----------------------------------------------------------------------
--
-- WARNING! You're entering a hackish area, proceed at your own risks!
--
-- This code results from the borrowing, then ruthless abuse, of
-- Yueliang's implementation of Lua 5.0 compiler. I claim
-- responsibility for all of the ugly, dirty stuff that you might spot
-- in it.
--
-- Eventually, this code will be rewritten, either in Lua or more
-- probably in C. Meanwhile, if you're interested into digging
-- metalua's sources, this is not the best part to invest your time
-- on.
--
-- End of warning.
--
----------------------------------------------------------------------
--[[--------------------------------------------------------------------
$Id$
lopcodes.lua
Lua 5 virtual machine opcodes in Lua
This file is part of Yueliang.
Copyright (c) 2005 Kein-Hong Man <khman@users.sf.net>
The COPYRIGHT file describes the conditions
under which this software may be distributed.
See the ChangeLog for more information.
------------------------------------------------------------------------
[FF] Slightly modified, mainly to produce Lua 5.1 bytecode.
----------------------------------------------------------------------]]
--[[--------------------------------------------------------------------
-- Notes:
-- * an Instruction is a table with OP, A, B, C, Bx elements; this
-- should allow instruction handling to work with doubles and ints
-- * Added:
-- luaP:Instruction(i): convert field elements to a 4-char string
-- luaP:DecodeInst(x): convert 4-char string into field elements
-- * WARNING luaP:Instruction outputs instructions encoded in little-
-- endian form and field size and positions are hard-coded
----------------------------------------------------------------------]]
module("bytecode", package.seeall)
local function debugf() end
luaP = { }
--[[
===========================================================================
We assume that instructions are unsigned numbers.
All instructions have an opcode in the first 6 bits.
Instructions can have the following fields:
'A' : 8 bits
'B' : 9 bits
'C' : 9 bits
'Bx' : 18 bits ('B' and 'C' together)
'sBx' : signed Bx
A signed argument is represented in excess K; that is, the number
value is the unsigned value minus K. K is exactly the maximum value
for that argument (so that -max is represented by 0, and +max is
represented by 2*max), which is half the maximum for the corresponding
unsigned argument.
===========================================================================
--]]
luaP.OpMode = {"iABC", "iABx", "iAsBx"} -- basic instruction format
------------------------------------------------------------------------
-- size and position of opcode arguments.
-- * WARNING size and position is hard-coded elsewhere in this script
------------------------------------------------------------------------
luaP.SIZE_C = 9
luaP.SIZE_B = 9
luaP.SIZE_Bx = luaP.SIZE_C + luaP.SIZE_B
luaP.SIZE_A = 8
luaP.SIZE_OP = 6
luaP.POS_C = luaP.SIZE_OP
luaP.POS_B = luaP.POS_C + luaP.SIZE_C
luaP.POS_Bx = luaP.POS_C
luaP.POS_A = luaP.POS_B + luaP.SIZE_B
--FF from 5.1
luaP.BITRK = 2^(luaP.SIZE_B - 1)
function luaP:ISK(x) return x >= self.BITRK end
luaP.MAXINDEXRK = luaP.BITRK - 1
function luaP:RKASK(x)
if x < self.BITRK then return x+self.BITRK else return x end
end
------------------------------------------------------------------------
-- limits for opcode arguments.
