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lua/lvm.c

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/*
** $Id: lvm.c,v 1.46 1999/02/08 17:07:59 roberto Exp roberto $
** Lua virtual machine
** See Copyright Notice in lua.h
*/
#include <ctype.h>
#include <limits.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include "lauxlib.h"
#include "ldo.h"
#include "lfunc.h"
#include "lgc.h"
#include "lmem.h"
#include "lobject.h"
#include "lopcodes.h"
#include "lstate.h"
#include "lstring.h"
#include "ltable.h"
#include "ltm.h"
#include "luadebug.h"
#include "lvm.h"
#ifdef OLD_ANSI
#define strcoll(a,b) strcmp(a,b)
#endif
#define highbyte(x) ((x)<<8)
/* Extra stack size to run a function: LUA_T_LINE(1), TM calls(2), ... */
#define EXTRA_STACK 5
static TaggedString *strconc (TaggedString *l, TaggedString *r) {
long nl = l->u.s.len;
long nr = r->u.s.len;
char *buffer = luaL_openspace(nl+nr);
memcpy(buffer, l->str, nl);
memcpy(buffer+nl, r->str, nr);
return luaS_newlstr(buffer, nl+nr);
}
int luaV_tonumber (TObject *obj) { /* LUA_NUMBER */
if (ttype(obj) != LUA_T_STRING)
return 1;
else {
double t;
char *e = svalue(obj);
int sig = 1;
while (isspace((unsigned char)*e)) e++;
if (*e == '+') e++;
else if (*e == '-') {
e++;
sig = -1;
}
t = luaO_str2d(e);
if (t<0) return 2;
nvalue(obj) = (real)t*sig;
ttype(obj) = LUA_T_NUMBER;
return 0;
}
}
int luaV_tostring (TObject *obj) { /* LUA_NUMBER */
if (ttype(obj) != LUA_T_NUMBER)
return 1;
else {
char s[32]; /* 16 digits, signal, point and \0 (+ some extra...) */
sprintf(s, "%.16g", (double)nvalue(obj));
tsvalue(obj) = luaS_new(s);
ttype(obj) = LUA_T_STRING;
return 0;
}
}
void luaV_setn (Hash *t, int val) {
TObject index, value;
ttype(&index) = LUA_T_STRING; tsvalue(&index) = luaS_new("n");
ttype(&value) = LUA_T_NUMBER; nvalue(&value) = val;
luaH_set(t, &index, &value);
}
void luaV_closure (int nelems) {
if (nelems > 0) {
struct Stack *S = &L->stack;
Closure *c = luaF_newclosure(nelems);
c->consts[0] = *(S->top-1);
memcpy(&c->consts[1], S->top-(nelems+1), nelems*sizeof(TObject));
S->top -= nelems;
ttype(S->top-1) = LUA_T_CLOSURE;
(S->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 *table = L->stack.top-2;
TObject *im;
if (ttype(table) != LUA_T_ARRAY) { /* not a table, get gettable method */
im = luaT_getimbyObj(table, IM_GETTABLE);
if (ttype(im) == LUA_T_NIL)
lua_error("indexed expression not a table");
}
else { /* object is a table... */
int tg = table->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(table), table+1);
if (ttype(h) == LUA_T_NIL &&
(ttype(im=luaT_getim(tg, IM_INDEX)) != LUA_T_NIL)) {
/* result is nil and there is an "index" tag method */
luaD_callTM(im, 2, 1); /* calls it */
}
else {
L->stack.top--;
*table = *h; /* "push" result into table position */
}
return;
}
/* else it has a "gettable" method, go through to next command */
}
/* object is not a table, or it has a "gettable" method */
luaD_callTM(im, 2, 1);
