ARM64: Add JIT compiler backend.

Contributed by Djordje Kovacevic and Stefan Pejic from RT-RK.com.
Sponsored by Cisco Systems, Inc.

1 files changed, 1215 insertions, 0 deletions

diff --git a/src/jit/dis_arm64.lua b/src/jit/dis_arm64.lua
new file mode 100644
index 00000000..909b33bc
--- /dev/null
+++ b/src/jit/dis_arm64.lua
@@ -0,0 +1,1215 @@
+----------------------------------------------------------------------------
+-- LuaJIT ARM64 disassembler module.
+--
+-- Copyright (C) 2005-2016 Mike Pall. All rights reserved.
+-- Released under the MIT license. See Copyright Notice in luajit.h
+--
+-- Contributed by Djordje Kovacevic and Stefan Pejic from RT-RK.com.
+-- Sponsored by Cisco Systems, Inc.
+----------------------------------------------------------------------------
+-- This is a helper module used by the LuaJIT machine code dumper module.
+--
+-- It disassembles most user-mode AArch64 instructions.
+-- NYI: Advanced SIMD and VFP instructions.
+------------------------------------------------------------------------------
+
+local type, tonumber = type, tonumber
+local sub, byte, format = string.sub, string.byte, string.format
+local match, gmatch, gsub = string.match, string.gmatch, string.gsub
+local rep = string.rep
+local concat = table.concat
+local bit = require("bit")
+local band, bor, bxor, tohex = bit.band, bit.bor, bit.bxor, bit.tohex
+local lshift, rshift, arshift = bit.lshift, bit.rshift, bit.arshift
+local ror = bit.ror
+
+------------------------------------------------------------------------------
+-- Opcode maps
+------------------------------------------------------------------------------
+
+local map_adr = { -- PC-relative addressing.
+  shift = 31, mask = 1,
+  [0] = "adrDBx", "adrpDBx"
+}
+
+local map_addsubi = { -- Add/subtract immediate.
+  shift = 29, mask = 3,
+  [0] = "add|movDNIg", "adds|cmnD0NIg", "subDNIg", "subs|cmpD0NIg",
+}
+
+local map_logi = { -- Logical immediate.
+  shift = 31, mask = 1,
+  [0] = {
+    shift = 22, mask = 1,
+    [0] = {
+      shift = 29, mask = 3,
+      [0] = "andDNig", "orr|movDN0ig", "eorDNig", "ands|tstD0Nig"
+    },
+    false -- unallocated
+  },
+  {
+    shift = 29, mask = 3,
+    [0] = "andDNig", "orr|movDN0ig", "eorDNig", "ands|tstD0Nig"
+  }
+}
+
+local map_movwi = { -- Move wide immediate.
+  shift = 31, mask = 1,
+  [0] = {
+    shift = 22, mask = 1,
+    [0] = {
+      shift = 29, mask = 3,
+      [0] = "movnDWRg", false, "movz|movDYRg", "movkDWRg"
+    }, false -- unallocated
+  },
+  {
+    shift = 29, mask = 3,
+    [0] = "movnDWRg", false, "movz|movDYRg", "movkDWRg"
+  },
+}
+
+local map_bitf = { -- Bitfield.
+  shift = 31, mask = 1,
+  [0] = {
+    shift = 22, mask = 1,
+    [0] = {
+      shift = 29, mask = 3,
+      [0] = "sbfm|sbfiz|sbfx|asr|sxtw|sxth|sxtbDN12w",
+      "bfm|bfi|bfxilDN13w",
+      "ubfm|ubfiz|ubfx|lsr|lsl|uxth|uxtbDN12w"
+    }
+  },
+  {
+    shift = 22, mask = 1,
+    {
+      shift = 29, mask = 3,
+      [0] = "sbfm|sbfiz|sbfx|asr|sxtw|sxth|sxtbDN12x",
+      "bfm|bfi|bfxilDN13x",
+      "ubfm|ubfiz|ubfx|lsr|lsl|uxth|uxtbDN12x"
+    }
+  }
+}
+
+local map_datai = { -- Data processing - immediate.
+  shift = 23, mask = 7,
+  [0] = map_adr, map_adr, map_addsubi, false,
+  map_logi, map_movwi, map_bitf,
+  {
+    shift = 15, mask = 0x1c0c1,
+    [0] = "extr|rorDNM4w", [0x10080] = "extr|rorDNM4x",
+    [0x10081] = "extr|rorDNM4x"
+  }
+}
+
+local map_logsr = { -- Logical, shifted register.
