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feat: add BitVec.intMax_add_one

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Kim Morrison 2024-08-27 11:01:44 +10:00
parent 30fa18816c
commit 9ef996259b
1 changed files with 6 additions and 0 deletions
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6
src/Init/Data/BitVec/Lemmas.lean
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@ -1836,4 +1836,10 @@ theorem getLsb_intMax (w : Nat) : (intMax w).getLsb i = decide (i + 1 < w) := by
rw [← testBit_toNat, toNat_intMax, Nat.testBit_two_pow_sub_one, decide_eq_decide]
omega
@[simp] theorem intMax_add_one {w : Nat} : intMax w + 1#w = intMin w := by
simp only [toNat_eq, toNat_intMax, toNat_add, toNat_intMin, toNat_ofNat, Nat.add_mod_mod]
by_cases h : w = 0
· simp [h]
· rw [Nat.sub_add_cancel (Nat.two_pow_pos (w - 1)), Nat.two_pow_pred_mod_two_pow (by omega)]
end BitVec