1 /* ----------------------------------------------------------------------------
3 * (c) The GHC Team, 1998-2002
7 * NOTE: this information is used by both the compiler and the RTS.
8 * Some of it is tweakable, and some of it must be kept up to date
9 * with various other parts of the system.
11 * Constants which are derived automatically from other definitions in
12 * the system (eg. structure sizes) are generated into the file
13 * DerivedConstants.h by a C program (mkDerivedConstantsHdr).
15 * -------------------------------------------------------------------------- */
20 /* -----------------------------------------------------------------------------
23 This is the minimum number of words in the payload of a
24 heap-allocated closure, so that the closure has enough room to be
25 overwritten with a forwarding pointer during garbage collection.
26 -------------------------------------------------------------------------- */
28 #define MIN_PAYLOAD_SIZE 1
30 /* -----------------------------------------------------------------------------
31 Constants to do with specialised closure types.
32 -------------------------------------------------------------------------- */
34 /* We have some pre-compiled selector thunks defined in rts/StgStdThunks.hc.
35 * This constant defines the highest selectee index that we can replace with a
36 * reference to the pre-compiled code.
39 #define MAX_SPEC_SELECTEE_SIZE 15
41 /* Vector-apply thunks. These thunks just push their free variables
42 * on the stack and enter the first one. They're a bit like PAPs, but
43 * don't have a dynamic size. We've pre-compiled a few to save
47 #define MAX_SPEC_AP_SIZE 7
49 /* Specialised FUN/THUNK/CONSTR closure types */
51 #define MAX_SPEC_THUNK_SIZE 2
52 #define MAX_SPEC_FUN_SIZE 2
53 #define MAX_SPEC_CONSTR_SIZE 2
55 /* Range of built-in table of static small int-like and char-like closures.
57 * NB. This corresponds with the number of actual INTLIKE/CHARLIKE
58 * closures defined in rts/StgMiscClosures.cmm.
60 #define MAX_INTLIKE 16
61 #define MIN_INTLIKE (-16)
63 #define MAX_CHARLIKE 255
64 #define MIN_CHARLIKE 0
66 /* -----------------------------------------------------------------------------
69 Note that in MachRegs.h we define how many of these registers are
70 *real* machine registers, and not just offsets in the Register Table.
71 -------------------------------------------------------------------------- */
73 #define MAX_VANILLA_REG 8
74 #define MAX_FLOAT_REG 4
75 #define MAX_DOUBLE_REG 2
76 #define MAX_LONG_REG 1
78 /* -----------------------------------------------------------------------------
79 Semi-Tagging constants
81 Old Comments about this stuff:
83 Tags for indirection nodes and ``other'' (probably unevaluated) nodes;
84 normal-form values of algebraic data types will have tags 0, 1, ...
86 @INFO_IND_TAG@ is different from @INFO_OTHER_TAG@ just so we can count
87 how often we bang into indirection nodes; that's all. (WDP 95/11)
89 ToDo: find out if we need any of this.
90 -------------------------------------------------------------------------- */
92 #define INFO_OTHER_TAG (-1)
93 #define INFO_IND_TAG (-2)
94 #define INFO_FIRST_TAG 0
96 /* -----------------------------------------------------------------------------
97 How much C stack to reserve for local temporaries when in the STG
98 world. Used in StgCRun.c.
99 -------------------------------------------------------------------------- */
101 #define RESERVED_C_STACK_BYTES (2048 * SIZEOF_LONG)
103 /* -----------------------------------------------------------------------------
104 How much Haskell stack space to reserve for the saving of registers
105 etc. in the case of a stack/heap overflow.
107 This must be large enough to accomodate the largest stack frame
108 pushed in one of the heap check fragments in HeapStackCheck.hc
109 (ie. currently the generic heap checks - 3 words for StgRetDyn,
110 18 words for the saved registers, see StgMacros.h).
112 In the event of an unboxed tuple or let-no-escape stack/heap check
113 failure, there will be other words on the stack which are covered
114 by the RET_DYN frame. These will have been accounted for by stack
115 checks however, so we don't need to allow for them here.
116 -------------------------------------------------------------------------- */
118 #define RESERVED_STACK_WORDS 21
120 /* -----------------------------------------------------------------------------
121 Storage manager constants
122 -------------------------------------------------------------------------- */
124 /* The size of a block (2^BLOCK_SHIFT bytes) */
125 #define BLOCK_SHIFT 12
127 /* The size of a megablock (2^MBLOCK_SHIFT bytes) */
128 #define MBLOCK_SHIFT 20
130 /* -----------------------------------------------------------------------------
131 Bitmap/size fields (used in info tables)
132 -------------------------------------------------------------------------- */
134 /* In a 32-bit bitmap field, we use 5 bits for the size, and 27 bits
135 * for the bitmap. If the bitmap requires more than 27 bits, then we
136 * store it in a separate array, and leave a pointer in the bitmap
137 * field. On a 64-bit machine, the sizes are extended accordingly.
