= malloc, mallocz, smalloc, free, realloc, calloc: kernel memory allocators     void* malloc(ulong size)     void* mallocz(ulong size, int clr)     void* smalloc(ulong size)     void* realloc(void *p, ulong size)     void* calloc(ulong n, ulong szelem)     void  free(void *p) These functions allocate memory from the mainmem memory pool.All but smalloc (which sleeps) may safely be called by inter‐rupt handlers. Malloc returns a pointer to a block of at least  size  bytes,initialised  to  zero.   The  result  is  aligned on a 32-bitboundary.  Mallocz is similar, but only clears the memory  ifclr is non-zero. Smalloc  returns  a  pointer  to  a block of size bytes, ini‐tialised to zero.  If the memory is  not  immediately  avail‐able, smalloc retries every 100 milliseconds until the memoryis acquired. Calloc returns a pointer to a block of  memory  of  at  leastn*szelem bytes, initialised to zero. Realloc changes the size of the block pointed to by p to sizebytes, if possible without moving the  data,  and  returns  apointer  to  the block.  The contents are unchanged up to thelesser of old and new sizes, and any new space  allocated  isinitialised to zero.  If p is a null pointer, realloc returnsthe equivalent of malloc(size). The argument to free is a pointer to a block of memory  allo‐cated  by one of the routines above, which is returned to theallocation pool, or a null pointer, which is ignored. == diagnosticsAll functions except smalloc return a null pointer  if  spaceis unavailable. == see ALSOxalloc(10.2)