Add label processing, mnemonic and label lookup maps

1 files changed, 32 insertions, 0 deletions

diff --git a/src/util.lisp b/src/util.lisp
index 87e4df9..1ea6dfc 100644
--- a/src/util.lisp
+++ b/src/util.lisp
@@ -3,3 +3,35 @@
 (defun asm-extension? (file)
   "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))
+
+(defmacro generate-type-map (type opsize ops)
+  "Generates an alist where the key corresponds to an element in
+OPS, while the value is the index of that key (padded to OPSIZE)
+concatenated with TYPE."
+  `(let ((i 0))
+     (mapcar (lambda (x)
+               (incf i)
+               (cons x (concatenate 'string ,type
+                                    (format-as-binary i ,opsize))))
+             ,ops)))
+
+(defparameter label-loc '()
+  "A symbol table mapping label names to line indices.")
+
+(defparameter mnemonic-loc
+  `(,@(generate-type-map "00" 5
+                         '(ADD SUB MUL QUOT REM SFTR SFTL AND OR NOT
+                           XOR ADDV SUBV MULV DIVV CMP CEV))
+    ,@(generate-type-map "01" 4
+                         '(LOAD LOADV ADDI SUBI SFTRI SFTLI ANDI ORI
+                           XORI STORE STOREV))
+    ,@(generate-type-map "10" 4
+                         '(JMP JRL JAL BEQ BGT BUF BOF PUSH POP)))
+  "An alist mapping known mnemonics to their binary representation.")