Implement 5.38a

ex-5_31-xx.scm

@@ -391,11 +391,6 @@ ev-appl-did-operator-no-restore
 
 (display "\nex-5.38 - optimize-procedure-application\n")
 
-; The expression (+ a 1) might be compiled into something as simple as:
-
-; (assign val (op lookup-variable-value) (const a) (reg env))
-; (assign val (op +) (reg val) (const 1))
-
 ; a.  The open-coded primitives, unlike the special forms, all need their
 ; operands evaluated. Write a code generator spread-arguments for use by all
 ; the open-coding code generators. Spread-arguments should take an operand list
@@ -403,12 +398,35 @@ ev-appl-did-operator-no-restore
 ; Note that an operand may contain a call to an open-coded primitive, so
 ; argument registers will have to be preserved during operand evaluation.
 
-(define (spread-arguments operand-codes)
-  (assert (length operand-codes) 2)
-  (make-instruction-sequence
-    '()
-    '()
-    '((assign ))))
+(define (spread-arguments operand-list)
+  (define (compile-operands operand-list operand-number)
+    (cond
+      ((null? operand-list) (empty-instruction-sequence))
+      ((and (= operand-number 1))
+       (preserving
+         '(arg1)
+         (compile (car operand-list) 'arg1 'next)
+         (compile-operands (cdr operand-list) (+ operand-number 1))))
+      ((and (= operand-number 2))
+       (preserving
+         '(arg1 arg2)
+         (compile (car operand-list) 'arg2 'next)
+         (compile-operands (cdr operand-list) (+ operand-number 1))))
+      (else
+       (error "Only two arg registers supported -- SPREAD-ARGUMENTS"))))
+
+  (let ((operand-codes (compile-operands operand-list 1)))
+    operand-codes))
+
+(define (display-lines xs)
+  (define (display-line x)
+    (display x) (newline))
+  (map display-line xs))
+
+(display-lines (third (spread-arguments '(1 1))))
+(newline)
+
+(display "b. CONTINUE HERE\n")
 
 ; b.  For each of the primitive procedures =, *, -, and +, write a code
 ; generator that takes a combination with that operator, together with a target