From 7acfca905d76140f4cc0b09c9a12de237de364cd Mon Sep 17 00:00:00 2001
From: Nick Barnes
Date: Wed, 31 Oct 2001 14:40:56 +0000
Subject: Branch imports for masters.

Copied from Perforce
 Change: 23678
 ServerID: perforce.ravenbrook.com

---
 mps/code/boot.c | 125 ++++++++++++++++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 125 insertions(+)
 create mode 100644 mps/code/boot.c

(limited to 'mps/code/boot.c')

diff --git a/mps/code/boot.c b/mps/code/boot.c
new file mode 100644
index 00000000000..7888c8e381e
--- /dev/null
+++ b/mps/code/boot.c
@@ -0,0 +1,125 @@
+/* impl.c.boot: BOOTSTRAP ALLOCATOR
+ *
+ * $HopeName: MMsrc!boot.c(MMdevel_pekka_locus.2) $
+ * Copyright (C) 1999 Harlequin Limited.  All rights reserved.
+ *
+ * .overview: A structure and protocols for allocating memory from a
+ * given block.  Very simple, it basically just increments a pointer.
+ *
+ * .boot.c: The Bootstrap Allocator is used to allocate C structures
+ * for use in the implementation, not client objects.  Therefore,
+ * we use "C types" (void *, size_t) not "client types" (Addr, Size).
+ */
+
+#include "boot.h"
+#include "mpm.h"
+
+SRCID(boot, "$HopeName: MMsrc!boot.c(MMdevel_pekka_locus.2) $");
+
+
+#define BootBlockSig ((Sig)0x519B002B) /* SIGnature BOOT Block */
+
+
+/* BootBlockCheck -- check a BootBlock structure */
+
+Bool BootBlockCheck(BootBlock boot)
+{
+  CHECKS(BootBlock, boot);
+  CHECKL(boot->base != NULL);
+  CHECKL(boot->alloc != NULL);
+  CHECKL(boot->limit != NULL);
+  CHECKL(boot->base <= boot->alloc);
+  CHECKL(boot->alloc <= boot->limit);
+  CHECKL(boot->alloc < boot->limit);
+
+  return TRUE;
+}
+
+
+/* BootBlockInit -- initialize a BootBlock
+ *
+ * boot: a pointer to the structure to be initialized
+ *   (must have been allocated by the caller, probably on the stack).
+ * base: a pointer to the base of the memory to be allocated from
+ *   from (the memory need not be committed)
+ * limit: a pointer to the limit of the memory to be allocated from
+ */
+
+Res BootBlockInit(BootBlockStruct *boot, void *base, void *limit)
+{
+  /* Can't check boot as we are supposed to be initializing it */
+  AVER(boot != NULL);
+  AVER(base != NULL);
+  AVER(limit != NULL);
+  AVER(base < limit);
+
+  boot->base = base;
+  boot->alloc = base;
+  boot->limit = limit;
+  boot->sig = BootBlockSig;
+
+  AVERT(BootBlock, boot);
+  return ResOK;
+}
+
+
+/* BootBlockFinish -- finish a BootBlock structure */
+
+void BootBlockFinish(BootBlock boot)
+{
+  AVERT(BootBlock, boot);
+
+  boot->base = boot->alloc = boot->limit = NULL;
+  boot->sig = SigInvalid;
+}
+
+
+/* BootAllocated
+ *
+ * Returns the total amount allocated using this descriptor
+ */
+size_t BootAllocated(BootBlock boot)
+{
+  AVERT(BootBlock, boot);
+
+  return PointerOffset(boot->base, boot->alloc);
+}
+
+
+/* BootAlloc -- allocate from BootBlock structure
+ *
+ * preturn: The returned pointer, see .boot.c.
+ * boot: must have been initialized with BootBlockInit().
+ * size: size of requested object, see .boot.c.
+ * align: required alignment of object, see .boot.c.
+ */
+
+Res BootAlloc(void **pReturn, BootBlock boot, size_t size, size_t align)
+{
+  void *blockBase, *blockLimit;  /* base, limit of candidate block */
+
+  AVER(pReturn != NULL);
+  AVERT(BootBlock, boot);
+  AVER(size > 0);
+  AVER(AlignCheck((Align)align));
+
+  /* Align alloc pointer up and bounds check. */
+  blockBase = PointerAlignUp(boot->alloc, align);
+  if(boot->limit <= blockBase || blockBase < boot->alloc) {
+    return ResMEMORY;
+  }
+  blockLimit = PointerAdd(blockBase, size);
+  /* Following checks that the ordering constraint holds: */
+  /* boot->alloc <= blockBase < blockLimit <= boot->limit */
+  /* (if it doesn't hold then something overallocated/wrapped round) */
+  if(blockBase < boot->alloc ||
+     blockLimit <= blockBase ||
+     boot->limit < blockLimit) {
+    return ResMEMORY;
+  }
+
+  /* Fits!  So allocate it */
+  boot->alloc = blockLimit;
+  *pReturn = blockBase;
+  return ResOK;
+}
-- 
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