-- we use (signed) int to manipulate most arguments,
-- so they must fit in BITS_INT-1 bits (-1 for sign)
------------------------------------------------------------------------
-- removed "#if SIZE_Bx < BITS_INT-1" test, assume this script is
-- running on a Lua VM with double or int as LUA_NUMBER
luaP.MAXARG_Bx = math.ldexp(1, luaP.SIZE_Bx) - 1
luaP.MAXARG_sBx = math.floor(luaP.MAXARG_Bx / 2) -- 'sBx' is signed
luaP.MAXARG_A = math.ldexp(1, luaP.SIZE_A) - 1
luaP.MAXARG_B = math.ldexp(1, luaP.SIZE_B) - 1
luaP.MAXARG_C = math.ldexp(1, luaP.SIZE_C) - 1
-- creates a mask with 'n' 1 bits at position 'p'
-- MASK1(n,p) deleted
-- creates a mask with 'n' 0 bits at position 'p'
-- MASK0(n,p) deleted
--[[--------------------------------------------------------------------
Visual representation for reference:
31 | | | 0 bit position
+-----+-----+-----+----------+
| B | C | A | Opcode | iABC format
+-----+-----+-----+----------+
- 9 - 9 - 8 - 6 - field sizes
+-----+-----+-----+----------+
| [s]Bx | A | Opcode | iABx | iAsBx format
+-----+-----+-----+----------+
----------------------------------------------------------------------]]
------------------------------------------------------------------------
-- the following macros help to manipulate instructions
-- * changed to a table object representation, very clean compared to
-- the [nightmare] alternatives of using a number or a string
------------------------------------------------------------------------
-- these accept or return opcodes in the form of string names
function luaP:GET_OPCODE(i) return self.ROpCode[i.OP] end
function luaP:SET_OPCODE(i, o) i.OP = self.OpCode[o] end
function luaP:GETARG_A(i) return i.A end
function luaP:SETARG_A(i, u) i.A = u end
function luaP:GETARG_B(i) return i.B end
function luaP:SETARG_B(i, b) i.B = b end
function luaP:GETARG_C(i) return i.C end
function luaP:SETARG_C(i, b) i.C = b end
function luaP:GETARG_Bx(i) return i.Bx end
function luaP:SETARG_Bx(i, b) i.Bx = b end
function luaP:GETARG_sBx(i) return i.Bx - self.MAXARG_sBx end
function luaP:SETARG_sBx(i, b) i.Bx = b + self.MAXARG_sBx end
function luaP:CREATE_ABC(o,a,b,c)
return {OP = self.OpCode[o], A = a, B = b, C = c}
end
function luaP:CREATE_ABx(o,a,bc)
return {OP = self.OpCode[o], A = a, Bx = bc}
end
------------------------------------------------------------------------
-- Bit shuffling stuffs
------------------------------------------------------------------------
if false and pcall (require, 'bit') then
------------------------------------------------------------------------
-- Return a 4-char string little-endian encoded form of an instruction
------------------------------------------------------------------------
function luaP:Instruction(i)
--FIXME
end
else
------------------------------------------------------------------------
-- Version without bit manipulation library.
------------------------------------------------------------------------
local p2 = {1,2,4,8,16,32,64,128,256, 512, 1024, 2048, 4096}
-- keeps [n] bits from [x]
local function keep (x, n) return x % p2[n+1] end
-- shifts bits of [x] [n] places to the right
local function srb (x,n) return math.floor (x / p2[n+1]) end
-- shifts bits of [x] [n] places to the left
local function slb (x,n) return x * p2[n+1] end
------------------------------------------------------------------------
-- Return a 4-char string little-endian encoded form of an instruction
------------------------------------------------------------------------
function luaP:Instruction(i)
-- printf("Instr->string: %s %s", self.opnames[i.OP], table.tostring(i))
local c0, c1, c2, c3
-- change to OP/A/B/C format if needed
if i.Bx then i.C = keep (i.Bx, 9); i.B = srb (i.Bx, 9) end
-- c0 = 6B from opcode + 2LSB from A (flushed to MSB)
c0 = i.OP + slb (keep (i.A, 2), 6)
-- c1 = 6MSB from A + 2LSB from C (flushed to MSB)
c1 = srb (i.A, 2) + slb (keep (i.C, 2), 6)
-- c2 = 7MSB from C + 1LSB from B (flushed to MSB)
