Add not instruction.

Author: dvanhorn

langs/a86/ast.rkt

@@ -149,6 +149,7 @@
 (instruct Push   (a1)      check:push)
 (instruct Pop    (a1)      check:register)
 (instruct Lea    (dst x)   check:lea)
+(instruct Not    (x)       check:register)
 (instruct Div    (den)     check:register)
 
 (instruct Offset (r i)     check:offset)
@@ -217,6 +218,7 @@
       (Push? x)
       (Pop? x)
       (Lea? x)
+      (Not? x)
       (Div? x)
       (Comment? x)
       (Equ? x)

langs/a86/printer.rkt

@@ -170,6 +170,9 @@
        (string-append tab "lea "
                       (arg->string d) ", [rel "
                       (exp->string x) "]")]
+      [(Not r)
+       (string-append tab "not "
+                      (reg->string r))]
       [(Div r)
        (string-append tab "div "
                       (arg->string r))]

www/notes/a86.scrbl

@@ -1216,6 +1216,20 @@ Each register plays the same role as in x86, so for example
  ]
 }
 
+@defstruct*[Not ([a1 register?])]{
+Perform bitwise not operation (each 1 is set to 0, and each 0 is set to 1) on the destination operand.
+
+ @ex[
+ (asm-interp
+  (prog
+   (Global 'entry)
+   (Label 'entry)
+   (Mov 'rax 0)
+   (Not 'rax)
+   (Ret)))
+ ]
+}
+
 @defstruct*[Lea ([dst (or/c register? offset?)] [x label?])]{
  Loads the address of the given label into @racket[dst].