ljx

dasm_arm64.lua (34807B)

---

 ------------------------------------------------------------------------------
 -- DynASM ARM64 module.
 --
 -- Copyright (C) 2005-2016 Mike Pall. All rights reserved.
 -- See dynasm.lua for full copyright notice.
 ------------------------------------------------------------------------------
 
 -- Module information:
 local _info = {
   arch =	"arm",
   description =	"DynASM ARM64 module",
   version =	"1.4.0",
   vernum =	 10400,
   release =	"2015-10-18",
   author =	"Mike Pall",
   license =	"MIT",
 }
 
 -- Exported glue functions for the arch-specific module.
 local _M = { _info = _info }
 
 -- Cache library functions.
 local type, tonumber, pairs, ipairs = type, tonumber, pairs, ipairs
 local assert, setmetatable, rawget = assert, setmetatable, rawget
 local _s = string
 local sub, format, byte, char = _s.sub, _s.format, _s.byte, _s.char
 local match, gmatch, gsub = _s.match, _s.gmatch, _s.gsub
 local concat, sort, insert = table.concat, table.sort, table.insert
 local bit = bit or require("bit")
 local band, shl, shr, sar = bit.band, bit.lshift, bit.rshift, bit.arshift
 local ror, tohex = bit.ror, bit.tohex
 
 -- Inherited tables and callbacks.
 local g_opt, g_arch
 local wline, werror, wfatal, wwarn
 
 -- Action name list.
 -- CHECK: Keep this in sync with the C code!
 local action_names = {
   "STOP", "SECTION", "ESC", "REL_EXT",
   "ALIGN", "REL_LG", "LABEL_LG",
   "REL_PC", "LABEL_PC", "IMM", "IMM6", "IMM12", "IMM13W", "IMM13X", "IMML",
 }
 
 -- Maximum number of section buffer positions for dasm_put().
 -- CHECK: Keep this in sync with the C code!
 local maxsecpos = 25 -- Keep this low, to avoid excessively long C lines.
 
 -- Action name -> action number.
 local map_action = {}
 for n,name in ipairs(action_names) do
   map_action[name] = n-1
 end
 
 -- Action list buffer.
 local actlist = {}
 
 -- Argument list for next dasm_put(). Start with offset 0 into action list.
 local actargs = { 0 }
 
 -- Current number of section buffer positions for dasm_put().
 local secpos = 1
 
 ------------------------------------------------------------------------------
 
 -- Dump action names and numbers.
 local function dumpactions(out)
   out:write("DynASM encoding engine action codes:\n")
   for n,name in ipairs(action_names) do
     local num = map_action[name]
     out:write(format("  %-10s %02X  %d\n", name, num, num))
   end
   out:write("\n")
 end
 
 -- Write action list buffer as a huge static C array.
 local function writeactions(out, name)
   local nn = #actlist
   if nn == 0 then nn = 1; actlist[0] = map_action.STOP end
   out:write("static const unsigned int ", name, "[", nn, "] = {\n")
   for i = 1,nn-1 do
     assert(out:write("0x", tohex(actlist[i]), ",\n"))
   end
   assert(out:write("0x", tohex(actlist[nn]), "\n};\n\n"))
 end
 
 ------------------------------------------------------------------------------
 
 -- Add word to action list.
 local function wputxw(n)
   assert(n >= 0 and n <= 0xffffffff and n % 1 == 0, "word out of range")
   actlist[#actlist+1] = n
 end
 
 -- Add action to list with optional arg. Advance buffer pos, too.
 local function waction(action, val, a, num)
   local w = assert(map_action[action], "bad action name `"..action.."'")
   wputxw(w * 0x10000 + (val or 0))
   if a then actargs[#actargs+1] = a end
   if a or num then secpos = secpos + (num or 1) end
 end
 
 -- Flush action list (intervening C code or buffer pos overflow).
 local function wflush(term)
   if #actlist == actargs[1] then return end -- Nothing to flush.
   if not term then waction("STOP") end -- Terminate action list.
   wline(format("dasm_put(Dst, %s);", concat(actargs, ", ")), true)
   actargs = { #actlist } -- Actionlist offset is 1st arg to next dasm_put().
   secpos = 1 -- The actionlist offset occupies a buffer position, too.
 end
 
 -- Put escaped word.
 local function wputw(n)
   if n <= 0x000fffff then waction("ESC") end
   wputxw(n)
 end
 
 -- Reserve position for word.
 local function wpos()
   local pos = #actlist+1
   actlist[pos] = ""
   return pos
 end
 
 -- Store word to reserved position.
 local function wputpos(pos, n)
   assert(n >= 0 and n <= 0xffffffff and n % 1 == 0, "word out of range")
   if n <= 0x000fffff then
     insert(actlist, pos+1, n)
     n = map_action.ESC * 0x10000
   end
   actlist[pos] = n
 end
 
 ------------------------------------------------------------------------------
 
 -- Global label name -> global label number. With auto assignment on 1st use.
 local next_global = 20
 local map_global = setmetatable({}, { __index = function(t, name)
   if not match(name, "^[%a_][%w_]*$") then werror("bad global label") end
   local n = next_global
   if n > 2047 then werror("too many global labels") end
   next_global = n + 1
   t[name] = n
   return n
 end})
 
 -- Dump global labels.
 local function dumpglobals(out, lvl)
   local t = {}
   for name, n in pairs(map_global) do t[n] = name end
   out:write("Global labels:\n")
   for i=20,next_global-1 do
     out:write(format("  %s\n", t[i]))
   end
   out:write("\n")
 end
 