c2 = srb (i.C, 2) + slb (keep (i.B, 1), 7)
-- c3 = 8MSB from B
c3 = srb (i.B, 1)
--printf ("Instruction: %s %s", self.opnames[i.OP], tostringv (i))
--printf ("Bin encoding: %x %x %x %x", c0, c1, c2, c3)
return string.char(c0, c1, c2, c3)
end
end
------------------------------------------------------------------------
-- decodes a 4-char little-endian string into an instruction struct
------------------------------------------------------------------------
function luaP:DecodeInst(x)
error "Not implemented"
end
------------------------------------------------------------------------
-- invalid register that fits in 8 bits
------------------------------------------------------------------------
luaP.NO_REG = luaP.MAXARG_A
------------------------------------------------------------------------
-- R(x) - register
-- Kst(x) - constant (in constant table)
-- RK(x) == if x < MAXSTACK then R(x) else Kst(x-MAXSTACK)
------------------------------------------------------------------------
------------------------------------------------------------------------
-- grep "ORDER OP" if you change these enums
------------------------------------------------------------------------
--[[--------------------------------------------------------------------
Lua virtual machine opcodes (enum OpCode):
------------------------------------------------------------------------
name args description
------------------------------------------------------------------------
OP_MOVE A B R(A) := R(B)
OP_LOADK A Bx R(A) := Kst(Bx)
OP_LOADBOOL A B C R(A) := (Bool)B; if (C) PC++
OP_LOADNIL A B R(A) := ... := R(B) := nil
OP_GETUPVAL A B R(A) := UpValue[B]
OP_GETGLOBAL A Bx R(A) := Gbl[Kst(Bx)]
OP_GETTABLE A B C R(A) := R(B)[RK(C)]
OP_SETGLOBAL A Bx Gbl[Kst(Bx)] := R(A)
OP_SETUPVAL A B UpValue[B] := R(A)
OP_SETTABLE A B C R(A)[RK(B)] := RK(C)
OP_NEWTABLE A B C R(A) := {} (size = B,C)
OP_SELF A B C R(A+1) := R(B); R(A) := R(B)[RK(C)]
OP_ADD A B C R(A) := RK(B) + RK(C)
OP_SUB A B C R(A) := RK(B) - RK(C)
OP_MUL A B C R(A) := RK(B) * RK(C)
OP_DIV A B C R(A) := RK(B) / RK(C)
OP_POW A B C R(A) := RK(B) ^ RK(C)
OP_UNM A B R(A) := -R(B)
OP_NOT A B R(A) := not R(B)
OP_CONCAT A B C R(A) := R(B).. ... ..R(C)
OP_JMP sBx PC += sBx
OP_EQ A B C if ((RK(B) == RK(C)) ~= A) then pc++
OP_LT A B C if ((RK(B) < RK(C)) ~= A) then pc++
OP_LE A B C if ((RK(B) <= RK(C)) ~= A) then pc++
OP_TEST A B C if (R(B) <=> C) then R(A) := R(B) else pc++
OP_CALL A B C R(A), ... ,R(A+C-2) := R(A)(R(A+1), ... ,R(A+B-1))
OP_TAILCALL A B C return R(A)(R(A+1), ... ,R(A+B-1))
OP_RETURN A B return R(A), ... ,R(A+B-2) (see note)
OP_FORLOOP A sBx R(A)+=R(A+2); if R(A) <?= R(A+1) then PC+= sBx
OP_TFORLOOP A C R(A+2), ... ,R(A+2+C) := R(A)(R(A+1), R(A+2));
if R(A+2) ~= nil then pc++
OP_TFORPREP A sBx if type(R(A)) == table then R(A+1):=R(A), R(A):=next;
PC += sBx
OP_SETLIST A Bx R(A)[Bx-Bx%FPF+i] := R(A+i), 1 <= i <= Bx%FPF+1
OP_SETLISTO A Bx (see note)
OP_CLOSE A close all variables in the stack up to (>=) R(A)
OP_CLOSURE A Bx R(A) := closure(KPROTO[Bx], R(A), ... ,R(A+n))
----------------------------------------------------------------------]]
luaP.opnames = {} -- opcode names
luaP.OpCode = {} -- lookup name -> number
luaP.ROpCode = {} -- lookup number -> name
local i = 0
for v in string.gfind([[
MOVE -- 0
LOADK
LOADBOOL
LOADNIL
GETUPVAL
GETGLOBAL -- 5
GETTABLE
SETGLOBAL
SETUPVAL
SETTABLE
NEWTABLE -- 10
SELF
ADD
SUB
MUL
DIV -- 15
MOD
POW
UNM
NOT
LEN -- 20
CONCAT
JMP
EQ
LT
LE -- 25
TEST
TESTSET
CALL
TAILCALL
RETURN -- 30
FORLOOP
FORPREP
TFORLOOP
SETLIST
CLOSE -- 35
CLOSURE
VARARG
]], "[%a]+") do
local n = "OP_"..v
luaP.opnames[i] = v
luaP.OpCode[n] = i
luaP.ROpCode[i] = n
i = i + 1
end
luaP.NUM_OPCODES = i
--[[
===========================================================================
Notes:
(1) In OP_CALL, if (B == 0) then B = top. C is the number of returns - 1,
and can be 0: OP_CALL then sets 'top' to last_result+1, so
next open instruction (OP_CALL, OP_RETURN, OP_SETLIST) may use 'top'.
