Store pointers to heap data in 32-bit words

Store Erlang terms in 32-bit entities on the heap, expanding the
pointers to 64-bit when needed. This works because all terms are stored
on addresses in the 32-bit address range (the 32 most significant bits
of pointers to term data are always 0).

Introduce a new datatype called UWord (along with its companion SWord),
which is an integer having the exact same size as the machine word
(a void *), but might be larger than Eterm/Uint.

Store code as machine words, as the instructions are pointers to
executable code which might reside outside the 32-bit address range.

Continuation pointers are stored on the 32-bit stack and hence must
point to addresses in the low range, which means that loaded beam code
much be placed in the low 32-bit address range (but, as said earlier,
the instructions themselves are full words).

No Erlang term data can be stored on C stacks (enforced by an
earlier commit).

This version gives a prompt, but test cases still fail (and dump core).

The loader (and emulator loop) has instruction packing disabled.

The main issues has been in rewriting loader and actual virtual
machine. Subsystems (like distribution) does not work yet.

2 files changed, 11 insertions, 11 deletions

diff --git a/erts/emulator/drivers/common/efile_drv.c b/erts/emulator/drivers/common/efile_drv.c
index 95510a16b2..cbd4dcb682 100644
--- a/erts/emulator/drivers/common/efile_drv.c
+++ b/erts/emulator/drivers/common/efile_drv.c
@@ -196,9 +196,9 @@ enum e_timer {timer_idle, timer_again, timer_write};
 struct t_data;
 
 typedef struct {
-    Sint            fd;
+    SWord           fd;
     ErlDrvPort      port;
-    unsigned        key;      /* Async queue key */
+    unsigned long   key;      /* Async queue key */
     unsigned        flags;    /* Original flags from FILE_OPEN. */
     void          (*invoke)(void *);
     struct t_data  *d;
@@ -306,7 +306,7 @@ struct t_data
     int            result_ok;
     Efile_error    errInfo;
     int            flags;
-    Sint           fd;
+    SWord          fd;
     /**/
     Efile_info        info;
     EFILE_DIR_HANDLE  dir_handle; /* Handle to open directory. */
@@ -605,7 +605,7 @@ file_start(ErlDrvPort port, char* command)
     }
     desc->fd = FILE_FD_INVALID;
     desc->port = port;
-    desc->key = (unsigned) (Uint) port;
+    desc->key = (unsigned long) (UWord) port;
     desc->flags = 0;
     desc->invoke = NULL;
     desc->d = NULL;
@@ -630,7 +630,7 @@ static void free_data(void *data)
     EF_FREE(data);
 }
 
-static void do_close(int flags, Sint fd) {
+static void do_close(int flags, SWord fd) {
     if (flags & EFILE_COMPRESSED) {
 	erts_gzclose((gzFile)(fd));
     } else {
@@ -709,7 +709,7 @@ static void reply_Uint_posix_error(file_descriptor *desc, Uint num,
     TRACE_C('N');
 
     response[0] = FILE_RESP_NUMERR;
-#if SIZEOF_VOID_P == 4
+#if SIZEOF_VOID_P == 4 || HALFWORD_HEAP
     put_int32(0, response+1);
 #else
     put_int32(num>>32, response+1);
@@ -767,7 +767,7 @@ static int reply_Uint(file_descriptor *desc, Uint result) {
     TRACE_C('R');
 
     tmp[0] = FILE_RESP_NUMBER;
-#if SIZEOF_VOID_P == 4
+#if SIZEOF_VOID_P == 4 || HALFWORD_HEAP
     put_int32(0, tmp+1);
 #else
     put_int32(result>>32, tmp+1);
@@ -1620,7 +1620,7 @@ static void invoke_open(void *data)
 	    status = efile_may_openfile(&d->errInfo, d->b);
 	    if (status || (d->errInfo.posix_errno != EISDIR)) {
 		mode = (d->flags & EFILE_MODE_READ) ? "rb" : "wb";
-		d->fd = (Sint) erts_gzopen(d->b, mode);
+		d->fd = (SWord) erts_gzopen(d->b, mode);
 		if ((gzFile)d->fd) {
 		    status = 1;
 		} else {
diff --git a/erts/emulator/drivers/unix/ttsl_drv.c b/erts/emulator/drivers/unix/ttsl_drv.c
index 4cd54c073f..d782b044a9 100644
--- a/erts/emulator/drivers/unix/ttsl_drv.c
+++ b/erts/emulator/drivers/unix/ttsl_drv.c
@@ -314,7 +314,7 @@ static ErlDrvData ttysl_start(ErlDrvPort port, char* buf)
     sys_sigset(SIGCONT, cont);
     sys_sigset(SIGWINCH, winch);
 
-    driver_select(port, (ErlDrvEvent)(Uint)ttysl_fd, ERL_DRV_READ|ERL_DRV_USE, 1);
+    driver_select(port, (ErlDrvEvent)(UWord)ttysl_fd, ERL_DRV_READ|ERL_DRV_USE, 1);
     ttysl_port = port;
 
     /* we need to know this when we enter the break handler */
@@ -394,7 +394,7 @@ static void ttysl_stop(ErlDrvData ttysl_data)
 	stop_lbuf();
 	stop_termcap();
 	tty_reset(ttysl_fd);
-	driver_select(ttysl_port, (ErlDrvEvent)(Uint)ttysl_fd, ERL_DRV_READ|ERL_DRV_USE, 0);
+	driver_select(ttysl_port, (ErlDrvEvent)(UWord)ttysl_fd, ERL_DRV_READ|ERL_DRV_USE, 0);
 	sys_sigset(SIGCONT, SIG_DFL);
 	sys_sigset(SIGWINCH, SIG_DFL);
     }
@@ -685,7 +685,7 @@ static void ttysl_from_tty(ErlDrvData ttysl_data, ErlDrvEvent fd)
 	utf8buf_size = 0;
     }
     
-    if ((i = read((int)(Sint)fd, (char *) p, left)) >= 0) {
+    if ((i = read((int)(SWord)fd, (char *) p, left)) >= 0) {
 	if (p != b) {
 	    i += (p - b);
 	}