 -- Write global label enum.
 local function writeglobals(out, prefix)
   local t = {}
   for name, n in pairs(map_global) do t[n] = name end
   out:write("enum {\n")
   for i=20,next_global-1 do
     out:write("  ", prefix, t[i], ",\n")
   end
   out:write("  ", prefix, "_MAX\n};\n")
 end
 
 -- Write global label names.
 local function writeglobalnames(out, name)
   local t = {}
   for name, n in pairs(map_global) do t[n] = name end
   out:write("static const char *const ", name, "[] = {\n")
   for i=20,next_global-1 do
     out:write("  \"", t[i], "\",\n")
   end
   out:write("  (const char *)0\n};\n")
 end
 
 ------------------------------------------------------------------------------
 
 -- Extern label name -> extern label number. With auto assignment on 1st use.
 local next_extern = 0
 local map_extern_ = {}
 local map_extern = setmetatable({}, { __index = function(t, name)
   -- No restrictions on the name for now.
   local n = next_extern
   if n > 2047 then werror("too many extern labels") end
   next_extern = n + 1
   t[name] = n
   map_extern_[n] = name
   return n
 end})
 
 -- Dump extern labels.
 local function dumpexterns(out, lvl)
   out:write("Extern labels:\n")
   for i=0,next_extern-1 do
     out:write(format("  %s\n", map_extern_[i]))
   end
   out:write("\n")
 end
 
 -- Write extern label names.
 local function writeexternnames(out, name)
   out:write("static const char *const ", name, "[] = {\n")
   for i=0,next_extern-1 do
     out:write("  \"", map_extern_[i], "\",\n")
   end
   out:write("  (const char *)0\n};\n")
 end
 
 ------------------------------------------------------------------------------
 
 -- Arch-specific maps.
 
 -- Ext. register name -> int. name.
 local map_archdef = { xzr = "@x31", wzr = "@w31", lr = "x30", }
 
 -- Int. register name -> ext. name.
 local map_reg_rev = { ["@x31"] = "xzr", ["@w31"] = "wzr", x30 = "lr", }
 
 local map_type = {}		-- Type name -> { ctype, reg }
 local ctypenum = 0		-- Type number (for Dt... macros).
 
 -- Reverse defines for registers.
 function _M.revdef(s)
   return map_reg_rev[s] or s
 end
 
 local map_shift = { lsl = 0, lsr = 1, asr = 2, }
 
 local map_extend = {
   uxtb = 0, uxth = 1, uxtw = 2, uxtx = 3,
   sxtb = 4, sxth = 5, sxtw = 6, sxtx = 7,
 }
 
 local map_cond = {
   eq = 0, ne = 1, cs = 2, cc = 3, mi = 4, pl = 5, vs = 6, vc = 7,
   hi = 8, ls = 9, ge = 10, lt = 11, gt = 12, le = 13, al = 14,
   hs = 2, lo = 3,
 }
 
 ------------------------------------------------------------------------------
 
 local parse_reg_type
 
 local function parse_reg(expr)
   if not expr then werror("expected register name") end
   local tname, ovreg = match(expr, "^([%w_]+):(@?%l%d+)$")
   local tp = map_type[tname or expr]
   if tp then
     local reg = ovreg or tp.reg
     if not reg then
       werror("type `"..(tname or expr).."' needs a register override")
     end
     expr = reg
   end
   local ok31, rt, r = match(expr, "^(@?)([xwqdshb])([123]?[0-9])$")
   if r then
     r = tonumber(r)
     if r <= 30 or (r == 31 and ok31 ~= "" or (rt ~= "w" and rt ~= "x")) then
       if not parse_reg_type then
 	parse_reg_type = rt
       elseif parse_reg_type ~= rt then
 	werror("register size mismatch")
       end
       return r, tp
     end
   end
   werror("bad register name `"..expr.."'")
 end
 
 local function parse_reg_base(expr)
   if expr == "sp" then return 0x3e0 end
   local base, tp = parse_reg(expr)
   if parse_reg_type ~= "x" then werror("bad register type") end
   parse_reg_type = false
   return shl(base, 5), tp
 end
 
 local parse_ctx = {}
 
 local loadenv = setfenv and function(s)
   local code = loadstring(s, "")
   if code then setfenv(code, parse_ctx) end
   return code
 end or function(s)
   return load(s, "", nil, parse_ctx)
 end
 
 -- Try to parse simple arithmetic, too, since some basic ops are aliases.
 local function parse_number(n)
   local x = tonumber(n)
   if x then return x end
   local code = loadenv("return "..n)
   if code then
     local ok, y = pcall(code)
     if ok then return y end
   end
   return nil
 end
 
 local function parse_imm(imm, bits, shift, scale, signed)
   imm = match(imm, "^#(.*)$")
   if not imm then werror("expected immediate operand") end
   local n = parse_number(imm)
   if n then
     local m = sar(n, scale)
     if shl(m, scale) == n then
       if signed then
 	local s = sar(m, bits-1)
 	if s == 0 then return shl(m, shift)
 	elseif s == -1 then return shl(m + shl(1, bits), shift) end
       else
 	if sar(m, bits) == 0 then return shl(m, shift) end
       end
     end
     werror("out of range immediate `"..imm.."'")
   else
     waction("IMM", (signed and 32768 or 0)+scale*1024+bits*32+shift, imm)
     return 0
   end
 end
 
 local function parse_imm12(imm)
   imm = match(imm, "^#(.*)$")
   if not imm then werror("expected immediate operand") end
   local n = parse_number(imm)
   if n then
     if shr(n, 12) == 0 then
       return shl(n, 10)
     elseif band(n, 0xff000fff) == 0 then
       return shr(n, 2) + 0x00400000
     end
     werror("out of range immediate `"..imm.."'")
   else
     waction("IMM12", 0, imm)
     return 0
   end
 end
 
