.
  11 --
  12 -- NYI: VMX, VMX128
  13 ------------------------------------------------------------------------------
  14
  15 local type = type
  16 local sub, byte, format = string.sub, string.byte, string.format
  17 local match, gmatch, gsub = string.match, string.gmatch, string.gsub
  18 local concat = table.concat
  19 local bit = require("bit")
  20 local band, bor, tohex = bit.band, bit.bor, bit.tohex
  21 local lshift, rshift, arshift = bit.lshift, bit.rshift, bit.arshift
  22
  23 ------------------------------------------------------------------------------
  24 -- Primary and extended opcode maps
  25 ------------------------------------------------------------------------------
  26
  27 local map_crops = {
  28   shift = 1, mask = 1023,
  29   [0] = "mcrfXX",
  30   [33] = "crnor|crnotCCC=", [129] = "crandcCCC",
  31   [193] = "crxor|crclrCCC%", [225] = "crnandCCC",
  32   [257] = "crandCCC", [289] = "creqv|crsetCCC%",
  33   [417] = "crorcCCC", [449] = "cror|crmoveCCC=",
  34   [16] = "b_lrKB", [528] = "b_ctrKB",
  35   [150] = "isync",
  36 }
  37
  38 local map_rld = {
  39   shift = 2, mask = 7,
  40   [0] = "rldiclRR~HM.", "rldicrRR~HM.", "rldicRR~HM.", "rldimiRR~HM.",
  41   {
  42     shift = 1, mask = 1,
  43     [0] = "rldclRR~HM.", "rldcrRR~HM.",
  44   },
  45 }
  46
  47 local map_ext = setmetatable({
  48   shift = 1, mask = 1023,
  49
  50   [0] = "cmp_YLRR", [32] = "cmpl_YLRR",
  51   [4] = "twARR", [68] = "tdARR",
  52
  53   [8] = "subfcRRR.", [40] = "subfRRR.",
  54   [104] = "negRR.", [136] = "subfeRRR.",
  55   [200] = "subfzeRR.", [232] = "subfmeRR.",
  56   [520] = "subfcoRRR.", [552] = "subfoRRR.",
  57   [616] = "negoRR.", [648] = "subfeoRRR.",
  58   [712] = "subfzeoRR.", [744] = "subfmeoRR.",
  59
  60   [9] = "mulhduRRR.", [73] = "mulhdRRR.", [233] = "mulldRRR.",
  61   [457] = "divduRRR.", [489] = "divdRRR.",
  62   [745] = "mulldoRRR.",
  63   [969] = "divduoRRR.", [1001] = "divdoRRR.",
  64
  65   [10] = "addcRRR.", [138] = "addeRRR.",
  66   [202] = "addzeRR.", [234] = "addmeRR.", [266] = "addRRR.",
  67   [522] = "addcoRRR.", [650] = "addeoRRR.",
  68   [714] = "addzeoRR.", [746] = "addmeoRR.", [778] = "addoRRR.",
  69
  70   [11] = "mulhwuRRR.", [75] = "mulhwRRR.", [235] = "mullwRRR.",
  71   [459] = "divwuRRR.", [491] = "divwRRR.",
  72   [747] = "mullwoRRR.",
  73   [971] = "divwouRRR.", [1003] = "divwoRRR.",
  74
  75   [15] = "iselltRRR", [47] = "iselgtRRR", [79] = "iseleqRRR",
  76
  77   [144] = { shift = 20, mask = 1, [0] = "mtcrfRZ~", "mtocrfRZ~", },
  78   [19] = { shift = 20, mask = 1, [0] = "mfcrR", "mfocrfRZ", },
