[lwip-users] NIOS II port: Request for memory alignement macro to be included in lwip source

[Jan Ulvesten]

Hi

In Alteras uCOS II port of lwIP for NIOS II, 3 source files have been
changed.

__attribute__ ((aligned (MEM_ALIGNMENT))) is added to a few defs (5) to
control the memory alignment (gnu C syntax).

Patching the standard code base is by no mean the preferred method of
targeting alignment. I suppose that an array is always aligned at an
even boundary, but the 4-byte alignment is only achieved using
__attribute__ ((aligned (4))). 

It could easily be avoided adding a macro the defs below, e.g.:

#define MEM_ALIGMENT_ATTR __attribute__ ((aligned (MEM_ALIGNMENT)))

- or -

#define MEM_ALIGMENT_ATTR

The definition could then be:

static u8_t ram[MEM_SIZE + sizeof(struct mem) + MEM_ALIGNMENT]
MEM_ALIGMENT_ATTR;


Altera changes:

------------------------------------------------------------------------
----
mem.c                 
static u8_t ram[MEM_SIZE + sizeof(struct mem) + MEM_ALIGNMENT]
__attribute__ ((aligned (MEM_ALIGNMENT)));

------------------------------------------------------------------------
----ipfrag.c:
static u8_t ip_reassbuf[IP_HLEN + IP_REASS_BUFSIZE] __attribute__
((aligned (MEM_ALIGNMENT)));

static u8_t ip_reassbitmap[IP_REASS_BUFSIZE / (8 * 8)] __attribute__
((aligned (MEM_ALIGNMENT)));

static u8_t ip_reassbuf[IP_HLEN + IP_REASS_BUFSIZE] __attribute__
((aligned (MEM_ALIGNMENT)));

------------------------------------------------------------------------
----pbuf.c
static u8_t pbuf_pool_memory[(PBUF_POOL_SIZE *
MEM_ALIGN_SIZE(PBUF_POOL_BUFSIZE + sizeof(struct pbuf)))] __attribute__
((aligned (MEM_ALIGNMENT)));

------------------------------------------------------------------------
----




+ in dhcp.h a 
#if LWIP_DHCP==1 could be used to avoid defining protos when DHCP is
disabled.



Jan Ulvesten
SICOM