 local function parse_imm13(imm)
   imm = match(imm, "^#(.*)$")
   if not imm then werror("expected immediate operand") end
   local n = parse_number(imm)
   local r64 = parse_reg_type == "x"
   if n and n % 1 == 0 and n >= 0 and n <= 0xffffffff then
     local inv = false
     if band(n, 1) == 1 then n = bit.bnot(n); inv = true end
     local t = {}
     for i=1,32 do t[i] = band(n, 1); n = shr(n, 1) end
     local b = table.concat(t)
     b = b..(r64 and (inv and "1" or "0"):rep(32) or b)
     local p0, p1, p0a, p1a = b:match("^(0+)(1+)(0*)(1*)")
     if p0 then
       local w = p1a == "" and (r64 and 64 or 32) or #p1+#p0a
       if band(w, w-1) == 0 and b == b:sub(1, w):rep(64/w) then
 	local s = band(-2*w, 0x3f) - 1
 	if w == 64 then s = s + 0x1000 end
 	if inv then
 	  return shl(w-#p1-#p0, 16) + shl(s+w-#p1, 10)
 	else
 	  return shl(w-#p0, 16) + shl(s+#p1, 10)
 	end
       end
     end
     werror("out of range immediate `"..imm.."'")
   elseif r64 then
     waction("IMM13X", 0, format("(unsigned int)(%s)", imm))
     actargs[#actargs+1] = format("(unsigned int)((unsigned long long)(%s)>>32)", imm)
     return 0
   else
     waction("IMM13W", 0, imm)
     return 0
   end
 end
 
 local function parse_imm6(imm)
   imm = match(imm, "^#(.*)$")
   if not imm then werror("expected immediate operand") end
   local n = parse_number(imm)
   if n then
     if n >= 0 and n <= 63 then
       return shl(band(n, 0x1f), 19) + (n >= 32 and 0x80000000 or 0)
     end
     werror("out of range immediate `"..imm.."'")
   else
     waction("IMM6", 0, imm)
     return 0
   end
 end
 
 local function parse_imm_load(imm, scale)
   local n = parse_number(imm)
   if n then
     local m = sar(n, scale)
     if shl(m, scale) == n and m >= 0 and m < 0x1000 then
       return shl(m, 10) + 0x01000000 -- Scaled, unsigned 12 bit offset.
     elseif n >= -256 and n < 256 then
       return shl(band(n, 511), 12) -- Unscaled, signed 9 bit offset.
     end
     werror("out of range immediate `"..imm.."'")
   else
     waction("IMML", 0, imm)
     return 0
   end
 end
 
 local function parse_fpimm(imm)
   imm = match(imm, "^#(.*)$")
   if not imm then werror("expected immediate operand") end
   local n = parse_number(imm)
   if n then
     local m, e = math.frexp(n)
     local s, e2 = 0, band(e-2, 7)
     if m < 0 then m = -m; s = 0x00100000 end
     m = m*32-16
     if m % 1 == 0 and m >= 0 and m <= 15 and sar(shl(e2, 29), 29)+2 == e then
       return s + shl(e2, 17) + shl(m, 13)
     end
     werror("out of range immediate `"..imm.."'")
   else
     werror("NYI fpimm action")
   end
 end
 
 local function parse_shift(expr)
   local s, s2 = match(expr, "^(%S+)%s*(.*)$")
   s = map_shift[s]
   if not s then werror("expected shift operand") end
   return parse_imm(s2, 6, 10, 0, false) + shl(s, 22)
 end
 
 local function parse_lslx16(expr)
   local n = match(expr, "^lsl%s*#(%d+)$")
   n = tonumber(n)
   if not n then werror("expected shift operand") end
   if band(n, parse_reg_type == "x" and 0xffffffcf or 0xffffffef) ~= 0 then
     werror("bad shift amount")
   end
   return shl(n, 17)
 end
 
 local function parse_extend(expr)
   local s, s2 = match(expr, "^(%S+)%s*(.*)$")
   if s == "lsl" then
     s = parse_reg_type == "x" and 3 or 2
   else
     s = map_extend[s]
   end
   if not s then werror("expected extend operand") end
   return (s2 == "" and 0 or parse_imm(s2, 3, 10, 0, false)) + shl(s, 13)
 end
 
 local function parse_cond(expr, inv)
   local c = map_cond[expr]
   if not c then werror("expected condition operand") end
   return shl(bit.bxor(c, inv), 12)
 end
 
