ARM: Add DynASM ARM module and encoding engine.

1 files changed, 933 insertions, 0 deletions

diff --git a/dynasm/dasm_arm.lua b/dynasm/dasm_arm.lua
new file mode 100644
index 00000000..37ba7fab
--- /dev/null
+++ b/dynasm/dasm_arm.lua
@@ -0,0 +1,933 @@
+------------------------------------------------------------------------------
+-- DynASM ARM module.
+--
+-- Copyright (C) 2005-2011 Mike Pall. All rights reserved.
+-- See dynasm.lua for full copyright notice.
+------------------------------------------------------------------------------
+
+-- Module information:
+local _info = {
+  arch =	"arm",
+  description =	"DynASM ARM module",
+  version =	"1.2.2",
+  vernum =	 10202,
+  release =	"2011-03-23",
+  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 = table.concat, table.sort
+
+-- 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", "IMM12", "IMM16", "IMML8", "IMML12",
+}
+
+-- 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
+
+------------------------------------------------------------------------------
+
+-- Return 8 digit hex number.
+local function tohex(x)
+  return sub(format("%08x", x), -8) -- Avoid 64 bit portability problem in Lua.
+end
+
+-- 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")
+  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 = { sp = "r13", lr = "r14", pc = "r15", }
+
+-- Int. register name -> ext. name.
+local map_reg_rev = { r13 = "sp", r14 = "lr", r15 = "pc", }
+
+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, ror = 3, }
+
+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,
+}
+
+------------------------------------------------------------------------------
+
+-- Template strings for ARM instructions.
+local map_op = {
+  -- Basic data processing instructions.
+  and_3 = "e0000000DNPs",
+  eor_3 = "e0200000DNPs",
+  sub_3 = "e0400000DNPs",
+  rsb_3 = "e0600000DNPs",
+  add_3 = "e0800000DNPs",
+  adc_3 = "e0a00000DNPs",
+  sbc_3 = "e0c00000DNPs",
+  rsc_3 = "e0e00000DNPs",
+  tst_2 = "e1100000NP",
+  teq_2 = "e1300000NP",
+  cmp_2 = "e1500000NP",
+  cmn_2 = "e1700000NP",
+  orr_3 = "e1800000DNPs",
+  mov_2 = "e1a00000DPs",
+  bic_3 = "e1c00000DNPs",
+  mvn_2 = "e1e00000DPs",
+
+  and_4 = "e0000000DNMps",
+  eor_4 = "e0200000DNMps",
+  sub_4 = "e0400000DNMps",
+  rsb_4 = "e0600000DNMps",
+  add_4 = "e0800000DNMps",
+  adc_4 = "e0a00000DNMps",
+  sbc_4 = "e0c00000DNMps",
+  rsc_4 = "e0e00000DNMps",
+  tst_3 = "e1100000NMp",
+  teq_3 = "e1300000NMp",
+  cmp_3 = "e1500000NMp",
+  cmn_3 = "e1700000NMp",
+  orr_4 = "e1800000DNMps",
+  mov_3 = "e1a00000DMps",
+  bic_4 = "e1c00000DNMps",
+  mvn_3 = "e1e00000DMps",
+
+  lsl_3 = "e1a00000DMvs",
+  lsr_3 = "e1a00020DMvs",
+  asr_3 = "e1a00040DMvs",
+  ror_3 = "e1a00060DMvs",
+  rrx_2 = "e1a00060DMs",
+
+  -- Multiply and multiply-accumulate.
+  mul_3 = "e0000090NMSs",
+  mla_4 = "e0200090NMSDs",
+  umaal_4 = "e0400090DNMSs",	-- v6
+  mls_4 = "e0600090DNMSs",	-- v6T2
+  umull_4 = "e0800090DNMSs",
+  umlal_4 = "e0a00090DNMSs",
+  smull_4 = "e0c00090DNMSs",
+  smlal_4 = "e0e00090DNMSs",
+
+  -- Halfword multiply and multiply-accumulate.
