shithub: libmujs

ref: 67de4965c6190526606344edc59af8b621835e50
dir: /jsrun.c/

#include "js.h"
#include "jscompile.h"
#include "jsrun.h"
#include "jsstate.h"

static js_Value stack[256];
static int top = 0;

static inline int i32(double d)
{
	double two32 = 4294967296.0;
	double two31 = 2147483648.0;

	if (!isfinite(d) || d == 0)
		return 0;

	d = fmod(d, two32);
	d = d >= 0 ? floor(d) : ceil(d) + two32;
	if (d >= two31)
		return d - two32;
	else
		return d;
}

static inline unsigned int u32(double d)
{
	return i32(d);
}

static inline void push(js_State *J, js_Value v)
{
	stack[top++] = v;
}

static inline js_Value pop(js_State *J)
{
	return stack[--top];
}

static inline void pushnumber(js_State *J, double number)
{
	js_Value v;
	v.type = JS_TNUMBER;
	v.u.number = number;
	push(J, v);
}

static inline double popnumber(js_State *J)
{
	js_Value v = pop(J);
	if (v.type == JS_TNUMBER)
		return v.u.number;
	if (v.type == JS_TSTRING)
		return strtod(v.u.string, 0);
	return 0;
}

static inline void pushundefined(js_State *J)
{
	js_Value v;
	v.type = JS_TUNDEFINED;
	push(J, v);
}

static inline void pushnull(js_State *J)
{
	js_Value v;
	v.type = JS_TNULL;
	push(J, v);
}

static inline void pushboolean(js_State *J, int boolean)
{
	js_Value v;
	v.type = JS_TBOOLEAN;
	v.u.boolean = boolean;
	push(J, v);
}

static inline int popboolean(js_State *J)
{
	js_Value v = pop(J);
	if (v.type == JS_TBOOLEAN)
		return v.u.boolean;
	return 0;
}

static void dumpstack(js_State *J)
{
	int i;
	for (i = 0; i < top; i++) {
		printf("stack %d: ", i);
		jsC_dumpvalue(J, stack[i]);
		putchar('\n');
	}
}

#define UNARY(X) a = popnumber(J); pushnumber(J, X)
#define BINARY(X) b = popnumber(J); a = popnumber(J); pushnumber(J, X)

static void runfun(js_State *J, js_Function *F)
{
	unsigned char *pc = F->code;
	int opcode, i;
	double a, b;

	while (1) {
		opcode = *pc++;
		switch (opcode) {
		case OP_CONST:
			i = *pc++;
			push(J, F->klist[i]);
			break;

		case OP_UNDEF: pushundefined(J); break;
		case OP_NULL: pushnull(J); break;
		case OP_TRUE: pushboolean(J, 1); break;
		case OP_FALSE: pushboolean(J, 0); break;

		case OP_POS: UNARY(a); break;
		case OP_NEG: UNARY(-a); break;
		case OP_BITNOT: UNARY(~i32(a)); break;

		case OP_ADD: BINARY(a + b); break;
		case OP_SUB: BINARY(a - b); break;
		case OP_MUL: BINARY(a * b); break;
		case OP_DIV: BINARY(a / b); break;
		case OP_MOD: BINARY(fmod(a, b)); break;
		case OP_SHL: BINARY(i32(a) << (u32(b) & 0x1F)); break;
		case OP_SHR: BINARY(i32(a) >> (u32(b) & 0x1F)); break;
		case OP_USHR: BINARY(u32(a) >> (u32(b) & 0x1F)); break;
		case OP_BITAND: BINARY(i32(a) & i32(b)); break;
		case OP_BITXOR: BINARY(i32(a) ^ i32(b)); break;
		case OP_BITOR: BINARY(i32(a) | i32(b)); break;

		case OP_RETURN: return;

		default:
			fprintf(stderr, "illegal instruction: %d\n", opcode);
			return;
		}
	}
}

void jsR_runfunction(js_State *J, js_Function *F)
{
	runfun(J, F);
	dumpstack(J);
}