lua 1.0 源码分析 -- 1 lua 的虚拟指令

　　lua的解释器拿到 lua 编写的源码，首先进行解析，就是进行词法分析和语法分析，将源码转换成 lua 的指令集，然后执行这个指令集。

　　lua 源码：

function f(val)

    return val;

end

function main()

    local i = 1;

    local j = 2;

    local b = i + f(2);

    --local b = i + j;

    print("retval = "..b);

    return b;

end

　　　调用 main 的指令集分析：

 in while  opcode = [CALLFUNC]. -- main

 in while  opcode = [NOP].

 in while  opcode = [SETFUNCTION].

 in while  opcode = [ADJUST].

 in while  opcode = [NOP].

 in while  opcode = [SETLINE].

 in while  opcode = [PUSH1].  -- i

 in while  opcode = [SETLINE].

 in while  opcode = [PUSH2].  -- j

 in while  opcode = [SETLINE].  -- local b = i + f(2)

 in while  opcode = [PUSHLOCAL0]. -- i

 in while  opcode = [PUSHGLOBAL]. -- f

 in while  opcode = [PUSHMARK].

 in while  opcode = [PUSH2].    -- val

 in while  opcode = [CALLFUNC]. -- f()

 in while  opcode = [NOP].

 in while  opcode = [SETFUNCTION].

 in while  opcode = [ADJUST].

 in while  opcode = [NOP].

 in while  opcode = [SETLINE].

 in while  opcode = [PUSHLOCAL0]. -- val

 in while  opcode = [RESET].

 in while  opcode = [RETCODE].

 in while  opcode = [SETLINE].

 in while  opcode = [ADJUST].

 in while  opcode = [ADDOP].  -- local b = i + f(2)

 in while  opcode = [SETLINE].

 in while  opcode = [NOP].

 in while  opcode = [PUSHGLOBAL]. --  print

 in while  opcode = [PUSHMARK].

 in while  opcode = [PUSHSTRING]. -- retval =

 in while  opcode = [PUSHLOCAL2]. -- b

 in while  opcode = [CONCOP].

 in while  opcode = [CALLFUNC]. -- print()

retval = 3

 in while  opcode = [ADJUST].

 in while  opcode = [SETLINE].

 in while  opcode = [PUSHLOCAL2].

 in while  opcode = [RESET].

 in while  opcode = [RETCODE].

 in while  opcode = [HALT].

PS:

　　函数就是一个入口地址，入口是通向将要执行的指令集。想下汇编中的 call，ret。lua 中的虚拟指令类似，只不过入口中的指令集是 lua 自己的虚拟指令，不是像 c 那样的机器指令。

巴特西

lua 1.0 源码分析 -- 1 lua 的虚拟指令

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