(2) In OP_RETURN, if (B == 0) then return up to 'top'
(3) For comparisons, B specifies what conditions the test should accept.
(4) All 'skips' (pc++) assume that next instruction is a jump
(5) OP_SETLISTO is used when the last item in a table constructor is a
function, so the number of elements set is up to top of stack
===========================================================================
--]]
------------------------------------------------------------------------
-- masks for instruction properties
------------------------------------------------------------------------
-- was enum OpModeMask:
luaP.OpModeBreg = 2 -- B is a register
luaP.OpModeBrk = 3 -- B is a register/constant
luaP.OpModeCrk = 4 -- C is a register/constant
luaP.OpModesetA = 5 -- instruction set register A
luaP.OpModeK = 6 -- Bx is a constant
luaP.OpModeT = 1 -- operator is a test
------------------------------------------------------------------------
-- get opcode mode, e.g. "iABC"
------------------------------------------------------------------------
function luaP:getOpMode(m)
--printv(m)
--printv(self.OpCode[m])
--printv(self.opmodes [self.OpCode[m]+1])
return self.OpMode[tonumber(string.sub(self.opmodes[self.OpCode[m] + 1], 7, 7))]
end
------------------------------------------------------------------------
-- test an instruction property flag
-- * b is a string, e.g. "OpModeBreg"
------------------------------------------------------------------------
function luaP:testOpMode(m, b)
return (string.sub(self.opmodes[self.OpCode[m] + 1], self[b], self[b]) == "1")
end
-- number of list items to accumulate before a SETLIST instruction
-- (must be a power of 2)
-- * used in lparser, lvm, ldebug, ltests
luaP.LFIELDS_PER_FLUSH = 50 --FF updated to match 5.1
-- luaP_opnames[] is set above, as the luaP.opnames table
-- opmode(t,b,bk,ck,sa,k,m) deleted
--[[--------------------------------------------------------------------
Legend for luaP:opmodes:
1 T -> T (is a test?)
2 B -> B is a register
3 b -> B is an RK register/constant combination
4 C -> C is an RK register/constant combination
5 A -> register A is set by the opcode
6 K -> Bx is a constant
7 m -> 1 if iABC layout,
2 if iABx layout,
3 if iAsBx layout
----------------------------------------------------------------------]]
luaP.opmodes = {
-- TBbCAKm opcode
"0100101", -- OP_MOVE 0
"0000112", -- OP_LOADK
"0000101", -- OP_LOADBOOL
"0100101", -- OP_LOADNIL
"0000101", -- OP_GETUPVAL
"0000112", -- OP_GETGLOBAL 5
"0101101", -- OP_GETTABLE
"0000012", -- OP_SETGLOBAL
"0000001", -- OP_SETUPVAL
"0011001", -- OP_SETTABLE
"0000101", -- OP_NEWTABLE 10
"0101101", -- OP_SELF
"0011101", -- OP_ADD
"0011101", -- OP_SUB
"0011101", -- OP_MUL
"0011101", -- OP_DIV 15
"0011101", -- OP_MOD
"0011101", -- OP_POW
"0100101", -- OP_UNM
"0100101", -- OP_NOT
"0100101", -- OP_LEN 20
"0101101", -- OP_CONCAT
"0000003", -- OP_JMP
"1011001", -- OP_EQ
"1011001", -- OP_LT
"1011001", -- OP_LE 25
"1000101", -- OP_TEST
"1100101", -- OP_TESTSET
"0000001", -- OP_CALL
"0000001", -- OP_TAILCALL
"0000001", -- OP_RETURN 30
"0000003", -- OP_FORLOOP
"0000103", -- OP_FORPREP
"1000101", -- OP_TFORLOOP
"0000001", -- OP_SETLIST
"0000001", -- OP_CLOSE 35
"0000102", -- OP_CLOSURE
"0000101" -- OP_VARARG
}
) is private.
