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2079cfe8fa
lua/lvm.c
Roberto Ierusalimschy 2079cfe8fa new way to code globals, using const table instead of putting global 
index inside the opcode.
1997-09-19 18:17:52 -03:00

621 lines
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/*
** $Id: lvm.c,v 1.2 1997/09/19 18:40:32 roberto Exp roberto $
** Lua virtual machine
** See Copyright Notice in lua.h
*/
#include <stdio.h>
#include <string.h>
#include "lauxlib.h"
#include "ldo.h"
#include "lfunc.h"
#include "lgc.h"
#include "lglobal.h"
#include "lmem.h"
#include "lopcodes.h"
#include "lstring.h"
#include "ltable.h"
#include "ltm.h"
#include "luadebug.h"
#include "lvm.h"
#define get_prevword(pc) (*(pc-2)+(*(pc-1)<<8))
#define get_word(pc) (pc+=2, get_prevword(pc))
#define skip_word(pc) {pc+=2;}
/* Extra stack to run a function: LUA_T_LINE(1), TM calls(2), ... */
#define EXTRA_STACK 4
static TaggedString *strconc (char *l, char *r)
{
size_t nl = strlen(l);
char *buffer = luaM_buffer(nl+strlen(r)+1);
strcpy(buffer, l);
strcpy(buffer+nl, r);
return luaS_new(buffer);
}
int luaV_tonumber (TObject *obj)
{
double t;
char c;
if (ttype(obj) != LUA_T_STRING)
return 1;
else if (sscanf(svalue(obj), "%lf %c",&t, &c) == 1) {
nvalue(obj) = (real)t;
ttype(obj) = LUA_T_NUMBER;
return 0;
}
else
return 2;
}
int luaV_tostring (TObject *obj)
{
if (ttype(obj) != LUA_T_NUMBER)
return 1;
else {
char s[60];
real f = nvalue(obj);
int i;
if ((real)(-MAX_INT) <= f && f <= (real)MAX_INT && (real)(i=(int)f) == f)
sprintf (s, "%d", i);
else
sprintf (s, "%g", (double)nvalue(obj));
tsvalue(obj) = luaS_new(s);
ttype(obj) = LUA_T_STRING;
return 0;
}
}
void luaV_closure (void)
{
int nelems = (luaD_stack.top-1)->value.tf->nupvalues;
Closure *c = luaF_newclosure(nelems);
c->consts[0] = *(luaD_stack.top-1);
memcpy(&c->consts[1], luaD_stack.top-(nelems+1), nelems*sizeof(TObject));
luaD_stack.top -= nelems;
ttype(luaD_stack.top-1) = LUA_T_FUNCTION;
(luaD_stack.top-1)->value.cl = c;