}
/*
** Receives table at *t, index at *(t+1) and value at top.
*/
void luaV_settable (TObject *t) {
struct Stack *S = &L->stack;
TObject *im;
if (ttype(t) != LUA_T_ARRAY) { /* not a table, get "settable" method */
im = luaT_getimbyObj(t, IM_SETTABLE);
if (ttype(im) == LUA_T_NIL)
lua_error("indexed expression not a table");
}
else { /* object is a table... */
im = luaT_getim(avalue(t)->htag, IM_SETTABLE);
if (ttype(im) == LUA_T_NIL) { /* and does not have a "settable" method */
luaH_set(avalue(t), t+1, S->top-1);
S->top--; /* pop value */
return;
}
/* else it has a "settable" method, go through to next command */
}
/* object is not a table, or it has a "settable" method */
/* prepare arguments and call the tag method */
*(S->top+1) = *(L->stack.top-1);
*(S->top) = *(t+1);
*(S->top-1) = *t;
S->top += 2; /* WARNING: caller must assure stack space */
luaD_callTM(im, 3, 0);
}
void luaV_rawsettable (TObject *t) {
if (ttype(t) != LUA_T_ARRAY)
lua_error("indexed expression not a table");
else {
struct Stack *S = &L->stack;
luaH_set(avalue(t), t+1, S->top-1);
S->top -= 3;
}
}
void luaV_getglobal (TaggedString *ts) {
/* WARNING: caller must assure stack space */
/* only userdata, tables and nil can have getglobal tag methods */
static char valid_getglobals[] = {1, 0, 0, 1, 0, 0, 1, 0}; /* ORDER LUA_T */
TObject *value = &ts->u.s.globalval;
if (valid_getglobals[-ttype(value)]) {
TObject *im = luaT_getimbyObj(value, IM_GETGLOBAL);
if (ttype(im) != LUA_T_NIL) { /* is there a tag method? */
struct Stack *S = &L->stack;
ttype(S->top) = LUA_T_STRING;
tsvalue(S->top) = ts;
S->top++;
*S->top++ = *value;
luaD_callTM(im, 2, 1);
return;
}
/* else no tag method: go through to default behavior */
}
*L->stack.top++ = *value; /* default behavior */
}
void luaV_setglobal (TaggedString *ts) {
TObject *oldvalue = &ts->u.s.globalval;
TObject *im = luaT_getimbyObj(oldvalue, IM_SETGLOBAL);
if (ttype(im) == LUA_T_NIL) /* is there a tag method? */
luaS_rawsetglobal(ts, --L->stack.top);
else {
/* WARNING: caller must assure stack space */
struct Stack *S = &L->stack;
TObject newvalue = *(S->top-1);
ttype(S->top-1) = LUA_T_STRING;
tsvalue(S->top-1) = ts;
*S->top++ = *oldvalue;
*S->top++ = newvalue;
luaD_callTM(im, 3, 0);
}
}
static void call_binTM (IMS event, char *msg)
{
TObject *im = luaT_getimbyObj(L->stack.top-2, event);/* try first operand */
if (ttype(im) == LUA_T_NIL) {
im = luaT_getimbyObj(L->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 in arithmetic operation");
}
static int luaV_strcomp (char *l, long ll, char *r, long lr)
{
for (;;) {
long temp = strcoll(l, r);
if (temp != 0) return temp;
/* strings are equal up to a '\0' */
temp = strlen(l); /* index of first '\0' in both strings */
if (temp == ll) /* l is finished? */
return (temp == lr) ? 0 : -1; /* l is equal or smaller than r */
else if (temp == lr) /* r is finished? */
return 1; /* l is greater than r (because l is not finished) */
/* both strings longer than temp; go on comparing (after the '\0') */
temp++;
l += temp; ll -= temp; r += temp; lr -= temp;
}
}
void luaV_comparison (lua_Type ttype_less, lua_Type ttype_equal,
lua_Type ttype_great, IMS op) {
struct Stack *S = &L->stack;
TObject *l = S->top-2;
TObject *r = S->top-1;
real result;
if (ttype(l) == LUA_T_NUMBER && ttype(r) == LUA_T_NUMBER)
result = nvalue(l)-nvalue(r);
else if (ttype(l) == LUA_T_STRING && ttype(r) == LUA_T_STRING)
result = luaV_strcomp(svalue(l), tsvalue(l)->u.s.len,
svalue(r), tsvalue(r)->u.s.len);
else {
call_binTM(op, "unexpected type in comparison");
return;
}
S->top--;
nvalue(S->top-1) = 1;
ttype(S->top-1) = (result < 0) ? ttype_less :
(result == 0) ? ttype_equal : ttype_great;
}
void luaV_pack (StkId firstel, int nvararg, TObject *tab) {
TObject *firstelem = L->stack.stack+firstel;
int i;
Hash *htab;
if (nvararg < 0) nvararg = 0;
htab = avalue(tab) = luaH_new(nvararg+1); /* +1 for field 'n' */
ttype(tab) = LUA_T_ARRAY;
for (i=0; i<nvararg; i++)
luaH_setint(htab, i+1, firstelem+i);
luaV_setn(htab, nvararg); /* store counter in field "n" */
}
static void adjust_varargs (StkId first_extra_arg)
{
TObject arg;
luaV_pack(first_extra_arg,
(L->stack.top-L->stack.stack)-first_extra_arg, &arg);
luaD_adjusttop(first_extra_arg);
*L->stack.top++ = arg;
