/* -----------------------------------------------------------------------------
- * $Id: Regs.h,v 1.9 2000/03/23 17:45:31 simonpj Exp $
*
- * (c) The GHC Team, 1998-1999
+ * (c) The GHC Team, 1998-2004
*
- * Registers used in STG code. Might or might not correspond to
- * actual machine registers.
+ * Registers in the STG machine.
+ *
+ * The STG machine has a collection of "registers", each one of which
+ * may or may not correspond to an actual machine register when
+ * running code.
+ *
+ * The register set is backed by a table in memory (struct
+ * StgRegTable). If a particular STG register is not mapped to a
+ * machine register, then the apprpriate slot in this table is used
+ * instead.
+ *
+ * This table is itself pointed to by another register, BaseReg. If
+ * BaseReg is not in a machine register, then the register table is
+ * used from an absolute location (MainCapability).
*
* ---------------------------------------------------------------------------*/
#ifndef REGS_H
#define REGS_H
-/*
- * This file should do the right thing if we have no machine-registers
- * defined, i.e. everything lives in the RegTable.
- */
/*
* This is the table that holds shadow-locations for all the STG
StgClosure **tl;
} StgSparkPool;
+typedef struct {
+ StgFunPtr stgGCEnter1;
+ StgFunPtr stgGCFun;
+} StgFunTable;
+
+/*
+ * Vanilla registers are given this union type, which is purely so
+ * that we can cast the vanilla reg to a variety of types with the
+ * minimum of syntax. eg. R1.w instead of (StgWord)R1.
+ */
+typedef union {
+ StgWord w;
+ StgAddr a;
+ StgChar c;
+ StgInt8 i8;
+ StgFloat f;
+ StgInt i;
+ StgPtr p;
+ StgClosurePtr cl;
+ StgStackOffset offset; /* unused? */
+ StgByteArray b;
+ StgTSOPtr t;
+} StgUnion;
+
typedef struct StgRegTable_ {
StgUnion rR1;
StgUnion rR2;
StgUnion rR6;
StgUnion rR7;
StgUnion rR8;
- StgUnion rR9; /* used occasionally by heap/stack checks */
- StgUnion rR10; /* used occasionally by heap/stack checks */
+ StgUnion rR9; // used occasionally by heap/stack checks
+ StgUnion rR10; // used occasionally by heap/stack checks
StgFloat rF1;
StgFloat rF2;
StgFloat rF3;
StgDouble rD2;
StgWord64 rL1;
StgPtr rSp;
- StgUpdateFrame *rSu;
StgPtr rSpLim;
StgPtr rHp;
StgPtr rHpLim;
- StgTSO *rCurrentTSO;
- struct _bdescr *rNursery;
- struct _bdescr *rCurrentNursery;
+ struct StgTSO_ *rCurrentTSO;
+ struct bdescr_ *rNursery;
+ struct bdescr_ *rCurrentNursery;
+ StgWord rHpAlloc; // number of *bytes* being allocated in heap
#if defined(SMP) || defined(PAR)
- StgSparkPool rSparks; /* per-task spark pool */
+ StgSparkPool rSparks; // per-task spark pool
#endif
+} StgRegTable;
+
+
+/* A capability is a combination of a FunTable and a RegTable. In STG
+ * code, BaseReg normally points to the RegTable portion of this
+ * structure, so that we can index both forwards and backwards to take
+ * advantage of shorter instruction forms on some archs (eg. x86).
+ */
+typedef struct Capability_ {
+ StgFunTable f;
+ StgRegTable r;
#if defined(SMP)
- struct StgRegTable_ *link; /* per-task register tables are linked together */
+ struct Capability_ *link; /* per-task register tables are linked together */
#endif
-} StgRegTable;
+} Capability;
-/* No such thing as a MainRegTable under SMP - each thread must
- * have its own MainRegTable.
+/* No such thing as a MainCapability under SMP - each thread must have
+ * its own Capability.
*/
#ifndef SMP
-extern DLL_IMPORT_RTS StgRegTable MainRegTable;
+#if IN_STG_CODE
+extern W_ MainCapability[];
+#else
+extern DLL_IMPORT_RTS Capability MainCapability;
+#endif
#endif
#if IN_STG_CODE
* Registers Hp and HpLim are global across the entire system, and are
* copied into the RegTable before executing a thread.
*
- * Registers Sp, Su, and SpLim are saved in the TSO for the
+ * Registers Sp and SpLim are saved in the TSO for the
* thread, but are copied into the RegTable before executing a thread.