+  smlabb_4 = "e1000080NMSD",	-- v5TE
+  smlatb_4 = "e10000a0NMSD",	-- v5TE
+  smlabt_4 = "e10000c0NMSD",	-- v5TE
+  smlatt_4 = "e10000e0NMSD",	-- v5TE
+  smlawb_4 = "e1200080NMSD",	-- v5TE
+  smulwb_3 = "e12000a0NMS",	-- v5TE
+  smlawt_4 = "e12000c0NMSD",	-- v5TE
+  smulwt_3 = "e12000e0NMS",	-- v5TE
+  smlalbb_4 = "e1400080NMSD",	-- v5TE
+  smlaltb_4 = "e14000a0NMSD",	-- v5TE
+  smlalbt_4 = "e14000c0NMSD",	-- v5TE
+  smlaltt_4 = "e14000e0NMSD",	-- v5TE
+  smulbb_3 = "e1600080NMS",	-- v5TE
+  smultb_3 = "e16000a0NMS",	-- v5TE
+  smulbt_3 = "e16000c0NMS",	-- v5TE
+  smultt_3 = "e16000e0NMS",	-- v5TE
+
+  -- Miscellaneous data processing instructions.
+  clz_2 = "e16f0f10DM", -- v5T
+  rev_2 = "e6bf0f30DM", -- v6
+  rev16_2 = "e6bf0fb0DM", -- v6
+  revsh_2 = "e6ff0fb0DM", -- v6
+  sel_3 = "e6800fb0DNM", -- v6
+  usad8_3 = "e780f010NMS", -- v6
+  usada8_4 = "e7800010NMSD", -- v6
+  rbit_2 = "e6ff0f30DM", -- v6T2
+  movw_2 = "e3000000DW", -- v6T2
+  movt_2 = "e3400000DW", -- v6T2
+  -- Note: the X encodes width-1, not width.
+  sbfx_4 = "e7a00050DMvX", -- v6T2
+  ubfx_4 = "e7e00050DMvX", -- v6T2
+  -- Note: the X encodes the msb field, not the width.
+  bfc_3 = "e7c0001fDvX", -- v6T2
+  bfi_4 = "e7c00010DMvX", -- v6T2
+
+  -- Packing and unpacking instructions.
+  pkhbt_3 = "e6800010DNM", pkhbt_4 = "e6800010DNMv", -- v6
+  pkhtb_3 = "e6800050DNM", pkhtb_4 = "e6800050DNMv", -- v6
+  sxtab_3 = "e6a00070DNM", sxtab_4 = "e6a00070DNMv", -- v6
+  sxtab16_3 = "e6800070DNM", sxtab16_4 = "e6800070DNMv", -- v6
+  sxtah_3 = "e6b00070DNM", sxtah_4 = "e6b00070DNMv", -- v6
+  sxtb_2 = "e6af0070DM", sxtb_3 = "e6af0070DMv", -- v6
+  sxtb16_2 = "e68f0070DM", sxtb16_3 = "e68f0070DMv", -- v6
+  sxth_2 = "e6bf0070DM", sxth_3 = "e6bf0070DMv", -- v6
+  uxtab_3 = "e6e00070DNM", uxtab_4 = "e6e00070DNMv", -- v6
+  uxtab16_3 = "e6c00070DNM", uxtab16_4 = "e6c00070DNMv", -- v6
+  uxtah_3 = "e6f00070DNM", uxtah_4 = "e6f00070DNMv", -- v6
+  uxtb_2 = "e6ef0070DM", uxtb_3 = "e6ef0070DMv", -- v6
+  uxtb16_2 = "e6cf0070DM", uxtb16_3 = "e6cf0070DMv", -- v6
+  uxth_2 = "e6ff0070DM", uxth_3 = "e6ff0070DMv", -- v6
+
+  -- Saturating instructions.
+  qadd_3 = "e1000050DMN",	-- v5TE
+  qsub_3 = "e1200050DMN",	-- v5TE
+  qdadd_3 = "e1400050DMN",	-- v5TE
+  qdsub_3 = "e1600050DMN",	-- v5TE
+  -- Note: the X for ssat* encodes sat_imm-1, not sat_imm.
+  ssat_3 = "e6a00010DXM", ssat_4 = "e6a00010DXMp", -- v6
+  usat_3 = "e6e00010DXM", usat_4 = "e6e00010DXMp", -- v6
+  ssat16_3 = "e6a00f30DXM", -- v6
+  usat16_3 = "e6e00f30DXM", -- v6
+
+  -- Parallel addition and subtraction.