+  shift = 31, mask = 1,
+  [0] = {
+    shift = 15, mask = 1,
+    [0] = {
+      shift = 29, mask = 3,
+      [0] = {
+        shift = 21, mask = 7,
+        [0] = "andDNMSg", "bicDNMSg", "andDNMSg", "bicDNMSg",
+        "andDNMSg", "bicDNMSg", "andDNMg", "bicDNMg"
+      },
+      {
+        shift = 21, mask = 7,
+        [0] ="orr|movDN0MSg", "orn|mvnDN0MSg", "orr|movDN0MSg", "orn|mvnDN0MSg",
+             "orr|movDN0MSg", "orn|mvnDN0MSg", "orr|movDN0Mg", "orn|mvnDN0Mg"
+      },
+      {
+        shift = 21, mask = 7,
+        [0] = "eorDNMSg", "eonDNMSg", "eorDNMSg", "eonDNMSg",
+        "eorDNMSg", "eonDNMSg", "eorDNMg", "eonDNMg"
+      },
+      {
+        shift = 21, mask = 7,
+        [0] = "ands|tstD0NMSg", "bicsDNMSg", "ands|tstD0NMSg", "bicsDNMSg",
+        "ands|tstD0NMSg", "bicsDNMSg", "ands|tstD0NMg", "bicsDNMg"
+      }
+    },
+    false -- unallocated
+  },
+  {
+    shift = 29, mask = 3,
+    [0] = {
+      shift = 21, mask = 7,
+      [0] = "andDNMSg", "bicDNMSg", "andDNMSg", "bicDNMSg",
+      "andDNMSg", "bicDNMSg", "andDNMg", "bicDNMg"
+    },
+    {
+      shift = 21, mask = 7,
+      [0] = "orr|movDN0MSg", "orn|mvnDN0MSg", "orr|movDN0MSg", "orn|mvnDN0MSg",
+      "orr|movDN0MSg", "orn|mvnDN0MSg", "orr|movDN0Mg", "orn|mvnDN0Mg"
+    },
+    {
+      shift = 21, mask = 7,
+      [0] = "eorDNMSg", "eonDNMSg", "eorDNMSg", "eonDNMSg",
+      "eorDNMSg", "eonDNMSg", "eorDNMg", "eonDNMg"
+    },
+    {
+      shift = 21, mask = 7,
+      [0] = "ands|tstD0NMSg", "bicsDNMSg", "ands|tstD0NMSg", "bicsDNMSg",
+      "ands|tstD0NMSg", "bicsDNMSg", "ands|tstD0NMg", "bicsDNMg"
+    }
+  }
+}
+
+local map_assh = {
+  shift = 31, mask = 1,
+  [0] = {
+    shift = 15, mask = 1,
+    [0] = {
+      shift = 29, mask = 3,
+      [0] = {
+        shift = 22, mask = 3,
+        [0] = "addDNMSg", "addDNMSg", "addDNMSg", "addDNMg"
+      },
+      {
+        shift = 22, mask = 3,
+        [0] = "adds|cmnD0NMSg", "adds|cmnD0NMSg",
+              "adds|cmnD0NMSg", "adds|cmnD0NMg"
+      },
+      {
+        shift = 22, mask = 3,
+        [0] = "sub|negDN0MSg", "sub|negDN0MSg", "sub|negDN0MSg", "sub|negDN0Mg"
+      },
+      {
+        shift = 22, mask = 3,
+        [0] = "subs|cmp|negsD0N0MzSg", "subs|cmp|negsD0N0MzSg",
+              "subs|cmp|negsD0N0MzSg", "subs|cmp|negsD0N0Mzg"
+      },
+    },
+    false -- unallocated
+  },
+  {
+    shift = 29, mask = 3,
+    [0] = {
+      shift = 22, mask = 3,
+      [0] = "addDNMSg", "addDNMSg", "addDNMSg", "addDNMg"
+    },
+    {
+      shift = 22, mask = 3,
+      [0] = "adds|cmnD0NMSg", "adds|cmnD0NMSg", "adds|cmnD0NMSg",
+            "adds|cmnD0NMg"
+    },
+    {
+      shift = 22, mask = 3,
+      [0] = "sub|negDN0MSg", "sub|negDN0MSg", "sub|negDN0MSg", "sub|negDN0Mg"
+    },
+    {
+      shift = 22, mask = 3,
+      [0] = "subs|cmp|negsD0N0MzSg", "subs|cmp|negsD0N0MzSg",
+            "subs|cmp|negsD0N0MzSg", "subs|cmp|negsD0N0Mzg"
+    }
+  }
+}
+
+local map_addsubsh = { -- Add/subtract, shifted register.
+  shift = 22, mask = 3,
+  [0] = map_assh, map_assh, map_assh
+}
+
+local map_addsubex = { -- Add/subtract, extended register.
+  shift = 22, mask = 3,
+  [0] = {
+    shift = 29, mask = 3,
+    [0] = "addDNMXg", "adds|cmnD0NMXg", "subDNMXg", "subs|cmpD0NMzXg",
+  }
+}
+
+local map_addsubc = { -- Add/subtract, with carry.
+  shift = 10, mask = 63,
+  [0] = {
+    shift = 29, mask = 3,
+    [0] = "adcDNMg", "adcsDNMg", "sbc|ngcDN0Mg", "sbcs|ngcsDN0Mg",
+  }
+}
+
+local map_ccomp = {
+  shift = 4, mask = 1,
+  [0] = {
+    shift = 10, mask = 3,
+    [0] = { -- Conditional compare register.
+      shift = 29, mask = 3,
+      "ccmnNMVCg", false, "ccmpNMVCg",
+    },
+    [2] = {  -- Conditional compare immediate.
+      shift = 29, mask = 3,
+      "ccmnN5VCg", false, "ccmpN5VCg",
+    }
+  }
+}
+
+local map_csel = { -- Conditional select.
+  shift = 11, mask = 1,
+  [0] = {
+    shift = 10, mask = 1,
+    [0] = {
+      shift = 29, mask = 3,
+      [0] = "cselDNMzCg", false, "csinv|cinv|csetmDNMcg", false,
+    },
+    {
+      shift = 29, mask = 3,
+      [0] = "csinc|cinc|csetDNMcg", false, "csneg|cnegDNMcg", false,
+    }
+  }
+}
+
+local map_data1s = { -- Data processing, 1 source.
