/* ----------------------------------------------------------------------------
- * $Id: Constants.h,v 1.17 2001/08/01 08:20:33 simonmar Exp $
*
- * (c) The GHC Team, 1998-1999
+ * (c) The GHC Team, 1998-2002
*
* Constants
*
- * NOTE: this information is used by both the compiler and the RTS,
- * and *must* be kept up-to-date with respect to the rest of the
- * world.
+ * NOTE: this information is used by both the compiler and the RTS.
+ * Some of it is tweakable, and some of it must be kept up to date
+ * with various other parts of the system.
+ *
+ * Constants which are derived automatically from other definitions in
+ * the system (eg. structure sizes) are generated into the file
+ * DerivedConstants.h by a C program (mkDerivedConstantsHdr).
*
* -------------------------------------------------------------------------- */
#define CONSTANTS_H
/* -----------------------------------------------------------------------------
- Header Sizes
-
- NOTE: keep these in line with the real definitions in Closures.h
- HWL: checked GRAN_HDR_SIZE; ok
- -------------------------------------------------------------------------- */
-
-#define STD_HDR_SIZE 1
-#define PROF_HDR_SIZE 1
-#define GRAN_HDR_SIZE 1
-#define PAR_HDR_SIZE 0
-#define TICKY_HDR_SIZE 0
-
-#define ARR_WORDS_HDR_SIZE 1
-#define ARR_PTRS_HDR_SIZE 2
-
-/* -----------------------------------------------------------------------------
- Info Table sizes
-
- The native code generator needs to know these things, and can't use
- the C sizeof() function.
-
- NOTE: keep these in line with the real definitions in InfoTables.h
-
- NOTE: the PROF, and GRAN values are *wrong* (ToDo)
- HWL: checked GRAN_ITBL_SIZE; ok
- -------------------------------------------------------------------------- */
-
-#define STD_ITBL_SIZE 3
-#define PROF_ITBL_SIZE 1
-#define GRAN_ITBL_SIZE 1
-#define PAR_ITBL_SIZE 0
-#define TICKY_ITBL_SIZE 0
-
-/* -----------------------------------------------------------------------------
Minimum closure sizes
- Here We define the minimum size for updatable closures. This must be at
- least 2, to allow for cons cells and linked indirections. All updates
- will be performed on closures of this size. For non-updatable closures
- the minimum size is 1 to allow for a forwarding pointer.
-
- Linked indirections are UPD_OLDGEN things: see Closures.h
-
- o MIN_UPD_SIZE doesn't apply to stack closures, static closures
- or non-updateable objects like PAPs or CONSTRs
- o MIN_UPD_SIZE is big enough to contain any of the following:
- o EVACUATED
- o BLACKHOLE
- o BLOCKING QUEUE
- o IND, IND_PERM, IND_OLDGEN and IND_OLDGEN_PERM
- (it need not be big enough for IND_STATIC - but it is)
- o MIN_NONUPD_SIZE doesn't apply to stack closures, static closures
- or updateable objects like APs, THUNKS or THUNK_SELECTORs
- o MIN_NONUPD_SIZE is big enough to contain any of the following:
- o EVACUATED
+ This is the minimum number of words in the payload of a
+ heap-allocated closure, so that the closure has enough room to be
+ overwritten with a forwarding pointer during garbage collection.
-------------------------------------------------------------------------- */
-#define MIN_UPD_SIZE 2
-#define MIN_NONUPD_SIZE 1
+#define MIN_PAYLOAD_SIZE 1
/* -----------------------------------------------------------------------------
Constants to do with specialised closure types.
-------------------------------------------------------------------------- */
-/* We have some pre-compiled selector thunks defined in
- * StgSelectors.hc in the runtime system. This constant defines the
- * highest selectee index that we can replace with a reference to the
- * pre-compiled code.
+/* We have some pre-compiled selector thunks defined in rts/StgStdThunks.hc.
+ * This constant defines the highest selectee index that we can replace with a
+ * reference to the pre-compiled code.
*/
#define MAX_SPEC_SELECTEE_SIZE 15
* space.
*/
-#define MAX_SPEC_AP_SIZE 8
+#define MAX_SPEC_AP_SIZE 7
/* Specialised FUN/THUNK/CONSTR closure types */
#define MAX_SPEC_FUN_SIZE 2
#define MAX_SPEC_CONSTR_SIZE 2
-/* -----------------------------------------------------------------------------
- Update Frame Layout
- GranSim uses an additional word as bitmask in the update frame; actually,
- not really necessary, but uses standard closure layout that way
- NB: UF_RET etc are *wrong* in a GranSim setup; should be increased by 1
- if compiling for GranSim (currently not used in compiler) -- HWL
- -------------------------------------------------------------------------- */
-#define NOSCC_UF_SIZE 3
-#define GRAN_UF_SIZE 4
-#define SCC_UF_SIZE 4
-
-#define UF_RET 0
-#define UF_SU 1
-#define UF_UPDATEE 2
-
-/* -----------------------------------------------------------------------------
- SEQ frame size
-
- I don't think seq frames really need sccs --SDM
- They don't need a GranSim bitmask either, but who cares anyway -- HWL
- -------------------------------------------------------------------------- */
+/* Range of built-in table of static small int-like and char-like closures.