}
/*
** Function to index a table.
** Receives the table at top-2 and the index at top-1.
*/
void luaV_gettable (void)
{
TObject *im;
if (ttype(luaD_stack.top-2) != LUA_T_ARRAY) /* not a table, get "gettable" method */
im = luaT_getimbyObj(luaD_stack.top-2, IM_GETTABLE);
else { /* object is a table... */
int tg = (luaD_stack.top-2)->value.a->htag;
im = luaT_getim(tg, IM_GETTABLE);
if (ttype(im) == LUA_T_NIL) { /* and does not have a "gettable" method */
TObject *h = luaH_get(avalue(luaD_stack.top-2), luaD_stack.top-1);
if (h != NULL && ttype(h) != LUA_T_NIL) {
--luaD_stack.top;
*(luaD_stack.top-1) = *h;
}
else if (ttype(im=luaT_getim(tg, IM_INDEX)) != LUA_T_NIL)
luaD_callTM(im, 2, 1);
else {
--luaD_stack.top;
ttype(luaD_stack.top-1) = LUA_T_NIL;
}
return;
}
/* else it has a "gettable" method, go through to next command */
}
/* object is not a table, or it has a "gettable" method */
if (ttype(im) != LUA_T_NIL)
luaD_callTM(im, 2, 1);
else
lua_error("indexed expression not a table");
}
/*
** Function to store indexed based on values at the luaD_stack.top
** mode = 0: raw store (without internal methods)
** mode = 1: normal store (with internal methods)
** mode = 2: "deep luaD_stack.stack" store (with internal methods)
*/
void luaV_settable (TObject *t, int mode)
{
TObject *im = (mode == 0) ? NULL : luaT_getimbyObj(t, IM_SETTABLE);
if (ttype(t) == LUA_T_ARRAY && (im == NULL || ttype(im) == LUA_T_NIL)) {
TObject *h = luaH_set(avalue(t), t+1);
*h = *(luaD_stack.top-1);
luaD_stack.top -= (mode == 2) ? 1 : 3;
}
else { /* object is not a table, and/or has a specific "settable" method */
if (im && ttype(im) != LUA_T_NIL) {
if (mode == 2) {
*(luaD_stack.top+1) = *(luaD_stack.top-1);
*(luaD_stack.top) = *(t+1);
*(luaD_stack.top-1) = *t;
luaD_stack.top += 2; /* WARNING: caller must assure stack space */
}
luaD_callTM(im, 3, 0);
}
else
lua_error("indexed expression not a table");
}
}
void luaV_getglobal (Word n)
{
/* WARNING: caller must assure stack space */
TObject *value = &luaG_global[n].object;
TObject *im = luaT_getimbyObj(value, IM_GETGLOBAL);
if (ttype(im) == LUA_T_NIL) { /* default behavior */
*luaD_stack.top++ = *value;
}
else {
ttype(luaD_stack.top) = LUA_T_STRING;
tsvalue(luaD_stack.top) = luaG_global[n].varname;
luaD_stack.top++;
*luaD_stack.top++ = *value;
luaD_callTM(im, 2, 1);
}
}
void luaV_setglobal (Word n)
{
TObject *oldvalue = &luaG_global[n].object;
TObject *im = luaT_getimbyObj(oldvalue, IM_SETGLOBAL);
if (ttype(im) == LUA_T_NIL) /* default behavior */
s_object(n) = *(--luaD_stack.top);
else {
/* WARNING: caller must assure stack space */
TObject newvalue = *(luaD_stack.top-1);
ttype(luaD_stack.top-1) = LUA_T_STRING;
tsvalue(luaD_stack.top-1) = luaG_global[n].varname;
*luaD_stack.top++ = *oldvalue;
*luaD_stack.top++ = newvalue;
luaD_callTM(im, 3, 0);
}
}
static void call_binTM (IMS event, char *msg)
{