+  shift = 29, mask = 1,
+  [0] = {
+    shift = 31, mask = 1,
+    [0] = {
+      shift = 10, mask = 0x7ff,
+      [0] = "rbitDNg", "rev16DNg", "revDNw", false, "clzDNg", "clsDNg"
+    },
+    {
+      shift = 10, mask = 0x7ff,
+      [0] = "rbitDNg", "rev16DNg", "rev32DNx", "revDNx", "clzDNg", "clsDNg"
+    }
+  }
+}
+
+local map_data2s = { -- Data processing, 2 sources.
+  shift = 29, mask = 1,
+  [0] = {
+    shift = 10, mask = 63,
+    false, "udivDNMg", "sdivDNMg", false, false, false, false, "lslDNMg",
+    "lsrDNMg", "asrDNMg", "rorDNMg"
+  }
+}
+
+local map_data3s = { -- Data processing, 3 sources.
+  shift = 29, mask = 7,
+  [0] = {
+    shift = 21, mask = 7,
+    [0] = {
+      shift = 15, mask = 1,
+      [0] = "madd|mulDNMA0g", "msub|mnegDNMA0g"
+    }
+  }, false, false, false,
+  {
+    shift = 15, mask = 1,
+    [0] = {
+      shift = 21, mask = 7,
+      [0] = "madd|mulDNMA0g", "smaddl|smullDxNMwA0x", "smulhDNMx", false,
+      false, "umaddl|umullDxNMwA0x", "umulhDNMx"
+    },
+    {
+      shift = 21, mask = 7,
+      [0] = "msub|mnegDNMA0g", "smsubl|smneglDxNMwA0x", false, false,
+      false, "umsubl|umneglDxNMwA0x"
+    }
+  }
+}
+
+local map_datar = { -- Data processing, register.
+  shift = 28, mask = 1,
+  [0] = {
+    shift = 24, mask = 1,
+    [0] = map_logsr,
+    {
+      shift = 21, mask = 1,
+      [0] = map_addsubsh, map_addsubex
+    }
+  },
+  {
+    shift = 21, mask = 15,
+    [0] = map_addsubc, false, map_ccomp, false, map_csel, false,
+    {
+      shift = 30, mask = 1,
+      [0] = map_data2s, map_data1s
+    },
+    false, map_data3s, map_data3s, map_data3s, map_data3s, map_data3s,
+    map_data3s, map_data3s, map_data3s
+  }
+}
+
+local map_lrl = { -- Load register, literal.
+  shift = 26, mask = 1,
+  [0] = {
+    shift = 30, mask = 3,
+    [0] = "ldrDwB", "ldrDxB", "ldrswDxB"
+  },
+  {
+    shift = 30, mask = 3,
+    [0] = "ldrDsB", "ldrDdB"
+  }
+}
+
+local map_lsriind = { -- Load/store register, immediate pre/post-indexed.
+  shift = 30, mask = 3,
+  [0] = {
+    shift = 26, mask = 1,
+    [0] = {
+      shift = 22, mask = 3,
+      [0] = "strbDwzL", "ldrbDwzL", "ldrsbDxzL", "ldrsbDwzL"
+    }
+  },
+  {
+    shift = 26, mask = 1,
+    [0] = {
+      shift = 22, mask = 3,
+      [0] = "strhDwzL", "ldrhDwzL", "ldrshDxzL", "ldrshDwzL"
+    }
+  },
+  {
+    shift = 26, mask = 1,
+    [0] = {
+      shift = 22, mask = 3,
+      [0] = "strDwzL", "ldrDwzL", "ldrswDxzL"
+    },
+    {
+      shift = 22, mask = 3,
+      [0] = "strDszL", "ldrDszL"
+    }
+  },
+  {
+    shift = 26, mask = 1,
+    [0] = {
+      shift = 22, mask = 3,
+      [0] = "strDxzL", "ldrDxzL"
+    },
+    {
+      shift = 22, mask = 3,
+      [0] = "strDdzL", "ldrDdzL"
+    }
+  }
+}
+
+local map_lsriro = {
+  shift = 21, mask = 1,
+  [0] = {  -- Load/store register immediate.
+    shift = 10, mask = 3,
+    [0] = { -- Unscaled immediate.
+      shift = 26, mask = 1,
+      [0] = {
+        shift = 30, mask = 3,
+        [0] = {
+          shift = 22, mask = 3,
+          [0] = "sturbDwK", "ldurbDwK"
+        },
+        {
+          shift = 22, mask = 3,
+          [0] = "sturhDwK", "ldurhDwK"
+        },
+        {
+          shift = 22, mask = 3,
+          [0] = "sturDwK", "ldurDwK"
+        },
+        {
+          shift = 22, mask = 3,
+          [0] = "sturDxK", "ldurDxK"
+        }
+      }
+    }, map_lsriind, false, map_lsriind
+  },
+  {  -- Load/store register, register offset.
