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/***********************************************************************/
/* */
/* Objective Caml */
/* */
/* Xavier Leroy, projet Cristal, INRIA Rocquencourt */
/* */
/* Copyright 2002 Institut National de Recherche en Informatique et */
/* en Automatique. All rights reserved. This file is distributed */
/* under the terms of the GNU Library General Public License, with */
/* the special exception on linking described in file ../LICENSE. */
/* */
/***********************************************************************/
/* $Id$ */
/* Software emulation of 64-bit integer arithmetic, for C compilers
that do not support it. */
#ifndef CAML_INT64_EMUL_H
#define CAML_INT64_EMUL_H
#include <math.h>
#ifdef ARCH_BIG_ENDIAN
#define I64_literal(hi,lo) { hi, lo }
#else
#define I64_literal(hi,lo) { lo, hi }
#endif
/* Unsigned comparison */
static int I64_ucompare(uint64 x, uint64 y)
{
if (x.h > y.h) return 1;
if (x.h < y.h) return -1;
if (x.l > y.l) return 1;
if (x.l < y.l) return -1;
return 0;
}
#define I64_ult(x, y) (I64_ucompare(x, y) < 0)
/* Signed comparison */
static int I64_compare(int64 x, int64 y)
{
if ((int32)x.h > (int32)y.h) return 1;
if ((int32)x.h < (int32)y.h) return -1;
if (x.l > y.l) return 1;
if (x.l < y.l) return -1;
return 0;
}
/* Negation */
static int64 I64_neg(int64 x)
{
int64 res;
res.l = -x.l;
res.h = ~x.h;
if (res.l == 0) res.h++;
return res;
}
/* Addition */
static int64 I64_add(int64 x, int64 y)
{
int64 res;
res.l = x.l + y.l;
res.h = x.h + y.h;
if (res.l < x.l) res.h++;
return res;
}
/* Subtraction */
static int64 I64_sub(int64 x, int64 y)
{
int64 res;
res.l = x.l - y.l;
res.h = x.h - y.h;
if (x.l < y.l) res.h--;
return res;
}
/* Multiplication */
static int64 I64_mul(int64 x, int64 y)
{
int64 res;
uint32 prod00 = (x.l & 0xFFFF) * (y.l & 0xFFFF);
uint32 prod10 = (x.l >> 16) * (y.l & 0xFFFF);
uint32 prod01 = (x.l & 0xFFFF) * (y.l >> 16);
uint32 prod11 = (x.l >> 16) * (y.l >> 16);
res.l = prod00;
res.h = prod11 + (prod01 >> 16) + (prod10 >> 16);
prod01 = prod01 << 16; res.l += prod01; if (res.l < prod01) res.h++;
prod10 = prod10 << 16; res.l += prod10; if (res.l < prod10) res.h++;
res.h += x.l * y.h + x.h * y.l;
return res;
}
#define I64_is_zero(x) (((x).l | (x).h) == 0)
#define I64_is_negative(x) ((int32) (x).h < 0)
/* Bitwise operations */
static int64 I64_and(int64 x, int64 y)
{
int64 res;
res.l = x.l & y.l;
res.h = x.h & y.h;
return res;
}
static int64 I64_or(int64 x, int64 y)
{
int64 res;
res.l = x.l | y.l;
res.h = x.h | y.h;
return res;
}
static int64 I64_xor(int64 x, int64 y)
{
int64 res;
res.l = x.l ^ y.l;
res.h = x.h ^ y.h;
return res;
}
/* Shifts */
static int64 I64_lsl(int64 x, int s)
{
int64 res;
s = s & 63;
if (s == 0) return x;
if (s < 32) {
res.l = x.l << s;
res.h = (x.h << s) | (x.l >> (32 - s));
} else {
res.l = 0;
res.h = x.l << (s - 32);
}
return res;
}
static int64 I64_lsr(int64 x, int s)
{
int64 res;
s = s & 63;
if (s == 0) return x;
if (s < 32) {
res.l = (x.l >> s) | (x.h << (32 - s));
res.h = x.h >> s;
} else {
res.l = x.h >> (s - 32);
res.h = 0;
}
return res;
}
static int64 I64_asr(int64 x, int s)
{
int64 res;
s = s & 63;
if (s == 0) return x;
if (s < 32) {
res.l = (x.l >> s) | (x.h << (32 - s));
res.h = (int32) x.h >> s;
} else {
res.l = (int32) x.h >> (s - 32);
res.h = (int32) x.h >> 31;
}
return res;
}
/* Division and modulus */
#define I64_SHL1(x) x.h = (x.h << 1) | (x.l >> 31); x.l <<= 1
#define I64_SHR1(x) x.l = (x.l >> 1) | (x.h << 31); x.h >>= 1
static void I64_udivmod(uint64 modulus, uint64 divisor,
uint64 * quo, uint64 * mod)
{
int64 quotient, mask;
int cmp;
quotient.h = 0; quotient.l = 0;
mask.h = 0; mask.l = 1;
while ((int32) divisor.h >= 0) {
cmp = I64_ucompare(divisor, modulus);
I64_SHL1(divisor);
I64_SHL1(mask);
if (cmp >= 0) break;
}
while (mask.l | mask.h) {
if (I64_ucompare(modulus, divisor) >= 0) {
quotient.h |= mask.h; quotient.l |= mask.l;
modulus = I64_sub(modulus, divisor);
}
I64_SHR1(mask);
I64_SHR1(divisor);
}
*quo = quotient;
*mod = modulus;
}
static int64 I64_div(int64 x, int64 y)
{
int64 q, r;
int32 sign;
sign = x.h ^ y.h;
if ((int32) x.h < 0) x = I64_neg(x);
if ((int32) y.h < 0) y = I64_neg(y);
I64_udivmod(x, y, &q, &r);
if (sign < 0) q = I64_neg(q);
return q;
}
static int64 I64_mod(int64 x, int64 y)
{
int64 q, r;
int32 sign;
sign = x.h;
if ((int32) x.h < 0) x = I64_neg(x);
if ((int32) y.h < 0) y = I64_neg(y);
I64_udivmod(x, y, &q, &r);
if (sign < 0) r = I64_neg(r);
return r;
}
/* Coercions */
static int64 I64_of_int32(int32 x)
{
int64 res;
res.l = x;
res.h = x >> 31;
return res;
}
#define I64_to_int32(x) ((int32) (x).l)
/* Note: we assume sizeof(intnat) = 4 here, which is true otherwise
autoconfiguration would have selected native 64-bit integers */
#define I64_of_intnat I64_of_int32
#define I64_to_intnat I64_to_int32
static double I64_to_double(int64 x)
{
double res;
int32 sign = x.h;
if (sign < 0) x = I64_neg(x);
res = ldexp((double) x.h, 32) + x.l;
if (sign < 0) res = -res;
return res;
}
static int64 I64_of_double(double f)
{
int64 res;
double frac, integ;
int neg;
neg = (f < 0);
f = fabs(f);
frac = modf(ldexp(f, -32), &integ);
res.h = (uint32) integ;
res.l = (uint32) ldexp(frac, 32);
if (neg) res = I64_neg(res);
return res;
}
#endif /* CAML_INT64_EMUL_H */
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