+  sadd16_3 = "e6100f10DNM", -- v6
+  sasx_3 = "e6100f30DNM", -- v6
+  ssax_3 = "e6100f50DNM", -- v6
+  ssub16_3 = "e6100f70DNM", -- v6
+  sadd8_3 = "e6100f90DNM", -- v6
+  ssub8_3 = "e6100ff0DNM", -- v6
+  qadd16_3 = "e6200f10DNM", -- v6
+  qasx_3 = "e6200f30DNM", -- v6
+  qsax_3 = "e6200f50DNM", -- v6
+  qsub16_3 = "e6200f70DNM", -- v6
+  qadd8_3 = "e6200f90DNM", -- v6
+  qsub8_3 = "e6200ff0DNM", -- v6
+  shadd16_3 = "e6300f10DNM", -- v6
+  shasx_3 = "e6300f30DNM", -- v6
+  shsax_3 = "e6300f50DNM", -- v6
+  shsub16_3 = "e6300f70DNM", -- v6
+  shadd8_3 = "e6300f90DNM", -- v6
+  shsub8_3 = "e6300ff0DNM", -- v6
+  uadd16_3 = "e6500f10DNM", -- v6
+  uasx_3 = "e6500f30DNM", -- v6
+  usax_3 = "e6500f50DNM", -- v6
+  usub16_3 = "e6500f70DNM", -- v6
+  uadd8_3 = "e6500f90DNM", -- v6
+  usub8_3 = "e6500ff0DNM", -- v6
+  uqadd16_3 = "e6600f10DNM", -- v6
+  uqasx_3 = "e6600f30DNM", -- v6
+  uqsax_3 = "e6600f50DNM", -- v6
+  uqsub16_3 = "e6600f70DNM", -- v6
+  uqadd8_3 = "e6600f90DNM", -- v6
+  uqsub8_3 = "e6600ff0DNM", -- v6
+  uhadd16_3 = "e6700f10DNM", -- v6
+  uhasx_3 = "e6700f30DNM", -- v6
+  uhsax_3 = "e6700f50DNM", -- v6
+  uhsub16_3 = "e6700f70DNM", -- v6
+  uhadd8_3 = "e6700f90DNM", -- v6
+  uhsub8_3 = "e6700ff0DNM", -- v6
+
+  -- Load/store instructions.
+  str_2 = "e4000000DL", str_3 = "e4000000DL", str_4 = "e4000000DL",
+  strb_2 = "e4400000DL", strb_3 = "e4400000DL", strb_4 = "e4400000DL",
+  ldr_2 = "e4100000DL", ldr_3 = "e4100000DL", ldr_4 = "e4100000DL",
+  ldrb_2 = "e4500000DL", ldrb_3 = "e4500000DL", ldrb_4 = "e4500000DL",
+  strh_2 = "e00000b0DL", strh_3 = "e00000b0DL",
+  ldrh_2 = "e01000b0DL", ldrh_3 = "e01000b0DL",
+  ldrd_2 = "e00000d0DL", ldrd_3 = "e00000d0DL", -- v5TE
+  ldrsb_2 = "e01000d0DL", ldrsb_3 = "e01000d0DL",
+  strd_2 = "e00000f0DL", strd_3 = "e00000f0DL", -- v5TE
+  ldrsh_2 = "e01000f0DL", ldrsh_3 = "e01000f0DL",
+
+  ldm_2 = "e8900000nR", ldmia_2 = "e8900000nR", ldmfd_2 = "e8900000nR",
+  ldmda_2 = "e8100000nR", ldmfa_2 = "e8100000nR",
+  ldmdb_2 = "e9100000nR", ldmea_2 = "e9100000nR",
+  ldmib_2 = "e9900000nR", ldmed_2 = "e9900000nR",
+  stm_2 = "e8800000nR", stmia_2 = "e8800000nR", stmfd_2 = "e8800000nR",
+  stmda_2 = "e8000000nR", stmfa_2 = "e8000000nR",
+  stmdb_2 = "e9000000nR", stmea_2 = "e9000000nR",
+  stmib_2 = "e9800000nR", stmed_2 = "e9800000nR",
+  pop_1 = "e8bd0000R", push_1 = "e92d0000R",
+
+  -- Branch instructions.