+ *
+ * NB. This corresponds with the number of actual INTLIKE/CHARLIKE
+ * closures defined in rts/StgMiscClosures.cmm.
+ */
+#define MAX_INTLIKE 16
+#define MIN_INTLIKE (-16)
-#define NOSCC_SEQ_FRAME_SIZE 2
-#define GRAN_SEQ_FRAME_SIZE 3
-#define SCC_SEQ_FRAME_SIZE 3
+#define MAX_CHARLIKE 255
+#define MIN_CHARLIKE 0
/* -----------------------------------------------------------------------------
STG Registers.
#define MAX_VANILLA_REG 8
#define MAX_FLOAT_REG 4
#define MAX_DOUBLE_REG 2
-/* register is only used for returning (unboxed) 64-bit vals */
#define MAX_LONG_REG 1
-/*---- The size of an StgDouble, in StgWords. */
-
-#if SIZEOF_VOID_P == SIZEOF_DOUBLE
-#define DOUBLE_SIZE 1
-#else
-#define DOUBLE_SIZE 2
-#endif
-
-/*---- The size of Stg{Int,Word}64e, in StgWords. */
-#if SIZEOF_VOID_P == 8
-#define WORD64_SIZE 1
-#define INT64_SIZE 1
-#else
-#define WORD64_SIZE 2
-#define INT64_SIZE 2
-#endif
-
-
-/*---- The size of StgWord, in bytes. */
-#define WORD_SIZE SIZEOF_VOID_P
-
-/*---- Maximum number of constructors in a data type for direct-returns. */
+/* -----------------------------------------------------------------------------
+ * Maximum number of constructors in a data type for direct-returns.
+ *
+ * NB. There are various places that assume the value of this
+ * constant, such as the polymorphic return frames for updates
+ * (stg_upd_frame_info) and catch frames (stg_catch_frame_info).
+ * -------------------------------------------------------------------------- */
#define MAX_VECTORED_RTN 8
-/*---- Range of built-in table of static small int-like and char-like closures. */
-
-#define MAX_INTLIKE 16
-#define MIN_INTLIKE (-16)
-
-#define MAX_CHARLIKE 255
-#define MIN_CHARLIKE 0
-
-/* You can change these constants (I hope) but be sure to modify
- rts/StgMiscClosures.hs accordingly. */
-
-/*---- Minimum number of words left in heap after GC to carry on */
-
-#define HEAP_HWM_WORDS 1024
-
/* -----------------------------------------------------------------------------
Semi-Tagging constants
/* -----------------------------------------------------------------------------
How much C stack to reserve for local temporaries when in the STG
- world. Used in StgRun.S and StgCRun.c.
+ world. Used in StgCRun.c.
-------------------------------------------------------------------------- */
#define RESERVED_C_STACK_BYTES (2048 * SIZEOF_LONG)
This must be large enough to accomodate the largest stack frame
pushed in one of the heap check fragments in HeapStackCheck.hc
- (ie. currently the generic heap checks - 19 words).
+ (ie. currently the generic heap checks - 3 words for StgRetDyn,
+ 18 words for the saved registers, see StgMacros.h).
+
+ In the event of an unboxed tuple or let-no-escape stack/heap check
+ failure, there will be other words on the stack which are covered
+ by the RET_DYN frame. These will have been accounted for by stack
+ checks however, so we don't need to allow for them here.
-------------------------------------------------------------------------- */
-#define RESERVED_STACK_WORDS 19
+#define RESERVED_STACK_WORDS 21
/* -----------------------------------------------------------------------------
Storage manager constants
-------------------------------------------------------------------------- */
-/* The size of a block */
-#define BLOCK_SIZE 0x1000
+/* The size of a block (2^BLOCK_SHIFT bytes) */
#define BLOCK_SHIFT 12
-/* The size of a megablock */
-#define MBLOCK_SIZE 0x100000
+/* The size of a megablock (2^MBLOCK_SHIFT bytes) */
#define MBLOCK_SHIFT 20
-/* the largest size an object can be before we give it a block of its
- * own and treat it as an immovable object during GC, expressed as a
- * fraction of BLOCK_SIZE.
+/* -----------------------------------------------------------------------------
+ Bitmap/size fields (used in info tables)
+ -------------------------------------------------------------------------- */
+
+/* In a 32-bit bitmap field, we use 5 bits for the size, and 27 bits
+ * for the bitmap. If the bitmap requires more than 27 bits, then we
+ * store it in a separate array, and leave a pointer in the bitmap
+ * field. On a 64-bit machine, the sizes are extended accordingly.
