两个立即数相加
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| 1 local c
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3 c = 1 + 2
4 print(c)
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luajit 字节码
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| $ luajit -bL t.lua:w
-- BYTECODE -- t.lua:0-5
KGC 0 "print"
0001 [1] KPRI 0 0 ; set c to nil
0002 [3] KSHORT 0 3 ; set reg 0 to 3
0003 [4] GGET 1 0 ; "print"
0004 [4] MOV 3 0 ; move reg 0 to reg 3
0005 [4] CALL 1 1 2 ; call func on reg 1 with 1 arg at reg 3 whit 0 return val
0006 [4] RET0 0 1 ; return with 0 return val
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可见两个常量相加已经被优化了。
两个变量相加
lua 代码
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| 1 local a
2 local b
3 local c
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5 a = 1
6 b = 2
7 c = a + b
8 print(c)
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luajit 字节码
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| $ luajit -bL t.lua
-- BYTECODE -- t.lua:0-9
KGC 0 "print"
0001 [1] KNIL 0 2 ; set reg 0-2 to nil
0002 [5] KSHORT 0 1 ; set reg 0 to 1
0003 [6] KSHORT 1 2 ; sert reg 1 to 2
0004 [7] ADDVV 2 0 1 ; add reg 0 and reg 1 and store it in reg 2
0005 [8] GGET 3 0 ; "print"
0006 [8] MOV 5 2 ; move reg 2 to reg 5
0007 [8] CALL 3 1 2 ; call "print" fun in reg 3 with 1 arg at reg 5 and 0 return value.
0008 [8] RET0 0 1 ; return with 0 return value
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比较大小
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| 1 local x = 1
2 local y = 2
3 if x < y then
4 print("t")
5 else
6 print("f")
7 end
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luajit 字节码
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| -- BYTECODE -- t.lua:0-8
KGC 0 "print"
KGC 1 "t"
KGC 2 "f"
0001 [1] KSHORT 0 1 ; set reg 0 to 1
0002 [2] KSHORT 1 2 ; set reg 1 to 2
0003 [3] ISGE 0 1 ; test if reg 0 >= reg 1
0004 [3] JMP 2 => 0009 ; if true goto 009 and print "f"
0005 [4] GGET 2 0 ; "print"
0006 [4] KSTR 4 1 ; "t"
0007 [4] CALL 2 1 2 ; call "print" with 1 arg at reg 4 and 0 return value
0008 [4] JMP 2 => 0012
0009 [6] => GGET 2 0 ; "print"
0010 [6] KSTR 4 2 ; "f"
0011 [6] CALL 2 1 2
0012 [7] => RET0 0 1
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字符串赋值
lua 代码
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| 1 local x = "1"
2 local y = "2"
3 local c = x .. y
4 print(c)
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luajit 字节码
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| $ luajit -bL t.lua
-- BYTECODE -- t.lua:0-5
KGC 0 "1"
KGC 1 "2"
KGC 2 "print"
0001 [1] KSTR 0 0 ; "1"
0002 [2] KSTR 1 1 ; "2"
0003 [3] MOV 2 0 ; reg[2] = "1"
0004 [3] MOV 3 1 ; reg[3] = "2"
0005 [3] CAT 2 2 3 ; reg[2] = CAT(reg[2], reg[3])
0006 [4] GGET 3 2 ; "print"
0007 [4] MOV 5 2 ; reg[5] = reg[2]
0008 [4] CALL 3 1 2 ; print(reg[5])
0009 [4] RET0 0 1 ; return
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多参数调用
lua 代码
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| 1 local x = "1"
2 local y = "2"
3 local c = x .. y
4 print(x, y, c)
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lua 字节码
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| $ luajit -bL t.lua
-- BYTECODE -- t.lua:0-5
KGC 0 "1"
KGC 1 "2"
KGC 2 "print"
0001 [1] KSTR 0 0 ; reg[0] = "1"