  79   [371] = { shift = 11, mask = 1023, [392] = "mftbR", [424] = "mftbuR", },
  80   [339] = {
  81     shift = 11, mask = 1023,
  82     [32] = "mferR", [256] = "mflrR", [288] = "mfctrR", [16] = "mfspefscrR",
  83   },
  84   [467] = {
  85     shift = 11, mask = 1023,
  86     [32] = "mtxerR", [256] = "mtlrR", [288] = "mtctrR", [16] = "mtspefscrR",
  87   },
  88
  89   [20] = "lwarxRR0R", [84] = "ldarxRR0R",
  90
  91   [21] = "ldxRR0R", [53] = "lduxRRR",
  92   [149] = "stdxRR0R", [181] = "stduxRRR",
  93   [341] = "lwaxRR0R", [373] = "lwauxRRR",
  94
  95   [23] = "lwzxRR0R", [55] = "lwzuxRRR",
  96   [87] = "lbzxRR0R", [119] = "lbzuxRRR",
  97   [151] = "stwxRR0R", [183] = "stwuxRRR",
  98   [215] = "stbxRR0R", [247] = "stbuxRRR",
  99   [279] = "lhzxRR0R", [311] = "lhzuxRRR",
 100   [343] = "lhaxRR0R", [375] = "lhauxRRR",
 101   [407] = "sthxRR0R", [439] = "sthuxRRR",
 102
 103   [54] = "dcbst-R0R", [86] = "dcbf-R0R",
 104   [150] = "stwcxRR0R.", [214] = "stdcxRR0R.",
 105   [246] = "dcbtst-R0R", [278] = "dcbt-R0R",
 106   [310] = "eciwxRR0R", [438] = "ecowxRR0R",
 107   [470] = "dcbi-RR",
 108
 109   [598] = {
 110     shift = 21, mask = 3,
 111     [0] = "sync", "lwsync", "ptesync",
 112   },
 113   [758] = "dcba-RR",
 114   [854] = "eieio", [982] = "icbi-R0R", [1014] = "dcbz-R0R",
 115
 116   [26] = "cntlzwRR~", [58] = "cntlzdRR~",
 117   [122] = "popcntbRR~",
 118   [154] = "prtywRR~", [186] = "prtydRR~",
 119
 120   [28] = "andRR~R.", [60] = "andcRR~R.", [124] = "nor|notRR~R=.",
 121   [284] = "eqvRR~R.", [316] = "xorRR~R.",
 122   [412] = "orcRR~R.", [444] = "or|mrRR~R=.", [476] = "nandRR~R.",
 123   [508] = "cmpbRR~R",
 124
 125   [512] = "mcrxrX",
 126
 127   [532] = "ldbrxRR0R", [660] = "stdbrxRR0R",
 128
 129   [533] = "lswxRR0R", [597] = "lswiRR0A",
 130   [661] = "stswxRR0R", [725] = "stswiRR0A",
 131
 132   [534] = "lwbrxRR0R", [662] = "stwbrxRR0R",
 133   [790] = "lhbrxRR0R", [918] = "sthbrxRR0R",
 134
 135   [535] = "lfsxFR0R", [567] = "lfsuxFRR",
 136   [599] = "lfdxFR0R", [631] = "lfduxFRR",
 137   [663] = "stfsxFR0R", [695] = "stfsuxFRR",
 138   [727] = "stfdxFR0R", [759] = "stfduxFR0R",
 139   [855] = "lfiwaxFR0R",
 140   [983] = "stfiwxFR0R",
 141
 142   [24] = "slwRR~R.",
 143
 144   [27] = "sldRR~R.", [536] = "srwRR~R.",
 145   [792] = "srawRR~R.", [824] = "srawiRR~A.",
 146
 147   [794] = "sradRR~R.", [826] = "sradiRR~H.", [827] = "sradiRR~H.",
 148   [922] = "extshRR~.", [954] = "extsbRR~.", [986] = "extswRR~.",
 149
 150   [539] = "srdRR~R.",
 151 },
 152 { __index = function(t, x)
 153     if band(x, 31) == 15 then return "iselRRRC" end