 local function parse_load(params, nparams, n, op)
   if params[n+2] then werror("too many operands") end
   local pn, p2 = params[n], params[n+1]
   local p1, wb = match(pn, "^%[%s*(.-)%s*%](!?)$")
   if not p1 then
     if not p2 then
       local reg, tailr = match(pn, "^([%w_:]+)%s*(.*)$")
       if reg and tailr ~= "" then
 	local base, tp = parse_reg_base(reg)
 	if tp then
 	  waction("IMML", 0, format(tp.ctypefmt, tailr))
 	  return op + base
 	end
       end
     end
     werror("expected address operand")
   end
   local scale = shr(op, 30)
   if p2 then
     if wb == "!" then werror("bad use of '!'") end
     op = op + parse_reg_base(p1) + parse_imm(p2, 9, 12, 0, true) + 0x400
   elseif wb == "!" then
     local p1a, p2a = match(p1, "^([^,%s]*)%s*,%s*(.*)$")
     if not p1a then werror("bad use of '!'") end
     op = op + parse_reg_base(p1a) + parse_imm(p2a, 9, 12, 0, true) + 0xc00
   else
     local p1a, p2a = match(p1, "^([^,%s]*)%s*(.*)$")
     op = op + parse_reg_base(p1a)
     if p2a ~= "" then
       local imm = match(p2a, "^,%s*#(.*)$")
       if imm then
 	op = op + parse_imm_load(imm, scale)
       else
 	local p2b, p3b, p3s = match(p2a, "^,%s*([^,%s]*)%s*,?%s*(%S*)%s*(.*)$")
 	op = op + shl(parse_reg(p2b), 16) + 0x00200800
 	if parse_reg_type ~= "x" and parse_reg_type ~= "w" then
 	  werror("bad index register type")
 	end
 	if p3b == "" then
 	  if parse_reg_type ~= "x" then werror("bad index register type") end
 	  op = op + 0x6000
 	else
 	  if p3s == "" or p3s == "#0" then
 	  elseif p3s == "#"..scale then
 	    op = op + 0x1000
 	  else
 	    werror("bad scale")
 	  end
 	  if parse_reg_type == "x" then
 	    if p3b == "lsl" and p3s ~= "" then op = op + 0x6000
 	    elseif p3b == "sxtx" then op = op + 0xe000
 	    else
 	      werror("bad extend/shift specifier")
 	    end
 	  else
 	    if p3b == "uxtw" then op = op + 0x4000
 	    elseif p3b == "sxtw" then op = op + 0xc000
 	    else
 	      werror("bad extend/shift specifier")
 	    end
 	  end
 	end
       end
     else
       if wb == "!" then werror("bad use of '!'") end
       op = op + 0x01000000
     end
   end
   return op
 end
 
 local function parse_load_pair(params, nparams, n, op)
   if params[n+2] then werror("too many operands") end
   local pn, p2 = params[n], params[n+1]
   local scale = shr(op, 30) == 0 and 2 or 3
   local p1, wb = match(pn, "^%[%s*(.-)%s*%](!?)$")
   if not p1 then
     if not p2 then
       local reg, tailr = match(pn, "^([%w_:]+)%s*(.*)$")
       if reg and tailr ~= "" then
 	local base, tp = parse_reg_base(reg)
 	if tp then
 	  waction("IMM", 32768+7*32+15+scale*1024, format(tp.ctypefmt, tailr))
 	  return op + base + 0x01000000
 	end
       end
     end
     werror("expected address operand")
   end
   if p2 then
     if wb == "!" then werror("bad use of '!'") end
     op = op + 0x00800000
   else
     local p1a, p2a = match(p1, "^([^,%s]*)%s*,%s*(.*)$")
     if p1a then p1, p2 = p1a, p2a else p2 = "#0" end
     op = op + (wb == "!" and 0x01800000 or 0x01000000)
   end
   return op + parse_reg_base(p1) + parse_imm(p2, 7, 15, scale, true)
 end
 
 local function parse_label(label, def)
   local prefix = sub(label, 1, 2)
   -- =>label (pc label reference)
   if prefix == "=>" then
     return "PC", 0, sub(label, 3)
   end
   -- ->name (global label reference)
   if prefix == "->" then
     return "LG", map_global[sub(label, 3)]
   end
   if def then
     -- [1-9] (local label definition)
     if match(label, "^[1-9]$") then
       return "LG", 10+tonumber(label)
     end
   else
     -- [<>][1-9] (local label reference)
     local dir, lnum = match(label, "^([<>])([1-9])$")
     if dir then -- Fwd: 1-9, Bkwd: 11-19.
       return "LG", lnum + (dir == ">" and 0 or 10)
     end
     -- extern label (extern label reference)
     local extname = match(label, "^extern%s+(%S+)$")
     if extname then
       return "EXT", map_extern[extname]
     end
   end
   werror("bad label `"..label.."'")
 end
 
 local function branch_type(op)
   if band(op, 0x7c000000) == 0x14000000 then return 0 -- B, BL
   elseif shr(op, 24) == 0x54 or band(op, 0x7e000000) == 0x34000000 or
 	 band(op, 0x3b000000) == 0x18000000 then
     return 0x800 -- B.cond, CBZ, CBNZ, LDR* literal
   elseif band(op, 0x7e000000) == 0x36000000 then return 0x1000 -- TBZ, TBNZ
   elseif band(op, 0x9f000000) == 0x10000000 then return 0x2000 -- ADR
   elseif band(op, 0x9f000000) == band(0x90000000) then return 0x3000 -- ADRP
   else
     assert(false, "unknown branch type")
   end
 end
 
 ------------------------------------------------------------------------------
 
 local map_op, op_template
 
 local function op_alias(opname, f)
   return function(params, nparams)
     if not params then return "-> "..opname:sub(1, -3) end
     f(params, nparams)
     op_template(params, map_op[opname], nparams)
   end
 end
 
 local function alias_bfx(p)
   p[4] = "#("..p[3]:sub(2)..")+("..p[4]:sub(2)..")-1"
 end
 
 local function alias_bfiz(p)
   parse_reg(p[1])
   if parse_reg_type == "w" then
     p[3] = "#-("..p[3]:sub(2)..")%32"
     p[4] = "#("..p[4]:sub(2)..")-1"
   else
     p[3] = "#-("..p[3]:sub(2)..")%64"
     p[4] = "#("..p[4]:sub(2)..")-1"
   end
 end
 
 local alias_lslimm = op_alias("ubfm_4", function(p)
   parse_reg(p[1])
   local sh = p[3]:sub(2)
   if parse_reg_type == "w" then
     p[3] = "#-("..sh..")%32"
     p[4] = "#31-("..sh..")"
   else
     p[3] = "#-("..sh..")%64"
     p[4] = "#63-("..sh..")"
   end
 end)
 
