%
% (c) The GRASP/AQUA Project, Glasgow University, 1992-1998
%
\section[Constants]{Info about this compilation}

\begin{code}
module Constants (module Constants) where

import Data.Bits (shiftL)

-- This magical #include brings in all the everybody-knows-these magic
-- constants unfortunately, we need to be *explicit* about which one
-- we want; if we just hope a -I... will get the right one, we could
-- be in trouble.

#include "HsVersions.h"
#include "../includes/MachRegs.h"
#include "../includes/Constants.h"
#include "../includes/MachDeps.h"
#include "../includes/DerivedConstants.h"

-- import Util
\end{code}

All pretty arbitrary:

\begin{code}
mAX_TUPLE_SIZE :: Int
mAX_TUPLE_SIZE = 62 -- Should really match the number
                    -- of decls in Data.Tuple

mAX_CONTEXT_REDUCTION_DEPTH :: Int
mAX_CONTEXT_REDUCTION_DEPTH = 20
\end{code}


\begin{code}
-- specialised fun/thunk/constr closure types
mAX_SPEC_THUNK_SIZE :: Int
mAX_SPEC_THUNK_SIZE = MAX_SPEC_THUNK_SIZE

mAX_SPEC_FUN_SIZE :: Int
mAX_SPEC_FUN_SIZE = MAX_SPEC_FUN_SIZE

mAX_SPEC_CONSTR_SIZE :: Int
mAX_SPEC_CONSTR_SIZE = MAX_SPEC_CONSTR_SIZE

-- pre-compiled thunk types
mAX_SPEC_SELECTEE_SIZE :: Int
mAX_SPEC_SELECTEE_SIZE = MAX_SPEC_SELECTEE_SIZE

mAX_SPEC_AP_SIZE :: Int
mAX_SPEC_AP_SIZE = MAX_SPEC_AP_SIZE

-- closure sizes: these do NOT include the header (see below for header sizes)
mIN_PAYLOAD_SIZE ::Int
mIN_PAYLOAD_SIZE = MIN_PAYLOAD_SIZE
\end{code}

\begin{code}
mIN_INTLIKE, mAX_INTLIKE :: Int	
mIN_INTLIKE = MIN_INTLIKE
mAX_INTLIKE = MAX_INTLIKE

mIN_CHARLIKE, mAX_CHARLIKE :: Int
mIN_CHARLIKE = MIN_CHARLIKE
mAX_CHARLIKE = MAX_CHARLIKE
\end{code}

A section of code-generator-related MAGIC CONSTANTS.

\begin{code}
mAX_Vanilla_REG :: Int
mAX_Vanilla_REG	= MAX_VANILLA_REG

mAX_Float_REG :: Int
mAX_Float_REG = MAX_FLOAT_REG

mAX_Double_REG :: Int
mAX_Double_REG = MAX_DOUBLE_REG

mAX_Long_REG :: Int
mAX_Long_REG = MAX_LONG_REG

mAX_Real_Vanilla_REG :: Int
mAX_Real_Vanilla_REG = MAX_REAL_VANILLA_REG

mAX_Real_Float_REG :: Int
mAX_Real_Float_REG = MAX_REAL_FLOAT_REG

mAX_Real_Double_REG :: Int
mAX_Real_Double_REG	= MAX_REAL_DOUBLE_REG

mAX_Real_Long_REG :: Int
#ifdef MAX_REAL_LONG_REG
mAX_Real_Long_REG = MAX_REAL_LONG_REG
#else
mAX_Real_Long_REG = 0
#endif
\end{code}

Closure header sizes.

\begin{code}
sTD_HDR_SIZE :: Int
sTD_HDR_SIZE = STD_HDR_SIZE

pROF_HDR_SIZE :: Int
pROF_HDR_SIZE = PROF_HDR_SIZE
\end{code}

Size of a double in StgWords.

\begin{code}
dOUBLE_SIZE :: Int
dOUBLE_SIZE = SIZEOF_DOUBLE

wORD64_SIZE :: Int
wORD64_SIZE = 8

iNT64_SIZE :: Int
iNT64_SIZE = wORD64_SIZE
\end{code}

This tells the native code generator the size of the spill
area is has available.

\begin{code}
rESERVED_C_STACK_BYTES :: Int
rESERVED_C_STACK_BYTES = RESERVED_C_STACK_BYTES
\end{code}

The amount of (Haskell) stack to leave free for saving registers when
returning to the scheduler.

\begin{code}
rESERVED_STACK_WORDS :: Int
rESERVED_STACK_WORDS = RESERVED_STACK_WORDS
\end{code}

Continuations that need more than this amount of stack should do their
own stack check (see bug #1466).

\begin{code}
aP_STACK_SPLIM :: Int
aP_STACK_SPLIM = AP_STACK_SPLIM
\end{code}

Size of a word, in bytes

\begin{code}
wORD_SIZE :: Int
wORD_SIZE = SIZEOF_HSWORD

wORD_SIZE_IN_BITS :: Int
wORD_SIZE_IN_BITS = wORD_SIZE * 8
\end{code}

Amount of pointer bits used for semi-tagging constructor closures

\begin{code}
tAG_BITS :: Int
tAG_BITS = TAG_BITS

tAG_MASK :: Int
tAG_MASK = (1 `shiftL` tAG_BITS) - 1

mAX_PTR_TAG :: Int
mAX_PTR_TAG = tAG_MASK
\end{code}

Size of a C int, in bytes. May be smaller than wORD_SIZE.

\begin{code}
cINT_SIZE :: Int
cINT_SIZE = SIZEOF_INT
\end{code}

Size of a storage manager block (in bytes).

\begin{code}
bLOCK_SIZE :: Int
bLOCK_SIZE = BLOCK_SIZE
bLOCK_SIZE_W :: Int
bLOCK_SIZE_W = bLOCK_SIZE `quot` wORD_SIZE
\end{code}

Number of bits to shift a bitfield left by in an info table.

\begin{code}
bITMAP_BITS_SHIFT :: Int
bITMAP_BITS_SHIFT = BITMAP_BITS_SHIFT
\end{code}

Constants derived from headers in ghc/includes, generated by the program
../includes/mkDerivedConstants.c.

\begin{code}
#include "../includes/GHCConstants.h"
\end{code}