*/
-#define LARGE_OBJECT_THRESHOLD ((nat)(BLOCK_SIZE * 8 / 10))
+#if SIZEOF_VOID_P == 4
+#define BITMAP_SIZE_MASK 0x1f
+#define BITMAP_BITS_SHIFT 5
+#elif SIZEOF_VOID_P == 8
+#define BITMAP_SIZE_MASK 0x3f
+#define BITMAP_BITS_SHIFT 6
+#else
+#error unknown SIZEOF_VOID_P
+#endif
-#endif /* CONSTANTS_H */
+/* -----------------------------------------------------------------------------
+ Lag/Drag/Void constants
+ -------------------------------------------------------------------------- */
+
+/*
+ An LDV word is divided into 3 parts: state bits (LDV_STATE_MASK), creation
+ time bits (LDV_CREATE_MASK), and last use time bits (LDV_LAST_MASK).
+ */
+#if SIZEOF_VOID_P == 8
+#define LDV_SHIFT 30
+#define LDV_STATE_MASK 0x1000000000000000
+#define LDV_CREATE_MASK 0x0FFFFFFFC0000000
+#define LDV_LAST_MASK 0x000000003FFFFFFF
+#define LDV_STATE_CREATE 0x0000000000000000
+#define LDV_STATE_USE 0x1000000000000000
+#else
+#define LDV_SHIFT 15
+#define LDV_STATE_MASK 0x40000000
+#define LDV_CREATE_MASK 0x3FFF8000
+#define LDV_LAST_MASK 0x00007FFF
+#define LDV_STATE_CREATE 0x00000000
+#define LDV_STATE_USE 0x40000000
+#endif /* SIZEOF_VOID_P */
+/* -----------------------------------------------------------------------------
+ TSO related constants
+ -------------------------------------------------------------------------- */
+
+/*
+ * Constants for the what_next field of a TSO, which indicates how it
+ * is to be run.
+ */
+#define ThreadRunGHC 1 /* return to address on top of stack */
+#define ThreadInterpret 2 /* interpret this thread */
+#define ThreadKilled 3 /* thread has died, don't run it */
+#define ThreadRelocated 4 /* thread has moved, link points to new locn */
+#define ThreadComplete 5 /* thread has finished */
+
+/*
+ * Constants for the why_blocked field of a TSO
+ */
+#define NotBlocked 0
+#define BlockedOnMVar 1
+#define BlockedOnBlackHole 2
+#define BlockedOnException 3
+#define BlockedOnRead 4
+#define BlockedOnWrite 5
+#define BlockedOnDelay 6
+#define BlockedOnSTM 7
+
+/* Win32 only: */
+#define BlockedOnDoProc 8
+
+/* Only relevant for PAR: */
+ /* blocked on a remote closure represented by a Global Address: */
+#define BlockedOnGA 9
+ /* same as above but without sending a Fetch message */
+#define BlockedOnGA_NoSend 10
+/* Only relevant for THREADED_RTS: */
+#define BlockedOnCCall 11
+#define BlockedOnCCall_NoUnblockExc 12
+ /* same as above but don't unblock async exceptions in resumeThread() */
+
+/*
+ * These constants are returned to the scheduler by a thread that has
+ * stopped for one reason or another. See typedef StgThreadReturnCode
+ * in TSO.h.
+ */
+#define HeapOverflow 1 /* might also be StackOverflow */
+#define StackOverflow 2
+#define ThreadYielding 3
+#define ThreadBlocked 4
+#define ThreadFinished 5
+
+/* -----------------------------------------------------------------------------
+ RET_DYN stack frames
+ -------------------------------------------------------------------------- */
+
+/* VERY MAGIC CONSTANTS!
+ * must agree with code in HeapStackCheck.c, stg_gen_chk, and
+ * RESERVED_STACK_WORDS in Constants.h.
+ */
+#define RET_DYN_BITMAP_SIZE 8
+#define RET_DYN_NONPTR_REGS_SIZE 10
+
+/* Sanity check that RESERVED_STACK_WORDS is reasonable. We can't
+ * just derive RESERVED_STACK_WORDS because it's used in Haskell code
+ * too.
+ */
+#if RESERVED_STACK_WORDS != (3 + RET_DYN_BITMAP_SIZE + RET_DYN_NONPTR_REGS_SIZE)
+#error RESERVED_STACK_WORDS may be wrong!
+#endif
+
+/* -----------------------------------------------------------------------------
+ How often our context-switch timer ticks
+ -------------------------------------------------------------------------- */
+
+#define TICK_FREQUENCY 50 /* ticks per second */
+
+#endif /* CONSTANTS_H */