Merge pull request #2 from bdunahu/bdunahu

Finish parser, add .text and .data directives, variable names, label processing

1 files changed, 53 insertions, 11 deletions

diff --git a/src/util.lisp b/src/util.lisp
index 5edee4a..f3035fe 100644
--- a/src/util.lisp
+++ b/src/util.lisp
@@ -4,24 +4,66 @@
   "Returns t if FILE is extended with .asm, nil otherwise."
   (string= (pathname-type file) "asm"))
 
-;; TODO this won't work for negative numbers of odd sizes quite yet.
+
 (defun format-as-binary (num len)
   "Formats NUM as a binary number, and pads to LEN with zeros."
   (declare (type number        num))
   (declare (type (integer 0 *) len))
-  (format nil "~V,'0b" len num))
+  (let ((max-val (1- (expt 2 len))))
+    (format nil "~V,'0b" len (logand num max-val))))
+
+(defun insert-in-middle (list element)
+  (append (list (car list)) (list element) (cdr list)))
+
+(defun iota (n)
+  "Generates a number sequence from 0 to N."
+  (when (> n 0)
+    (do ((i 0 (1+ i))
+         (item 0 (1+ item))
+         (result nil (push item result)))
+        ((= i n) (nreverse result)))))
+
+(defun riffle (lst1 lst2)
+  "Given LST1 and LST2, returns a new list which is the an alternating sequence
+of the elements from both lists. Returns nil if the lists are not equal size."
+  (when (eq (length lst1) (length lst2))
+    (loop for l1 in lst1
+          for l2 in lst2
+          append (list l1 l2))))
+
+(defvar variable-table (make-hash-table :test #'equalp))
+(defvar label-table (make-hash-table :test #'equalp))
 
-(defparameter type-r
-  '(ADD SUB MUL QUOT REM SFTR SFTL AND OR NOT XOR ADDV SUBV MULV DIVV CMP CEV)
+(defun add-variable (name value)
+  (if (gethash name variable-table)
+      (error "~@<Variable declared twice: ~S.~@:>" name)
+      (setf (gethash name variable-table) value)))
+
+(defun add-label (name value)
+  (if (gethash name label-table)
+      (error "~@<Label declared twice: ~S.~@:>" name)
+      (setf (gethash name label-table) value)))
+
+(defun get-variable (name)
+  (alexandria:if-let ((value (gethash name variable-table)))
+    value
+    (progn (maphash #'(lambda (k v) (format t "~A => ~A~%" k v)) variable-table)
+	   (error "~@<Variable ~S not declared.~@:>" name))))
+
+(defun get-label (name)
+  (alexandria:if-let ((value (gethash name label-table)))
+    value
+    (error "~@<Label ~S not found.~@:>" name)))
+
+(defvar r-type
+  '("ADD" "SUB" "MUL" "QUOT" "REM" "SFTR" "SFTL" "AND" "OR"
+    "NOT" "XOR" "ADDV" "SUBV" "MULV" "DIVV" "CMP" "CEV")
   "R-type instructions.")
 
-(defparameter type-i
-  '(LOAD LOADV ADDI SUBI SFTRI SFTLI ANDI ORI XORI STORE STOREV)
+(defvar i-type
+  '("LOAD" "LOADV" "ADDI" "SUBI" "SFTRI" "SFTLI" "ANDI" "ORI" "XORI" "STORE" "STOREV")
   "I-type instructions.")
 
-(defparameter type-j
-  '(JMP JRL JAL BEQ BGT BUF BOF PUSH POP)
+(defvar j-type
+  '("JMP" "JRL" "JAL" "BEQ" "BGT" "BUF" "BOF" "PUSH" "POP")
   "J-type instructions.")
-
-(defparameter label-loc '()
-  "A symbol table mapping label names to line indices.")