+    shift = 10, mask = 3,
+    [2] = {
+      shift = 26, mask = 1,
+      [0] = {
+        shift = 30, mask = 3,
+        [1] = {
+          shift = 22, mask = 3,
+          [0] = "strhDwO", "ldrhDwO", "ldrshDwO", "ldrshDxO"
+        },
+        [2] = {
+          shift = 22, mask = 3,
+          [0] = "strDwO", "ldrDwO", "ldrswDxO"
+        },
+        [3] = {
+          shift = 22, mask = 3,
+          [0] = "strDxO", "ldrDxO"
+        }
+      },
+      {
+        shift = 30, mask = 3,
+        [2] = {
+          shift = 22, mask = 3,
+          [0] = "strDsO", "ldrDsO"
+        },
+        [3] = {
+          shift = 22, mask = 3,
+          [0] = "strDdO", "ldrDdO"
+        }
+      }
+    }
+  }
+}
+
+local map_lsp = { -- Load/store register pair, offset.
+  shift = 22, mask = 1,
+  [0] = {
+    shift = 30, mask = 3,
+    [0] = {
+      shift = 26, mask = 1,
+      [0] = "stpDzAzwP", "stpDzAzsP",
+    },
+    {
+      shift = 26, mask = 1,
+      "stpDzAzdP"
+    },
+    {
+      shift = 26, mask = 1,
+      [0] = "stpDzAzxP"
+    }
+  },
+  {
+    shift = 30, mask = 3,
+    [0] = {
+      shift = 26, mask = 1,
+      [0] = "ldpDzAzwP", "ldpDzAzsP",
+    },
+    {
+      shift = 26, mask = 1,
+      [0] = "ldpswDAxP", "ldpDzAzdP"
+    },
+    {
+      shift = 26, mask = 1,
+      [0] = "ldpDzAzxP"
+    }
+  }
+}
+
+local map_ls = { -- Loads and stores.
+  shift = 24, mask = 0x31,
+  [0x10] = map_lrl, [0x30] = map_lsriro,
+  [0x20] = {
+    shift = 23, mask = 3,
+    map_lsp, map_lsp, map_lsp
+  },
+  [0x21] = {
+    shift = 23, mask = 3,
+    map_lsp, map_lsp, map_lsp
+  },
+  [0x31] = {
+    shift = 26, mask = 1,
+    [0] = {
+      shift = 30, mask = 3,
+      [0] = {
+        shift = 22, mask = 3,
+        [0] = "strbDwzU", "ldrbDwzU"
+      },
+      {
+        shift = 22, mask = 3,
+        [0] = "strhDwzU", "ldrhDwzU"
+      },
+      {
+        shift = 22, mask = 3,
+        [0] = "strDwzU", "ldrDwzU"
+      },
+      {
+        shift = 22, mask = 3,
+        [0] = "strDxzU", "ldrDxzU"
+      }
+    },
+    {
+      shift = 30, mask = 3,
+      [2] = {
+        shift = 22, mask = 3,
+        [0] = "strDszU", "ldrDszU"
+      },
+      [3] = {
+        shift = 22, mask = 3,
+        [0] = "strDdzU", "ldrDdzU"
+      }
+    }
+  },
+}
+
+local map_datafp = { -- Data processing, SIMD and FP.
+  shift = 28, mask = 7,
+  { -- 001
+    shift = 24, mask = 1,
+    [0] = {
+      shift = 21, mask = 1,
+      {
+        shift = 10, mask = 3,
+        [0] = {
+          shift = 12, mask = 1,
+          [0] = {
+            shift = 13, mask = 1,
+            [0] = {
+              shift = 14, mask = 1,
+              [0] = {
+                shift = 15, mask = 1,
+                [0] = { -- FP/int conversion.
+                  shift = 31, mask = 1,
+                  [0] = {
+                    shift = 16, mask = 0xff,
+                    [0x20] = "fcvtnsDwNs", [0x21] = "fcvtnuDwNs",
+                    [0x22] = "scvtfDsNw", [0x23] = "ucvtfDsNw",
+                    [0x24] = "fcvtasDwNs", [0x25] = "fcvtauDwNs",
+                    [0x26] = "fmovDwNs", [0x27] = "fmovDsNw",
+                    [0x28] = "fcvtpsDwNs", [0x29] = "fcvtpuDwNs",
+                    [0x30] = "fcvtmsDwNs", [0x31] = "fcvtmuDwNs",
+                    [0x38] = "fcvtzsDwNs", [0x39] = "fcvtzuDwNs",
+                    [0x60] = "fcvtnsDwNd", [0x61] = "fcvtnuDwNd",
+                    [0x62] = "scvtfDdNw", [0x63] = "ucvtfDdNw",
+                    [0x64] = "fcvtasDwNd", [0x65] = "fcvtauDwNd",
+                    [0x68] = "fcvtpsDwNd", [0x69] = "fcvtpuDwNd",
+                    [0x70] = "fcvtmsDwNd", [0x71] = "fcvtmuDwNd",
+                    [0x78] = "fcvtzsDwNd", [0x79] = "fcvtzuDwNd"
+                  },
+                  {
+                    shift = 16, mask = 0xff,
+                    [0x20] = "fcvtnsDxNs", [0x21] = "fcvtnuDxNs",
+                    [0x22] = "scvtfDsNx", [0x23] = "ucvtfDsNx",
+                    [0x24] = "fcvtasDxNs", [0x25] = "fcvtauDxNs",
+                    [0x28] = "fcvtpsDxNs", [0x29] = "fcvtpuDxNs",
+                    [0x30] = "fcvtmsDxNs", [0x31] = "fcvtmuDxNs",
+                    [0x38] = "fcvtzsDxNs", [0x39] = "fcvtzuDxNs",
+                    [0x60] = "fcvtnsDxNd", [0x61] = "fcvtnuDxNd",
+                    [0x62] = "scvtfDdNx", [0x63] = "ucvtfDdNx",
+                    [0x64] = "fcvtasDxNd", [0x65] = "fcvtauDxNd",
+                    [0x66] = "fmovDxNd", [0x67] = "fmovDdNx",
+                    [0x68] = "fcvtpsDxNd", [0x69] = "fcvtpuDxNd",
+                    [0x70] = "fcvtmsDxNd", [0x71] = "fcvtmuDxNd",
+                    [0x78] = "fcvtzsDxNd", [0x79] = "fcvtzuDxNd"
+                  }
+                }
+              },
+              { -- FP data-processing, 1 source.