 -- Template strings for ARM instructions.
 map_op = {
   -- Basic data processing instructions.
   add_3  = "0b000000DNMg|11000000pDpNIg|8b206000pDpNMx",
   add_4  = "0b000000DNMSg|0b200000DNMXg|8b200000pDpNMXx|8b200000pDpNxMwX",
   adds_3 = "2b000000DNMg|31000000DpNIg|ab206000DpNMx",
   adds_4 = "2b000000DNMSg|2b200000DNMXg|ab200000DpNMXx|ab200000DpNxMwX",
   cmn_2  = "2b00001fNMg|3100001fpNIg|ab20601fpNMx",
   cmn_3  = "2b00001fNMSg|2b20001fNMXg|ab20001fpNMXx|ab20001fpNxMwX",
 
   sub_3  = "4b000000DNMg|51000000pDpNIg|cb206000pDpNMx",
   sub_4  = "4b000000DNMSg|4b200000DNMXg|cb200000pDpNMXx|cb200000pDpNxMwX",
   subs_3 = "6b000000DNMg|71000000DpNIg|eb206000DpNMx",
   subs_4 = "6b000000DNMSg|6b200000DNMXg|eb200000DpNMXx|eb200000DpNxMwX",
   cmp_2  = "6b00001fNMg|7100001fpNIg|eb20601fpNMx",
   cmp_3  = "6b00001fNMSg|6b20001fNMXg|eb20001fpNMXx|eb20001fpNxMwX",
 
   neg_2  = "4b0003e0DMg",
   neg_3  = "4b0003e0DMSg",
   negs_2 = "6b0003e0DMg",
   negs_3 = "6b0003e0DMSg",
 
   adc_3  = "1a000000DNMg",
   adcs_3 = "3a000000DNMg",
   sbc_3  = "5a000000DNMg",
   sbcs_3 = "7a000000DNMg",
   ngc_2  = "5a0003e0DMg",
   ngcs_2 = "7a0003e0DMg",
 
   and_3  = "0a000000DNMg|12000000pDNig",
   and_4  = "0a000000DNMSg",
   orr_3  = "2a000000DNMg|32000000pDNig",
   orr_4  = "2a000000DNMSg",
   eor_3  = "4a000000DNMg|52000000pDNig",
   eor_4  = "4a000000DNMSg",
   ands_3 = "6a000000DNMg|72000000DNig",
   ands_4 = "6a000000DNMSg",
   tst_2  = "6a00001fNMg|7200001fNig",
   tst_3  = "6a00001fNMSg",
 
   bic_3  = "0a200000DNMg",
   bic_4  = "0a200000DNMSg",
   orn_3  = "2a200000DNMg",
   orn_4  = "2a200000DNMSg",
   eon_3  = "4a200000DNMg",
   eon_4  = "4a200000DNMSg",
   bics_3 = "6a200000DNMg",
   bics_4 = "6a200000DNMSg",
 
   movn_2 = "12800000DWg",
   movn_3 = "12800000DWRg",
   movz_2 = "52800000DWg",
   movz_3 = "52800000DWRg",
   movk_2 = "72800000DWg",
   movk_3 = "72800000DWRg",
 
   -- TODO: this doesn't cover all valid immediates for mov reg, #imm.
   mov_2  = "2a0003e0DMg|52800000DW|320003e0pDig|11000000pDpNg",
   mov_3  = "2a0003e0DMSg",
   mvn_2  = "2a2003e0DMg",
   mvn_3  = "2a2003e0DMSg",
 
   adr_2  = "10000000DBx",
   adrp_2 = "90000000DBx",
 
   csel_4  = "1a800000DNMCg",
   csinc_4 = "1a800400DNMCg",
   csinv_4 = "5a800000DNMCg",
   csneg_4 = "5a800400DNMCg",
   cset_2  = "1a9f07e0Dcg",
   csetm_2 = "5a9f03e0Dcg",
   cinc_3  = "1a800400DNmcg",
   cinv_3  = "5a800000DNmcg",
   cneg_3  = "5a800400DNmcg",
 
   ccmn_4 = "3a400000NMVCg|3a400800N5VCg",
   ccmp_4 = "7a400000NMVCg|7a400800N5VCg",
 
   madd_4 = "1b000000DNMAg",
   msub_4 = "1b008000DNMAg",
   mul_3  = "1b007c00DNMg",
   mneg_3 = "1b00fc00DNMg",
 
   smaddl_4 = "9b200000DxNMwAx",
   smsubl_4 = "9b208000DxNMwAx",
   smull_3  = "9b207c00DxNMw",
   smnegl_3 = "9b20fc00DxNMw",
   smulh_3  = "9b407c00DNMx",
   umaddl_4 = "9ba00000DxNMwAx",
   umsubl_4 = "9ba08000DxNMwAx",
   umull_3  = "9ba07c00DxNMw",
   umnegl_3 = "9ba0fc00DxNMw",
   umulh_3  = "9bc07c00DNMx",
 
   udiv_3 = "1ac00800DNMg",
   sdiv_3 = "1ac00c00DNMg",
 
   -- Bit operations.
   sbfm_4 = "13000000DN12w|93400000DN12x",
   bfm_4  = "33000000DN12w|b3400000DN12x",
   ubfm_4 = "53000000DN12w|d3400000DN12x",
   extr_4 = "13800000DNM2w|93c00000DNM2x",
 
