0.pre7.34:

[sbcl.git] / src / compiler / generic / vm-tran.lisp

diff --git a/src/compiler/generic/vm-tran.lisp b/src/compiler/generic/vm-tran.lisp
index a78cf36..0d5849e 100644 (file)
--- a/src/compiler/generic/vm-tran.lisp
+++ b/src/compiler/generic/vm-tran.lisp
@@ -244,34 +244,44 @@
        (setf (%raw-bits result-bit-array index)
             (32bit-logical-not (%raw-bits bit-array index))))))
 \f
-;;;; primitive translator for BYTE-BLT
+;;;; %BYTE-BLT
 
-(def-primitive-translator byte-blt (src src-start dst dst-start dst-end)
-  `(let ((src ,src)
-        (src-start (* ,src-start sb!vm:byte-bits))
-        (dst ,dst)
-        (dst-start (* ,dst-start sb!vm:byte-bits))
-        (dst-end (* ,dst-end sb!vm:byte-bits)))
-     (let ((length (- dst-end dst-start)))
-       (etypecase src
-        (system-area-pointer
-         (etypecase dst
-           (system-area-pointer
-            (system-area-copy src src-start dst dst-start length))
-           ((simple-unboxed-array (*))
-            (copy-from-system-area src src-start
-                                   dst (+ dst-start ,vector-data-bit-offset)
-                                   length))))
-        ((simple-unboxed-array (*))
-         (etypecase dst
-           (system-area-pointer
-            (copy-to-system-area src (+ src-start ,vector-data-bit-offset)
-                                 dst dst-start
-                                 length))
-           ((simple-unboxed-array (*))
-            (bit-bash-copy src (+ src-start ,vector-data-bit-offset)
-                           dst (+ dst-start ,vector-data-bit-offset)
-                           length))))))))
+;;; FIXME: The old CMU CL code used various COPY-TO/FROM-SYSTEM-AREA
+;;; stuff (with all the associated bit-index cruft and overflow
+;;; issues) even for byte moves. In SBCL, we're converting to byte
+;;; moves as problems are discovered with the old code, and this is
+;;; currently (ca. sbcl-0.6.12.30) the main interface for code in
+;;; SB!KERNEL and SB!SYS (e.g. i/o code). It's not clear that it's the
+;;; ideal interface, though, and it probably deserves some thought.
+(deftransform %byte-blt ((src src-start dst dst-start dst-end)
+                        ((or (simple-unboxed-array (*)) system-area-pointer)
+                         index
+                         (or (simple-unboxed-array (*)) system-area-pointer)
+                         index
+                         index))
+  ;; FIXME: CMU CL had a hairier implementation of this (back when it
+  ;; was still called (%PRIMITIVE BYTE-BLT). It had the small problem
+  ;; that it didn't work for large (>16M) values of SRC-START or
+  ;; DST-START. However, it might have been more efficient. In
+  ;; particular, I don't really know how much the foreign function
+  ;; call costs us here. My guess is that if the overhead is
+  ;; acceptable for SQRT and COS, it's acceptable here, but this
+  ;; should probably be checked. -- WHN
+  '(flet ((sapify (thing)
+           (etypecase thing
+             (system-area-pointer thing)
+             ;; FIXME: The code here rather relies on the simple
+             ;; unboxed array here having byte-sized entries. That
+             ;; should be asserted explicitly, I just haven't found
+             ;; a concise way of doing it. (It would be nice to
+             ;; declare it in the DEFKNOWN too.)
+             ((simple-unboxed-array (*)) (vector-sap thing)))))
+     (declare (inline sapify))
+     (without-gcing
+      (memmove (sap+ (sapify dst) dst-start)
+              (sap+ (sapify src) src-start)
+              (- dst-end dst-start)))
+     nil))
 \f
 ;;;; transforms for EQL of floating point values