Design big-endian uuo link execute caches.

The little-endian hack to overwrite the tag with instructions doesn't
work on big-endian because it's the datum, not the tag, that's at the
end of the word in the frame size.

There's no room for the instructions before anything here, so add
another word and move the frame size to the end.  Kinda wasteful --
for that matter, it's not clear why we need to have any instructions
here at all, when we could just have INVOCATION:UUO-LINK compile to
an IJUMP instruction itself.

diff --git a/src/compiler/machines/svm/rules.scm b/src/compiler/machines/svm/rules.scm
index 8958974222cfec30dea29f2d0f0a08c9b5267a0f..23d8924816afdaf851d51c26d94e63e9dc061393 100644 (file)
--- a/src/compiler/machines/svm/rules.scm
+++ b/src/compiler/machines/svm/rules.scm
@@ -1341,14 +1341,23 @@ USA.
        (LAP))))
 
 (define (generate/uuos name.caches-list)
-  (append-map (lambda (name.caches)
-               (append-map (let ((name (car name.caches)))
-                             (lambda (cache)
-                               (let ((frame-size (car cache))
-                                     (label (cdr cache)))
-                                 `((,frame-size . ,label)
-                                   (,name . ,(allocate-constant-label))))))
-                           (cdr name.caches)))
+  (append-map
+   (lambda (name.caches)
+     (append-map (let ((name (car name.caches)))
+                  (lambda (cache)
+                    (let ((frame-size (car cache))
+                          (label (cdr cache)))
+                      (case endianness
+                        ((BIG)
+                         `((,name . ,label)
+                           (#f . ,(allocate-constant-label))
+                           (,frame-size . ,(allocate-constant-label))))
+                        ((LITTLE)
+                         `((,frame-size . ,label)
+                           (,name . ,(allocate-constant-label))))
+                        (else
+                         (error "Unknown endianness:" endianness))))))
+                (cdr name.caches)))
              name.caches-list))
 
 (define (make-linkage-type-marker linkage-type n-entries)

diff --git a/src/microcode/cmpintmd/svm1.c b/src/microcode/cmpintmd/svm1.c
index 73b32fbdd366939513bd32da94a4922c25db75ab..66f4d886b4a5a1dd914df2229e56ffbb815b0c80 100644 (file)
--- a/src/microcode/cmpintmd/svm1.c
+++ b/src/microcode/cmpintmd/svm1.c
@@ -298,7 +298,7 @@ compiled_closure_entry_to_target (insn_t * entry)
    information: (1) the name of the procedure being called (a symbol),
    and (2) the number of arguments that will be passed to the
    procedure.  It is laid out in memory like this (on a 32-bit
-   machine):
+   little-endian machine):
 
    0x00    frame-size (fixnum)
    0x04    name encoded as symbol
@@ -318,34 +318,60 @@ compiled_closure_entry_to_target (insn_t * entry)
    0x07    offset = 0
    0x08    64-bit address
 
+   On a big-endian machine, the frame size comes after the
+   name/instructions:
+
+   (unlinked, Scheme objects, any word size)
+           name encoded as symbol
+           padding #f
+           frame-size (fixnum below 2^16)
+
+   (linked, 32-bit)
+   0x00    2 padding bytes
+   0x02    SVM1_INST_IJUMP_U8
+   0x03    offset = 0
+   0x04    32-bit address
+   0x08    2 padding bytes
+   0x0a    frame-size (u16)
+
+   (linked, 64-bit)
+   0x00    6 padding bytes
+   0x06    SVM1_INST_IJUMP_U8
+   0x07    offset = 0
+   0x08    64-bit address
+   0x10    6 padding bytes
+   0x1e    frame-size (fixnum below 2^16)
    */
 
 unsigned int
 read_uuo_frame_size (SCHEME_OBJECT * saddr)
 {
-  return (read_u16 ((insn_t *) saddr));
+#ifdef WORDS_BIGENDIAN
+  insn_t * addr = (((insn_t *) (saddr + 3)) - 2);
+  unsigned hi = (addr[0]);
+  unsigned lo = (addr[1]);
+#else
+  insn_t * addr = ((insn_t *) saddr);
+  unsigned lo = (addr[0]);
+  unsigned hi = (addr[1]);
+#endif
+  return ((hi << 8) | lo);
 }
 
