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git-svn-id: https://yap.svn.sf.net/svnroot/yap/trunk@5 b08c6af1-5177-4d33-ba66-4b1c6b8b522a

OPTYap/opt.mavar.h

@@ -0,0 +1,94 @@
+
+#ifdef MULTI_ASSIGNMENT_VARIABLES
+/* 
+   Set of routines to allow restoring updatable variables when we go *up*
+   in the tree. Required by copying, SBA, and tabling. Not required by ACOW.
+*/
+
+#ifndef OPT_MAVAR_STATIC
+#define OPT_MAVAR_STATIC inline static
+#endif
+
+#define MAVARS_HASH_SIZE 512
+
+typedef struct ma_h_entry {
+  CELL* addr;
+  struct ma_h_entry *next;
+} ma_h_inner_struct;
+
+typedef struct {
+  UInt timestmp;
+  struct ma_h_entry val;
+} ma_hash_entry;
+
+extern ma_hash_entry ma_hash_table[MAVARS_HASH_SIZE];
+
+extern UInt timestamp;    /* an unsigned int */
+
+OPT_MAVAR_STATIC unsigned int MAVAR_HASH(CELL *);
+OPT_MAVAR_STATIC struct ma_h_entry *ALLOC_NEW_MASPACE(void);
+OPT_MAVAR_STATIC int lookup_ma_var(CELL *);
+OPT_MAVAR_STATIC UInt NEW_MAHASH(ma_h_inner_struct *);
+
+OPT_MAVAR_STATIC unsigned int
+MAVAR_HASH(CELL *addr) {
+#if SIZEOF_INT_P==8
+  return((((unsigned int)((CELL)(addr)))>>3)%MAVARS_HASH_SIZE);
+#else
+  return((((unsigned int)((CELL)(addr)))>>2)%MAVARS_HASH_SIZE); 
+#endif
+}
+
+extern ma_h_inner_struct *ma_h_top;
+
+OPT_MAVAR_STATIC struct ma_h_entry *
+ALLOC_NEW_MASPACE(void)
+{
+  ma_h_inner_struct *new = ma_h_top;
+  ma_h_top++;
+  return(new);
+}
+
+OPT_MAVAR_STATIC int
+lookup_ma_var(CELL *addr) {
+  unsigned int i = MAVAR_HASH(addr);
+  struct ma_h_entry *nptr, *optr;
+
+  if (ma_hash_table[i].timestmp != timestamp) {
+    ma_hash_table[i].timestmp = timestamp;
+    ma_hash_table[i].val.addr = addr;
+    ma_hash_table[i].val.next = NULL;
+    return(FALSE);
+  }
+  if (ma_hash_table[i].val.addr == addr) 
+    return(TRUE);
+  optr = &(ma_hash_table[i].val);
+  nptr = ma_hash_table[i].val.next;
+  while (nptr != NULL) {
+    if (nptr->addr == addr) {
+      return(TRUE);
+    }
+    optr = nptr;
+    nptr = nptr->next;
+  }
+  nptr = ALLOC_NEW_MASPACE();
+  nptr->addr = addr;
+  nptr->next = optr;
+  return(FALSE);
+}
+
+OPT_MAVAR_STATIC UInt
+NEW_MAHASH(ma_h_inner_struct *top) {
+  UInt time = ++timestamp;
+  if (time == 0) {
+    unsigned int i;
+    /* damn, we overflowed */
+    for (i = 0; i < MAVARS_HASH_SIZE; i++)
+      ma_hash_table[i].timestmp = 0;
+    time = ++timestamp;
+  }
+  ma_h_top = top;
+  return(time);
+}
+
+#endif