Fit all heap data into the 32-bit address range

This is the first step in the implementation of the half-word emulator,
a 64-bit emulator where all pointers to heap data will be stored
in 32-bit words. Code specific for this emulator variant is
conditionally compiled when the HALFWORD_HEAP define has
a non-zero value.

First force all pointers to heap data to fall into a single 32-bit range,
but still store them in 64-bit words.

Temporary term data stored on C stack is moved into scheduler specific
storage (allocated as heaps) and macros are added to make this
happen only in emulators where this is needed. For a vanilla VM the
temporary terms are still stored on the C stack.

1 files changed, 3 insertions, 2 deletions

diff --git a/erts/emulator/beam/erl_bif_lists.c b/erts/emulator/beam/erl_bif_lists.c
index a9e8dd86f7..5df4783fcb 100644
--- a/erts/emulator/beam/erl_bif_lists.c
+++ b/erts/emulator/beam/erl_bif_lists.c
@@ -89,13 +89,14 @@ BIF_RETTYPE append_2(BIF_ALIST_2)
     BIF_RET(copy);
 }
 
+#define SMALL_VEC_SIZE 10
 BIF_RETTYPE subtract_2(BIF_ALIST_2)
 {
     Eterm  list;
     Eterm* hp;
     Uint  need;
     Eterm  res;
-    Eterm  small_vec[10];	/* Preallocated memory for small lists */
+    Eterm small_vec[SMALL_VEC_SIZE];	/* Preallocated memory for small lists */
     Eterm* vec_p;
     Eterm* vp;
     int     i;
@@ -115,7 +116,7 @@ BIF_RETTYPE subtract_2(BIF_ALIST_2)
 	BIF_RET(BIF_ARG_1);
     
     /* allocate element vector */
-    if (n <= sizeof(small_vec)/sizeof(small_vec[0]))
+    if (n <= SMALL_VEC_SIZE)
 	vec_p = small_vec;
     else
 	vec_p = (Eterm*) erts_alloc(ERTS_ALC_T_TMP, n * sizeof(Eterm));