288 lines
6.4 KiB
C
288 lines
6.4 KiB
C
/***********************************************************************/
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/* */
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/* OCaml */
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/* */
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/* Xavier Leroy, projet Cristal, INRIA Rocquencourt */
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/* */
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/* Copyright 2002 Institut National de Recherche en Informatique et */
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/* en Automatique. All rights reserved. This file is distributed */
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/* under the terms of the GNU Library General Public License, with */
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/* the special exception on linking described in file ../LICENSE. */
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/* */
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/***********************************************************************/
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/* Software emulation of 64-bit integer arithmetic, for C compilers
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that do not support it. */
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#ifndef CAML_INT64_EMUL_H
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#define CAML_INT64_EMUL_H
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#include <math.h>
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#ifdef ARCH_BIG_ENDIAN
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#define I64_literal(hi,lo) { hi, lo }
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#else
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#define I64_literal(hi,lo) { lo, hi }
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#endif
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#define I64_split(x,hi,lo) (hi = (x).h, lo = (x).l)
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/* Unsigned comparison */
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static int I64_ucompare(uint64 x, uint64 y)
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{
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if (x.h > y.h) return 1;
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if (x.h < y.h) return -1;
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if (x.l > y.l) return 1;
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if (x.l < y.l) return -1;
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return 0;
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}
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#define I64_ult(x, y) (I64_ucompare(x, y) < 0)
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/* Signed comparison */
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static int I64_compare(int64 x, int64 y)
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{
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if ((int32)x.h > (int32)y.h) return 1;
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if ((int32)x.h < (int32)y.h) return -1;
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if (x.l > y.l) return 1;
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if (x.l < y.l) return -1;
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return 0;
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}
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/* Negation */
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static int64 I64_neg(int64 x)
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{
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int64 res;
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res.l = -x.l;
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res.h = ~x.h;
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if (res.l == 0) res.h++;
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return res;
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}
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/* Addition */
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static int64 I64_add(int64 x, int64 y)
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{
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int64 res;
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res.l = x.l + y.l;
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res.h = x.h + y.h;
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if (res.l < x.l) res.h++;
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return res;
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}
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/* Subtraction */
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static int64 I64_sub(int64 x, int64 y)
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{
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int64 res;
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res.l = x.l - y.l;
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res.h = x.h - y.h;
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if (x.l < y.l) res.h--;
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return res;
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}
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/* Multiplication */
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static int64 I64_mul(int64 x, int64 y)
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{
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int64 res;
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uint32 prod00 = (x.l & 0xFFFF) * (y.l & 0xFFFF);
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uint32 prod10 = (x.l >> 16) * (y.l & 0xFFFF);
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uint32 prod01 = (x.l & 0xFFFF) * (y.l >> 16);
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uint32 prod11 = (x.l >> 16) * (y.l >> 16);
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res.l = prod00;
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res.h = prod11 + (prod01 >> 16) + (prod10 >> 16);
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prod01 = prod01 << 16; res.l += prod01; if (res.l < prod01) res.h++;
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prod10 = prod10 << 16; res.l += prod10; if (res.l < prod10) res.h++;
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res.h += x.l * y.h + x.h * y.l;
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return res;
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}
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#define I64_is_zero(x) (((x).l | (x).h) == 0)
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#define I64_is_negative(x) ((int32) (x).h < 0)
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#define I64_is_min_int(x) ((x).l == 0 && (x).h == 0x80000000U)
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#define I64_is_minus_one(x) (((x).l & (x).h) == 0xFFFFFFFFU)
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/* Bitwise operations */
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static int64 I64_and(int64 x, int64 y)
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{
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int64 res;
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res.l = x.l & y.l;
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res.h = x.h & y.h;
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return res;
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}
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static int64 I64_or(int64 x, int64 y)
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{
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int64 res;
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res.l = x.l | y.l;
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res.h = x.h | y.h;
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return res;
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}
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static int64 I64_xor(int64 x, int64 y)
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{
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int64 res;
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res.l = x.l ^ y.l;
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res.h = x.h ^ y.h;
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return res;
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}
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/* Shifts */
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static int64 I64_lsl(int64 x, int s)
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{
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int64 res;
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s = s & 63;
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if (s == 0) return x;
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if (s < 32) {
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res.l = x.l << s;
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res.h = (x.h << s) | (x.l >> (32 - s));
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} else {
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res.l = 0;
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res.h = x.l << (s - 32);
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}