0002 [2] KSTR 1 1 ; reg[1] = "2"
0003 [3] MOV 2 0 ; reg[2] = reg[0]
0004 [3] MOV 3 1 ; reg[3] = reg[1]
0005 [3] CAT 2 2 3 ; reg[2] = CAT(reg[2], reg[3])
0006 [4] GGET 3 2 ; "print"
0007 [4] MOV 5 0 ; reg[5] = reg[0]
0008 [4] MOV 6 1 ; reg[6] = reg[1]
0009 [4] MOV 7 2 ; reg[7] = reg[2]
0010 [4] CALL 3 1 4 ; print(reg[5], reg[6], reg[7])
0011 [4] RET0 0 1 ; return
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调用函数的参数是一个函数
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| 1 local function mret()
2 return 10, 20, 30
3 end
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5 print(mret())
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luajit 字节码
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| $ luajit -bL t.lua
-- BYTECODE -- t.lua:1-3
0001 [2] KSHORT 0 10 ;reg[0] = 10
0002 [2] KSHORT 1 20 ;reg[1] = 20
0003 [2] KSHORT 2 30 ;reg[2] = 30
0004 [2] RET 0 4 ;return reg[0], reg[1], reg[2]
-- BYTECODE -- t.lua:0-6
KGC 0 t.lua:1
KGC 1 "print"
0001 [3] FNEW 0 0 ; t.lua:1
0002 [5] GGET 1 1 ; "print"
0003 [5] MOV 3 0 ; reg[3] = mret
0004 [5] CALL 3 0 1 ; reg[3], ..., reg[3 + MULTRES - 1] = mret()
0005 [5] CALLM 1 1 0 ; print(reg[1 + 2], ... reg[1 + 2 + MULTRES + 0 - 1])
0006 [5] RET0 0 1 ; return
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多值函数作为第一个参数
lua 代码
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| 1 local function mret()
2 return 10, 20, 30
3 end
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5 print(mret(), 123)
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luajit 字节码
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| [ljl@localhost ~]$ luajit -bL t.lua
-- BYTECODE -- t.lua:1-3
0001 [2] KSHORT 0 10 ; reg[0] = 10
0002 [2] KSHORT 1 20 ; reg[1] = 20
0003 [2] KSHORT 2 30 ; reg[2] = 30
0004 [2] RET 0 4 ; return reg[0], reg[1], reg[2]
-- BYTECODE -- t.lua:0-6
KGC 0 t.lua:1
KGC 1 "print"
0001 [3] FNEW 0 0 ; t.lua:1
0002 [5] GGET 1 1 ; "print"
0003 [5] MOV 3 0 ; reg[3] = mret
0004 [5] CALL 3 2 1 ; reg[3] = mret()
0005 [5] KSHORT 4 123 ; reg[4] = 123
0006 [5] CALL 1 1 3 ; print(reg[3], reg[4])
0007 [5] RET0 0 1 ; return
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多值函数作为最后一个参数 CALLM
## lua 代码
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| 1 local function mret()
2 return 10, 20, 30
3 end
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5 print(123,mret())
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lua 字节码
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| -- BYTECODE -- t.lua:1-3
0001 [2] KSHORT 0 10 ; reg[0] = 10
0002 [2] KSHORT 1 20 ; reg[1] = 20
0003 [2] KSHORT 2 30 ; reg[2] = 30
0004 [2] RET 0 4 ; return reg[0], reg[1], reg[2]
-- BYTECODE -- t.lua:0-6
KGC 0 t.lua:1
KGC 1 "print"
0001 [3] FNEW 0 0 ; t.lua:1
0002 [5] GGET 1 1 ; "print"
0003 [5] KSHORT 3 123 ; reg[3] = 123
0004 [5] MOV 4 0 ; reg[4] = mret
0005 [5] CALL 4 0 1 ; reg[4], ..., reg[4 + MULTRES - 1] = mret()
0006 [5] CALLM 1 1 1 ; print(reg[3], reg[4], ..., reg[3 + MULTRES + 1 - 1])
0007 [5] RET0 0 1 ; return
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| OP |
A |
B |
C/D |
Description |
| CALLM |
base |
lit |
lit |
Call: A, …, A+B-2 = A(A+2, …, A+1+C+MULTRES) |
函数调用
返回值个数多于赋值的个数
lua 代码
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| 1 local function mret()