}
/*
** Execute the given opcode, until a RET. Parameters are between
** [stack+base,top). Returns n such that the the results are between
** [stack+n,top).
*/
StkId luaV_execute (Closure *cl, TProtoFunc *tf, StkId base) {
struct Stack *S = &L->stack; /* to optimize */
register Byte *pc = tf->code;
TObject *consts = tf->consts;
if (L->callhook)
luaD_callHook(base, tf, 0);
luaD_checkstack((*pc++)+EXTRA_STACK);
if (*pc < ZEROVARARG)
luaD_adjusttop(base+*(pc++));
else { /* varargs */
luaC_checkGC();
adjust_varargs(base+(*pc++)-ZEROVARARG);
}
for (;;) {
register int aux = 0;
switchentry:
switch ((OpCode)*pc++) {
case ENDCODE: aux = 1;
S->top = S->stack + base;
/* goes through */
case RETCODE:
if (L->callhook)
luaD_callHook(base, NULL, 1);
return base + (aux ? 0 : *pc);
case PUSHNIL: aux = *pc++;
do {
ttype(S->top++) = LUA_T_NIL;
} while (aux--);
break;
case POP: aux = *pc++;
S->top -= aux;
break;
case POPDUP: aux = *pc++;
*(S->top-aux-1) = *(S->top-1);
S->top -= aux;
break;
case PUSHNUMBERW: aux += highbyte(*pc++);
case PUSHNUMBER: aux += *pc++;
ttype(S->top) = LUA_T_NUMBER;
nvalue(S->top) = aux-NUMOFFSET;
S->top++;
break;
case PUSHCONSTANTW: aux += highbyte(*pc++);
case PUSHCONSTANT: aux += *pc++;
*S->top++ = consts[aux];
break;
case PUSHUPVALUE: aux = *pc++;
*S->top++ = cl->consts[aux+1];
break;
case PUSHLOCAL: aux = *pc++;
*S->top++ = *((S->stack+base) + aux);
break;
case GETGLOBALW: aux += highbyte(*pc++);
case GETGLOBAL: aux += *pc++;
luaV_getglobal(tsvalue(&consts[aux]));
break;
case GETTABLE:
luaV_gettable();
break;
case GETDOTTEDW: aux += highbyte(*pc++);
case GETDOTTED: aux += *pc++;
*S->top++ = consts[aux];
luaV_gettable();
break;
case PUSHSELFW: aux += highbyte(*pc++);
case PUSHSELF: aux += *pc++; {
TObject receiver = *(S->top-1);
*S->top++ = consts[aux];
luaV_gettable();
*S->top++ = receiver;
break;
}
case CREATEARRAYW: aux += highbyte(*pc++);
case CREATEARRAY: aux += *pc++;
luaC_checkGC();
avalue(S->top) = luaH_new(aux);
ttype(S->top) = LUA_T_ARRAY;
S->top++;
break;
case SETLOCAL: aux = *pc++;
*((S->stack+base) + aux) = *(--S->top);
break;
case SETLOCALDUP: aux = *pc++;
*((S->stack+base) + aux) = *(S->top-1);
break;
case SETGLOBALW: aux += highbyte(*pc++);
case SETGLOBAL: aux += *pc++;
luaV_setglobal(tsvalue(&consts[aux]));
break;
case SETGLOBALDUPW: aux += highbyte(*pc++);
case SETGLOBALDUP: aux += *pc++;
*S->top = *(S->top-1);
S->top++;
luaV_setglobal(tsvalue(&consts[aux]));
break;
case SETTABLEPOP:
luaV_settable(S->top-3);
S->top -= 2; /* pop table and index */
break;
case SETTABPPDUP: {
TObject temp = *(S->top-1);
luaV_settable(S->top-3);
S->top--; /* pop index (temp goes into "table" position) */
*(S->top-1) = temp;
break;
}
case SETTABLE:
luaV_settable(S->top-3-(*pc++));
break;
case SETTABLEDUP:
*S->top = *(S->top-1);
S->top++;
luaV_settable(S->top-(3+1)-(*pc++));
break;
case SETLISTW: aux += highbyte(*pc++);
case SETLIST: aux += *pc++; {
int n = *(pc++);
TObject *arr = S->top-n-1;
aux *= LFIELDS_PER_FLUSH;
for (; n; n--)
luaH_setint(avalue(arr), n+aux, --S->top);
break;
}
case SETMAP: aux = *pc++; {
TObject *arr = S->top-(2*aux)-3;
do {
luaH_set(avalue(arr), S->top-2, S->top-1);