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return res;
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}
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static int64 I64_lsr(int64 x, int s)
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{
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int64 res;
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s = s & 63;
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if (s == 0) return x;
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if (s < 32) {
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res.l = (x.l >> s) | (x.h << (32 - s));
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res.h = x.h >> s;
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} else {
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res.l = x.h >> (s - 32);
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res.h = 0;
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}
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return res;
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}
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static int64 I64_asr(int64 x, int s)
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{
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int64 res;
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s = s & 63;
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if (s == 0) return x;
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if (s < 32) {
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res.l = (x.l >> s) | (x.h << (32 - s));
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res.h = (int32) x.h >> s;
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} else {
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res.l = (int32) x.h >> (s - 32);
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res.h = (int32) x.h >> 31;
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}
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return res;
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}
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/* Division and modulus */
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#define I64_SHL1(x) x.h = (x.h << 1) | (x.l >> 31); x.l <<= 1
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#define I64_SHR1(x) x.l = (x.l >> 1) | (x.h << 31); x.h >>= 1
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static void I64_udivmod(uint64 modulus, uint64 divisor,
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uint64 * quo, uint64 * mod)
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{
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int64 quotient, mask;
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int cmp;
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quotient.h = 0; quotient.l = 0;
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mask.h = 0; mask.l = 1;
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while ((int32) divisor.h >= 0) {
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cmp = I64_ucompare(divisor, modulus);
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I64_SHL1(divisor);
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I64_SHL1(mask);
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if (cmp >= 0) break;
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}
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while (mask.l | mask.h) {
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if (I64_ucompare(modulus, divisor) >= 0) {
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quotient.h |= mask.h; quotient.l |= mask.l;
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modulus = I64_sub(modulus, divisor);
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}
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I64_SHR1(mask);
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I64_SHR1(divisor);
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}
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*quo = quotient;
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*mod = modulus;
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}
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static int64 I64_div(int64 x, int64 y)
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{
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int64 q, r;
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int32 sign;
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sign = x.h ^ y.h;
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if ((int32) x.h < 0) x = I64_neg(x);
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if ((int32) y.h < 0) y = I64_neg(y);
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I64_udivmod(x, y, &q, &r);
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if (sign < 0) q = I64_neg(q);
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return q;
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}
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static int64 I64_mod(int64 x, int64 y)
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{
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int64 q, r;
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int32 sign;
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sign = x.h;
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if ((int32) x.h < 0) x = I64_neg(x);
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if ((int32) y.h < 0) y = I64_neg(y);
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I64_udivmod(x, y, &q, &r);
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if (sign < 0) r = I64_neg(r);
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return r;
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}
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/* Coercions */
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static int64 I64_of_int32(int32 x)
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{
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int64 res;
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res.l = x;
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res.h = x >> 31;
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return res;
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}
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#define I64_to_int32(x) ((int32) (x).l)
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/* Note: we assume sizeof(intnat) = 4 here, which is true otherwise
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autoconfiguration would have selected native 64-bit integers */
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#define I64_of_intnat I64_of_int32
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#define I64_to_intnat I64_to_int32
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static double I64_to_double(int64 x)
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{
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double res;
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int32 sign = x.h;
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if (sign < 0) x = I64_neg(x);
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res = ldexp((double) x.h, 32) + x.l;
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if (sign < 0) res = -res;
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return res;
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}
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static int64 I64_of_double(double f)
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{
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int64 res;
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double frac, integ;
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int neg;
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neg = (f < 0);
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f = fabs(f);
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frac = modf(ldexp(f, -32), &integ);
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res.h = (uint32) integ;
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res.l = (uint32) ldexp(frac, 32);
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if (neg) res = I64_neg(res);
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return res;
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}
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static int64 I64_bswap(int64 x)
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{
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int64 res;
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res.h = (((x.l & 0x000000FF) << 24) |
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((x.l & 0x0000FF00) << 8) |
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((x.l & 0x00FF0000) >> 8) |
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((x.l & 0xFF000000) >> 24));
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res.l = (((x.h & 0x000000FF) << 24) |
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((x.h & 0x0000FF00) << 8) |
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((x.h & 0x00FF0000) >> 8) |
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((x.h & 0xFF000000) >> 24));
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return res;
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}
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#endif /* CAML_INT64_EMUL_H */
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