Index: /trunk/ccl/lib/ffi-darwinppc32.lisp
===================================================================
--- /trunk/ccl/lib/ffi-darwinppc32.lisp	(revision 5745)
+++ /trunk/ccl/lib/ffi-darwinppc32.lisp	(revision 5746)
@@ -15,2 +15,103 @@
 ;;;   http://opensource.franz.com/preamble.html
 
+(in-package "CCL")
+
+;;; If a record type has a single scalar field, return the type
+;;; of that field.
+(defun darwin32::record-type-has-single-scalar-field (record-type)
+  (when (typep record-type 'foreign-structure-type)
+    (ensure-foreign-type-bits record-type)
+    (let* ((fields (foreign-record-type-fields record-type)))
+      (when (null (cdr fields))
+        (let* ((f0 (car fields))
+               (type (foreign-record-field-type f0)))
+          (typecase type
+            ((or foreign-record-type foreign-array-type) nil)
+            (otherwise type)))))))
+
+;;; If type denotes a foreign record type, return T if it would
+;;; be "returned" by passing it as the first argument to the callee.
+;;; On DarwinPPC32, this is true of all record types except for
+;;; those for which RECORD-TYPE-HAS-SINGLE-SCALAR-FIELD returns
+;;; true.
+(defun darwin32::record-type-returns-structure-as-first-arg (rtype)
+  (when (and rtype
+             (not (typep rtype 'unsigned-byte))
+             (not (member rtype *foreign-representation-type-keywords*
+                          :test #'eq)))
+    (let* ((ftype (if (typep rtype 'foreign-type)
+                    rtype
+                    (parse-foreign-type rtype))))
+      (and (typep ftype 'foreign-record-type)
+           (not (darwin32::record-type-has-single-scalar-field ftype))))))
+
+
+;;; Structures that contain a single scalar field are "returned"
+;;; as a value with that field's type.
+;;; Other structures are "returned" by passing a pointer to a structure
+;;; of the appropriate type as the first argument.
+;;; Structures that contain a single scalar field are passed by value
+;;; by passing the value of that field as a scalar.
+;;; Structures that contain more than one field are passed by value
+;;; as a sequence of N 32-bit words; %ff-call understands an unsigned
+;;; integer argument "type" specifier to denote this.
+
+(defun darwin32::expand-ff-call (callform args)
+  (let* ((result-type-spec (or (car (last args)) :void))
+         (enclosing-form nil))
+    (multiple-value-bind (result-type error)
+        (parse-foreign-type result-type-spec)
+      (if error
+        (setq result-type-spec :void result-type *void-foreign-type*)
+        (setq args (butlast args)))
+      (collect ((argforms))
+        (when (eq (car args) :monitor-exception-ports)
+          (argforms (pop args)))
+        (when (typep result-type 'foreign-record-type)
+          (let* ((single-scalar (darwin32::record-type-has-single-scalar-field result-type))
+                 (result-form (pop args)))
+            (if single-scalar
+              (progn
+                (setq enclosing-form `(setf ,(%foreign-access-form result-form single-scalar 0 nil))
+                      result-type single-scalar
+                      result-type-spec (foreign-type-to-representation-type result-type)))
+                      
+              (progn
+                (argforms :address)
+                (argforms result-form)
+                (setq result-type *void-foreign-type*
+                      result-type-spec :void)))))
+        (unless (evenp (length args))
+          (error "~s should be an even-length list of alternating foreign types and values" args))
+        (do* ((args args (cddr args)))
+             ((null args))
+          (let* ((arg-type-spec (car args))
+                 (arg-value-form (cadr args)))
+            (if (or (member arg-type-spec *foreign-representation-type-keywords*
+                           :test #'eq)
+                    (typep arg-type-spec 'unsigned-byte))
+              (progn
+                (argforms arg-type-spec)
+                (argforms arg-value-form))
+              (let* ((ftype (parse-foreign-type arg-type-spec)))
+                (if (typep ftype 'foreign-record-type)
+                  (let* ((single-scalar (darwin32::record-type-has-single-scalar-field ftype)))
+                    (if single-scalar
+                      (progn
+                        (argforms (foreign-type-to-representation-type single-scalar))
+                        (argforms (%foreign-access-form arg-value-form single-scalar 0 nil)))
+                      (let* ((bits (ensure-foreign-type-bits ftype)))
+                        (argforms (ceiling bits 32))
+                        (argforms arg-value-form))))
+                  (progn
+                    (argforms (foreign-type-to-representation-type ftype))
+                    (argforms arg-value-form)))))))
+        (argforms (foreign-type-to-representation-type result-type))
+        (let* ((call `(,@callform ,@(argforms))))
+          (if enclosing-form
+            `(,@enclosing-form ,call)
+            call))))))
+                  
+            
+            
+