   sxtb_2 = "13001c00DNw|93401c00DNx",
   sxth_2 = "13003c00DNw|93403c00DNx",
   sxtw_2 = "93407c00DxNw",
   uxtb_2 = "53001c00DNw",
   uxth_2 = "53003c00DNw",
 
   sbfx_4  = op_alias("sbfm_4", alias_bfx),
   bfxil_4 = op_alias("bfm_4", alias_bfx),
   ubfx_4  = op_alias("ubfm_4", alias_bfx),
   sbfiz_4 = op_alias("sbfm_4", alias_bfiz),
   bfi_4   = op_alias("bfm_4", alias_bfiz),
   ubfiz_4 = op_alias("ubfm_4", alias_bfiz),
 
   lsl_3  = function(params, nparams)
     if params and params[3]:byte() == 35 then
       return alias_lslimm(params, nparams)
     else
       return op_template(params, "1ac02000DNMg", nparams)
     end
   end,
   lsr_3  = "1ac02400DNMg|53007c00DN1w|d340fc00DN1x",
   asr_3  = "1ac02800DNMg|13007c00DN1w|9340fc00DN1x",
   ror_3  = "1ac02c00DNMg|13800000DNm2w|93c00000DNm2x",
 
   clz_2   = "5ac01000DNg",
   cls_2   = "5ac01400DNg",
   rbit_2  = "5ac00000DNg",
   rev_2   = "5ac00800DNw|dac00c00DNx",
   rev16_2 = "5ac00400DNg",
   rev32_2 = "dac00800DNx",
 
   -- Loads and stores.
   ["strb_*"]  = "38000000DwL",
   ["ldrb_*"]  = "38400000DwL",
   ["ldrsb_*"] = "38c00000DwL|38800000DxL",
   ["strh_*"]  = "78000000DwL",
   ["ldrh_*"]  = "78400000DwL",
   ["ldrsh_*"] = "78c00000DwL|78800000DxL",
   ["str_*"]   = "b8000000DwL|f8000000DxL|bc000000DsL|fc000000DdL",
   ["ldr_*"]   = "18000000DwB|58000000DxB|1c000000DsB|5c000000DdB|b8400000DwL|f8400000DxL|bc400000DsL|fc400000DdL",
   ["ldrsw_*"] = "98000000DxB|b8800000DxL",
   -- NOTE: ldur etc. are handled by ldr et al.
 
   ["stp_*"]   = "28000000DAwP|a8000000DAxP|2c000000DAsP|6c000000DAdP",
   ["ldp_*"]   = "28400000DAwP|a8400000DAxP|2c400000DAsP|6c400000DAdP",
   ["ldpsw_*"] = "68400000DAxP",
 
   -- Branches.
   b_1    = "14000000B",
   bl_1   = "94000000B",
   blr_1  = "d63f0000Nx",
   br_1   = "d61f0000Nx",
   ret_0  = "d65f03c0",
   ret_1  = "d65f0000Nx",
   -- b.cond is added below.
   cbz_2  = "34000000DBg",
   cbnz_2 = "35000000DBg",
   tbz_3  = "36000000DTBw|36000000DTBx",
   tbnz_3 = "37000000DTBw|37000000DTBx",
 
   -- Miscellaneous instructions.
   -- TODO: hlt, hvc, smc, svc, eret, dcps[123], drps, mrs, msr
   -- TODO: sys, sysl, ic, dc, at, tlbi
   -- TODO: hint, yield, wfe, wfi, sev, sevl
   -- TODO: clrex, dsb, dmb, isb
   nop_0  = "d503201f",
   brk_0  = "d4200000",
   brk_1  = "d4200000W",
 
   -- Floating point instructions.
   fmov_2  = "1e204000DNf|1e260000DwNs|1e270000DsNw|9e660000DxNd|9e670000DdNx|1e201000DFf",
   fabs_2  = "1e20c000DNf",
   fneg_2  = "1e214000DNf",
   fsqrt_2 = "1e21c000DNf",
 
   fcvt_2  = "1e22c000DdNs|1e624000DsNd",
 
   -- TODO: half-precision and fixed-point conversions.
   fcvtas_2 = "1e240000DwNs|9e240000DxNs|1e640000DwNd|9e640000DxNd",
   fcvtau_2 = "1e250000DwNs|9e250000DxNs|1e650000DwNd|9e650000DxNd",
   fcvtms_2 = "1e300000DwNs|9e300000DxNs|1e700000DwNd|9e700000DxNd",
   fcvtmu_2 = "1e310000DwNs|9e310000DxNs|1e710000DwNd|9e710000DxNd",
   fcvtns_2 = "1e200000DwNs|9e200000DxNs|1e600000DwNd|9e600000DxNd",
   fcvtnu_2 = "1e210000DwNs|9e210000DxNs|1e610000DwNd|9e610000DxNd",
   fcvtps_2 = "1e280000DwNs|9e280000DxNs|1e680000DwNd|9e680000DxNd",
   fcvtpu_2 = "1e290000DwNs|9e290000DxNs|1e690000DwNd|9e690000DxNd",
   fcvtzs_2 = "1e380000DwNs|9e380000DxNs|1e780000DwNd|9e780000DxNd",
   fcvtzu_2 = "1e390000DwNs|9e390000DxNs|1e790000DwNd|9e790000DxNd",
 
   scvtf_2  = "1e220000DsNw|9e220000DsNx|1e620000DdNw|9e620000DdNx",
   ucvtf_2  = "1e230000DsNw|9e230000DsNx|1e630000DdNw|9e630000DdNx",
 