 154   end
 155 })
 156
 157 local map_ld = {
 158   shift = 0, mask = 3,
 159   [0] = "ldRRE", "lduRRE", "lwaRRE",
 160 }
 161
 162 local map_std = {
 163   shift = 0, mask = 3,
 164   [0] = "stdRRE", "stduRRE",
 165 }
 166
 167 local map_fps = {
 168   shift = 5, mask = 1,
 169   {
 170     shift = 1, mask = 15,
 171     [0] = false, false, "fdivsFFF.", false,
 172     "fsubsFFF.", "faddsFFF.", "fsqrtsF-F.", false,
 173     "fresF-F.", "fmulsFF-F.", "frsqrtesF-F.", false,
 174     "fmsubsFFFF~.", "fmaddsFFFF~.", "fnmsubsFFFF~.", "fnmaddsFFFF~.",
 175   }
 176 }
 177
 178 local map_fpd = {
 179   shift = 5, mask = 1,
 180   [0] = {
 181     shift = 1, mask = 1023,
 182     [0] = "fcmpuXFF", [32] = "fcmpoXFF", [64] = "mcrfsXX",
 183     [38] = "mtfsb1A.", [70] = "mtfsb0A.", [134] = "mtfsfiA>>-A>",
 184     [8] = "fcpsgnFFF.", [40] = "fnegF-F.", [72] = "fmrF-F.",
 185     [136] = "fnabsF-F.", [264] = "fabsF-F.",
 186     [12] = "frspF-F.",
 187     [14] = "fctiwF-F.", [15] = "fctiwzF-F.",
 188     [583] = "mffsF.", [711] = "mtfsfZF.",
 189     [392] = "frinF-F.", [424] = "frizF-F.",
 190     [456] = "fripF-F.", [488] = "frimF-F.",
 191     [814] = "fctidF-F.", [815] = "fctidzF-F.", [846] = "fcfidF-F.",
 192   },
 193   {
 194     shift = 1, mask = 15,
 195     [0] = false, false, "fdivFFF.", false,
 196     "fsubFFF.", "faddFFF.", "fsqrtF-F.", "fselFFFF~.",
 197     "freF-F.", "fmulFF-F.", "frsqrteF-F.", false,
 198     "fmsubFFFF~.", "fmaddFFFF~.", "fnmsubFFFF~.", "fnmaddFFFF~.",
 199   }
 200 }
 201
 202 local map_spe = {
 203   shift = 0, mask = 2047,
 204
 205   [512] = "evaddwRRR", [514] = "evaddiwRAR~",
 206   [516] = "evsubwRRR~", [518] = "evsubiwRAR~",
 207   [520] = "evabsRR", [521] = "evnegRR",
 208   [522] = "evextsbRR", [523] = "evextshRR", [524] = "evrndwRR",
 209   [525] = "evcntlzwRR", [526] = "evcntlswRR",
 210
 211   [527] = "brincRRR",
 212
 213   [529] = "evandRRR", [530] = "evandcRRR", [534] = "evxorRRR",
 214   [535] = "evor|evmrRRR=", [536] = "evnor|evnotRRR=",
 215   [537] = "eveqvRRR", [539] = "evorcRRR", [542] = "evnandRRR",
 216
 217   [544] = "evsrwuRRR", [545] = "evsrwsRRR",
 218   [546] = "evsrwiuRRA", [547] = "evsrwisRRA",
 219   [548] = "evslwRRR", [550] = "evslwiRRA",
 220   [552] = "evrlwRRR", [553] = "evsplatiRS",
 221   [554] = "evrlwiRRA", [555] = "evsplatfiRS",
 222   [556] = "evmergehiRRR", [557] = "evmergeloRRR",
 223   [558] = "evmergehiloRRR", [559] = "evmergelohiRRR",
 224
 225   [560] = "evcmpgtuYRR", [561] = "evcmpgtsYRR",
 226   [562] = "evcmpltuYRR", [563] = "evcmpltsYRR",
 227   [564] = "evcmpeqYRR",
 228