2 return 10, 20, 30
3 end
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5 local a, b = mret()
6 print(123, a, b)
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lua 字节码
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| -- BYTECODE -- t.lua:1-3
0001 [2] KSHORT 0 10 ; reg[0] = 10
0002 [2] KSHORT 1 20 ; reg[1] = 20
0003 [2] KSHORT 2 30 ; reg[2] = 30
0004 [2] RET 0 4 ; return reg[0], reg[1], reg[2]
-- BYTECODE -- t.lua:0-7
KGC 0 t.lua:1
KGC 1 "print"
0001 [3] FNEW 0 0 ; t.lua:1
0002 [5] MOV 1 0 ; reg[1] = mret
0003 [5] CALL 1 3 1 ; reg[1], reg[2] = mret()
0004 [6] GGET 3 1 ; "print"
0005 [6] KSHORT 5 123 ; reg[5] = 123
0006 [6] MOV 6 1 ; reg[6] = reg[1]
0007 [6] MOV 7 2 ; reg[7] = reg[2]
0008 [6] CALL 3 1 4 ; print(reg[5], reg[6], reg[7])
0009 [6] RET0 0 1 ; return
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返回值个数少于赋值参数个数
lua 代码
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| 1 local function mret(a, b, c)
2 return a + b + c
3 end
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5 local a = mret(10, 20, 30)
6 print(a)
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luajit 字节码
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| -- BYTECODE -- t.lua:1-3
0001 [2] ADDVV 3 0 1 ; reg[3] = reg[0] + reg[1]
0002 [2] ADDVV 3 3 2 ; reg[3] = reg[3] + reg[2]
0003 [2] RET1 3 2 ; return reg[3]
-- BYTECODE -- t.lua:0-7
KGC 0 t.lua:1
KGC 1 "print"
0001 [3] FNEW 0 0 ; t.lua:1
0002 [5] MOV 1 0 ; reg[1] = mret
0003 [5] KSHORT 3 10 ; reg[3] = 10
0004 [5] KSHORT 4 20 ; reg[4] = 20
0005 [5] KSHORT 5 30 ; ret[5] = 30
0006 [5] CALL 1 2 4 ; reg[1] = mret(reg[3], reg[4], reg[5])
0007 [6] GGET 2 1 ; "print"
0008 [6] MOV 4 1 ; reg[4] = reg[1]
0009 [6] CALL 2 1 2 ; print(reg[4])
0010 [6] RET0 0 1 ; return
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返回值个数少于赋值参数个数
lua 代码
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| 1 local function mret(a, b, c)
2 return a + b + c
3 end
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5 local a, b = mret(10, 20, 30)
6 print(a, b)
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luajit 字节码
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| $ luajit -bL t.lua
-- BYTECODE -- t.lua:1-3
0001 [2] ADDVV 3 0 1 ; reg[3] = reg[0] + reg[1]
0002 [2] ADDVV 3 3 2 ; reg[3] = reg[3] + reg[2]
0003 [2] RET1 3 2 ; return reg[3]
-- BYTECODE -- t.lua:0-7
KGC 0 t.lua:1
KGC 1 "print"
0001 [3] FNEW 0 0 ; t.lua:1
0002 [5] MOV 1 0 ; reg[1] = mret
0003 [5] KSHORT 3 10 ; reg[3] = 10
0004 [5] KSHORT 4 20 ; reg[4] = 20
0005 [5] KSHORT 5 30 ; reg[5] = 30
0006 [5] CALL 1 3 4 ; reg[1], reg[2] = mret(reg[3], reg[4], reg[5])
0007 [6] GGET 3 1 ; "print"
0008 [6] MOV 5 1 ; reg[5] = reg[1]
0009 [6] MOV 6 2 ; reg[6] = reg[2]
0010 [6] CALL 3 1 3 ; print(reg[5], reg[6])
0011 [6] RET0 0 1 ; return
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简单 for 循环
lua 代码
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| 1 local array = {"Google", "Runoob"}
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3 for key,value in ipairs(array)
4 do
5 print(key, value)
6 end
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字节码
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| -- BYTECODE -- t.lua:0-7
KGC 0 table
KGC 1 "ipairs"
KGC 2 "print"
0001 [1] TDUP 0 0 ; reg[0] = tables[0]
