用arm64汇编编写一个刷新cache的代码

下面是一个简单的 ARM64 汇编代码，用于刷新缓存：

.global _start

.section .data
msg:
    .ascii "Cache flushed.\n\0"

.section .text
_start:
    ; Flush cache using DC CVAC instruction
    mov x0, #0
    mrs x1, s3_0_c15_c10_1 ; Read CLIDR_EL1
    and x2, x1, #0x7 ; Extract Cache level
    lsr x1, x1, #3 ; Shift to Type field
    ubfx x1, x1, #0, #3 ; Extract Type field
    cmp x2, #0 ; Check if Cache level is greater than 0
    b.ge done ; If not, skip cache flush
    mov x3, #0 ; Set cache line pointer to 0
1:
    ; Clean cache line by line
    dc cvac, x3
    add x3, x3, #64 ; Increment cache line pointer by 64 bytes
    cmp x3, x0 ; Check if cache line pointer is equal to 0
    b.ne 1b ; If not, continue cleaning cache
done:
    ; Print message to console
    adr x0, msg
    mov x1, #1
    mov x2, #14
    mov x8, #4
    svc #0

    ; Exit program
    mov x0, #0
    mov x8, #93
    svc #0

这个代码使用 `DC CVAC` 汇编指令来刷新缓存。它通过读取 `CLIDR_EL1` 寄存器来确定缓存的级别，然后使用 `DC CVAC` 指令逐行清除缓存。然后，它使用 `svc #0` 系统调用来将消息打印到控制台，并使用 `svc #0` 系统调用来退出程序。