 229   [632] = "evselRRR", [633] = "evselRRRW",
 230   [634] = "evselRRRW", [635] = "evselRRRW",
 231   [636] = "evselRRRW", [637] = "evselRRRW",
 232   [638] = "evselRRRW", [639] = "evselRRRW",
 233
 234   [640] = "evfsaddRRR", [641] = "evfssubRRR",
 235   [644] = "evfsabsRR", [645] = "evfsnabsRR", [646] = "evfsnegRR",
 236   [648] = "evfsmulRRR", [649] = "evfsdivRRR",
 237   [652] = "evfscmpgtYRR", [653] = "evfscmpltYRR", [654] = "evfscmpeqYRR",
 238   [656] = "evfscfuiR-R", [657] = "evfscfsiR-R",
 239   [658] = "evfscfufR-R", [659] = "evfscfsfR-R",
 240   [660] = "evfsctuiR-R", [661] = "evfsctsiR-R",
 241   [662] = "evfsctufR-R", [663] = "evfsctsfR-R",
 242   [664] = "evfsctuizR-R", [666] = "evfsctsizR-R",
 243   [668] = "evfststgtYRR", [669] = "evfststltYRR", [670] = "evfststeqYRR",
 244
 245   [704] = "efsaddRRR", [705] = "efssubRRR",
 246   [708] = "efsabsRR", [709] = "efsnabsRR", [710] = "efsnegRR",
 247   [712] = "efsmulRRR", [713] = "efsdivRRR",
 248   [716] = "efscmpgtYRR", [717] = "efscmpltYRR", [718] = "efscmpeqYRR",
 249   [719] = "efscfdR-R",
 250   [720] = "efscfuiR-R", [721] = "efscfsiR-R",
 251   [722] = "efscfufR-R", [723] = "efscfsfR-R",
 252   [724] = "efsctuiR-R", [725] = "efsctsiR-R",
 253   [726] = "efsctufR-R", [727] = "efsctsfR-R",
 254   [728] = "efsctuizR-R", [730] = "efsctsizR-R",
 255   [732] = "efststgtYRR", [733] = "efststltYRR", [734] = "efststeqYRR",
 256
 257   [736] = "efdaddRRR", [737] = "efdsubRRR",
 258   [738] = "efdcfuidR-R", [739] = "efdcfsidR-R",
 259   [740] = "efdabsRR", [741] = "efdnabsRR", [742] = "efdnegRR",
 260   [744] = "efdmulRRR", [745] = "efddivRRR",
 261   [746] = "efdctuidzR-R", [747] = "efdctsidzR-R",
 262   [748] = "efdcmpgtYRR", [749] = "efdcmpltYRR", [750] = "efdcmpeqYRR",
 263   [751] = "efdcfsR-R",
 264   [752] = "efdcfuiR-R", [753] = "efdcfsiR-R",
 265   [754] = "efdcfufR-R", [755] = "efdcfsfR-R",
 266   [756] = "efdctuiR-R", [757] = "efdctsiR-R",
 267   [758] = "efdctufR-R", [759] = "efdctsfR-R",
 268   [760] = "efdctuizR-R", [762] = "efdctsizR-R",
 269   [764] = "efdtstgtYRR", [765] = "efdtstltYRR", [766] = "efdtsteqYRR",
 270
 271   [768] = "evlddxRR0R", [769] = "evlddRR8",
 272   [770] = "evldwxRR0R", [771] = "evldwRR8",
 273   [772] = "evldhxRR0R", [773] = "evldhRR8",
 274   [776] = "evlhhesplatxRR0R", [777] = "evlhhesplatRR2",
 275   [780] = "evlhhousplatxRR0R", [781] = "evlhhousplatRR2",
 276   [782] = "evlhhossplatxRR0R", [783] = "evlhhossplatRR2",
 277   [784] = "evlwhexRR0R", [785] = "evlwheRR4",
 278   [788] = "evlwhouxRR0R", [789] = "evlwhouRR4",
 279   [790] = "evlwhosxRR0R", [791] = "evlwhosRR4",