 SCHEME_OBJECT
 read_uuo_symbol (SCHEME_OBJECT * saddr)
 {
+#ifdef WORDS_BIGENDIAN
+  return (saddr[0]);
+#else
   return (saddr[1]);
+#endif
 }
 \f
 insn_t *
 read_uuo_target (SCHEME_OBJECT * saddr)
 {
-  insn_t * addr = ((insn_t *) (saddr + 2));
-  insn_t * end = ((insn_t *) (saddr + 1));
-  unsigned long eaddr = 0;
-
-  while (true)
-    {
-      eaddr |= (*--addr);
-      if (addr == end)
-       return ((insn_t *) eaddr);
-      eaddr <<= 8;
-    }
+  return ((insn_t *) (saddr[1]));
 }
 
 insn_t *
@@ -357,28 +383,42 @@ read_uuo_target_no_reloc (SCHEME_OBJECT * saddr)
 void
 write_uuo_target (insn_t * target, SCHEME_OBJECT * saddr)
 {
-  unsigned long eaddr = ((unsigned long) target);
-  unsigned long frame_size = (OBJECT_DATUM (saddr[0]));
+  unsigned long frame_size = (read_uuo_frame_size (saddr));
   insn_t * addr = ((insn_t *) saddr);
   insn_t * end = ((insn_t *) (saddr + 1));
 
+#ifndef WORDS_BIGENDIAN
+  /* Write the frame size.  */
   (*addr++) = (frame_size & 0x00FF);
   (*addr++) = ((frame_size & 0xFF00) >> 8);
+#endif
+
+  /* Pad to a word boundary, minus two bytes.  */
   while (addr < (end - 2))
     (*addr++) = 0;
+
+  /* Write the instruction prefix.  */
   (*addr++) = SVM1_INST_IJUMP_U8;
   (*addr++) = 0;
 
-  end = ((insn_t *) (saddr + 2));
-  while (true)
-    {
-      (*addr++) = (eaddr & 0xFF);
-      if (addr == end)
-       break;
-      eaddr >>= 8;
-    }
-}
+  /* We now have a word-aligned address.  Write the target here.  */
+  assert (addr == ((insn_t *) (saddr + 1)));
+  (saddr[1]) = ((SCHEME_OBJECT) target);
 
+#ifdef WORDS_BIGENDIAN
+  /* Pad to a word boundary, minus one 16-bit quantity.  */
+  addr = ((insn_t *) (saddr + 2));
+  end = ((insn_t *) (saddr + 3));
+  while (addr < (end - 2))
+    (*addr++) = 0;
+
+  /* Write the frame size.  */
+  (*addr++) = ((frame_size & 0xFF00) >> 8);
+  (*addr++) = (frame_size & 0x00FF);
+  assert (addr == ((insn_t *) (saddr + 3)));
+#endif
+}
+\f
 unsigned long
 trampoline_entry_size (unsigned long n_entries)
 {

diff --git a/src/microcode/cmpintmd/svm1.h b/src/microcode/cmpintmd/svm1.h
index 67c1746c6872e0a6b6266f3dd4ed49c978451955..09a556745b29b75f912c03b84a1b99bf61f810ce 100644 (file)
--- a/src/microcode/cmpintmd/svm1.h
+++ b/src/microcode/cmpintmd/svm1.h
@@ -62,7 +62,11 @@ typedef uint8_t insn_t;
 #define CLOSURE_ENTRY_SIZE 5
 
 /* Size of execution cache in SCHEME_OBJECTS.  */
+#ifdef WORDS_BIGENDIAN
+#define UUO_LINK_SIZE 3
+#else
 #define UUO_LINK_SIZE 2
+#endif
 #define READ_UUO_TARGET(a, r) read_uuo_target (a)
 
 #define UTILITY_RESULT_DEFINED 1