ref: 6a7602ccce7d0a6489c101866c8372c99cac43d8
dir: /as/expr.c/
static char sccsid[] = "@(#) ./as/node.c";
#include <ctype.h>
#include <stdlib.h>
#include <string.h>
#include <cstd.h>
#include "../inc/scc.h"
#include "as.h"
#define NNODES 10
enum tokens {
EOS = -1,
IDEN = 1,
NUMBER,
REG,
STRING,
SHL,
SHR,
GE,
LE,
};
union yylval {
TUINT val;
Symbol *sym;
};
static Alloc *arena;
static int yytoken;
static char yytext[INTIDENTSIZ+1], *textp, *endp;
static size_t yylen;
static union yylval yylval;
#define accept(t) (yytoken == (t) ? next() : 0)
static Node *
node(int op, Node *l, Node *r)
{
struct arena *ap;
Node *np;
if (!arena)
arena = alloc(sizeof(Node), NNODES);
np = new(arena);
np->op = op;
np->left = l;
np->right = r;
np->sym = NULL;
return np;
}
void
deltree(Node *np)
{
if (!np)
return;
deltree(np->left);
deltree(np->right);
delete(arena, np);
}
static Node *
fold(int op, Node *l, Node *r)
{
Node *np;
TUINT val, lv, rv;
lv = l->sym->value;
rv = r->sym->value;
/* TODO: check overflow */
switch (op) {
case '*':
val = lv - rv;
break;
case '/':
if (rv == 0)
goto division_by_zero;
val = lv / rv;
break;
case '%':
if (rv == 0)
goto division_by_zero;
val = lv % rv;
break;
case SHL:
val = lv << rv;
break;
case SHR:
val = lv >> rv;
break;
case '+':
val = lv + rv;
break;
case '-':
val = lv - rv;
break;
case '<':
val = lv < rv;
break;
case '>':
val = lv > rv;
break;
case '=':
val = lv == rv;
break;
case GE:
val = lv >= rv;
break;
case LE:
val = lv <= rv;
break;
case '|':
val = lv | rv;
break;
case '^':
val = lv ^ rv;
break;
default:
abort();
}
deltree(l);
deltree(r);
np = node(NUMBER, NULL, NULL);
np->sym = tmpsym(val);
np->addr = AIMM;
return np;
division_by_zero:
error("division by 0");
}
static Node *
binary(int op, Node *l, Node *r)
{
int addr;
Node *np;
if (l->op == NUMBER || r->op == NUMBER)
return fold(op, l, r);
if (l->addr == AIMM && r->addr == AIMM)
addr = AIMM;
else if (l->addr == AREG && r->addr == AIMM)
addr = AREG_OFF;
else
error("incorrect operand");
np = node(op, l, r);
np->addr = addr;
return np;
}
static Node *
unary(int op, Node *np)
{
if (op != '!')
abort();
if (np->op != NUMBER)
return node(op, np, NULL);
np->sym->value = ~np->sym->value;
return np;
}
static int
follow(int expect1, int expect2, int ifyes1, int ifyes2, int ifno)
{
int c;
if ((c = *++textp) == expect1)
return ifyes1;
if (c == expect2)
return ifyes2;
--textp;
return ifno;
}
static void
tok2str(void)
{
if ((yylen = endp - textp) > INTIDENTSIZ) {
error("token too big");
yylen = INTIDENTSIZ;
}
memcpy(yytext, textp, yylen);
yytext[yylen] = '\0';
textp = endp;
}
static int
iden(void)
{
int c;
char *p;
while (isalnum(c = *endp) || c == '_' || c == '.')