 280   [792] = "evlwwsplatxRR0R", [793] = "evlwwsplatRR4",
 281   [796] = "evlwhsplatxRR0R", [797] = "evlwhsplatRR4",
 282
 283   [800] = "evstddxRR0R", [801] = "evstddRR8",
 284   [802] = "evstdwxRR0R", [803] = "evstdwRR8",
 285   [804] = "evstdhxRR0R", [805] = "evstdhRR8",
 286   [816] = "evstwhexRR0R", [817] = "evstwheRR4",
 287   [820] = "evstwhoxRR0R", [821] = "evstwhoRR4",
 288   [824] = "evstwwexRR0R", [825] = "evstwweRR4",
 289   [828] = "evstwwoxRR0R", [829] = "evstwwoRR4",
 290
 291   [1027] = "evmhessfRRR", [1031] = "evmhossfRRR", [1032] = "evmheumiRRR",
 292   [1033] = "evmhesmiRRR", [1035] = "evmhesmfRRR", [1036] = "evmhoumiRRR",
 293   [1037] = "evmhosmiRRR", [1039] = "evmhosmfRRR", [1059] = "evmhessfaRRR",
 294   [1063] = "evmhossfaRRR", [1064] = "evmheumiaRRR", [1065] = "evmhesmiaRRR",
 295   [1067] = "evmhesmfaRRR", [1068] = "evmhoumiaRRR", [1069] = "evmhosmiaRRR",
 296   [1071] = "evmhosmfaRRR", [1095] = "evmwhssfRRR", [1096] = "evmwlumiRRR",
 297   [1100] = "evmwhumiRRR", [1101] = "evmwhsmiRRR", [1103] = "evmwhsmfRRR",
 298   [1107] = "evmwssfRRR", [1112] = "evmwumiRRR", [1113] = "evmwsmiRRR",
 299   [1115] = "evmwsmfRRR", [1127] = "evmwhssfaRRR", [1128] = "evmwlumiaRRR",
 300   [1132] = "evmwhumiaRRR", [1133] = "evmwhsmiaRRR", [1135] = "evmwhsmfaRRR",
 301   [1139] = "evmwssfaRRR", [1144] = "evmwumiaRRR", [1145] = "evmwsmiaRRR",
 302   [1147] = "evmwsmfaRRR",
 303
 304   [1216] = "evaddusiaawRR", [1217] = "evaddssiaawRR",
 305   [1218] = "evsubfusiaawRR", [1219] = "evsubfssiaawRR",
 306   [1220] = "evmraRR",
 307   [1222] = "evdivwsRRR", [1223] = "evdivwuRRR",
 308   [1224] = "evaddumiaawRR", [1225] = "evaddsmiaawRR",
 309   [1226] = "evsubfumiaawRR", [1227] = "evsubfsmiaawRR",
 310
 311   [1280] = "evmheusiaawRRR", [1281] = "evmhessiaawRRR",
 312   [1283] = "evmhessfaawRRR", [1284] = "evmhousiaawRRR",
 313   [1285] = "evmhossiaawRRR", [1287] = "evmhossfaawRRR",
 314   [1288] = "evmheumiaawRRR", [1289] = "evmhesmiaawRRR",
 315   [1291] = "evmhesmfaawRRR", [1292] = "evmhoumiaawRRR",
 316   [1293] = "evmhosmiaawRRR", [1295] = "evmhosmfaawRRR",
 317   [1320] = "evmhegumiaaRRR", [1321] = "evmhegsmiaaRRR",
 318   [1323] = "evmhegsmfaaRRR", [1324] = "evmhogumiaaRRR",
 319   [1325] = "evmhogsmiaaRRR", [1327] = "evmhogsmfaaRRR",
 320   [1344] = "evmwlusiaawRRR", [1345] = "evmwlssiaawRRR",
 321   [1352] = "evmwlumiaawRRR", [1353] = "evmwlsmiaawRRR",
 322   [1363] = "evmwssfaaRRR", [1368] = "evmwumiaaRRR",
 323   [1369] = "evmwsmiaaRRR", [1371] = "evmwsmfaaRRR",
 324   [1408] = "evmheusianwRRR", [1409] = "evmhessianwRRR",
 325   [1411] = "evmhessfanwRRR", [1412] = "evmhousianwRRR",
