Xor-mem-region
- Signature
(xor-mem-region n sum mem) → mem
- Arguments
- mem — Guard (memp mem).
Definitions and Theorems
Function: xor-mem-region
(defun xor-mem-region (n sum mem)
(declare (xargs :stobjs (mem)))
(declare (type (unsigned-byte 50) n)
(type (unsigned-byte 8) sum))
(declare (xargs :guard (memp mem)))
(let ((__function__ 'xor-mem-region))
(declare (ignorable __function__))
(if (mbe :logic (zp n) :exec (= n 0))
mem
(b* ((val (the (unsigned-byte 8)
(read-mem n mem)))
(xor-sum (logxor (the (unsigned-byte 8) val)
(the (unsigned-byte 8) sum))))
(xor-mem-region (the (unsigned-byte 50) (1- n))
(the (unsigned-byte 8) xor-sum)
mem)))))
