nuttx/arch/sim
YAMAMOTO Takashi 7f307f9765 sim: Restore stack alignemnt
Reapply the following commit [1], which has been reverted by
the recent change [2] with no obvious reasons.

Also, add a comment block to explain the calculation.

[1]
```
commit 298c2e5e4f
Author: YAMAMOTO Takashi <yamamoto@midokura.com>
Date:   Wed Jan 29 03:26:43 2020 +0900

    sim: Fix stack alignment

    The recent x86-64 convention requires 16-byte alignment before
    (not after) calling a function.

    This fixes snprintf crash I observed on macOS while saving XMM registers.
```

[2]
```
commit 2335b69120
Author: Xiang Xiao <xiaoxiang@xiaomi.com>
Date:   Mon Apr 12 23:44:08 2021 +0800

    arch: Allocate the space from the beginning in up_stack_frame

    arch: Allocate the space from the beginning in up_stack_frame

    and modify the affected portion:
    1.Correct the stack dump and check
    2.Allocate tls_info_s by up_stack_frame too
    3.Move the stack fork allocation from arch to sched

    Signed-off-by: Xiang Xiao <xiaoxiang@xiaomi.com>
```
2021-04-19 01:29:38 -05:00
..
include arch/sim: Move setjmp/longjmp to libc/machine/sim 2021-04-05 09:00:42 -03:00
src sim: Restore stack alignemnt 2021-04-19 01:29:38 -05:00
Kconfig sim: add the simulated lower-half FOC device 2021-03-31 04:32:26 -05:00