 326   [1413] = "evmhossianwRRR", [1415] = "evmhossfanwRRR",
 327   [1416] = "evmheumianwRRR", [1417] = "evmhesmianwRRR",
 328   [1419] = "evmhesmfanwRRR", [1420] = "evmhoumianwRRR",
 329   [1421] = "evmhosmianwRRR", [1423] = "evmhosmfanwRRR",
 330   [1448] = "evmhegumianRRR", [1449] = "evmhegsmianRRR",
 331   [1451] = "evmhegsmfanRRR", [1452] = "evmhogumianRRR",
 332   [1453] = "evmhogsmianRRR", [1455] = "evmhogsmfanRRR",
 333   [1472] = "evmwlusianwRRR", [1473] = "evmwlssianwRRR",
 334   [1480] = "evmwlumianwRRR", [1481] = "evmwlsmianwRRR",
 335   [1491] = "evmwssfanRRR", [1496] = "evmwumianRRR",
 336   [1497] = "evmwsmianRRR", [1499] = "evmwsmfanRRR",
 337 }
 338
 339 local map_pri = {
 340   [0] = false,  false,          "tdiARI",       "twiARI",
 341   map_spe,      false,          false,          "mulliRRI",
 342   "subficRRI",  false,          "cmpl_iYLRU",   "cmp_iYLRI",
 343   "addicRRI",   "addic.RRI",    "addi|liRR0I",  "addis|lisRR0I",
 344   "b_KBJ",      "sc",            "bKJ",         map_crops,
 345   "rlwimiRR~AAA.", "rlwinmRR~AAA.", false,      "rlwnmRR~RAA.",
 346   "oriNRR~U",   "orisRR~U",     "xoriRR~U",     "xorisRR~U",
 347   "andi.RR~U",  "andis.RR~U",   map_rld,        map_ext,
 348   "lwzRRD",     "lwzuRRD",      "lbzRRD",       "lbzuRRD",
 349   "stwRRD",     "stwuRRD",      "stbRRD",       "stbuRRD",
 350   "lhzRRD",     "lhzuRRD",      "lhaRRD",       "lhauRRD",
 351   "sthRRD",     "sthuRRD",      "lmwRRD",       "stmwRRD",
 352   "lfsFRD",     "lfsuFRD",      "lfdFRD",       "lfduFRD",
 353   "stfsFRD",    "stfsuFRD",     "stfdFRD",      "stfduFRD",
 354   false,        false,          map_ld,         map_fps,
 355   false,        false,          map_std,        map_fpd,
 356 }
 357
 358 ------------------------------------------------------------------------------
 359
 360 local map_gpr = {
 361   [0] = "r0", "sp", "r2", "r3", "r4", "r5", "r6", "r7",
 362   "r8", "r9", "r10", "r11", "r12", "r13", "r14", "r15",
 363   "r16", "r17", "r18", "r19", "r20", "r21", "r22", "r23",
 364   "r24", "r25", "r26", "r27", "r28", "r29", "r30", "r31",
 365 }
 366
 367 local map_cond = { [0] = "lt", "gt", "eq", "so", "ge", "le", "ne", "ns", }
 368
 369 -- Format a condition bit.
 370 local function condfmt(cond)
 371   if cond <= 3 then
 372     return map_cond[band(cond, 3)]
 373   else
 374     return format("4*cr%d+%s", rshift(cond, 2), map_cond[band(cond, 3)])
 375   end
 376 end
 377
 378 ------------------------------------------------------------------------------
 379
 380 -- Output a nicely formatted line with an opcode and operands.
