$ ./Foundation_v8pkg/Foundation_v8 --image ./Foundation_v8pkg/example/hello.axf
terminal_0: Listening for serial connection on port 5000
terminal_1: Listening for serial connection on port 5001
terminal_2: Listening for serial connection on port 5002
terminal_3: Listening for serial connection on port 5003
Simulation is started
Hello, 64-bit world!
$
它正常退出命令行提示符。我想写一个可以在裸机上运行的最小装配程序，但我不知道如何操作。所以我使用linaro armv8 toolchain反汇编hello.axf来寻找一些线索：
aarch64-linux-gnu-objdump -S hello.axf
并获取exit子例程：
1663 00000000800017c8 <_sys_exit>:
1664 800017c8: d10043ff sub sp, sp, #0x10
1665 800017cc: d28004c1 movz x1, #0x26
1666 800017d0: f2a00041 movk x1, #0x2, lsl #16
1667 800017d4: f90003e1 str x1, [sp]
1668 800017d8: 93407c00 sxtw x0, w0
1669 800017dc: f90007e0 str x0, [sp,#8]
1670 800017e0: 910003e1 mov x1, sp
1671 800017e4: 52800300 movz w0, #0x18
1672 800017e8: d45e0000 hlt #0xf000
1673 800017ec: 14000000 b 800017ec <_sys_exit+0x24>
我编写了一个汇编文件test.s，其中只包含exit snippet：
.section .text, "ax"
.global _start
_start:
sub sp, sp, #0x10
movz x1, #0x26
movk x1, #0x2, lsl #16
str x1, [sp]
sxtw x0, w0
str x0, [sp,#8]
mov x1, sp
movz w0, #0x18
hlt #0xf000
b .
用以下内容构建它：
aarch64-linux-gnu-as test.s -o a.out
aarch64-linux-gnu-ld -Ttext=0x80000000 a.out -o test
使用以下命令运行：
$ ./Foundation_v8pkg/Foundation_v8 --image test
terminal_0: Listening for serial connection on port 5000
terminal_1: Listening for serial connection on port 5001
terminal_2: Listening for serial connection on port 5002
terminal_3: Listening for serial connection on port 5003
Simulation is started
模拟器正在运行，但它无法正常退出命令行，就像上面的hello.axf示例一样。对不起详细说明。我的问题是如何在ARMv8 Foundation Model上编写最小裸机装配程序。