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diff --git a/src/LegacyArithmetic/Double/Proofs/ShiftRightDoubleWordImmediate.v b/src/LegacyArithmetic/Double/Proofs/ShiftRightDoubleWordImmediate.v
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+++ b/src/LegacyArithmetic/Double/Proofs/ShiftRightDoubleWordImmediate.v
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+Require Import Coq.ZArith.ZArith.
+Require Import Crypto.LegacyArithmetic.Interface.
+Require Import Crypto.LegacyArithmetic.Double.Core.
+Require Import Crypto.LegacyArithmetic.Double.Proofs.Decode.
+Require Import Crypto.LegacyArithmetic.Double.Proofs.ShiftLeftRightTactic.
+Require Import Crypto.Util.ZUtil.
+(*Require Import Crypto.Util.Tactics.*)
+
+Local Open Scope Z_scope.
+
+Local Opaque tuple_decoder.
+Local Arguments Z.pow !_ !_.
+Local Arguments Z.mul !_ !_.
+
+Section shrd.
+  Context (n : Z) {W}
+          {ldi : load_immediate W}
+          {shrd : shift_right_doubleword_immediate W}
+          {decode : decoder n W}
+          {isdecode : is_decode decode}
+          {isldi : is_load_immediate ldi}
+          {isshrd : is_shift_right_doubleword_immediate shrd}.
+
+  Local Ltac zutil_arith ::= solve [ auto with nocore omega ].
+
+  Global Instance is_shift_right_doubleword_immediate_double : is_shift_right_doubleword_immediate (shrd_double n).
+  Proof using isdecode isshrd.
+    intros high low count Hcount; hnf in Hcount.
+    unfold shrd_double, shift_right_doubleword_immediate_double; simpl.
+    generalize (decode_range low).
+    generalize (decode_range high).
+    generalize (decode_range (fst low)).
+    generalize (decode_range (snd low)).
+    generalize (decode_range (fst high)).
+    generalize (decode_range (snd high)).
+    assert (forall x, 0 <= Z.pow2_mod x n < 2^n) by auto with zarith.
+    assert (forall n' x, 2^n <= 2^n' -> 0 <= x < 2^n -> 0 <= x < 2^n') by auto with zarith.
+    assert (forall n' x, n <= n' -> 0 <= x < 2^n -> 0 <= x < 2^n') by auto with zarith omega.
+    autorewrite with simpl_tuple_decoder; push_decode.
+    shift_left_right_t.
+  Qed.
+End shrd.