 381 local function putop(ctx, text, operands)
 382   local pos = ctx.pos
 383   local extra = ""
 384   if ctx.rel then
 385     local sym = ctx.symtab[ctx.rel]
 386     if sym then extra = "\t->"..sym end
 387   end
 388   if ctx.hexdump > 0 then
 389     ctx.out(format("%08x  %s  %-7s %s%s\n",
 390             ctx.addr+pos, tohex(ctx.op), text, concat(operands, ", "), extra))
 391   else
 392     ctx.out(format("%08x  %-7s %s%s\n",
 393             ctx.addr+pos, text, concat(operands, ", "), extra))
 394   end
 395   ctx.pos = pos + 4
 396 end
 397
 398 -- Fallback for unknown opcodes.
 399 local function unknown(ctx)
 400   return putop(ctx, ".long", { "0x"..tohex(ctx.op) })
 401 end
 402
 403 -- Disassemble a single instruction.
 404 local function disass_ins(ctx)
 405   local pos = ctx.pos
 406   local b0, b1, b2, b3 = byte(ctx.code, pos+1, pos+4)
 407   local op = bor(lshift(b0, 24), lshift(b1, 16), lshift(b2, 8), b3)
 408   local operands = {}
 409   local last = nil
 410   local rs = 21
 411   ctx.op = op
 412   ctx.rel = nil
 413
 414   local opat = map_pri[rshift(b0, 2)]
 415   while type(opat) ~= "string" do
 416     if not opat then return unknown(ctx) end
 417     opat = opat[band(rshift(op, opat.shift), opat.mask)]
 418   end
 419   local name, pat = match(opat, "^([a-z0-9_.]*)(.*)")
 420   local altname, pat2 = match(pat, "|([a-z0-9_.]*)(.*)")
 421   if altname then pat = pat2 end
 422
 423   for p in gmatch(pat, ".") do
 424     local x = nil
 425     if p == "R" then
 426       x = map_gpr[band(rshift(op, rs), 31)]
 427       rs = rs - 5
 428     elseif p == "F" then
 429       x = "f"..band(rshift(op, rs), 31)
 430       rs = rs - 5
 431     elseif p == "A" then
 432       x = band(rshift(op, rs), 31)
 433       rs = rs - 5
 434     elseif p == "S" then
 435       x = arshift(lshift(op, 27-rs), 27)
 436       rs = rs - 5
 437     elseif p == "I" then
 438       x = arshift(lshift(op, 16), 16)
 439     elseif p == "U" then
 440       x = band(op, 0xffff)
 441     elseif p == "D" or p == "E" then
 442       local disp = arshift(lshift(op, 16), 16)
 443       if p == "E" then disp = band(disp, -4) end
 444       if last == "r0" then last = "0" end
 445       operands[#operands] = format("%d(%s)", disp, last)
 446     elseif p >= "2" and p <= "8" then
 447       local disp = band(rshift(op, rs), 31) * p
 448       if last == "r0" then last = "0" end
 449       operands[#operands] = format("%d(%s)", disp, last)
 450     elseif p == "H" then
 451       x = band(rshift(op, rs), 31) + lshift(band(op, 2), 4)
 452       rs = rs - 5
 453     elseif p == "M" then
 454       x = band(rshift(op, rs), 31) + band(op, 0x20)
 455     elseif p == "C" then
 456       x = condfmt(band(rshift(op, rs), 31))
 457       rs = rs - 5
 458     elseif p == "B" then
 459       local bo = rshift(op, 21)
 460       local cond = band(rshift(op, 16), 31)
 461       local cn = ""
 462       rs = rs - 10
 463       if band(bo, 4) == 0 then
 464         cn = band(bo, 2) == 0 and "dnz" or "dz"
 465         if band(bo, 0x10) == 0 then
 466           cn = cn..(band(bo, 8) == 0 and "f" or "t")
 467           if band(bo, 1) ~= 0 then
 468             name = name..(band(op, 0x8000) ~= 0 and "-" or "+")
 469           end
 470         elseif band(bo, 8) ~= 0 then
 471           name = name..(band(bo, 1) == 0 and "-" or "+")
 472         elseif band(bo, 1) ~= 0 then
 473           name = name..(band(op, 0x8000) ~= 0 and "-" or "+")
 474         end