+  b_1 = "ea000000B",
+  bl_1 = "eb000000B",
+  blx_1 = "e12fff30C",
+  bx_1 = "e12fff10M",
+
+  -- Miscellaneous instructions.
+  nop_0 = "e1a00000",
+  mrs_1 = "e10f0000D",
+  bkpt_1 = "e1200070K", -- v5T
+  svc_1 = "ef000000T", swi_1 = "ef000000T",
+  ud_0 = "e7f001f0",
+
+  -- NYI: Advanced SIMD and VFP instructions.
+
+  -- NYI instructions, since I have no need for them right now:
+  -- swp, swpb, strex, ldrex, strexd, ldrexd, strexb, ldrexb, strexh, ldrexh
+  -- msr, nopv6, yield, wfe, wfi, sev, dbg, bxj, smc, srs, rfe
+  -- cps, setend, pli, pld, pldw, clrex, dsb, dmb, isb
+  -- stc, ldc, mcr, mcr2, mrc, mrc2, mcrr, mcrr2, mrrc, mrrc2, cdp, cdp2
+}
+
+-- Add mnemonics for "s" variants.
+do
+  local t = {}
+  for k,v in pairs(map_op) do
+    if sub(v, -1) == "s" then
+      local v2 = sub(v, 1, 2)..char(byte(v, 3)+1)..sub(v, 4, -2)
+      t[sub(k, 1, -3).."s"..sub(k, -2)] = v2
+    end
+  end
+  for k,v in pairs(t) do
+    map_op[k] = v
+  end
+end
+
+------------------------------------------------------------------------------
+
+local function parse_gpr(expr)
+  local tname, ovreg = match(expr, "^([%w_]+):(r1?[0-9])$")
+  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 r = match(expr, "^r(1?[0-9])$")
+  if r then
+    r = tonumber(r)
+    if r <= 15 then return r, tp end
+  end
+  werror("bad register name `"..expr.."'")
+end
+
+local function parse_gpr_pm(expr)
+  local pm, expr2 = match(expr, "^([+-]?)(.*)$")
+  return parse_gpr(expr2), (pm == "-")
+end
+
+local function parse_reglist(reglist)
+  reglist = match(reglist, "^{%s*([^}]*)}$")
+  if not reglist then werror("register list expected") end
+  local rr = 0
+  for p in gmatch(reglist..",", "%s*([^,]*),") do
+    local rbit = 2^parse_gpr(gsub(p, "%s+$", ""))
+    if ((rr - (rr % rbit)) / rbit) % 2 ~= 0 then
+      werror("duplicate register `"..p.."'")
+    end
+    rr = rr + rbit
+  end
+  return rr
+end
+
+local function parse_imm(imm, bits, shift, scale, signed)
+  imm = match(imm, "^#(.*)$")
+  if not imm then werror("expected immediate operand") end
+  local n = tonumber(imm)
+  if n then
+    if n % 2^scale == 0 then
+      n = n / 2^scale
+      if signed then
+	if n >= 0 then
+	  if n < 2^(bits-1) then return n*2^shift end
+	else
+	  if n >= -(2^(bits-1))-1 then return (n+2^bits)*2^shift end
+	end
+      else
+	if n >= 0 and n <= 2^bits-1 then return n*2^shift end
+      end
+    end
+    werror("out of range immediate `"..imm.."'")
+  else
+    waction("IMM", (signed and 32768 or 0)+scale*1024+bits*32+shift, imm)
+    return 0
+  end
+end
+
+local function parse_imm12(imm)
+  local n = tonumber(imm)
+  if n then
+    local m = n
+    for i=0,-15,-1 do
+      if m >= 0 and m <= 255 and n % 1 == 0 then return m + (i%16) * 256 end
+      local t = m % 4
+      m = (m - t) / 4 + t * 2^30
+    end
+    werror("out of range immediate `"..imm.."'")
+  else
+    waction("IMM12", 0, imm)
+    return 0
+  end
+end
+
+local function parse_imm16(imm)
+  imm = match(imm, "^#(.*)$")
+  if not imm then werror("expected immediate operand") end
+  local n = tonumber(imm)
+  if n then
+    if n >= 0 and n <= 65535 and n % 1 == 0 then
+      local t = n % 4096
+      return (n - t) * 16 + t
+    end
+    werror("out of range immediate `"..imm.."'")