+                shift = 31, mask = 1,
+                [0] = {
+                  shift = 22, mask = 3,
+                  [0] = {
+                    shift = 15, mask = 63,
+                    [0] = "fmovDNf", "fabsDNf", "fnegDNf",
+                    "fsqrtDNf", false, "fcvtDdNs", false, false,
+                    "frintnDNf", "frintpDNf", "frintmDNf", "frintzDNf",
+                    "frintaDNf", false, "frintxDNf", "frintiDNf",
+                  },
+                  {
+                    shift = 15, mask = 63,
+                    [0] = "fmovDNf", "fabsDNf", "fnegDNf",
+                    "fsqrtDNf", "fcvtDsNd", false, false, false,
+                    "frintnDNf", "frintpDNf", "frintmDNf", "frintzDNf",
+                    "frintaDNf", false, "frintxDNf", "frintiDNf",
+                  }
+                }
+              }
+            },
+            { -- FP compare.
+              shift = 31, mask = 1,
+              [0] = {
+                shift = 14, mask = 3,
+                [0] = {
+                  shift = 23, mask = 1,
+                  [0] = {
+                    shift = 0, mask = 31,
+                    [0] = "fcmpNMf", [8] = "fcmpNZf",
+                    [16] = "fcmpeNMf", [24] = "fcmpeNZf",
+                  }
+                }
+              }
+            }
+          },
+          { -- FP immediate.
+            shift = 31, mask = 1,
+            [0] = {
+              shift = 5, mask = 31,
+              [0] = {
+                shift = 23, mask = 1,
+                [0] = "fmovDFf"
+              }
+            }
+          }
+        },
+        { -- FP conditional compare.
+          shift = 31, mask = 1,
+          [0] = {
+            shift = 23, mask = 1,
+            [0] = {
+              shift = 4, mask = 1,
+              [0] = "fccmpNMVCf", "fccmpeNMVCf"
+            }
+          }
+        },
+        { -- FP data-processing, 2 sources.
+          shift = 31, mask = 1,
+          [0] = {
+            shift = 23, mask = 1,
+            [0] = {
+              shift = 12, mask = 15,
+              [0] = "fmulDNMf", "fdivDNMf", "faddDNMf", "fsubDNMf",
+              "fmaxDNMf", "fminDNMf", "fmaxnmDNMf", "fminnmDNMf",
+              "fnmulDNMf"
+            }
+          }
+        },
+        { -- FP conditional select.
+          shift = 31, mask = 1,
+          [0] = {
+            shift = 23, mask = 1,
+            [0] = "fcselDNMCf"
+          }
+        }
+      }
+    },
+    { -- FP data-processing, 3 sources.
+      shift = 31, mask = 1,
+      [0] = {
+        shift = 15, mask = 1,
+        [0] = {
+          shift = 21, mask = 5,
+          [0] = "fmaddDNMAf", "fnmaddDNMAf"
+        },
+        {
+          shift = 21, mask = 5,
+          [0] = "fmsubDNMAf", "fnmsubDNMAf"
+        }
+      }
+    }
+  }
+}
+
+local map_br = { -- Branches, exception generating and system instructions.
+  shift = 29, mask = 7,
+  [0] = "bB",
+  { -- Compare & branch, immediate.
+    shift = 24, mask = 3,
+    [0] = "cbzDBg", "cbnzDBg", "tbzDTBw", "tbnzDTBw"
+  },
+  { -- Conditional branch, immediate.
+    shift = 24, mask = 3,
+    [0] = {
+      shift = 4, mask = 1,
+      [0] = {
+        shift = 0, mask = 15,
+        [0] = "beqB", "bneB", "bhsB", "bloB", "bmiB", "bplB", "bvsB", "bvcB",
+        "bhiB", "blsB", "bgeB", "bltB", "bgtB", "bleB", "balB"
+      }
+    }
+  }, false, "blB",
+  { -- Compare & branch, immediate.
+    shift = 24, mask = 3,
+    [0] = "cbzDBg", "cbnzDBg", "tbzDTBx", "tbnzDTBx"
+  },
+  {
+    shift = 24, mask = 3,
+    [0] = { -- Exception generation.
+      shift = 0, mask = 0xe0001f,
+      [0x200000] = "brkW"
+    },
+    { -- System instructions.
+      shift = 0, mask = 0x3fffff,
+      [0x03201f] = "nop"
+    },
+    { -- Unconditional branch, register.
