fixes register assignments in p-code semantics

plugins/arm/semantics/arm-bits.lisp

@@ -26,9 +26,6 @@
         (set-flags r x y))
       (set$ rd r))))
 
-(defun logandnot (rd rn)
-  (logand rd (lnot rn)))
-
 (defmacro shift-with-carry (shift rd rn rm cnd)
   (when (condition-holds cnd)
     (let ((r (cast-signed (word-width) rn)))
@@ -61,4 +58,5 @@
 
 (defmacro setw (reg val)
   "(set Wx V) sets a Wx register clearing the upper 32 bits."
-  (set$ (alias-base-register reg) val))
+  (set$ (alias-base-register reg)
+        (cast-unsigned (word-width) val)))

plugins/ghidra/semantics/pcode.lisp

@@ -10,7 +10,10 @@
 (defmacro set# (typ dst src)
   (if (is-symbol typ)
     (store-word (cast-word dst) src)
-    (set$ dst src)))
+    (let ((typ (coerce (word-width dst) typ)))
+      (set$ dst (logor
+                 (logandnot dst (- (lshift 1 typ) 1))
+                 (cast-unsigned (word-width dst) src))))))
 
 (defmacro get# (typ src)
   (if (is-symbol typ) (load-word (cast-word src))

plugins/primus_lisp/semantics/bits.lisp

@@ -1,5 +1,9 @@
 (in-package core)
 
+(defun logandnot (rd rn)
+  "(logandnot X Y) is X & ~Y, i.e., X and complement of Y"
+  (logand rd (lnot rn)))
+
 (defun msb (x)
   "(msb X) is the most significant bit of X."
   (select (- (word-width x) 1) x))