DynASM/PPC: Add sub/shift/rotate/clear instruction aliases.

dynasm/dasm_ppc.lua

@@ -230,8 +230,18 @@ local map_cond = {
 
 ------------------------------------------------------------------------------
 
+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
+
 -- Template strings for PPC instructions.
-local map_op = {
+map_op = {
   tdi_3 =	"08000000ARI",
   twi_3 =	"0c000000ARI",
   mulli_3 =	"1c000000RRI",
@@ -299,6 +309,33 @@ local map_op = {
   std_2 =	"f8000000RD",
   stdu_2 =	"f8000001RD",
 
+  subi_3 =	op_alias("addi_3", function(p) p[3] = "-("..p[3]..")" end),
+  subis_3 =	op_alias("addis_3", function(p) p[3] = "-("..p[3]..")" end),
+  subic_3 =	op_alias("addic_3", function(p) p[3] = "-("..p[3]..")" end),
+  ["subic._3"] = op_alias("addic._3", function(p) p[3] = "-("..p[3]..")" end),
+
+  rotlwi_3 =	op_alias("rlwinm_5", function(p)
+    p[4] = "0"; p[5] = "31"
+  end),
+  rotrwi_3 =	op_alias("rlwinm_5", function(p)
+    p[3] = "32-("..p[3]..")"; p[4] = "0"; p[5] = "31"
+  end),
+  rotlw_3 =	op_alias("rlwnm_5", function(p)
+    p[4] = "0"; p[5] = "31"
+  end),
+  slwi_3 =	op_alias("rlwinm_5", function(p)
+    p[5] = "31-("..p[3]..")"; p[4] = "0"
+  end),
+  srwi_3 =	op_alias("rlwinm_5", function(p)
+    p[4] = p[3]; p[3] = "32-("..p[3]..")"; p[5] = "31"
+  end),
+  clrlwi_3 =	op_alias("rlwinm_5", function(p)
+    p[4] = p[3]; p[3] = "0"; p[5] = "31"
+  end),
+  clrrwi_3 =	op_alias("rlwinm_5", function(p)
+    p[5] = "31-("..p[3]..")"; p[3] = "0"; p[4] = "0"
+  end),
+
   -- Primary opcode 4:
   mulhhwu_3 =		"10000010RRR.",
   machhwu_3 =		"10000018RRR.",
@@ -790,6 +827,28 @@ local map_op = {
   rldcl_4 =	"78000010RR~RM.",
   rldcr_4 =	"78000012RR~RM.",
 
+  rotldi_3 =	op_alias("rldicl_4", function(p)
+    p[4] = "0"
+  end),
+  rotrdi_3 =	op_alias("rldicl_4", function(p)
+    p[3] = "64-("..p[3]..")"; p[4] = "0"
+  end),
+  rotld_3 =	op_alias("rldcl_4", function(p)
+    p[4] = "0"
+  end),
+  sldi_3 =	op_alias("rldicr_4", function(p)
+    p[4] = "63-("..p[3]..")"
+  end),
+  srdi_3 =	op_alias("rldicl_4", function(p)
+    p[4] = p[3]; p[3] = "64-("..p[3]..")"
+  end),
+  clrldi_3 =	op_alias("rldicl_4", function(p)
+    p[4] = p[3]; p[3] = "0"
+  end),
+  clrrdi_3 =	op_alias("rldicr_4", function(p)
+    p[4] = "63-("..p[3]..")"; p[3] = "0"
+  end),
+
   -- Primary opcode 56:
   lq_2 =	"e0000000R:D", -- NYI: displacement must be divisible by 8.
 
@@ -1358,7 +1417,7 @@ local map_op = {
 do
   local t = {}
   for k,v in pairs(map_op) do
-    if sub(v, -1) == "." then
+    if type(v) == "string" and sub(v, -1) == "." then
       local v2 = sub(v, 1, 7)..char(byte(v, 8)+1)..sub(v, 9, -2)
       t[sub(k, 1, -3).."."..sub(k, -2)] = v2
     end
@@ -1454,8 +1513,30 @@ local function parse_cond(expr)
   werror("bad condition bit name `"..expr.."'")
 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)
-  local n = tonumber(imm)
+  local n = parse_number(imm)
   if n then
     local m = sar(n, scale)
     if shl(m, scale) == n then
@@ -1479,7 +1560,7 @@ local function parse_imm(imm, bits, shift, scale, signed)
 end
 
 local function parse_shiftmask(imm, isshift)
-  local n = tonumber(imm)
+  local n = parse_number(imm)
   if n then
     if shr(n, 6) == 0 then
       local lsb = band(n, 31)
@@ -1567,7 +1648,7 @@ end
 ------------------------------------------------------------------------------
 
 -- Handle opcodes defined with template strings.
-map_op[".template__"] = function(params, template, nparams)
+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, rs = 1, 26
@@ -1669,6 +1750,8 @@ map_op[".template__"] = function(params, template, nparams)
   wputpos(pos, op)
 end
 
+map_op[".template__"] = op_template
+
 ------------------------------------------------------------------------------
 
 -- Pseudo-opcode to mark the position where the action list is to be emitted.

src/vm_ppc.dasc

@@ -320,13 +320,6 @@
 |
 |//-----------------------------------------------------------------------
 |
-|// These basic macros should really be part of DynASM.
-|.macro srwi, rx, ry, n; rlwinm rx, ry, 32-n, n, 31; .endmacro
-|.macro slwi, rx, ry, n; rlwinm rx, ry, n, 0, 31-n; .endmacro
-|.macro rotlwi, rx, ry, n; rlwinm rx, ry, n, 0, 31; .endmacro
-|.macro rotlw, rx, ry, rn; rlwnm rx, ry, rn, 0, 31; .endmacro
-|.macro subi, rx, ry, i; addi rx, ry, -i; .endmacro
-|
 |// Trap for not-yet-implemented parts.
 |.macro NYI; tw 4, sp, sp; .endmacro
 |