   frintn_2 = "1e244000DNf",
   frintp_2 = "1e24c000DNf",
   frintm_2 = "1e254000DNf",
   frintz_2 = "1e25c000DNf",
   frinta_2 = "1e264000DNf",
   frintx_2 = "1e274000DNf",
   frinti_2 = "1e27c000DNf",
 
   fadd_3   = "1e202800DNMf",
   fsub_3   = "1e203800DNMf",
   fmul_3   = "1e200800DNMf",
   fnmul_3  = "1e208800DNMf",
   fdiv_3   = "1e201800DNMf",
 
   fmadd_4  = "1f000000DNMAf",
   fmsub_4  = "1f008000DNMAf",
   fnmadd_4 = "1f200000DNMAf",
   fnmsub_4 = "1f208000DNMAf",
 
   fmax_3   = "1e204800DNMf",
   fmaxnm_3 = "1e206800DNMf",
   fmin_3   = "1e205800DNMf",
   fminnm_3 = "1e207800DNMf",
 
   fcmp_2   = "1e202000NMf|1e202008NZf",
   fcmpe_2  = "1e202010NMf|1e202018NZf",
 
   fccmp_4  = "1e200400NMVCf",
   fccmpe_4 = "1e200410NMVCf",
 
   fcsel_4  = "1e200c00DNMCf",
 
   -- TODO: crc32*, aes*, sha*, pmull
   -- TODO: SIMD instructions.
 }
 
 for cond,c in pairs(map_cond) do
   map_op["b"..cond.."_1"] = tohex(0x54000000+c).."B"
 end
 
 ------------------------------------------------------------------------------
 
 -- Handle opcodes defined with template strings.
 local function parse_template(params, template, nparams, pos)
   local op = tonumber(sub(template, 1, 8), 16)
   local n = 1
   local rtt = {}
 
   parse_reg_type = false
 
   -- Process each character.
   for p in gmatch(sub(template, 9), ".") do
     local q = params[n]
     if p == "D" then
       op = op + parse_reg(q); n = n + 1
     elseif p == "N" then
       op = op + shl(parse_reg(q), 5); n = n + 1
     elseif p == "M" then
       op = op + shl(parse_reg(q), 16); n = n + 1
     elseif p == "A" then
       op = op + shl(parse_reg(q), 10); n = n + 1
     elseif p == "m" then
       op = op + shl(parse_reg(params[n-1]), 16)
 
     elseif p == "p" then
       if q == "sp" then params[n] = "@x31" end
     elseif p == "g" then
       if parse_reg_type == "x" then
 	op = op + 0x80000000
       elseif parse_reg_type ~= "w" then
 	werror("bad register type")
       end
       parse_reg_type = false
     elseif p == "f" then
       if parse_reg_type == "d" then
 	op = op + 0x00400000
       elseif parse_reg_type ~= "s" then
 	werror("bad register type")
       end
       parse_reg_type = false
     elseif p == "x" or p == "w" or p == "d" or p == "s" then
       if parse_reg_type ~= p then
 	werror("register size mismatch")
       end
       parse_reg_type = false
 
     elseif p == "L" then
       op = parse_load(params, nparams, n, op)
     elseif p == "P" then
       op = parse_load_pair(params, nparams, n, op)
 
     elseif p == "B" then
       local mode, v, s = parse_label(q, false); n = n + 1
       local m = branch_type(op)
       waction("REL_"..mode, v+m, s, 1)
 
     elseif p == "I" then
       op = op + parse_imm12(q); n = n + 1
     elseif p == "i" then
       op = op + parse_imm13(q); n = n + 1
     elseif p == "W" then
       op = op + parse_imm(q, 16, 5, 0, false); n = n + 1
     elseif p == "T" then
       op = op + parse_imm6(q); n = n + 1
     elseif p == "1" then
       op = op + parse_imm(q, 6, 16, 0, false); n = n + 1
     elseif p == "2" then
       op = op + parse_imm(q, 6, 10, 0, false); n = n + 1
     elseif p == "5" then
       op = op + parse_imm(q, 5, 16, 0, false); n = n + 1
     elseif p == "V" then
       op = op + parse_imm(q, 4, 0, 0, false); n = n + 1
     elseif p == "F" then
       op = op + parse_fpimm(q); n = n + 1
     elseif p == "Z" then
       if q ~= "#0" and q ~= "#0.0" then werror("expected zero immediate") end
       n = n + 1
 
     elseif p == "S" then
       op = op + parse_shift(q); n = n + 1
     elseif p == "X" then
       op = op + parse_extend(q); n = n + 1
     elseif p == "R" then
       op = op + parse_lslx16(q); n = n + 1
     elseif p == "C" then
       op = op + parse_cond(q, 0); n = n + 1
     elseif p == "c" then
       op = op + parse_cond(q, 1); n = n + 1
 
     else
       assert(false)
     end
   end
   wputpos(pos, op)
 end
 
 function op_template(params, template, nparams)
   if not params then return template:gsub("%x%x%x%x%x%x%x%x", "") end
 
   -- Limit number of section buffer positions used by a single dasm_put().
   -- A single opcode needs a maximum of 3 positions.
   if secpos+3 > maxsecpos then wflush() end
   local pos = wpos()
   local lpos, apos, spos = #actlist, #actargs, secpos
 
   local ok, err
   for t in gmatch(template, "[^|]+") do
     ok, err = pcall(parse_template, params, t, nparams, pos)
     if ok then return end
     secpos = spos
     actlist[lpos+1] = nil
     actlist[lpos+2] = nil
     actlist[lpos+3] = nil
     actargs[apos+1] = nil
     actargs[apos+2] = nil
     actargs[apos+3] = nil
   end
   error(err, 0)
 end
 
 map_op[".template__"] = op_template
 
 ------------------------------------------------------------------------------
 
 -- Pseudo-opcode to mark the position where the action list is to be emitted.
 map_op[".actionlist_1"] = function(params)
   if not params then return "cvar" end
   local name = params[1] -- No syntax check. You get to keep the pieces.
   wline(function(out) writeactions(out, name) end)
 end
 