+  else
+    waction("IMM16", 32*16, imm)
+    return 0
+  end
+end
+
+local function parse_imm_load(imm, ext)
+  local n = tonumber(imm)
+  if n then
+    if ext then
+      if n >= -255 and n <= 255 then
+	local up = 0x00800000
+	if n < 0 then n = -n; up = 0 end
+	return (n-(n%16))*16+(n%16) + up
+      end
+    else
+      if n >= -4095 and n <= 4095 then
+	if n >= 0 then return n+0x00800000 end
+	return -n
+      end
+    end
+    werror("out of range immediate `"..imm.."'")
+  else
+    waction(ext and "IMML8" or "IMML12", 32768 + 32*(ext and 8 or 12), imm)
+    return 0
+  end
+end
+
+local function parse_shift(shift, gprok)
+  if shift == "rrx" then
+    return 3 * 32
+  else
+    local s, s2 = match(shift, "^(%S+)%s*(.*)$")
+    s = map_shift[s]
+    if not s then werror("expected shift operand") end
+    if sub(s2, 1, 1) == "#" then
+      return parse_imm(s2, 5, 7, 0, false) + s * 32
+    else
+      if not gprok then werror("expected immediate shift operand") end
+      return parse_gpr(s2) * 256 + s * 32 + 16
+    end
+  end
+end
+
+local function parse_load(params, nparams, n, op)
+  local oplo = op % 256
+  local ext, ldrd = (oplo ~= 0), (oplo == 208)
+  local d
+  if (ldrd or oplo == 240) then
+    d = ((op - (op % 4096)) / 4096) % 16
+    if d % 2 ~= 0 then werror("odd destination register") end
+  end
+  local p1, wb = match(params[n], "^%[%s*(.-)%s*%](!?)$")
+  local p2 = params[n+1]
+  if not p1 then
+    if not p2 then
+      local reg, tailr = match(params[n], "^([%w_:]+)%s*(.*)$")
+      if reg and tailr ~= "" then
+	local d, tp = parse_gpr(reg)
+	if tp then
+	  waction(ext and "IMML8" or "IMML12", 32768 + 32*(ext and 8 or 12),
+		  format(tp.ctypefmt, tailr))
+	  return op + d * 65536 + 0x01000000 + (ext and 0x00400000 or 0)
+	end
+      end
+    end
+    werror("expected address operand")
+  end
+  if wb == "!" then op = op + 0x00200000 end
+  if p2 then
+    if wb == "!" then werror("bad use of '!'") end
+    local p3 = params[n+2]
+    op = op + parse_gpr(p1) * 65536
+    local imm = match(p2, "^#(.*)$")
+    if imm then
+      local m = parse_imm_load(imm, ext)
+      if p3 then werror("too many parameters") end
+      op = op + m + (ext and 0x00400000 or 0)
+    else
+      local m, neg = parse_gpr_pm(p2)
+      if ldrd and (m == d or m-1 == d) then werror("register conflict") end
+      op = op + m + (neg and 0 or 0x00800000) + (ext and 0 or 0x02000000)
+      if p3 then op = op + parse_shift(p3) end
+    end
+  else
+    local p1a, p2 = match(p1, "^([^,%s]*)%s*(.*)$")
+    local n = parse_gpr(p1a)
+    op = op + parse_gpr(p1a) * 65536 + 0x01000000
+    if p2 ~= "" then
+      local imm = match(p2, "^,%s*#(.*)$")
+      if imm then
+	local m = parse_imm_load(imm, ext)
+	op = op + m + (ext and 0x00400000 or 0)
+      else
+	local p2a, p3 = match(p2, "^,%s*([^,%s]*)%s*,?%s*(.*)$")
+	local m, neg = parse_gpr_pm(p2a)
+	if ldrd and (m == d or m-1 == d) then werror("register conflict") end
+	op = op + m + (neg and 0 or 0x00800000) + (ext and 0 or 0x02000000)
+	if p3 ~= "" then
+	  if ext then werror("too many parameters") end
+	  op = op + parse_shift(p3)
+	end
+      end
+    else
+      if wb == "!" then werror("bad use of '!'") end
+      op = op + (ext and 0x00c00000 or 0x00800000)
+    end
+  end
+  return op
+end
+
+local function parse_label(label, def)
+  local prefix = sub(label, 1, 2)
+  -- =>label (pc label reference)
+  if prefix == "=>" then
+    return "PC", 0, sub(label, 3)
+  end
+  -- ->name (global label reference)
+  if prefix == "->" then
+    return "LG", map_global[sub(label, 3)]
+  end
+  if def then
+    -- [1-9] (local label definition)
+    if match(label, "^[1-9]$") 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
+
+------------------------------------------------------------------------------
+
+-- Handle opcodes defined with template strings.