+      shift = 0, mask = 0xfffc1f,
+      [0x1f0000] = "brNx", [0x3f0000] = "blrNx",
+      [0x5f0000] = "retNx"
+    },
+  }
+}
+
+local map_init = {
+  shift = 25, mask = 15,
+  [0] = false, false, false, false, map_ls, map_datar, map_ls, map_datafp,
+  map_datai, map_datai, map_br, map_br, map_ls, map_datar, map_ls, map_datafp
+}
+
+------------------------------------------------------------------------------
+
+local map_regs = { x = {}, w = {}, d = {}, s = {} }
+
+for i=0,30 do
+  map_regs.x[i] = "x"..i
+  map_regs.w[i] = "w"..i
+  map_regs.d[i] = "d"..i
+  map_regs.s[i] = "s"..i
+end
+map_regs.x[31] = "sp"
+map_regs.w[31] = "wsp"
+map_regs.d[31] = "d31"
+map_regs.s[31] = "s31"
+
+local map_cond = {
+  [0] = "eq", "ne", "cs", "cc", "mi", "pl", "vs", "vc",
+  "hi", "ls", "ge", "lt", "gt", "le", "al",
+}
+
+local map_shift = { [0] = "lsl", "lsr", "asr", }
+
+local map_extend = {
+  [0] = "uxtb", "uxth", "uxtw", "uxtx", "sxtb", "sxth", "sxtw", "sxtx",
+}
+
+------------------------------------------------------------------------------
+
+-- 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
+    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
+
+local function match_reg(p, pat, regnum)
+  return map_regs[match(pat, p.."%w-([xwds])")][regnum]
+end
+
+local function fmt_hex32(x)
+  if x < 0 then
+    return tohex(x)
+  else
+    return format("%x", x)
+  end
+end
+
+local imm13_rep = { 0x55555555, 0x11111111, 0x01010101, 0x00010001, 0x00000001 }
+
+local function decode_imm13(op)
+  local imms = band(rshift(op, 10), 63)
+  local immr = band(rshift(op, 16), 63)
+  if band(op, 0x00400000) == 0 then
+    local len = 5
+    if imms >= 56 then
+      if imms >= 60 then len = 1 else len = 2 end
+    elseif imms >= 48 then len = 3 elseif imms >= 32 then len = 4 end
+    local l = lshift(1, len)-1
+    local s = band(imms, l)
+    local r = band(immr, l)
+    local imm = ror(rshift(-1, 31-s), r)
+    if len ~= 5 then imm = band(imm, lshift(1, l)-1) + rshift(imm, 31-l) end
+    imm = imm * imm13_rep[len]
+    local ix = fmt_hex32(imm)
+    if rshift(op, 31) ~= 0 then
+      return ix..tohex(imm)
+    else
+      return ix
+    end
+  else
+    local lo, hi = -1, 0
+    if imms < 32 then lo = rshift(-1, 31-imms) else hi = rshift(-1, 63-imms) end
+    if immr ~= 0 then
+      lo, hi = ror(lo, immr), ror(hi, immr)
+      local x = immr == 32 and 0 or band(bxor(lo, hi), lshift(-1, 32-immr))
+      lo, hi = bxor(lo, x), bxor(hi, x)
+      if immr >= 32 then lo, hi = hi, lo end
+    end
+    if hi ~= 0 then
+      return fmt_hex32(hi)..tohex(lo)
+    else
+      return fmt_hex32(lo)
+    end
+  end
+end
+
+local function parse_immpc(op, name)
+  if name == "b" or name == "bl" then
+    return arshift(lshift(op, 6), 4)
+  elseif name == "adr" or name == "adrp" then
+    local immlo = band(rshift(op, 29), 3)
+    local immhi = lshift(arshift(lshift(op, 8), 13), 2)
+    return bor(immhi, immlo)
+  elseif name == "tbz" or name == "tbnz" then
+    return lshift(arshift(lshift(op, 13), 18), 2)
+  else
+    return lshift(arshift(lshift(op, 8), 13), 2)
+  end
+end
+
+local function parse_fpimm8(op)
+  local sign = band(op, 0x100000) == 0 and 1 or -1
+  local exp = bxor(rshift(arshift(lshift(op, 12), 5), 24), 0x80) - 131
+  local frac = 16+band(rshift(op, 13), 15)
+  return sign * frac * 2^exp
+end
+
+local function prefer_bfx(sf, uns, imms, immr)
+  if imms < immr or imms == 31 or imms == 63 then
+    return false
+  end
+  if immr == 0 then
+    if sf == 0 and (imms == 7 or imms == 15) then
+      return false
+    end
+    if sf ~= 0 and uns == 0 and (imms == 7 or imms == 15 or imms == 31) then
+      return false
+    end
+  end
+  return true
+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
+  local vr
+  local map_reg
+  ctx.op = op
+  ctx.rel = nil
+  last = nil
+  local opat
+  opat = map_init[band(rshift(op, 25), 15)]
+  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]*)(.*)")
+  local altname, pat2 = match(pat, "|([a-z0-9_.|]*)(.*)")
+  if altname then pat = pat2 end
+  if sub(pat, 1, 1) == "." then
+    local s2, p2 = match(pat, "^([a-z0-9.]*)(.*)")
+    suffix = suffix..s2
+    pat = p2
+  end
+
+  local rt = match(pat, "[gf]")