TObject *im = luaT_getimbyObj(luaD_stack.top-2, event);/* try first operand */
if (ttype(im) == LUA_T_NIL) {
im = luaT_getimbyObj(luaD_stack.top-1, event); /* try second operand */
if (ttype(im) == LUA_T_NIL) {
im = luaT_getim(0, event); /* try a 'global' i.m. */
if (ttype(im) == LUA_T_NIL)
lua_error(msg);
}
}
lua_pushstring(luaT_eventname[event]);
luaD_callTM(im, 3, 1);
}
static void call_arith (IMS event)
{
call_binTM(event, "unexpected type at arithmetic operation");
}
static void comparison (lua_Type ttype_less, lua_Type ttype_equal,
lua_Type ttype_great, IMS op)
{
TObject *l = luaD_stack.top-2;
TObject *r = luaD_stack.top-1;
int result;
if (ttype(l) == LUA_T_NUMBER && ttype(r) == LUA_T_NUMBER)
result = (nvalue(l) < nvalue(r)) ? -1 : (nvalue(l) == nvalue(r)) ? 0 : 1;
else if (ttype(l) == LUA_T_STRING && ttype(r) == LUA_T_STRING)
result = strcoll(svalue(l), svalue(r));
else {
call_binTM(op, "unexpected type at comparison");
return;
}
luaD_stack.top--;
nvalue(luaD_stack.top-1) = 1;
ttype(luaD_stack.top-1) = (result < 0) ? ttype_less :
(result == 0) ? ttype_equal : ttype_great;
}
void luaV_pack (StkId firstel, int nvararg, TObject *tab)
{
TObject *firstelem = luaD_stack.stack+firstel;
int i;
if (nvararg < 0) nvararg = 0;
avalue(tab) = luaH_new(nvararg+1); /* +1 for field 'n' */
ttype(tab) = LUA_T_ARRAY;
for (i=0; i<nvararg; i++) {
TObject index;
ttype(&index) = LUA_T_NUMBER;
nvalue(&index) = i+1;
*(luaH_set(avalue(tab), &index)) = *(firstelem+i);
}
/* store counter in field "n" */ {
TObject index, extra;
ttype(&index) = LUA_T_STRING;
tsvalue(&index) = luaS_new("n");
ttype(&extra) = LUA_T_NUMBER;
nvalue(&extra) = nvararg;
*(luaH_set(avalue(tab), &index)) = extra;
}
}
static void adjust_varargs (StkId first_extra_arg)
{
TObject arg;
luaV_pack(first_extra_arg,
(luaD_stack.top-luaD_stack.stack)-first_extra_arg, &arg);
luaD_adjusttop(first_extra_arg);
*luaD_stack.top++ = arg;
}
/*
** Execute the given opcode, until a RET. Parameters are between
** [luaD_stack.stack+base,luaD_stack.top). Returns n such that the the results are between
** [luaD_stack.stack+n,luaD_stack.top).
*/
StkId luaV_execute (Closure *cl, StkId base)
{
TProtoFunc *func = cl->consts[0].value.tf;
Byte *pc = func->code;
if (lua_callhook)
luaD_callHook(base, LUA_T_MARK, 0);
luaD_checkstack((*pc++)+EXTRA_STACK);
while (1) {
OpCode opcode;
switch (opcode = (OpCode)*pc++) {
case PUSHNIL:
ttype(luaD_stack.top++) = LUA_T_NIL;
break;
case PUSHNILS: {
int n = *pc++;
while (n--)
ttype(luaD_stack.top++) = LUA_T_NIL;
break;
}
case PUSH0: case PUSH1: case PUSH2:
ttype(luaD_stack.top) = LUA_T_NUMBER;
nvalue(luaD_stack.top) = opcode-PUSH0;
luaD_stack.top++;
break;
case PUSHBYTE:
ttype(luaD_stack.top) = LUA_T_NUMBER;
nvalue(luaD_stack.top) = *pc++;
luaD_stack.top++;
break;
case PUSHWORD:
ttype(luaD_stack.top) = LUA_T_NUMBER;
nvalue(luaD_stack.top) = get_word(pc);
luaD_stack.top++;
break;