139 #if SIZEOF_VOID_P == 4
140 #define BITMAP_SIZE_MASK 0x1f
141 #define BITMAP_BITS_SHIFT 5
142 #elif SIZEOF_VOID_P == 8
143 #define BITMAP_SIZE_MASK 0x3f
144 #define BITMAP_BITS_SHIFT 6
146 #error unknown SIZEOF_VOID_P
149 /* -----------------------------------------------------------------------------
150 Lag/Drag/Void constants
151 -------------------------------------------------------------------------- */
154 An LDV word is divided into 3 parts: state bits (LDV_STATE_MASK), creation
155 time bits (LDV_CREATE_MASK), and last use time bits (LDV_LAST_MASK).
157 #if SIZEOF_VOID_P == 8
159 #define LDV_STATE_MASK 0x1000000000000000
160 #define LDV_CREATE_MASK 0x0FFFFFFFC0000000
161 #define LDV_LAST_MASK 0x000000003FFFFFFF
162 #define LDV_STATE_CREATE 0x0000000000000000
163 #define LDV_STATE_USE 0x1000000000000000
166 #define LDV_STATE_MASK 0x40000000
167 #define LDV_CREATE_MASK 0x3FFF8000
168 #define LDV_LAST_MASK 0x00007FFF
169 #define LDV_STATE_CREATE 0x00000000
170 #define LDV_STATE_USE 0x40000000
171 #endif /* SIZEOF_VOID_P */
173 /* -----------------------------------------------------------------------------
174 TSO related constants
175 -------------------------------------------------------------------------- */
178 * Constants for the what_next field of a TSO, which indicates how it
181 #define ThreadRunGHC 1 /* return to address on top of stack */
182 #define ThreadInterpret 2 /* interpret this thread */
183 #define ThreadKilled 3 /* thread has died, don't run it */
184 #define ThreadRelocated 4 /* thread has moved, link points to new locn */
185 #define ThreadComplete 5 /* thread has finished */
188 * Constants for the why_blocked field of a TSO
191 #define BlockedOnMVar 1
192 #define BlockedOnBlackHole 2
193 #define BlockedOnException 3
194 #define BlockedOnRead 4
195 #define BlockedOnWrite 5
196 #define BlockedOnDelay 6
197 #define BlockedOnSTM 7
200 #define BlockedOnDoProc 8
202 /* Only relevant for PAR: */
203 /* blocked on a remote closure represented by a Global Address: */
204 #define BlockedOnGA 9
205 /* same as above but without sending a Fetch message */
206 #define BlockedOnGA_NoSend 10
207 /* Only relevant for THREADED_RTS: */
208 #define BlockedOnCCall 11
209 #define BlockedOnCCall_NoUnblockExc 12
210 /* same as above but don't unblock async exceptions in resumeThread() */
213 * These constants are returned to the scheduler by a thread that has
214 * stopped for one reason or another. See typedef StgThreadReturnCode
217 #define HeapOverflow 1 /* might also be StackOverflow */
218 #define StackOverflow 2
219 #define ThreadYielding 3
220 #define ThreadBlocked 4
221 #define ThreadFinished 5
224 * Flags for the tso->flags field.
226 * The TSO_DIRTY flag indicates that this TSO's stack should be
227 * scanned during garbage collection. The link field of a TSO is
228 * always scanned, so we don't have to dirty a TSO just for linking
229 * it on a different list.
231 * TSO_DIRTY is set by
232 * - schedule(), just before running a thread,
233 * - raiseAsync(), because it modifies a thread's stack
234 * - resumeThread(), just before running the thread again
235 * and unset by the garbage collector (only).
240 * TSO_LOCKED is set when a TSO is locked to a particular Capability.
245 * TSO_BLOCKEX: the TSO is blocking exceptions
247 * TSO_INTERRUPTIBLE: the TSO can be interrupted if it blocks
248 * interruptibly (eg. with BlockedOnMVar).
250 * TSO_STOPPED_ON_BREAKPOINT: the thread is currently stopped in a breakpoint
252 #define TSO_BLOCKEX 4
253 #define TSO_INTERRUPTIBLE 8
254 #define TSO_STOPPED_ON_BREAKPOINT 16
256 /* -----------------------------------------------------------------------------
258 -------------------------------------------------------------------------- */
260 /* VERY MAGIC CONSTANTS!
261 * must agree with code in HeapStackCheck.c, stg_gen_chk, and
262 * RESERVED_STACK_WORDS in Constants.h.
264 #define RET_DYN_BITMAP_SIZE 8
265 #define RET_DYN_NONPTR_REGS_SIZE 10
267 /* Sanity check that RESERVED_STACK_WORDS is reasonable. We can't
268 * just derive RESERVED_STACK_WORDS because it's used in Haskell code
271 #if RESERVED_STACK_WORDS != (3 + RET_DYN_BITMAP_SIZE + RET_DYN_NONPTR_REGS_SIZE)
272 #error RESERVED_STACK_WORDS may be wrong!
275 #endif /* CONSTANTS_H */