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/* ----------------------------------------------------------------------------
*
* (c) The GHC Team, 1998-2002
*
* Constants
*
* 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).
*
* -------------------------------------------------------------------------- */
#ifndef CONSTANTS_H
#define CONSTANTS_H
/* -----------------------------------------------------------------------------
Minimum closure sizes
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_PAYLOAD_SIZE 1
/* -----------------------------------------------------------------------------
Constants to do with specialised closure types.
-------------------------------------------------------------------------- */
/* 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
/* Vector-apply thunks. These thunks just push their free variables
* on the stack and enter the first one. They're a bit like PAPs, but
* don't have a dynamic size. We've pre-compiled a few to save
* space.
*/
#define MAX_SPEC_AP_SIZE 7
/* Specialised FUN/THUNK/CONSTR closure types */
#define MAX_SPEC_THUNK_SIZE 2
#define MAX_SPEC_FUN_SIZE 2
#define MAX_SPEC_CONSTR_SIZE 2
/* 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 MAX_CHARLIKE 255
#define MIN_CHARLIKE 0
/* -----------------------------------------------------------------------------
STG Registers.
Note that in MachRegs.h we define how many of these registers are
*real* machine registers, and not just offsets in the Register Table.
-------------------------------------------------------------------------- */
#define MAX_VANILLA_REG 8
#define MAX_FLOAT_REG 4
#define MAX_DOUBLE_REG 2
#define MAX_LONG_REG 1
/* -----------------------------------------------------------------------------
* 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
/* -----------------------------------------------------------------------------
Semi-Tagging constants
Old Comments about this stuff:
Tags for indirection nodes and ``other'' (probably unevaluated) nodes;
normal-form values of algebraic data types will have tags 0, 1, ...
@INFO_IND_TAG@ is different from @INFO_OTHER_TAG@ just so we can count
how often we bang into indirection nodes; that's all. (WDP 95/11)
ToDo: find out if we need any of this.
-------------------------------------------------------------------------- */
#define INFO_OTHER_TAG (-1)
#define INFO_IND_TAG (-2)
#define INFO_FIRST_TAG 0
/* -----------------------------------------------------------------------------
How much C stack to reserve for local temporaries when in the STG
world. Used in StgCRun.c.
-------------------------------------------------------------------------- */
#define RESERVED_C_STACK_BYTES (2048 * SIZEOF_LONG)
/* -----------------------------------------------------------------------------
How much Haskell stack space to reserve for the saving of registers
etc. in the case of a stack/heap overflow.
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 - 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 21
/* -----------------------------------------------------------------------------
Storage manager constants
-------------------------------------------------------------------------- */
/* The size of a block (2^BLOCK_SHIFT bytes) */
#define BLOCK_SHIFT 12
/* The size of a megablock (2^MBLOCK_SHIFT bytes) */
#define MBLOCK_SHIFT 20
/* -----------------------------------------------------------------------------
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.
*/
#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
/* -----------------------------------------------------------------------------
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 */
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