Add a up_stack_frame() interface to allocate a frame of data on a task's stack.

git-svn-id: svn://svn.code.sf.net/p/nuttx/code/trunk@5768 42af7a65-404d-4744-a932-0658087f49c3

1 files changed, 6 insertions, 8 deletions

diff --git a/nuttx/arch/z80/src/common/up_usestack.c b/nuttx/arch/z80/src/common/up_usestack.c
index 095b4f5d5..414040ec2 100644
--- a/nuttx/arch/z80/src/common/up_usestack.c
+++ b/nuttx/arch/z80/src/common/up_usestack.c
@@ -106,18 +106,16 @@ int up_use_stack(struct tcb_s *tcb, void *stack, size_t stack_size)
 
   tcb->stack_alloc_ptr = stack;
 
-  /* The Arm7Tdmi uses a push-down stack:  the stack grows
-   * toward loweraddresses in memory.  The stack pointer
-   * register, points to the lowest, valid work address
-   * (the "top" of the stack).  Items on the stack are
-   * referenced as positive word offsets from sp.
+  /* The Z80 uses a push-down stack:  the stack grows toward lower
+   * addresses in memory.  The stack pointer register, points to the
+   * lowest, valid work address (the "top" of the stack).  Items on
+   * the stack are* referenced as positive word offsets from sp.
    */
 
   top_of_stack = (uint32_t)tcb->stack_alloc_ptr + stack_size - 4;
 
-  /* The Arm7Tdmi stack must be aligned at word (4 byte)
-   * boundaries. If necessary top_of_stack must be rounded
-   * down to the next boundary
+  /* The Z80 stack does not need to be aligned.  Here is is aligned at
+   * word (4 byte) boundary.
    */
 
   top_of_stack &= ~3;