clean up NEW_FRAME macro

[bpt/guile.git] / libguile / vm-engine.h

diff --git a/libguile/vm-engine.h b/libguile/vm-engine.h
index dfbd2d9..370a42b 100644 (file)
--- a/libguile/vm-engine.h
+++ b/libguile/vm-engine.h
@@ -406,24 +406,29 @@ do {                                              \
 }
 
 /* See frames.h for the layout of stack frames */
-
+/* When this is called, bp points to the new program data,
+   and the arguments are already on the stack */
 #define NEW_FRAME()                            \
 {                                              \
   int i;                                       \
-  SCM ra = SCM_PACK (ip);                      \
-  SCM dl = SCM_PACK (fp);                      \
-  SCM *p = sp + 1;                             \
-  SCM *q = p + bp->nlocs;                      \
+  SCM *dl, *data;                               \
+  scm_byte_t *ra = ip;                          \
                                                \
-  /* New pointers */                           \
-  ip = bp->base;                               \
-  fp = p - bp->nargs;                          \
-  sp = q + 3;                                  \
+  /* Save old registers */                      \
+  ra = ip;                                      \
+  dl = fp;                                      \
+                                               \
+  /* New registers */                           \
+  fp = sp - bp->nargs + 1;                      \
+  data = SCM_FRAME_DATA_ADDRESS (fp);           \
+  sp = data + 3;                                \
   CHECK_OVERFLOW ();                           \
+  stack_base = sp;                             \
+  ip = bp->base;                               \
                                                \
   /* Init local variables */                   \
-  for (; p < q; p++)                           \
-    *p = SCM_UNDEFINED;                                \
+  for (i=bp->nlocs; i; i--)                     \
+    data[-i] = SCM_UNDEFINED;                   \
                                                \
   /* Create external variables */              \
   external = bp->external;                     \
@@ -431,11 +436,10 @@ do {                                              \
     CONS (external, SCM_UNDEFINED, external);  \
                                                \
   /* Set frame data */                         \
-  p[3] = ra;                                   \
-  p[2] = dl;                                   \
-  p[1] = SCM_BOOL_F;                           \
-  p[0] = external;                             \
-  stack_base = p + 3;                          \
+  data[3] = (SCM)ra;                            \
+  data[2] = (SCM)dl;                            \
+  data[1] = SCM_BOOL_F;                                \
+  data[0] = external;                          \
 }
 
 #define FREE_FRAME()                           \