diff --git a/C/alloc.c b/C/alloc.c
index 76ebeb4ed..0ed147aa0 100644
--- a/C/alloc.c
+++ b/C/alloc.c
@@ -88,7 +88,7 @@ minfo(char mtype)
 #endif
 
 static inline char *
-call_malloc(unsigned int size)
+call_malloc(unsigned long int size)
 {
   char *out;
 #if INSTRUMENT_MALLOC
@@ -104,7 +104,7 @@ call_malloc(unsigned int size)
 }
 
 char *
-Yap_AllocCodeSpace(unsigned int size)
+Yap_AllocCodeSpace(unsigned long int size)
 {
   return  call_malloc(size);
 }
@@ -124,7 +124,7 @@ Yap_FreeCodeSpace(char *p)
 }
 
 char *
-Yap_AllocAtomSpace(unsigned int size)
+Yap_AllocAtomSpace(unsigned long int size)
 {
   return call_malloc(size);
 }
@@ -353,8 +353,8 @@ Yap_givemallinfo(void)
 #if !USE_DL_MALLOC
 
 STATIC_PROTO(void FreeBlock, (BlockHeader *));
-STATIC_PROTO(BlockHeader *GetBlock, (unsigned int));
-STATIC_PROTO(char *AllocHeap, (unsigned int));
+STATIC_PROTO(BlockHeader *GetBlock, (unsigned long int));
+STATIC_PROTO(char *AllocHeap, (unsigned long int));
 STATIC_PROTO(void RemoveFromFreeList, (BlockHeader *));
 STATIC_PROTO(void AddToFreeList, (BlockHeader *));
 
@@ -480,7 +480,7 @@ FreeBlock(BlockHeader *b)
 }
 
 static BlockHeader *
-GetBlock(unsigned int n)
+GetBlock(unsigned long int n)
 {				/* get free block with size at least n */
   register BlockHeader **p, *b, *r;
 
@@ -509,7 +509,7 @@ GetBlock(unsigned int n)
 }
 
 static char *
-AllocHeap(unsigned int size)
+AllocHeap(unsigned long int size)
 {
   BlockHeader *b, *n;
   YAP_SEG_SIZE *sp;
@@ -609,7 +609,7 @@ FreeCodeSpace(char *p)
 }
 
 static char *
-AllocCodeSpace(unsigned int size)
+AllocCodeSpace(unsigned long int size)
 {
   if (size < SmallSize + 2 * OpCodeSize + 3 * CellSize)
     return (AllocHeap(SmallSize + 2 * OpCodeSize + 3 * CellSize));
@@ -634,7 +634,7 @@ Yap_FreeCodeSpace(char *p)
 }
 
 char *
-Yap_AllocAtomSpace(unsigned int size)
+Yap_AllocAtomSpace(unsigned long int size)
 {
   char *out = AllocHeap(size);
 #if DEBUG_ALLOC
@@ -654,7 +654,7 @@ Yap_FreeAtomSpace(char *p)
 }
 
 char *
-Yap_AllocCodeSpace(unsigned int size)
+Yap_AllocCodeSpace(unsigned long int size)
 {
   char *out = AllocCodeSpace(size);
 #if DEBUG_ALLOC
@@ -1361,9 +1361,9 @@ Yap_InitHeap(void *heap_addr)
 }
 
 void
-Yap_InitMemory(int Trail, int Heap, int Stack)
+Yap_InitMemory(UInt Trail, UInt Heap, UInt Stack)
 {
-  Int pm, sa, ta;
+  UInt pm, sa, ta;
 
   pm = (Trail + Heap + Stack);	/* memory to be
 				 * requested         */
diff --git a/C/init.c b/C/init.c
index 638e23574..54b3b36ba 100644
--- a/C/init.c
+++ b/C/init.c
@@ -1289,7 +1289,7 @@ InitVersion(void)
 
 
 void
-Yap_InitWorkspace(int Heap, int Stack, int Trail, int max_table_size, 
+Yap_InitWorkspace(UInt Heap, UInt Stack, UInt Trail, UInt max_table_size, 
                   int n_workers, int sch_loop, int delay_load)
 {
   int             i;
diff --git a/H/Yapproto.h b/H/Yapproto.h
index 5c7c007aa..22b4d4152 100644
--- a/H/Yapproto.h
+++ b/H/Yapproto.h
@@ -87,13 +87,13 @@ void    STD_PROTO(Yap_init_agc, (void));
 
 /* alloc.c */
 void	STD_PROTO(Yap_FreeCodeSpace,(char *));
-char   *STD_PROTO(Yap_AllocAtomSpace,(unsigned int));
-char   *STD_PROTO(Yap_AllocCodeSpace,(unsigned int));
+char   *STD_PROTO(Yap_AllocAtomSpace,(unsigned long int));
+char   *STD_PROTO(Yap_AllocCodeSpace,(unsigned long int));
 ADDR	STD_PROTO(Yap_AllocFromForeignArea,(Int));
 int     STD_PROTO(Yap_ExtendWorkSpace,(Int));
 void	STD_PROTO(Yap_FreeAtomSpace,(char *));
 int     STD_PROTO(Yap_FreeWorkSpace, (void));
-void	STD_PROTO(Yap_InitMemory,(int,int,int));
+void	STD_PROTO(Yap_InitMemory,(UInt,UInt,UInt));
 void	STD_PROTO(Yap_InitExStacks,(int,int));
 
 /* amasm.c */
@@ -221,7 +221,7 @@ void	STD_PROTO(Yap_InitCPredBack,(char *, unsigned long int, unsigned int, CPred
 void	STD_PROTO(Yap_InitCPredBackCut,(char *, unsigned long int, unsigned int, CPredicate,CPredicate,CPredicate,int));
 void    STD_PROTO(Yap_InitCPredBack_,(char *, unsigned long int, unsigned int, CPredicate,CPredicate,CPredicate,int));
 #endif
-void	STD_PROTO(Yap_InitWorkspace,(int,int,int,int,int,int,int));
+void	STD_PROTO(Yap_InitWorkspace,(UInt,UInt,UInt,UInt,int,int,int));
 
 #if defined(YAPOR) || defined(THREADS)
 void	STD_PROTO(Yap_KillStacks,(int));