 475         if band(bo, 0x10) == 0 then x = condfmt(cond) end
 476       elseif band(bo, 0x10) == 0 then
 477         cn = map_cond[band(cond, 3) + (band(bo, 8) == 0 and 4 or 0)]
 478         if band(bo, 2) ~= 0 then
 479           name = name..(band(bo, 1) == 0 and "-" or "+")
 480         elseif band(bo, 1) ~= 0 then
 481           name = name..(band(op, 0x8000) ~= 0 and "-" or "+")
 482         end
 483         if cond > 3 then x = "cr"..rshift(cond, 2) end
 484       end
 485       name = gsub(name, "_", cn)
 486     elseif p == "J" then
 487       x = arshift(lshift(op, 27-rs), 29-rs)*4
 488       if band(op, 2) == 0 then x = ctx.addr + pos + x end
 489       ctx.rel = x
 490       x = "0x"..tohex(x)
 491     elseif p == "K" then
 492       if band(op, 1) ~= 0 then name = name.."l" end
 493       if band(op, 2) ~= 0 then name = name.."a" end
 494     elseif p == "X" or p == "Y" then
 495       x = band(rshift(op, rs+2), 7)
 496       if x == 0 and p == "Y" then x = nil else x = "cr"..x end
 497       rs = rs - 5
 498     elseif p == "W" then
 499       x = "cr"..band(op, 7)
 500     elseif p == "Z" then
 501       x = band(rshift(op, rs-4), 255)
 502       rs = rs - 10
 503     elseif p == ">" then
 504       operands[#operands] = rshift(operands[#operands], 1)
 505     elseif p == "0" then
 506       if last == "r0" then
 507         operands[#operands] = nil
 508         if altname then name = altname end
 509       end
 510     elseif p == "L" then
 511       name = gsub(name, "_", band(op, 0x00200000) ~= 0 and "d" or "w")
 512     elseif p == "." then
 513       if band(op, 1) == 1 then name = name.."." end
 514     elseif p == "N" then
 515       if op == 0x60000000 then name = "nop"; break end
 516     elseif p == "~" then
 517       local n = #operands
 518       operands[n-1],  operands[n] = operands[n], operands[n-1]
 519     elseif p == "=" then
 520       local n = #operands
 521       if last == operands[n-1] then
 522         operands[n] = nil
 523         name = altname
 524       end
 525     elseif p == "%" then
 526       local n = #operands
 527       if last == operands[n-1] and last == operands[n-2] then
 528         operands[n] = nil
 529         operands[n-1] = nil
 530         name = altname
 531       end
 532     elseif p == "-" then
 533       rs = rs - 5
 534     else
 535       assert(false)
 536     end
 537     if x then operands[#operands+1] = x; last = x end
 538   end
 539
 540   return putop(ctx, name, operands)
 541 end
 542
 543 ------------------------------------------------------------------------------
 544
 545 -- Disassemble a block of code.
 546 local function disass_block(ctx, ofs, len)
 547   if not ofs then ofs = 0 end
 548   local stop = len and ofs+len or #ctx.code
 549   stop = stop - stop % 4
 550   ctx.pos = ofs - ofs % 4
 551   ctx.rel = nil
 552   while ctx.pos < stop do disass_ins(ctx) end
 553 end
 554
 555 -- Extended API: create a disassembler context. Then call ctx:disass(ofs, len).
 556 local function create_(code, addr, out)
 557   local ctx = {}
 558   ctx.code = code
 559   ctx.addr = addr or 0
 560   ctx.out = out or io.write
 561   ctx.symtab = {}
 562   ctx.disass = disass_block
 563   ctx.hexdump = 8
 564   return ctx
 565 end
 566
 567 -- Simple API: disassemble code (a string) at address and output via out.
 568 local function disass_(code, addr, out)
 569   create_(code, addr, out):disass()
 570 end
 571
 572
 573 -- Public module functions.
 574 module(...)
 575
 576 create = create_
 577 disass = disass_
 578