diff options
Diffstat (limited to '')
| -rw-r--r-- | cpukit/ChangeLog | 5 | ||||
| -rw-r--r-- | cpukit/score/include/rtems/score/heap.h | 16 | ||||
| -rw-r--r-- | cpukit/score/src/heap.c | 3 |
3 files changed, 13 insertions, 11 deletions
diff --git a/cpukit/ChangeLog b/cpukit/ChangeLog index 1a0a9be0ac..5d9bc7eff2 100644 --- a/cpukit/ChangeLog +++ b/cpukit/ChangeLog @@ -1,3 +1,8 @@ +2009-09-25 Sebastian Huber <Sebastian.Huber@embedded-brains.de> + + * score/src/heap.c, score/include/rtems/score/heap.h: Reduced alignment + requirement for CPU_ALIGNMENT from four to two. + 2009-09-25 Joel Sherrill <joel.sherrill@OARcorp.com> * posix/include/rtems/posix/threadsup.h: Add no return atrribute to diff --git a/cpukit/score/include/rtems/score/heap.h b/cpukit/score/include/rtems/score/heap.h index 10a267526e..c2286bf2af 100644 --- a/cpukit/score/include/rtems/score/heap.h +++ b/cpukit/score/include/rtems/score/heap.h @@ -38,12 +38,10 @@ extern "C" { * area. A heap control structure contains control information for the heap. * * The alignment routines could be made faster should we require only powers of - * two to be supported both for page size, alignment and boundary arguments. - * However, both workspace and malloc heaps are initialized with - * CPU_HEAP_ALIGNMENT as page size, and while all the BSPs seem to use - * CPU_ALIGNMENT (that is power of two) as CPU_HEAP_ALIGNMENT, for whatever - * reason CPU_HEAP_ALIGNMENT is only required to be multiple of CPU_ALIGNMENT - * and explicitly not required to be a power of two. + * two to be supported for page size, alignment and boundary arguments. The + * minimum alignment requirement for pages is currently CPU_ALIGNMENT and this + * value is only required to be multiple of two and explicitly not required to + * be a power of two. * * There are two kinds of blocks. One sort describes a free block from which * we can allocate memory. The other blocks are used and provide an allocated @@ -167,9 +165,9 @@ typedef struct Heap_Block { * If the flag @c HEAP_PREV_BLOCK_USED is set, then the previous block is * used, otherwise the previous block is free. A used previous block may * claim the @a prev_size field for allocation. This trick allows to - * decrease the overhead in the used blocks by the size of the - * @a prev_size field. As sizes are always multiples of four, the two least - * significant bits are always zero. We use one of them to store the flag. + * decrease the overhead in the used blocks by the size of the @a prev_size + * field. As sizes are required to be multiples of two, the least + * significant bits would be always zero. We use this bit to store the flag. * * This field is always valid. */ diff --git a/cpukit/score/src/heap.c b/cpukit/score/src/heap.c index b12bdd8fab..c851334679 100644 --- a/cpukit/score/src/heap.c +++ b/cpukit/score/src/heap.c @@ -26,7 +26,7 @@ #include <rtems/system.h> #include <rtems/score/heap.h> -#if CPU_ALIGNMENT == 0 || CPU_ALIGNMENT % 4 != 0 +#if CPU_ALIGNMENT == 0 || CPU_ALIGNMENT % 2 != 0 #error "invalid CPU_ALIGNMENT value" #endif @@ -213,7 +213,6 @@ uintptr_t _Heap_Initialize( stats->resizes = 0; stats->instance = instance++; - _HAssert( _Heap_Is_aligned( CPU_ALIGNMENT, 4 ) ); _HAssert( _Heap_Is_aligned( heap->page_size, CPU_ALIGNMENT ) ); _HAssert( _Heap_Is_aligned( heap->min_block_size, page_size ) ); _HAssert( |