0002 [3] GGET 1 1 ; "ipairs"
0003 [3] MOV 3 0 ; reg[3] = tables[0]
0004 [3] CALL 1 4 2 ; reg[1], reg[2], reg[3] = ipairs(reg[3])
0005 [4] JMP 4 => 0010 ; jump to 0010 if reg[3] ~= nil
0006 [5] => GGET 6 2 ; "print"
0007 [5] MOV 8 4 ; reg[8] = reg[4]
0008 [5] MOV 9 5 ; reg[9] = reg[5]
0009 [5] CALL 6 1 3 ; print(reg[8], reg[9])
0010 [3] => ITERC 4 3 3 ; reg[4], reg[5], reg[6] = reg[1], reg[2], reg[3];
; reg[4], reg[5] = reg[4](reg[5], reg[6])
0011 [3] ITERL 4 => 0006 ; goto 0006 if reg[4] ~= nil
0012 [6] RET0 0 1
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这里有点解释不通，ITERC 下一次执行还是用 reg[1],reg[2],reg[3] 覆盖 reg[4], reg[5], reg[6],
但是 reg[2], reg[3] 并没有用 新的 reg[5], reg[6] 覆盖。
| OP |
A |
B |
C/D |
Description |
| ITERC |
base |
lit |
lit |
A, A+1, A+2 = A-3, A-2, A-1; A, …, A+B-2 = A(A+1,A+2) |
| OP |
A |
D |
Description |
| ITERL |
base |
jump |
Iterator ‘for’ loop |
for 迭代器
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| 1 local function square(iteratorMaxCount, currentNumber)
2 if currentNumber < iteratorMaxCount then
3 currentNumber = currentNumber + 1
4 return currentNumber, currentNumber * currentNumber
5 end
6 end
7
8 for i, n in square, 3, 0 do
9 print(i, n)
10 end
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字节码
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| -- BYTECODE -- t.lua:1-6
0001 [t.lua:2] ISGE 1 0
0002 [t.lua:2] JMP 2 => 0007 ; if reg[1] >= reg[0] jump to 0007
0003 [t.lua:3] ADDVN 1 1 0 ; 1
0004 [t.lua:4] MOV 2 1
0005 [t.lua:4] MULVV 3 1 1
0006 [t.lua:4] RET 2 3
0007 [t.lua:6] => RET0 0 1
-- BYTECODE -- t.lua:0-11
KGC 0 t.lua:1
KGC 1 "print"
0001 [t.lua:6] FNEW 0 0 ; t.lua:1
0002 [t.lua:8] MOV 1 0 ; reg[1] = square
0003 [t.lua:8] KSHORT 2 3 ; reg[2] = 3
0004 [t.lua:8] KSHORT 3 0 ; reg[3] = 0
0005 [t.lua:8] JMP 4 => 0010 ; jump to 0010 if reg[3] ~= nil
0006 [t.lua:9] => GGET 6 1 ; "print"
0007 [t.lua:9] MOV 8 4 ; reg[8] = reg[4]
0008 [t.lua:9] MOV 9 5 ; reg[9] = reg[5]
0009 [t.lua:9] CALL 6 1 3 ; print(reg[8], reg[9])
0010 [t.lua:8] => ITERC 4 3 3 ; reg[4], reg[5], reg[6] = reg[1], reg[2], reg[3];
; reg[4], reg[5] = reg[4](reg[5], reg[6])
0011 [t.lua:8] ITERL 4 => 0006 ; jump to 0006 if reg[4] ~= nil
0012 [t.lua:10] RET0 0 1
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for 循环代码
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| local p = { x = 1, y = 1, [1] = 1 }
for i = 1, 100 do
p = { x = p.x + i,
y = p.y - i,
[1] = p[1] }
end
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字节码
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| -- BYTECODE -- t.lua:0-7
KGC 0 table
KGC 1 "x"
KGC 2 table
KGC 3 "y"
0001 [1] TDUP 0 0
0002 [2] KSHORT 1 1
0003 [2] KSHORT 2 100
0004 [2] KSHORT 3 1
0005 [2] FORI 1 => 0017 ; jump to 0017 if reg[1] == nil
0006 [3] => TDUP 5 2
0007 [3] TGETS 6 0 1 ; "x"
0008 [3] ADDVV 6 6 4 ; reg[6] = reg[6] + reg[4]
0009 [3] TSETS 6 5 1 ; "x" => reg[5]["x"] = reg[6]
0010 [4] TGETS 6 0 3 ; "y"
0011 [4] SUBVV 6 6 4 ; reg[6] = reg[6] + reg[4]
0012 [4] TSETS 6 5 3 ; "y" => reg[5]["x"] = reg[6]
0013 [5] TGETB 6 0 1 ; reg[6] = reg[0][1]
0014 [5] TSETB 6 5 1 ; reg[5][1] = reg[6]
0015 [5] MOV 0 5 ; reg[0] = reg[5]
0016 [2] FORL 1 => 0006 ; if reg[1] <= reg[2]
0017 [6] => RET0 0 1
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