S->top-=2;
} while (aux--);
break;
}
case NEQOP: aux = 1;
case EQOP: {
int res = luaO_equalObj(S->top-2, S->top-1);
if (aux) res = !res;
S->top--;
ttype(S->top-1) = res ? LUA_T_NUMBER : LUA_T_NIL;
nvalue(S->top-1) = 1;
break;
}
case LTOP:
luaV_comparison(LUA_T_NUMBER, LUA_T_NIL, LUA_T_NIL, IM_LT);
break;
case LEOP:
luaV_comparison(LUA_T_NUMBER, LUA_T_NUMBER, LUA_T_NIL, IM_LE);
break;
case GTOP:
luaV_comparison(LUA_T_NIL, LUA_T_NIL, LUA_T_NUMBER, IM_GT);
break;
case GEOP:
luaV_comparison(LUA_T_NIL, LUA_T_NUMBER, LUA_T_NUMBER, IM_GE);
break;
case ADDOP: {
TObject *l = S->top-2;
TObject *r = S->top-1;
if (tonumber(r) || tonumber(l))
call_arith(IM_ADD);
else {
nvalue(l) += nvalue(r);
--S->top;
}
break;
}
case SUBOP: {
TObject *l = S->top-2;
TObject *r = S->top-1;
if (tonumber(r) || tonumber(l))
call_arith(IM_SUB);
else {
nvalue(l) -= nvalue(r);
--S->top;
}
break;
}
case MULTOP: {
TObject *l = S->top-2;
TObject *r = S->top-1;
if (tonumber(r) || tonumber(l))
call_arith(IM_MUL);
else {
nvalue(l) *= nvalue(r);
--S->top;
}
break;
}
case DIVOP: {
TObject *l = S->top-2;
TObject *r = S->top-1;
if (tonumber(r) || tonumber(l))
call_arith(IM_DIV);
else {
nvalue(l) /= nvalue(r);
--S->top;
}
break;
}
case POWOP:
call_binTM(IM_POW, "undefined operation");
break;
case CONCOP: {
TObject *l = S->top-2;
TObject *r = S->top-1;
if (tostring(l) || tostring(r))
call_binTM(IM_CONCAT, "unexpected type for concatenation");
else {
tsvalue(l) = strconc(tsvalue(l), tsvalue(r));
--S->top;
}
luaC_checkGC();
break;
}
case MINUSOP:
if (tonumber(S->top-1)) {
ttype(S->top) = LUA_T_NIL;
S->top++;
call_arith(IM_UNM);
}
else
nvalue(S->top-1) = - nvalue(S->top-1);
break;
case NOTOP:
ttype(S->top-1) =
(ttype(S->top-1) == LUA_T_NIL) ? LUA_T_NUMBER : LUA_T_NIL;
nvalue(S->top-1) = 1;
break;
case ONTJMPW: aux += highbyte(*pc++);
case ONTJMP: aux += *pc++;
if (ttype(S->top-1) != LUA_T_NIL) pc += aux;
else S->top--;
break;
case ONFJMPW: aux += highbyte(*pc++);
case ONFJMP: aux += *pc++;
if (ttype(S->top-1) == LUA_T_NIL) pc += aux;
else S->top--;
break;
case JMPW: aux += highbyte(*pc++);
case JMP: aux += *pc++;
pc += aux;
break;
case IFFJMPW: aux += highbyte(*pc++);
case IFFJMP: aux += *pc++;
if (ttype(--S->top) == LUA_T_NIL) pc += aux;
break;
case IFTUPJMPW: aux += highbyte(*pc++);
case IFTUPJMP: aux += *pc++;
if (ttype(--S->top) != LUA_T_NIL) pc -= aux;
break;
case IFFUPJMPW: aux += highbyte(*pc++);
case IFFUPJMP: aux += *pc++;
if (ttype(--S->top) == LUA_T_NIL) pc -= aux;
break;
case CLOSURE: aux = *pc++;
*S->top++ = consts[aux];
luaV_closure(*pc++);
luaC_checkGC();
break;
case CALLFUNC: aux = *pc++; {
StkId newBase = (S->top-S->stack)-(*pc++);
luaD_call(newBase, aux);
break;
}
case SETLINEW: aux += highbyte(*pc++);
case SETLINE: aux += *pc++;
if ((S->stack+base-1)->ttype != LUA_T_LINE) {
/* open space for LINE value */
luaD_openstack((S->top-S->stack)-base);
base++;
(S->stack+base-1)->ttype = LUA_T_LINE;
}
(S->stack+base-1)->value.i = aux;
if (L->linehook)
luaD_lineHook(aux);
break;
case LONGARG:
aux = highbyte(highbyte(*pc++));
goto switchentry; /* do not reset "aux" */
}
}
}
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