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, 9 insertions, 0 deletions

diff --git a/erts/emulator/beam/erl_vm.h b/erts/emulator/beam/erl_vm.h
index 50b3e5b61c..1b61bca440 100644
--- a/erts/emulator/beam/erl_vm.h
+++ b/erts/emulator/beam/erl_vm.h
@@ -50,6 +50,15 @@
 #define MAX_ARG 256	        /* Max number of arguments allowed */
 #define MAX_REG 1024            /* Max number of x(N) registers used */
 
+/* Scheduler stores data for temporary heaps if
+   !HEAP_ON_C_STACK. Macros (*TmpHeap*) in global.h selects if we put temporary
+   heap data on the C stack or if we use the buffers in the scheduler data. */
+#define TMP_HEAP_SIZE 128            /* Number of Eterm in the schedulers
+				        small heap for transient heap data */
+#define CMP_TMP_HEAP_SIZE       2    /* cmp wants its own tmp-heap... */
+#define ERL_ARITH_TMP_HEAP_SIZE 4    /* as does erl_arith... */
+#define BEAM_EMU_TMP_HEAP_SIZE  2    /* and beam_emu... */
+
 /*
  * The new arithmetic operations need some extra X registers in the register array.
  */