*
* All other registers are "general purpose", and are used for passing
*/
#define SAVE_Sp (CurrentTSO->sp)
-#define SAVE_Su (CurrentTSO->su)
#define SAVE_SpLim (CurrentTSO->splim)
#define SAVE_Hp (BaseReg->rHp)
#define SAVE_CurrentTSO (BaseReg->rCurrentTSO)
#define SAVE_CurrentNursery (BaseReg->rCurrentNursery)
+#define SAVE_HpAlloc (BaseReg->rHpAlloc)
#if defined(SMP) || defined(PAR)
#define SAVE_SparkHd (BaseReg->rSparks.hd)
#define SAVE_SparkTl (BaseReg->rSparks.tl)
#ifdef SMP
#error BaseReg must be in a register for SMP
#endif
-#define BaseReg (&MainRegTable)
+#define BaseReg (&((Capability *)MainCapability)[0].r)
#endif
#ifdef REG_Sp
#define Sp (BaseReg->rSp)
#endif
-#ifdef REG_Su
-GLOBAL_REG_DECL(StgUpdateFrame *,Su,REG_Su)
-#else
-#define Su (BaseReg->rSu)
-#endif
-
#ifdef REG_SpLim
GLOBAL_REG_DECL(P_,SpLim,REG_SpLim)
#else
#endif
#ifdef REG_CurrentTSO
-GLOBAL_REG_DECL(StgTSO *,CurrentTSO,REG_CurrentTSO)
+GLOBAL_REG_DECL(struct _StgTSO *,CurrentTSO,REG_CurrentTSO)
#else
#define CurrentTSO (BaseReg->rCurrentTSO)
#endif
#define CurrentNursery (BaseReg->rCurrentNursery)
#endif
+#ifdef REG_HpAlloc
+GLOBAL_REG_DECL(bdescr *,HpAlloc,REG_HpAlloc)
+#else
+#define HpAlloc (BaseReg->rHpAlloc)
+#endif
+
#ifdef REG_SparkHd
GLOBAL_REG_DECL(bdescr *,SparkHd,REG_SparkHd)
#else
#endif
/* -----------------------------------------------------------------------------
+ Get absolute function pointers from the register table, to save
+ code space. On x86,
+
+ jmp *-12(%ebx)
+
+ is shorter than
+
+ jmp absolute_address
+
+ as long as the offset is within the range of a signed byte
+ (-128..+127). So we pick some common absolute_addresses and put
+ them in the register table. As a bonus, linking time should also
+ be reduced.
+
+ Other possible candidates in order of importance:
+
+ stg_upd_frame_info
+ stg_CAF_BLACKHOLE_info
+ stg_IND_STATIC_info
+
+ anything else probably isn't worth the effort.
+
+ -------------------------------------------------------------------------- */
+
+
+#define FunReg ((StgFunTable *)((void *)BaseReg - sizeof(StgFunTable)))
+
+#define stg_gc_enter_1 (FunReg->stgGCEnter1)
+#define stg_gc_fun (FunReg->stgGCFun)
+
+/* -----------------------------------------------------------------------------
For any registers which are denoted "caller-saves" by the C calling
convention, we have to emit code to save and restore them across C
calls.
#define CALLER_RESTORE_Sp /* nothing */
#endif
-#ifdef CALLER_SAVES_Su
-#define CALLER_SAVE_Su SAVE_Su = Su;
-#define CALLER_RESTORE_Su Su = SAVE_Su;
-#else
-#define CALLER_SAVE_Su /* nothing */
-#define CALLER_RESTORE_Su /* nothing */
-#endif
-
#ifdef CALLER_SAVES_SpLim
#define CALLER_SAVE_SpLim SAVE_SpLim = SpLim;
#define CALLER_RESTORE_SpLim SpLim = SAVE_SpLim;
#define CALLER_RESTORE_CurrentNursery /* nothing */
#endif
+#ifdef CALLER_SAVES_HpAlloc
+#define CALLER_SAVE_HpAlloc SAVE_HpAlloc = HpAlloc;
+#define CALLER_RESTORE_HpAlloc HpAlloc = SAVE_HpAlloc;
+#else
+#define CALLER_SAVE_HpAlloc /* nothing */
+#define CALLER_RESTORE_HpAlloc /* nothing */
+#endif
+
#ifdef CALLER_SAVES_SparkHd
#define CALLER_SAVE_SparkHd SAVE_SparkHd = SparkHd;
#define CALLER_RESTORE_SparkHd SparkHd = SAVE_SparkHd;
be addressed relative to it */
#define CALLER_SAVE_SYSTEM \
CALLER_SAVE_Sp \
- CALLER_SAVE_Su \
CALLER_SAVE_SpLim \
CALLER_SAVE_Hp \
CALLER_SAVE_HpLim \
#define CALLER_RESTORE_SYSTEM \
CALLER_RESTORE_Base \
CALLER_RESTORE_Sp \
- CALLER_RESTORE_Su \
CALLER_RESTORE_SpLim \
CALLER_RESTORE_Hp \
CALLER_RESTORE_HpLim \
#define CALLER_RESTORE_SYSTEM /* nothing */
#endif /* IN_STG_CODE */
-
#define CALLER_SAVE_ALL \
CALLER_SAVE_SYSTEM \
CALLER_SAVE_USER
CALLER_RESTORE_USER
#endif /* REGS_H */
-
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