case PUSHLOCAL0: case PUSHLOCAL1: case PUSHLOCAL2:
case PUSHLOCAL3: case PUSHLOCAL4: case PUSHLOCAL5:
case PUSHLOCAL6: case PUSHLOCAL7: case PUSHLOCAL8:
case PUSHLOCAL9:
*luaD_stack.top++ =
*((luaD_stack.stack+base) + (int)(opcode-PUSHLOCAL0));
break;
case PUSHLOCAL:
*luaD_stack.top++ = *((luaD_stack.stack+base) + (*pc++));
break;
case PUSHGLOBALB:
luaV_getglobal(luaG_findsymbol(tsvalue(&func->consts[*pc++])));
break;
case PUSHGLOBAL:
luaV_getglobal(luaG_findsymbol(tsvalue(&func->consts[get_word(pc)])));
break;
case GETTABLE:
luaV_gettable();
break;
case PUSHSELF: {
TObject receiver = *(luaD_stack.top-1);
*luaD_stack.top++ = func->consts[get_word(pc)];
luaV_gettable();
*luaD_stack.top++ = receiver;
break;
}
case PUSHCONSTANTB:
*luaD_stack.top++ = func->consts[*pc++];
break;
case PUSHCONSTANT:
*luaD_stack.top++ = func->consts[get_word(pc)];
break;
case PUSHUPVALUE0:
*luaD_stack.top++ = cl->consts[1];
break;
case PUSHUPVALUE:
*luaD_stack.top++ = cl->consts[(*pc++)+1];
break;
case SETLOCAL0: case SETLOCAL1: case SETLOCAL2:
case SETLOCAL3: case SETLOCAL4: case SETLOCAL5:
case SETLOCAL6: case SETLOCAL7: case SETLOCAL8:
case SETLOCAL9:
*((luaD_stack.stack+base) + (int)(opcode-SETLOCAL0)) =
*(--luaD_stack.top);
break;
case SETLOCAL:
*((luaD_stack.stack+base) + (*pc++)) = *(--luaD_stack.top); break;
case SETGLOBALB:
luaV_setglobal(luaG_findsymbol(tsvalue(&func->consts[*pc++])));
break;
case SETGLOBAL:
luaV_setglobal(luaG_findsymbol(tsvalue(&func->consts[get_word(pc)])));
break;
case SETTABLE0:
luaV_settable(luaD_stack.top-3, 1);
break;
case SETTABLE:
luaV_settable(luaD_stack.top-3-(*pc++), 2);
break;
case SETLIST0:
case SETLIST: {
int m = (opcode == SETLIST0) ? 0 : *(pc++) * LFIELDS_PER_FLUSH;
int n = *(pc++);
TObject *arr = luaD_stack.top-n-1;
for (; n; n--) {
ttype(luaD_stack.top) = LUA_T_NUMBER;
nvalue(luaD_stack.top) = n+m;
*(luaH_set (avalue(arr), luaD_stack.top)) = *(luaD_stack.top-1);
luaD_stack.top--;
}
break;
}
case SETMAP: {
int n = *(pc++);
TObject *arr = luaD_stack.top-(2*n)-1;
while (n--) {
*(luaH_set (avalue(arr), luaD_stack.top-2)) = *(luaD_stack.top-1);
luaD_stack.top-=2;
}
break;
}
case POPS:
luaD_stack.top -= *(pc++);
break;
case ARGS:
luaD_adjusttop(base + *(pc++));
break;
case VARARGS:
luaC_checkGC();
adjust_varargs(base + *(pc++));
break;
case CREATEARRAY:
luaC_checkGC();
avalue(luaD_stack.top) = luaH_new(get_word(pc));
ttype(luaD_stack.top) = LUA_T_ARRAY;
luaD_stack.top++;
break;
case EQOP: case NEQOP: {
int res = luaO_equalObj(luaD_stack.top-2, luaD_stack.top-1);
luaD_stack.top--;
if (opcode == NEQOP) res = !res;
ttype(luaD_stack.top-1) = res ? LUA_T_NUMBER : LUA_T_NIL;
nvalue(luaD_stack.top-1) = 1;
break;
}
case LTOP:
comparison(LUA_T_NUMBER, LUA_T_NIL, LUA_T_NIL, IM_LT);
break;
case LEOP:
comparison(LUA_T_NUMBER, LUA_T_NUMBER, LUA_T_NIL, IM_LE);
break;
case GTOP:
comparison(LUA_T_NIL, LUA_T_NIL, LUA_T_NUMBER, IM_GT);
