Add Db, Dw.

Author: dvanhorn

langs/a86/ast.rkt

@@ -250,6 +250,8 @@
 (instruct Const  (x)       check:label-symbol)
 
 ;; IMPROVE: do more checking
+(instruct Db (x) (lambda (a x n) (values a x)))
+(instruct Dw (x) (lambda (a x n) (values a x)))
 (instruct Dd (x) (lambda (a x n) (values a x)))
 (instruct Dq (x) (lambda (a x n) (values a x)))
 

langs/a86/printer.rkt

@@ -234,6 +234,10 @@
                       " equ "
                       (number->string c))]
 
+      [(Db x)
+       (string-append tab "db " (arg->string x))]
+      [(Dw x)
+       (string-append tab "dw " (arg->string x))]
       [(Dd x)
        (string-append tab "dd " (arg->string x))]
       [(Dq x)

www/notes/a86.scrbl

@@ -1584,6 +1584,14 @@ Perform bitwise not operation (each 1 is set to 0, and each 0 is set to 1) on th
  ]
 }
 
+@defstruct*[Db ([d integer?])]{
+ Psuedo-instruction for declaring 8-bits of initialized static memory.
+}
+
+@defstruct*[Dw ([d integer?])]{
+ Psuedo-instruction for declaring 16-bits of initialized static memory.
+}
+
 @defstruct*[Dd ([d integer?])]{
  Psuedo-instruction for declaring 32-bits of initialized static memory.
 }