Theorems about sbyte32 and IHS functions.
Theorem:
(defthm sbyte32p-of-logext-of-32 (sbyte32p (logext 32 x)))
Theorem:
(defthm logext-of-32-when-sbyte32p (implies (sbyte32p x) (equal (logext 32 x) x)))
Theorem:
(defthm logtail-of-32-when-sbyte32p (implies (sbyte32p x) (equal (logtail 32 x) (if (< x 0) -1 0))))