[build] Select uint63 using `ocamlc -config` variables.

This seems more robust and avoids having another implementation of
`cp`.

1 files changed, 220 insertions, 0 deletions

diff --git a/kernel/uint63_i386_31.ml b/kernel/uint63_i386_31.ml
new file mode 100644
index 0000000000..fa45c90241
--- /dev/null
+++ b/kernel/uint63_i386_31.ml
@@ -0,0 +1,220 @@
+(************************************************************************)
+(*         *   The Coq Proof Assistant / The Coq Development Team       *)
+(*  v      *   INRIA, CNRS and contributors - Copyright 1999-2018       *)
+(* <O___,, *       (see CREDITS file for the list of authors)           *)
+(*   \VV/  **************************************************************)
+(*    //   *    This file is distributed under the terms of the         *)
+(*         *     GNU Lesser General Public License Version 2.1          *)
+(*         *     (see LICENSE file for the text of the license)         *)
+(************************************************************************)
+
+(* Invariant: the msb should be 0 *)
+type t = Int64.t
+
+let _ = assert (Sys.word_size = 32)
+
+let uint_size = 63
+
+let maxuint63 = Int64.of_string "0x7FFFFFFFFFFFFFFF"
+let maxuint31 = Int64.of_string "0x7FFFFFFF"
+
+let zero = Int64.zero
+let one = Int64.one
+
+    (* conversion from an int *)
+let mask63 i = Int64.logand i maxuint63
+let of_int i = Int64.of_int i
+let to_int2 i = (Int64.to_int (Int64.shift_right_logical i 31), Int64.to_int i)
+let of_int64 i = i
+let hash i =
+  let (h,l) = to_int2 i in
+  (*Hashset.combine h l*)
+  h * 65599 + l
+
+    (* conversion of an uint63 to a string *)
+let to_string i = Int64.to_string i
+
+let of_string s =
+  let i64 = Int64.of_string s in
+  if Int64.compare Int64.zero i64 <= 0
+      && Int64.compare i64 maxuint63 <= 0
+  then i64
+  else raise (Failure "Int63.of_string")
+
+(* Compiles an unsigned int to OCaml code *)
+let compile i = Printf.sprintf "Uint63.of_int64 (%LiL)" i
+
+    (* comparison *)
+let lt x y =
+  Int64.compare x y < 0
+
+let le x y =
+  Int64.compare x y <= 0
+
+    (* logical shift *)
+let l_sl x y =
+  if le 0L y && lt y 63L then mask63 (Int64.shift_left x (Int64.to_int y)) else 0L
+
+let l_sr x y =
+  if le 0L y && lt y 63L then Int64.shift_right x (Int64.to_int y) else 0L
+
+let l_and x y = Int64.logand x y
+let l_or x y = Int64.logor x y
+let l_xor x y = Int64.logxor x y
+
+    (* addition of int63 *)
+let add x y = mask63 (Int64.add x y)
+
+let addcarry x y = add (add x y) Int64.one
+
+    (* subtraction *)
+let sub x y = mask63 (Int64.sub x y)
+
+let subcarry x y = sub (sub x y) Int64.one
+
+    (* multiplication *)
+let mul x y = mask63 (Int64.mul x y)
+
+    (* division *)
+let div x y =
+  if y = 0L then 0L else Int64.div x y
+
+    (* modulo *)
+let rem x y =
+  if y = 0L then 0L else Int64.rem x y
+
+let addmuldiv p x y =
+  l_or (l_sl x p) (l_sr y Int64.(sub (of_int uint_size) p))
+
+(* A few helper functions on 128 bits *)
+let lt128 xh xl yh yl =
+  lt xh yh || (xh = yh && lt xl yl)
+
+let le128 xh xl yh yl =
+  lt xh yh || (xh = yh && le xl yl)
+
+    (* division of two numbers by one *)
+(* precondition: y <> 0 *)
+(* outputs: q % 2^63, r s.t. x = q * y + r, r < y *)
+let div21 xh xl y =
+  let maskh = ref zero in
+  let maskl = ref one in
+  let dh = ref zero in
+  let dl = ref y in
+  let cmp = ref true in
+  (* n = ref 0 *)
+  (* loop invariant: mask = 2^n, d = mask * y, (2 * d <= x -> cmp), n >= 0 *)
+  while Int64.equal (l_sr !dh (of_int (uint_size - 1))) zero && !cmp do
+    (* We don't use addmuldiv below to avoid checks on 1 *)
+    dh := l_or (l_sl !dh one) (l_sr !dl (of_int (uint_size - 1)));
+    dl := l_sl !dl one;
+    maskh := l_or (l_sl !maskh one) (l_sr !maskl (of_int (uint_size - 1)));
+    maskl := l_sl !maskl one;
+    (* incr n *)
+    cmp := lt128 !dh !dl xh xl;
+  done; (* mask = 2^n, d = 2^n * d, 2 * d > x *)
+  let remh = ref xh in
+  let reml = ref xl in
+  (* quotienth = ref 0 *)
+  let quotientl = ref zero in
+  (* loop invariant: x = quotient * y + rem, y * 2^(n+1) > r,
+     mask = floor(2^n), d = mask * y, n >= -1 *)
+  while not (Int64.equal (l_or !maskh !maskl) zero) do
