1 files changed, 147 insertions, 0 deletions
diff --git a/bsps/powerpc/shared/start/sbrk.c b/bsps/powerpc/shared/start/sbrk.c
new file mode 100644
index 0000000000..f17a1511e4
--- /dev/null
+++ b/bsps/powerpc/shared/start/sbrk.c
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+/*
+ *  sbrk.c
+ *
+ * Authorship
+ * ----------
+ * This software was created by
+ *     Till Straumann <strauman@slac.stanford.edu>, 2002,
+ *        Stanford Linear Accelerator Center, Stanford University.
+ *
+ * Acknowledgement of sponsorship
+ * ------------------------------
+ * This software was produced by
+ *     the Stanford Linear Accelerator Center, Stanford University,
+ *        under Contract DE-AC03-76SFO0515 with the Department of Energy.
+ *
+ * Government disclaimer of liability
+ * ----------------------------------
+ * Neither the United States nor the United States Department of Energy,
+ * nor any of their employees, makes any warranty, express or implied, or
+ * assumes any legal liability or responsibility for the accuracy,
+ * completeness, or usefulness of any data, apparatus, product, or process
+ * disclosed, or represents that its use would not infringe privately owned
+ * rights.
+ *
+ * Stanford disclaimer of liability
+ * --------------------------------
+ * Stanford University makes no representations or warranties, express or
+ * implied, nor assumes any liability for the use of this software.
+ *
+ * Stanford disclaimer of copyright
+ * --------------------------------
+ * Stanford University, owner of the copyright, hereby disclaims its
+ * copyright and all other rights in this software.  Hence, anyone may
+ * freely use it for any purpose without restriction.
+ *
+ * Maintenance of notices
+ * ----------------------
+ * In the interest of clarity regarding the origin and status of this
+ * SLAC software, this and all the preceding Stanford University notices
+ * are to remain affixed to any copy or derivative of this software made
+ * or distributed by the recipient and are to be affixed to any copy of
+ * software made or distributed by the recipient that contains a copy or
+ * derivative of this software.
+ *
+ * ------------------ SLAC Software Notices, Set 4 OTT.002a, 2004 FEB 03
+ */
+
+/*
+ *  Hack around the 32bit powerpc 32M problem:
+ *
+ *  GCC by default uses relative branches which can not jump
+ *  farther than 32M. Hence all program text is confined to
+ *  a single 32M segment.
+ *  This hack gives the RTEMS malloc region all memory below
+ *  32M at startup. Only when this region is exhausted will sbrk
+ *  add more memory. Loading modules may fail at that point, hence
+ *  the user is expected to load all modules at startup _prior_
+ *  to malloc()ing lots of memory...
+ *
+ *  NOTE: it would probably be better to have a separate region
+ *        for module code.
+ */
+
+#include <errno.h>
+#include <unistd.h>
+
+#include <bsp/bootcard.h>
+
+#define INVALID_REMAINING_START ((uintptr_t) -1)
+
+static uintptr_t remaining_start = INVALID_REMAINING_START;
+static uintptr_t remaining_size = 0;
+
+/* App. may provide a value by defining the BSP_sbrk_policy
+ * variable.
+ *
+ *  (-1) -> give all memory to the heap at initialization time
+ *  > 0  -> value used as sbrk amount; initially give 32M
+ *    0  -> limit memory effectively to 32M.
+ *
+ */
+extern uintptr_t        BSP_sbrk_policy[] __attribute__((weak));
+
+#define LIMIT_32M  0x02000000
+
+ptrdiff_t bsp_sbrk_init(Heap_Area *area, uintptr_t min_size)
+{
+  uintptr_t         rval = 0;
+  uintptr_t         policy;
+  uintptr_t         remaining_end;
+
+  remaining_start = (uintptr_t) area->begin;
+  remaining_size  = area->size;
+  remaining_end   = remaining_start + remaining_size;
+
+  if (remaining_start < LIMIT_32M &&
+      remaining_end > LIMIT_32M &&
+      min_size <= LIMIT_32M - remaining_start) {
+    /* clip at LIMIT_32M */
+    rval = remaining_end - LIMIT_32M;
+    area->size = LIMIT_32M - remaining_start;
+    remaining_start = LIMIT_32M;
+    remaining_size  = rval;
+  }
+
+  policy = (0 == BSP_sbrk_policy[0] ? (uintptr_t)(-1) : BSP_sbrk_policy[0]);
+  switch ( policy ) {
+      case (uintptr_t)(-1):
+        area->size      += rval;
+        remaining_start  = (uintptr_t) area->begin + area->size;
+        remaining_size   = 0;
+      break;
+
+      case 0:
+        remaining_size = 0;
+      break;
+
+      default:
+        if ( rval > policy )
+          rval = policy;
+      break;
+  }
+
+  return (ptrdiff_t) (rval <= PTRDIFF_MAX ? rval : rval / 2);
+}
+
+/*
+ * This is just so the sbrk test can force its magic. All normal applications
+ * should just use the default implementation in this file.
+ */
+void *sbrk(ptrdiff_t incr) __attribute__ (( weak, alias("bsp_sbrk") ));
+static void *bsp_sbrk(ptrdiff_t incr)
+{
+  void *rval=(void*)-1;
+
+  if ( remaining_start != INVALID_REMAINING_START && incr <= remaining_size) {
+    remaining_size-=incr;
+    rval = (void *) remaining_start;
+    remaining_start += incr;
+  } else {
+    errno = ENOMEM;
+  }
+  #ifdef DEBUG
+    printk("************* SBRK 0x%08x (ret 0x%08x) **********\n", incr, rval);
+  #endif
+  return rval;
+}