From 5a8e6c4183a30f3b10de22fa5ba80950dfb2adea Mon Sep 17 00:00:00 2001 From: Patrik Nyblom Date: Mon, 7 Dec 2009 15:25:32 +0100 Subject: 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. --- erts/emulator/beam/erl_vm.h | 9 +++++++++ 1 file changed, 9 insertions(+) (limited to 'erts/emulator/beam/erl_vm.h') 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. */ -- cgit v1.2.3 From fb94cd974dc03baf149264ca4f4d50c6d1f80f21 Mon Sep 17 00:00:00 2001 From: Patrik Nyblom Date: Wed, 20 Jan 2010 16:26:14 +0100 Subject: 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. --- erts/emulator/beam/erl_vm.h | 4 ++++ 1 file changed, 4 insertions(+) (limited to 'erts/emulator/beam/erl_vm.h') diff --git a/erts/emulator/beam/erl_vm.h b/erts/emulator/beam/erl_vm.h index 1b61bca440..235bd7931d 100644 --- a/erts/emulator/beam/erl_vm.h +++ b/erts/emulator/beam/erl_vm.h @@ -139,8 +139,12 @@ #define HeapWordsLeft(p) (HEAP_LIMIT(p) - HEAP_TOP(p)) #if defined(DEBUG) || defined(CHECK_FOR_HOLES) +#if HALFWORD_HEAP +# define ERTS_HOLE_MARKER (0xaf5e78ccU) +#else # define ERTS_HOLE_MARKER (((0xaf5e78ccUL << 24) << 8) | 0xaf5e78ccUL) #endif +#endif /* * Allocate heap memory on the ordinary heap, NEVER in a heap -- cgit v1.2.3