linux汇编:如何调用syscall？

Question

我想在汇编中调用一个系统调用.问题是我做不到mov ecx,rsp.rsp是64位寄存器,ecx是32位寄存器.我想将缓冲区addr作为此系统调用的参数传递.我能做什么？谢谢.

section .data 
s0: db "Largest basic function number supported:%s\n",0
s0len: equ $-s0

section .text 
global main
extern write
main: 
sub rsp, 16
xor eax, eax
cpuid

mov [rsp], ebx
mov [rsp+4], edx
mov [rsp+8], ecx 
mov [rsp+12], word 0x0

mov eax, 4
mov ebx, 1
mov ecx, rsp
mov edx, 4 
int 80h

mov eax, 4
mov ebx, 1
mov ecx, s0
mov edx, s0len 
int 80h

mov eax, 1
int 80h

Answer 1

要在64位Linux中进行系统调用,请将系统调用号放在rax中,然后将其参数按顺序放在rdi,rsi,rdx,r10,r8和r9中,然后调用syscall.

这是一个例子

        .global _start

        .text
_start:
        # write(1, message, 13)
        mov     $1, %rax                # system call 1 is write
        mov     $1, %rdi                # file handle 1 is stdout
        lea     message(%rip), %rsi     # address of string to output
        mov     $13, %rdx               # number of bytes
        syscall

        # exit(0)
        mov     $60, %rax               # system call 60 is exit
        xor     %rdi, %rdi              # return code 0
        syscall

.section .rodata           # read-only data section
message:
        .ascii  "Hello, World\n"