+  if rt then
+    if rt == "g" then
+      map_reg = band(op, 0x80000000) ~= 0 and map_regs.x or map_regs.w
+    else
+      map_reg = band(op, 0x400000) ~= 0 and map_regs.d or map_regs.s
+    end
+  end
+
+  local second0, immr
+
+  for p in gmatch(pat, ".") do
+    local x = nil
+    if p == "D" then
+      local regnum = band(op, 31)
+      x = rt and map_reg[regnum] or match_reg(p, pat, regnum)
+    elseif p == "N" then
+      local regnum = band(rshift(op, 5), 31)
+      x = rt and map_reg[regnum] or match_reg(p, pat, regnum)
+    elseif p == "M" then
+      local regnum = band(rshift(op, 16), 31)
+      x = rt and map_reg[regnum] or match_reg(p, pat, regnum)
+    elseif p == "A" then
+      local regnum = band(rshift(op, 10), 31)
+      x = rt and map_reg[regnum] or match_reg(p, pat, regnum)
+    elseif p == "B" then
+      local addr = ctx.addr + pos + parse_immpc(op, name)
+      ctx.rel = addr
+      x = "0x"..tohex(addr)
+    elseif p == "T" then
+      x = bor(band(rshift(op, 26), 32), band(rshift(op, 19), 31))
+    elseif p == "V" then
+      x = band(op, 15)
+    elseif p == "C" then
+      x = map_cond[band(rshift(op, 12), 15)]
+    elseif p == "c" then
+      local rn = band(rshift(op, 5), 31)
+      local rm = band(rshift(op, 16), 31)
+      local cond = band(rshift(op, 12), 15)
+      local invc = bxor(cond, 1)
+      x = map_cond[cond]
+      if altname and cond ~= 14 and cond ~= 15 then
+        local a1, a2 = match(altname, "([^|]*)|(.*)")
+        if rn == rm then
+          local n = #operands
+          operands[n] = nil
+          x = map_cond[invc]
+          if rn ~= 31 then
+            if a1 then name = a1 else name = altname end
+          else
+            operands[n-1] = nil
+            name = a2
+          end
+        end
+      end
+    elseif p == "W" then
+      x = band(rshift(op, 5), 0xffff)
+    elseif p == "Y" then
+      x = band(rshift(op, 5), 0xffff)
+      local hw = band(rshift(op, 21), 3)
+      if altname and (hw == 0 or x ~= 0) then
+        name = altname
+      end
+    elseif p == "L" then
+      local rn = map_regs.x[band(rshift(op, 5), 31)]
+      local imm9 = arshift(lshift(op, 11), 23)
+      if band(op, 0x800) ~= 0 then
+        x = "["..rn..", #"..imm9.."]!"
+      else
+        x = "["..rn.."], #"..imm9
+      end
+    elseif p == "U" then
+      local rn = map_regs.x[band(rshift(op, 5), 31)]
+      local sz = band(rshift(op, 30), 3)
+      local imm12 = lshift(arshift(lshift(op, 10), 20), sz)
+      if imm12 ~= 0 then
+        x = "["..rn..", #"..imm12.."]"
+      else
+        x = "["..rn.."]"
+      end
+    elseif p == "K" then
+      local rn = map_regs.x[band(rshift(op, 5), 31)]
+      local imm9 = arshift(lshift(op, 11), 23)
+      if imm9 ~= 0 then
+        x = "["..rn..", #"..imm9.."]"
+      else
+        x = "["..rn.."]"
+      end
+    elseif p == "O" then
+      local rn, rm = map_regs.x[band(rshift(op, 5), 31)]
+      local m = band(rshift(op, 13), 1)
+      if m == 0 then
+        rm = map_regs.w[band(rshift(op, 16), 31)]
+      else
+        rm = map_regs.x[band(rshift(op, 16), 31)]
+      end
+      x = "["..rn..", "..rm
+      local opt = band(rshift(op, 13), 7)
+      local s = band(rshift(op, 12), 1)
+      local sz = band(rshift(op, 30), 3)
+      -- extension to be applied
+      if opt == 3 then
+       if s == 0 then x = nil
+       else x = x..", lsl #"..sz.."]" end
+      elseif opt == 2 or opt == 6 or opt == 7 then
+        if s == 0 then x = x..", "..map_extend[opt].."]"
+        else x = x..", "..map_extend[opt].." #"..sz.."]" end
+      else
+        x = x.."]"
+      end
+    elseif p == "P" then
+      local opcv, sh = rshift(op, 26), 2
+      if opcv >= 0x2a then sh = 4 elseif opcv >= 0x1b then sh = 3 end
+      local imm7 = lshift(arshift(lshift(op, 10), 25), sh)
+      local rn = map_regs.x[band(rshift(op, 5), 31)]
+      local ind = band(rshift(op, 23), 3)
+      if ind == 1 then
+        x = "["..rn.."], #"..imm7
+      elseif ind == 2 then
+        if imm7 == 0 then
+          x = "["..rn.."]"
+        else
+          x = "["..rn..", #"..imm7.."]"
+        end
+      elseif ind == 3 then
+        x = "["..rn..", #"..imm7.."]!"