break;
case GEOP:
comparison(LUA_T_NIL, LUA_T_NUMBER, LUA_T_NUMBER, IM_GE);
break;
case ADDOP: {
TObject *l = luaD_stack.top-2;
TObject *r = luaD_stack.top-1;
if (tonumber(r) || tonumber(l))
call_arith(IM_ADD);
else {
nvalue(l) += nvalue(r);
--luaD_stack.top;
}
break;
}
case SUBOP: {
TObject *l = luaD_stack.top-2;
TObject *r = luaD_stack.top-1;
if (tonumber(r) || tonumber(l))
call_arith(IM_SUB);
else {
nvalue(l) -= nvalue(r);
--luaD_stack.top;
}
break;
}
case MULTOP: {
TObject *l = luaD_stack.top-2;
TObject *r = luaD_stack.top-1;
if (tonumber(r) || tonumber(l))
call_arith(IM_MUL);
else {
nvalue(l) *= nvalue(r);
--luaD_stack.top;
}
break;
}
case DIVOP: {
TObject *l = luaD_stack.top-2;
TObject *r = luaD_stack.top-1;
if (tonumber(r) || tonumber(l))
call_arith(IM_DIV);
else {
nvalue(l) /= nvalue(r);
--luaD_stack.top;
}
break;
}
case POWOP:
call_arith(IM_POW);
break;
case CONCOP: {
TObject *l = luaD_stack.top-2;
TObject *r = luaD_stack.top-1;
if (tostring(l) || tostring(r))
call_binTM(IM_CONCAT, "unexpected type for concatenation");
else {
tsvalue(l) = strconc(svalue(l), svalue(r));
--luaD_stack.top;
}
luaC_checkGC();
break;
}
case MINUSOP:
if (tonumber(luaD_stack.top-1)) {
ttype(luaD_stack.top) = LUA_T_NIL;
luaD_stack.top++;
call_arith(IM_UNM);
}
else
nvalue(luaD_stack.top-1) = - nvalue(luaD_stack.top-1);
break;
case NOTOP:
ttype(luaD_stack.top-1) =
(ttype(luaD_stack.top-1) == LUA_T_NIL) ? LUA_T_NUMBER : LUA_T_NIL;
nvalue(luaD_stack.top-1) = 1;
break;
case ONTJMP:
skip_word(pc);
if (ttype(luaD_stack.top-1) != LUA_T_NIL)
pc += get_prevword(pc);
else
luaD_stack.top--;
break;
case ONFJMP:
skip_word(pc);
if (ttype(luaD_stack.top-1) == LUA_T_NIL)
pc += get_prevword(pc);
else
luaD_stack.top--;
break;
case JMP:
skip_word(pc);
pc += get_prevword(pc);
break;
case UPJMP:
skip_word(pc);
pc -= get_prevword(pc);
break;
case IFFJMP:
skip_word(pc);
if (ttype(--luaD_stack.top) == LUA_T_NIL)
pc += get_prevword(pc);
break;
case IFFUPJMP:
skip_word(pc);
if (ttype(--luaD_stack.top) == LUA_T_NIL)
pc -= get_prevword(pc);
break;
case CLOSURE:
luaV_closure();
luaC_checkGC();
break;
case CALLFUNC: {
StkId newBase = (luaD_stack.top-luaD_stack.stack)-(*pc++);
luaD_call(newBase, *pc++);
break;
}
case ENDCODE:
luaD_stack.top = luaD_stack.stack + base;
/* goes through */
case RETCODE:
if (lua_callhook)
luaD_callHook(base, LUA_T_MARK, 1);
return (base + ((opcode==RETCODE) ? *pc : 0));
case SETLINE: {
int line = get_word(pc);
if ((luaD_stack.stack+base-1)->ttype != LUA_T_LINE) {
/* open space for LINE value */
luaD_openstack((luaD_stack.top-luaD_stack.stack)-base);
base++;
(luaD_stack.stack+base-1)->ttype = LUA_T_LINE;
}
(luaD_stack.stack+base-1)->value.i = line;
if (lua_linehook)
luaD_lineHook(line);
break;
}
#ifdef DEBUG
default:
lua_error("internal error - opcode doesn't match");
#endif
}
}
}
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