From 0bf3db5df7fb8749c5ff0f386558260dc127b9df Mon Sep 17 00:00:00 2001
From: bg- <bg->
Date: Fri, 11 Aug 2006 13:41:31 +0000
Subject: [PATCH] Make malloc machine independent by relying on dependent
 sbrk(2).

---
 core/lib/malloc.c           | 34 +++++++++++++++-------------------
 core/lib/malloc.h           |  3 ++-
 cpu/msp430/msp430.c         | 30 +++++++++++++++++++++++++++++-
 platform/sky/contiki-conf.h |  7 ++-----
 4 files changed, 48 insertions(+), 26 deletions(-)

diff --git a/core/lib/malloc.c b/core/lib/malloc.c
index a06404596..134047c5d 100644
--- a/core/lib/malloc.c
+++ b/core/lib/malloc.c
@@ -30,7 +30,7 @@
 */
  
  
-/* $Id: malloc.c,v 1.1 2006/06/17 22:41:18 adamdunkels Exp $ */
+/* $Id: malloc.c,v 1.2 2006/08/11 13:41:31 bg- Exp $ */
 
 #include <stdlib.h>
 
@@ -54,6 +54,8 @@ char mymem[256];
  * with the data segment.
  */
  
+char *__malloc_heap_end;
+
 char *__brkval;
 struct __freelist *__flp;
 
@@ -64,7 +66,7 @@ malloc(size_t len)
 {
 	struct __freelist *fp1, *fp2;
 	char *cp;
-	size_t s, avail;
+	size_t s;
 
 	if (len <= 0)
 	    return 0;
@@ -161,23 +163,17 @@ malloc(size_t len)
 	 * that we don't collide with the stack.
 	 */
 	if (__brkval == 0)
-		__brkval = __malloc_heap_start;
-	cp = __malloc_heap_end;
-	avail = cp - __brkval;
-	/*
-	 * Both tests below are needed to catch the case len >= 0xfffe.
-	 */
-	if (avail >= len && avail >= len + sizeof(struct __freelist)) {
-		fp1 = (struct __freelist *)__brkval;
-		__brkval += len + sizeof(struct __freelist);
-		fp1->sz = len;
-		fp1->handle = NULL;
-		return &fp1[1];
-	}
-	/*
-	 * Step 4: There's no help, just fail. :-/
-	 */
-	return 0;
+		__brkval = sbrk(len + sizeof(struct __freelist));
+	else if (sbrk(len + sizeof(struct __freelist)) == (void *)-1)
+		return 0;	/* There's no help, just fail. :-/ */
+
+	__malloc_heap_end = sbrk(0);
+
+	fp1 = (struct __freelist *)__brkval;
+	__brkval += len + sizeof(struct __freelist);
+	fp1->sz = len;
+	fp1->handle = NULL;
+	return &fp1[1];
 }
 
 void
diff --git a/core/lib/malloc.h b/core/lib/malloc.h
index af8e6bc72..2a2eb3b69 100644
--- a/core/lib/malloc.h
+++ b/core/lib/malloc.h
@@ -27,7 +27,7 @@
   POSSIBILITY OF SUCH DAMAGE.
 */
 
-/* $Id: malloc.h,v 1.1 2006/06/17 22:41:18 adamdunkels Exp $ */
+/* $Id: malloc.h,v 1.2 2006/08/11 13:41:31 bg- Exp $ */
 
 #ifndef MALLOC_H
 #define MALLOC_H
@@ -57,6 +57,7 @@ void free(void *ptr);
 
 extern char *__brkval;		/* first location not yet allocated */
 extern struct __freelist *__flp; /* freelist pointer (head of freelist) */
+extern char *__malloc_heap_end;
 
 #define MALLOC_ROUNDUP (sizeof(int) - 1)
 
diff --git a/cpu/msp430/msp430.c b/cpu/msp430/msp430.c
index d13ece846..094fb85f1 100644
--- a/cpu/msp430/msp430.c
+++ b/cpu/msp430/msp430.c
@@ -28,10 +28,11 @@
  *
  * This file is part of the Contiki operating system.
  *
- * @(#)$Id: msp430.c,v 1.1 2006/06/17 22:41:21 adamdunkels Exp $
+ * @(#)$Id: msp430.c,v 1.2 2006/08/11 13:41:31 bg- Exp $
  */
 #include <io.h>
 #include <signal.h>
+#include <sys/unistd.h>
 
 #include "net/uip.h"
 
@@ -160,6 +161,33 @@ msp430_cpu_init(void)
 
 #define asmv(arg) __asm__ __volatile__(arg)
 
+#define STACK_EXTRA 32
+static char *cur_break = (char *)&__bss_end;
+
+/*
+ * Allocate memory from the heap. Check that we don't collide with the
+ * stack right now (some other routine might later). A watchdog might
+ * be used to check if cur_break and the stack pointer meet during
+ * runtime.
+ */
+void *
+sbrk(int incr)
+{
+  char *stack_pointer;
+
+  asmv("mov r1, %0" : "=r" (stack_pointer));
+  stack_pointer -= STACK_EXTRA;
+  if(incr > (stack_pointer - cur_break))
+    return (void *)-1;		/* ENOMEM */
+
+  void *old_break = cur_break;
+  cur_break += incr;
+  /*
+   * If the stack was never here then [old_break .. cur_break] should
+   * be filled with zeros.
+  */
+  return old_break; }
+
 /*
  * Mask all interrupts that can be masked.
  */
diff --git a/platform/sky/contiki-conf.h b/platform/sky/contiki-conf.h
index 320f71335..60aeb9549 100644
--- a/platform/sky/contiki-conf.h
+++ b/platform/sky/contiki-conf.h
@@ -1,5 +1,5 @@
 /* -*- C -*- */
-/* @(#)$Id: contiki-conf.h,v 1.1 2006/08/02 14:44:46 bg- Exp $ */
+/* @(#)$Id: contiki-conf.h,v 1.2 2006/08/11 13:41:31 bg- Exp $ */
 
 #ifndef CONTIKI_CONF_H
 #define CONTIKI_CONF_H
@@ -8,6 +8,7 @@
 #define UAODV_BAD_ROUTE
 
 /* Helper prototypes that should go somewhere. */
+void   *sbrk(int);
 void    splx_(int);
 int     splhigh_(void);
 void msp430_cpu_init(void);	/* Rename to cpu_init() later! */
@@ -54,10 +55,6 @@ void msp430_cpu_init(void);	/* Rename to cpu_init() later! */
 /* Button sensors. */
 #define IRQ_PORT2 0x02
 
-/* Reserve 64 bytes (only) for the runtime stack. */
-#define __malloc_heap_start ((char *)&__bss_end)
-#define __malloc_heap_end  (((char *)&__stack) - 64)
-
 typedef unsigned char u8_t;
 typedef unsigned short u16_t;
 typedef unsigned long u32_t;