+map_op[".template__"] = function(params, template, nparams)
+  if not params then return sub(template, 9) end
+  local op = tonumber(sub(template, 1, 8), 16)
+  local n = 1
+
+  -- Limit number of section buffer positions used by a single dasm_put().
+  -- A single opcode needs a maximum of 3 positions (rlwinm).
+  if secpos+3 > maxsecpos then wflush() end
+  local pos = wpos()
+
+  -- Process each character.
+  for p in gmatch(sub(template, 9), ".") do
+    if p == "D" then
+      op = op + parse_gpr(params[n]) * 4096; n = n + 1
+    elseif p == "N" then
+      op = op + parse_gpr(params[n]) * 65536; n = n + 1
+    elseif p == "S" then
+      op = op + parse_gpr(params[n]) * 256; n = n + 1
+    elseif p == "M" then
+      op = op + parse_gpr(params[n]); n = n + 1
+    elseif p == "P" then
+      local imm = match(params[n], "^#(.*)$")
+      if imm then
+	op = op + parse_imm12(imm) + 0x02000000
+      else
+	op = op + parse_gpr(params[n])
+      end
+      n = n + 1
+    elseif p == "p" then
+      op = op + parse_shift(params[n], true); n = n + 1
+    elseif p == "L" then
+      op = parse_load(params, nparams, n, op)
+    elseif p == "B" then
+      local mode, n, s = parse_label(params[n], false)
+      waction("REL_"..mode, n, s, 1)
+    elseif p == "C" then -- blx gpr vs. blx label.
+      local p = params[n]
+      if match(p, "^([%w_]+):(r1?[0-9])$") or match(p, "^r(1?[0-9])$") then
+	op = op + parse_gpr(p)
+      else
+	if op < 0xe0000000 then werror("unconditional instruction") end
+	local mode, n, s = parse_label(params[n], false)
+	waction("REL_"..mode, n, s, 1)
+	op = 0xfa000000
+      end
+    elseif p == "n" then
+      local r, wb = match(params[n], "^([^!]*)(!?)$")
+      op = op + parse_gpr(r) * 65536 + (wb == "!" and 0x00200000 or 0)
+      n = n + 1
+    elseif p == "R" then
+      op = op + parse_reglist(params[n]); n = n + 1
+    elseif p == "W" then
+      op = op + parse_imm16(params[n]); n = n + 1
+    elseif p == "v" then
+      op = op + parse_imm(params[n], 5, 7, 0, false); n = n + 1
+    elseif p == "X" then
+      op = op + parse_imm(params[n], 5, 16, 0, false); n = n + 1
+    elseif p == "K" then
+      local imm = tonumber(match(params[n], "^#(.*)$")); n = n + 1
+      if not imm or imm % 1 ~= 0 or imm < 0 or imm > 0xffff then
+	werror("bad immediate operand")
+      end
+      local t = imm % 16
+      op = op + (imm - t) * 16 + t
+    elseif p == "T" then
+      op = op + parse_imm(params[n], 24, 0, 0, false); n = n + 1
+    elseif p == "s" then
+      -- Ignored.
+    else
+      assert(false)
+    end
+  end
+  wputpos(pos, op)
+end
+
+------------------------------------------------------------------------------
+
+-- 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 = function(t, k)
+    local v = map_coreop[k]
+    if v then return v end
+    local cc = sub(k, -4, -3)
+    local cv = map_cond[cc]
+    if cv then
+      local v = rawget(t, sub(k, 1, -5)..sub(k, -2))
+      if v then return format("%x%s", cv, sub(v, 2)) end
+    end
+  end })
+  setmetatable(map_def, { __index = map_archdef })
+  return map_op, map_def
+end
+
+return _M
+
+------------------------------------------------------------------------------
+