*misc

1 files changed, 46 insertions, 8 deletions

diff --git a/src/lua51/lvm.c b/src/lua51/lvm.c
index 85e214a..21de678 100644
--- a/src/lua51/lvm.c
+++ b/src/lua51/lvm.c
@@ -373,7 +373,7 @@ static void Arith (lua_State *L, StkId ra, const TValue *rb,
       }
 
 
-
+//c 虚拟机主入口
 //c 执行lua函数（不含C函数，C函数在luaD_precall执行)
 //c 读取字节码并运行，沟通前端和后端的桥梁
 //c 在ldo.c->luaD_call函数中执行，前一步是luaD_precall()
@@ -390,7 +390,7 @@ void luaV_execute (lua_State *L, int nexeccalls) {
 	
   pc = L->savedpc;//c 最开始是luaD_precall中赋值的函数原型的指令开头
   cl = &clvalue(L->ci->func)->l;
-  base = L->base;
+  base = L->base; //c base是寄存器开始地址,每个方法被调用时都会得到自己的一组虚拟寄存器
   k = cl->p->k; //c 当前函数原型的常量，所有函数调用都会用到的
 
   /* main loop of interpreter */
@@ -407,7 +407,7 @@ void luaV_execute (lua_State *L, int nexeccalls) {
       base = L->base;
     }
     /* warning!! several calls may realloc the stack and invalidate `ra' */
-    ra = RA(i);
+    ra = RA(i); //c 从指令中拿到ra
     lua_assert(base == L->base && L->base == L->ci->base);
     lua_assert(base <= L->top && L->top <= L->stack + L->stacksize);
     lua_assert(L->top == L->ci->top || luaG_checkopenop(i));
@@ -729,18 +729,56 @@ void luaV_execute (lua_State *L, int nexeccalls) {
         continue;
       }
       case OP_CLOSURE: {
-        Proto *p;
+        Proto *p; //c 函数原型首地址
         Closure *ncl;
         int nup, j;
-        p = cl->p->p[GETARG_Bx(i)];
-        nup = p->nups;
+        p = cl->p->p[GETARG_Bx(i)]; //c 根据索引得到函数原型地址
+				//c lua的每个函数会记录这个函数的信息：参数个数、使用到的stack slot数目、upvalue数目、局部变量数目、常数表、局部函数
+        nup = p->nups; //c number of upvalues，
+				//c 创建闭包new closure
         ncl = luaF_newLclosure(L, nup, cl->env);
-        ncl->l.p = p;
+        ncl->l.p = p; // 设置函数原型
+				/* //c 一个闭包的创建如下
+-----------------------------------
+1 local a = 10
+2 local b = 20
+3 
+4 function foo ()
+5 	return a + b
+6 end
+7 
+8 local c = 30 
+9 foo()
+-----------------------------------
+main <main.lua:0,0> (10 instructions, 40 bytes at 009512A8)
+0+ params, 4 slots, 0 upvalues, 3 locals, 4 constants, 1 function
+	1	[1]	LOADK    	0 -1	; 10
+	2	[2]	LOADK    	1 -2	; 20
+	3	[6]	CLOSURE  	2 0	; 00951CC0
+	4	[6]	MOVE     	0 0
+	5	[6]	MOVE     	0 1
+	6	[4]	SETGLOBAL	2 -3	; foo
+	7	[8]	LOADK    	2 -4	; 30
+	8	[9]	GETGLOBAL	3 -3	; foo
+	9	[9]	CALL     	3 1 1
+	10	[9]	RETURN   	0 1
+
+function <main.lua:4,6> (5 instructions, 20 bytes at 00951CC0)
+0 params, 2 slots, 2 upvalues, 0 locals, 0 constants, 0 functions
+	1	[5]	GETUPVAL 	0 0	; a
+	2	[5]	GETUPVAL 	1 1	; b
+	3	[5]	ADD      	0 0 1
+	4	[5]	RETURN   	0 2
+	5	[6]	RETURN   	0 1
+-----------------------------------
+012712A8的[6]是闭包的创建过程，两个MOVE指令用来设置闭包的upvalue，两个MOVE的第一个操作数无用
+				*/
+				//c 设置闭包的upvalue值
         for (j=0; j<nup; j++, pc++) {
           if (GET_OPCODE(*pc) == OP_GETUPVAL)
             ncl->l.upvals[j] = cl->upvals[GETARG_B(*pc)];
           else {
-            lua_assert(GET_OPCODE(*pc) == OP_MOVE);
+            lua_assert(GET_OPCODE(*pc) == OP_MOVE); 
             ncl->l.upvals[j] = luaF_findupval(L, base + GETARG_B(*pc));
           }
         }