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Diffstat (limited to 'includes/Constants.h')
| -rw-r--r-- | includes/Constants.h | 258 |
1 files changed, 258 insertions, 0 deletions
diff --git a/includes/Constants.h b/includes/Constants.h new file mode 100644 index 0000000000..4f3c35b744 --- /dev/null +++ b/includes/Constants.h @@ -0,0 +1,258 @@ +/* ---------------------------------------------------------------------------- + * + * (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 */ |