/* Copy number or string content into already allocated target */
struct value *
stack_dup_value(const struct value *a, struct value *copy)
{
copy->type = a->type;
switch (a->type) {
case BCODE_NONE:
break;
case BCODE_NUMBER:
copy->u.num = dup_number(a->u.num);
break;
case BCODE_STRING:
copy->u.string = strdup(a->u.string);
if (copy->u.string == NULL)
err(1, NULL);
break;
}
copy->array = a->array == NULL ? NULL : array_dup(a->array);
return copy;
}
static void
bexp(void)
{
struct number *a, *p;
struct number *r;
bool neg;
u_int rscale;
p = pop_number();
if (p == NULL)
return;
a = pop_number();
if (a == NULL) {
push_number(p);
return;
}
if (p->scale != 0) {
BIGNUM *i, *f;
i = BN_new();
bn_checkp(i);
f = BN_new();
bn_checkp(f);
split_number(p, i, f);
if (!BN_is_zero(f))
warnx("Runtime warning: non-zero fractional part in exponent");
BN_free(i);
BN_free(f);
}
normalize(p, 0);
neg = false;
if (BN_is_negative(p->number)) {
neg = true;
negate(p);
rscale = bmachine.scale;
} else {
/* Posix bc says min(a.scale * b, max(a.scale, scale) */
u_long b;
u_int m;
b = BN_get_word(p->number);
m = max(a->scale, bmachine.scale);
rscale = a->scale * (u_int)b;
if (rscale > m || (a->scale > 0 && (b == ULONG_MAX ||
b > UINT_MAX)))
rscale = m;
}
if (BN_is_zero(p->number)) {
r = new_number();
bn_check(BN_one(r->number));
normalize(r, rscale);
} else {
u_int ascale, mscale;
ascale = a->scale;
while (!BN_is_bit_set(p->number, 0)) {
ascale *= 2;
bmul_number(a, a, a, ascale);
bn_check(BN_rshift1(p->number, p->number));
}
r = dup_number(a);
bn_check(BN_rshift1(p->number, p->number));
mscale = ascale;
while (!BN_is_zero(p->number)) {
ascale *= 2;
bmul_number(a, a, a, ascale);
if (BN_is_bit_set(p->number, 0)) {
mscale += ascale;
bmul_number(r, r, a, mscale);
}
bn_check(BN_rshift1(p->number, p->number));
}
if (neg) {
BN_CTX *ctx;
BIGNUM *one;
one = BN_new();
bn_checkp(one);
bn_check(BN_one(one));
ctx = BN_CTX_new();
bn_checkp(ctx);
scale_number(one, r->scale + rscale);
if (BN_is_zero(r->number))
warnx("divide by zero");
else
bn_check(BN_div(r->number, NULL, one,
r->number, ctx));
BN_free(one);
BN_CTX_free(ctx);
r->scale = rscale;
} else
normalize(r, rscale);
}
push_number(r);
free_number(a);
free_number(p);
}
static void
bexp(void)
{
struct number *a, *p;
struct number *r;
bool neg;
u_int scale;
p = pop_number();
if (p == NULL) {
return;
}
a = pop_number();
if (a == NULL) {
push_number(p);
return;
}
if (p->scale != 0)
warnx("Runtime warning: non-zero scale in exponent");
normalize(p, 0);
neg = false;
if (BN_cmp(p->number, &zero) < 0) {
neg = true;
negate(p);
scale = bmachine.scale;
} else {
/* Posix bc says min(a.scale * b, max(a.scale, scale) */
u_long b;
u_int m;
b = BN_get_word(p->number);
m = max(a->scale, bmachine.scale);
scale = a->scale * (u_int)b;
if (scale > m || (a->scale > 0 && (b == BN_MASK2 ||
b > UINT_MAX)))
scale = m;
}
if (BN_is_zero(p->number)) {
r = new_number();
bn_check(BN_one(r->number));
normalize(r, scale);
} else {
while (!BN_is_bit_set(p->number, 0)) {
bmul_number(a, a, a);
bn_check(BN_rshift1(p->number, p->number));
}
r = dup_number(a);
normalize(r, scale);
bn_check(BN_rshift1(p->number, p->number));
while (!BN_is_zero(p->number)) {
bmul_number(a, a, a);
if (BN_is_bit_set(p->number, 0))
bmul_number(r, r, a);
bn_check(BN_rshift1(p->number, p->number));
}
if (neg) {
BN_CTX *ctx;
BIGNUM *one;
one = BN_new();
bn_checkp(one);
bn_check(BN_one(one));
ctx = BN_CTX_new();
bn_checkp(ctx);
scale_number(one, r->scale + scale);
normalize(r, scale);
bn_check(BN_div(r->number, NULL, one, r->number, ctx));
BN_free(one);
BN_CTX_free(ctx);
} else
normalize(r, scale);
}
push_number(r);
free_number(a);
free_number(p);
}