+    if le128 !dh !dl !remh !reml then begin (* if rem >= d, add one bit and subtract d *)
+      (* quotienth := !quotienth lor !maskh *)
+      quotientl := l_or !quotientl !maskl;
+      remh := if lt !reml !dl then sub (sub !remh !dh) one else sub !remh !dh;
+      reml := sub !reml !dl
+    end;
+    maskl := l_or (l_sr !maskl one) (l_sl !maskh (of_int (uint_size - 1)));
+    maskh := l_sr !maskh one;
+    dl := l_or (l_sr !dl one) (l_sl !dh (of_int (uint_size - 1)));
+    dh := l_sr !dh one
+    (* decr n *)
+  done;
+  !quotientl, !reml
+
+let div21 xh xl y = if Int64.equal y zero then zero, zero else div21 xh xl y
+
+     (* exact multiplication *)
+let mulc x y =
+  let lx = ref (Int64.logand x maxuint31) in
+  let ly = ref (Int64.logand y maxuint31) in
+  let hx = Int64.shift_right x 31 in
+  let hy = Int64.shift_right y 31 in
+  let hr = ref (Int64.mul hx hy) in
+  let lr = ref (Int64.logor (Int64.mul !lx !ly) (Int64.shift_left !hr 62)) in
+  hr := (Int64.shift_right_logical !hr 1);
+  lx := Int64.mul !lx hy;
+  ly := Int64.mul hx !ly;
+  hr := Int64.logor !hr (Int64.add (Int64.shift_right !lx 32) (Int64.shift_right !ly 32));
+  lr := Int64.add !lr (Int64.shift_left !lx 31);
+  hr := Int64.add !hr (Int64.shift_right_logical !lr 63);
+  lr := Int64.add (Int64.shift_left !ly 31) (mask63 !lr);
+  hr := Int64.add !hr (Int64.shift_right_logical !lr 63);
+  if Int64.logand !lr Int64.min_int <> 0L
+  then Int64.(sub !hr one, mask63 !lr)
+  else (!hr, !lr)
+
+let equal x y = mask63 x = mask63 y
+
+let compare x y = Int64.compare x y
+
+(* Number of leading zeroes *)
+let head0 x =
+  let r = ref 0 in
+  let x = ref x in
+  if Int64.logand !x 0x7FFFFFFF00000000L = 0L then r := !r + 31
+  else x := Int64.shift_right !x 31;
+  if Int64.logand !x 0xFFFF0000L = 0L then (x := Int64.shift_left !x 16; r := !r + 16);
+  if Int64.logand !x 0xFF000000L = 0L then (x := Int64.shift_left !x 8; r := !r + 8);
+  if Int64.logand !x 0xF0000000L = 0L then (x := Int64.shift_left !x 4; r := !r + 4);
+  if Int64.logand !x 0xC0000000L = 0L then (x := Int64.shift_left !x 2; r := !r + 2);
+  if Int64.logand !x 0x80000000L = 0L then (x := Int64.shift_left !x 1; r := !r + 1);
+  if Int64.logand !x 0x80000000L = 0L then (r := !r + 1);
+  Int64.of_int !r
+
+(* Number of trailing zeroes *)
+let tail0 x =
+  let r = ref 0 in
+  let x = ref x in
+  if Int64.logand !x 0xFFFFFFFFL = 0L then (x := Int64.shift_right !x 32; r := !r + 32);
+  if Int64.logand !x 0xFFFFL = 0L then (x := Int64.shift_right !x 16; r := !r + 16);
+  if Int64.logand !x 0xFFL = 0L then (x := Int64.shift_right !x 8; r := !r + 8);
+  if Int64.logand !x 0xFL = 0L then (x := Int64.shift_right !x 4; r := !r + 4);
+  if Int64.logand !x 0x3L = 0L then (x := Int64.shift_right !x 2; r := !r + 2);
+  if Int64.logand !x 0x1L = 0L then (r := !r + 1);
+  Int64.of_int !r
+
+(* May an object be safely cast into an Uint63.t ? *)
+let is_uint63 t =
+  Obj.is_block t && Int.equal (Obj.tag t) Obj.custom_tag
+  && le (Obj.magic t) maxuint63
+
+(* Register all exported functions so that they can be called from C code *)
+
+let () =
+  Callback.register "uint63 add" add;
+  Callback.register "uint63 addcarry" addcarry;
+  Callback.register "uint63 addmuldiv" addmuldiv;
+  Callback.register "uint63 div" div;
+  Callback.register "uint63 div21_ml" div21;
+  Callback.register "uint63 eq" equal;
+  Callback.register "uint63 eq0" (equal Int64.zero);
+  Callback.register "uint63 head0" head0;
+  Callback.register "uint63 land" l_and;
+  Callback.register "uint63 leq" le;
+  Callback.register "uint63 lor" l_or;
+  Callback.register "uint63 lsl" l_sl;
+  Callback.register "uint63 lsl1" (fun x -> l_sl x Int64.one);
+  Callback.register "uint63 lsr" l_sr;
+  Callback.register "uint63 lsr1" (fun x -> l_sr x Int64.one);
+  Callback.register "uint63 lt" lt;
+  Callback.register "uint63 lxor" l_xor;
+  Callback.register "uint63 mod" rem;
+  Callback.register "uint63 mul" mul;
+  Callback.register "uint63 mulc_ml" mulc;
+  Callback.register "uint63 one" one;
+  Callback.register "uint63 sub" sub;
+  Callback.register "uint63 subcarry" subcarry;
+  Callback.register "uint63 tail0" tail0