 -- Pseudo-opcode to mark the position where the global enum is to be emitted.
 map_op[".globals_1"] = function(params)
   if not params then return "prefix" end
   local prefix = params[1] -- No syntax check. You get to keep the pieces.
   wline(function(out) writeglobals(out, prefix) end)
 end
 
 -- Pseudo-opcode to mark the position where the global names are to be emitted.
 map_op[".globalnames_1"] = function(params)
   if not params then return "cvar" end
   local name = params[1] -- No syntax check. You get to keep the pieces.
   wline(function(out) writeglobalnames(out, name) end)
 end
 
 -- Pseudo-opcode to mark the position where the extern names are to be emitted.
 map_op[".externnames_1"] = function(params)
   if not params then return "cvar" end
   local name = params[1] -- No syntax check. You get to keep the pieces.
   wline(function(out) writeexternnames(out, name) end)
 end
 
 ------------------------------------------------------------------------------
 
 -- Label pseudo-opcode (converted from trailing colon form).
 map_op[".label_1"] = function(params)
   if not params then return "[1-9] | ->global | =>pcexpr" end
   if secpos+1 > maxsecpos then wflush() end
   local mode, n, s = parse_label(params[1], true)
   if mode == "EXT" then werror("bad label definition") end
   waction("LABEL_"..mode, n, s, 1)
 end
 
 ------------------------------------------------------------------------------
 
 -- Pseudo-opcodes for data storage.
 map_op[".long_*"] = function(params)
   if not params then return "imm..." end
   for _,p in ipairs(params) do
     local n = tonumber(p)
     if not n then werror("bad immediate `"..p.."'") end
     if n < 0 then n = n + 2^32 end
     wputw(n)
     if secpos+2 > maxsecpos then wflush() end
   end
 end
 
 -- Alignment pseudo-opcode.
 map_op[".align_1"] = function(params)
   if not params then return "numpow2" end
   if secpos+1 > maxsecpos then wflush() end
   local align = tonumber(params[1])
   if align then
     local x = align
     -- Must be a power of 2 in the range (2 ... 256).
     for i=1,8 do
       x = x / 2
       if x == 1 then
 	waction("ALIGN", align-1, nil, 1) -- Action byte is 2**n-1.
 	return
       end
     end
   end
   werror("bad alignment")
 end
 
 ------------------------------------------------------------------------------
 
 -- Pseudo-opcode for (primitive) type definitions (map to C types).
 map_op[".type_3"] = function(params, nparams)
   if not params then
     return nparams == 2 and "name, ctype" or "name, ctype, reg"
   end
   local name, ctype, reg = params[1], params[2], params[3]
   if not match(name, "^[%a_][%w_]*$") then
     werror("bad type name `"..name.."'")
   end
   local tp = map_type[name]
   if tp then
     werror("duplicate type `"..name.."'")
   end
   -- Add #type to defines. A bit unclean to put it in map_archdef.
   map_archdef["#"..name] = "sizeof("..ctype..")"
   -- Add new type and emit shortcut define.
   local num = ctypenum + 1
   map_type[name] = {
     ctype = ctype,
     ctypefmt = format("Dt%X(%%s)", num),
     reg = reg,
   }
   wline(format("#define Dt%X(_V) (int)(ptrdiff_t)&(((%s *)0)_V)", num, ctype))
   ctypenum = num
 end
 map_op[".type_2"] = map_op[".type_3"]
 
 -- Dump type definitions.
 local function dumptypes(out, lvl)
   local t = {}
   for name in pairs(map_type) do t[#t+1] = name end
   sort(t)
   out:write("Type definitions:\n")
   for _,name in ipairs(t) do
     local tp = map_type[name]
     local reg = tp.reg or ""
     out:write(format("  %-20s %-20s %s\n", name, tp.ctype, reg))
   end
   out:write("\n")
 end
 
 ------------------------------------------------------------------------------
 
 -- Set the current section.
 function _M.section(num)
   waction("SECTION", num)
   wflush(true) -- SECTION is a terminal action.
 end
 
 ------------------------------------------------------------------------------
 
 -- Dump architecture description.
 function _M.dumparch(out)
   out:write(format("DynASM %s version %s, released %s\n\n",
     _info.arch, _info.version, _info.release))
   dumpactions(out)
 end
 
 -- Dump all user defined elements.
 function _M.dumpdef(out, lvl)
   dumptypes(out, lvl)
   dumpglobals(out, lvl)
   dumpexterns(out, lvl)
 end
 
 ------------------------------------------------------------------------------
 
 -- Pass callbacks from/to the DynASM core.
 function _M.passcb(wl, we, wf, ww)
   wline, werror, wfatal, wwarn = wl, we, wf, ww
   return wflush
 end
 
 -- Setup the arch-specific module.
 function _M.setup(arch, opt)
   g_arch, g_opt = arch, opt
 end
 
 -- Merge the core maps and the arch-specific maps.
 function _M.mergemaps(map_coreop, map_def)
   setmetatable(map_op, { __index = map_coreop })
   setmetatable(map_def, { __index = map_archdef })
   return map_op, map_def
 end
 
 return _M
 
 ------------------------------------------------------------------------------