+      end
+    elseif p == "I" then
+      local shf = band(rshift(op, 22), 3)
+      local imm12 = band(rshift(op, 10), 0x0fff)
+      local n = #operands
+      local rn, rd = band(rshift(op, 5), 31), band(op, 31)
+      if altname == "mov" and shf == 0 and imm12 == 0 and (rn == 31 or rd == 31) then
+        name = altname
+        x = nil
+      elseif shf == 0 then
+        x = imm12
+      elseif shf == 1 then
+        x = imm12..", lsl #12"
+      end
+    elseif p == "i" then
+      x = "#0x"..decode_imm13(op)
+    elseif p == "1" then
+      immr = band(rshift(op, 16), 63)
+      x = immr
+    elseif p == "2" then
+      x = band(rshift(op, 10), 63)
+      if altname then
+        local a1, a2, a3, a4, a5, a6 =
+          match(altname, "([^|]*)|([^|]*)|([^|]*)|([^|]*)|([^|]*)|(.*)")
+        local sf = band(rshift(op, 26), 32)
+        local uns = band(rshift(op, 30), 1)
+        if prefer_bfx(sf, uns, x, immr) then
+          name = a2
+          x = x - immr + 1
+        elseif immr == 0 and x == 7 then
+          local n = #operands
+          operands[n] = nil
+          if sf ~= 0 then
+            operands[n-1] = gsub(operands[n-1], "x", "w")
+          end
+          last = operands[n-1]
+          name = a6
+          x = nil
+        elseif immr == 0 and x == 15 then
+          local n = #operands
+          operands[n] = nil
+          if sf ~= 0 then
+            operands[n-1] = gsub(operands[n-1], "x", "w")
+          end
+          last = operands[n-1]
+          name = a5
+          x = nil
+        elseif x == 31 or x == 63 then
+          if x == 31 and immr == 0 and name == "sbfm" then
+            name = a4
+            local n = #operands
+            operands[n] = nil
+            if sf ~= 0 then
+              operands[n-1] = gsub(operands[n-1], "x", "w")
+            end
+            last = operands[n-1]
+          else
+            name = a3
+          end
+          x = nil
+        elseif band(x, 31) ~= 31 and immr == x+1 and name == "ubfm" then
+          name = a4
+          last = "#"..(sf+32 - immr)
+          operands[#operands] = last
+          x = nil
+        elseif x < immr then
+          name = a1
+          last = "#"..(sf+32 - immr)
+          operands[#operands] = last
+          x = x + 1
+        end
+      end
+    elseif p == "3" then
+      x = band(rshift(op, 10), 63)
+      if altname then
+        local a1, a2 = match(altname, "([^|]*)|(.*)")
+        if x < immr then
+          name = a1
+          local sf = band(rshift(op, 26), 32)
+          last = "#"..(sf+32 - immr)
+          operands[#operands] = last
+          x = x + 1
+        elseif x >= immr then
+          name = a2
+          x = x - immr + 1
+        end
+      end
+    elseif p == "4" then
+      x = band(rshift(op, 10), 63)
+      local rn = band(rshift(op, 5), 31)
+      local rm = band(rshift(op, 16), 31)
+      if altname and rn == rm then
+        local n = #operands
+        operands[n] = nil
+        last = operands[n-1]
+        name = altname
+      end
+    elseif p == "5" then
+      x = band(rshift(op, 16), 31)
+    elseif p == "S" then
+      x = band(rshift(op, 10), 63)
+      if x == 0 then x = nil
+      else x = map_shift[band(rshift(op, 22), 3)].." #"..x end
+    elseif p == "X" then
+      local opt = band(rshift(op, 13), 7)
+      -- Width specifier <R>.
+      if opt ~= 3 and opt ~= 7 then
+        last = map_regs.w[band(rshift(op, 16), 31)]
+        operands[#operands] = last
+      end
+      x = band(rshift(op, 10), 7)
+      -- Extension.
+      if opt == 2 + band(rshift(op, 31), 1) and
+         band(rshift(op, second0 and 5 or 0), 31) == 31 then
+        if x == 0 then x = nil
+        else x = "lsl #"..x end
+      else
+        if x == 0 then x = map_extend[band(rshift(op, 13), 7)]
+        else x = map_extend[band(rshift(op, 13), 7)].." #"..x end
+      end
+    elseif p == "R" then
+      x = band(rshift(op,21), 3)
+      if x == 0 then x = nil
+      else x = "lsl #"..x*16 end
+    elseif p == "z" then
+      local n = #operands
+      if operands[n] == "sp" then operands[n] = "xzr"
+      elseif operands[n] == "wsp" then operands[n] = "wzr"
+      end
+    elseif p == "Z" then
+      x = 0
+    elseif p == "F" then
+      x = parse_fpimm8(op)
+    elseif p == "g" or p == "f" or p == "x" or p == "w" or
+           p == "d" or p == "s" then
+      -- These are handled in D/N/M/A.
+    elseif p == "0" then
+      if last == "sp" or last == "wsp" then
+        local n = #operands
+        operands[n] = nil
+        last = operands[n-1]
+        if altname then
+          local a1, a2 = match(altname, "([^|]*)|(.*)")
+          if not a1 then
+            name = altname
+          elseif second0 then
+            name, altname = a2, a1
+          else
+            name, altname = a1, a2
+          end
+        end
+      end
+      second0 = true
+    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
+
+-- Return register name for RID.
+local function regname(r)
+  if r < 32 then return map_regs.x[r] end
+  return map_regs.d[r-32]
+end
+
+-- Public module functions.
+return {
+  create = create,
+  disass = disass,
+  regname = regname
+}
+