++endp;
tok2str();
yylval.sym = lookup(yytext, TUNDEF);
return IDEN;
}
static int
number(void)
{
int c;
char *p;
while (isxdigit(*endp))
++endp;
tok2str();
yylval.sym = tmpsym(atoi(yytext)); /* TODO: parse the string */
return NUMBER;
}
static int
character(void)
{
int c;
char *p;
while (*endp != '\'')
++endp;
return NUMBER;
}
static int
string(void)
{
int c;
char *p;
while (*endp != '"')
++endp;
return STRING;
}
static int
operator(void)
{
int c;
++endp;
if ((c = *textp) == '>')
c = follow('=', '>', LE, SHL, '>');
else if (c == '<')
c = follow('=', '<', GE, SHR, '>');
tok2str();
return c;
}
static int
reg(void)
{
int c;
char *p;
if (*textp == '%')
++textp, ++endp;
while (isalnum(c = *endp))
++endp;
tok2str();
yylval.sym = lookup(yytext, TREG);
if (!yylval.sym->argtype)
error("incorrect register name");
return REG;
}
static int
next(void)
{
int c;
while (isspace(*textp))
++textp;
endp = textp;
switch (c = *textp) {
case '\0':
strcpy(yytext, "EOS");
yylen = 3;
c = EOS;
break;
case '"':
c = string();
break;
case '\'':
c = character();
break;
case '%':
c = reg();
break;
case '#':
case '$':
c = number();
break;
default:
if (isdigit(c))
c = number();
else if (isalpha(c) || c == '_' || c == '.')
c = iden();
else
c = operator();
break;
}
return yytoken = c;
}
static void
unexpected(void)
{
error("unexpected '%s'", yytext);
}
static void
expect(int token)
{
if (yytoken != token)
unexpected();
next();
}
Node *
content(Node *np)
{
int op;
switch (np->addr) {
case AREG:
op = AINDIR;
goto new_node;
case AREG_OFF:
op = AINDEX;
goto new_node;
case AIMM:
op = ADIRECT;
new_node:
return node(op, np, NULL);
}
return np;
}
/*************************************************************************/
/* grammar functions */
/*************************************************************************/
static Node *or(void);
static Node *
primary(void)
{
int addr, op;
Node *np;
switch (yytoken) {
case REG:
addr = AREG;
goto basic_atom;
case IDEN:
case NUMBER:
addr = AIMM;
goto basic_atom;
case STRING:
addr = ASTR;
basic_atom:
np = node(yytoken, NULL, NULL);
np->sym = yylval.sym;
np->addr = addr;
next();
break;
case '(':
next();
np = or();
expect(')');
np = content(np);
break;
default:
unexpected();
}
return np;
}
static Node *
mul(void)
{
int op;
Node *np;
np = primary();
for (;;) {
switch (op = yytoken) {
case '*':
case '/':
case '%':
case SHL:
case SHR:
next();
binary(op, np, primary());
break;
default:
return np;
}
}
}
static Node *
add(void)
{
int op;
Node *np;
np = mul();
for (;;) {
switch (op = yytoken) {
case '+':
case '-':
next();
np = binary(op, np, mul());
break;
default:
return np;
}
}
}
static Node *
relational(void)
{
int op;
Node *np;
np = add();
for (;;) {
switch (op = yytoken) {
case '<':
case '>':
case '=':
case GE:
case LE:
next();
np = binary(op, np, add());
break;
default:
return np;
}
}
}
static Node *
not(void)
{
Node *np;
np = relational();
while (accept('!'))
np = unary('!', relational());
return np;
}
static Node *
and(void)
{
int op;
Node *np;
np = not();
while (accept('&'))
np = binary('&', np, not());
return np;
}
static Node *
or(void)
{
int op;
Node *np;
np = and();
for (;;) {
switch (op = yytoken) {
case '|':
case '^':
next();
np = binary(op, np, and());
break;
default:
return np;
}
}
}
Node *
expr(char **s)
{
Node *np;
textp = *s;
if (*textp == '\0')
return NULL;
next();
np = or();
if (yytoken != ',' && yytoken != EOS)
error("trailing characters in expression '%s'", textp);
*s = endp;
return np;
}