Linux 新行字节0Ah被x86_64系统调用打印程序忽略
在创建NASM x86_64程序时，我遵循了一个简单的教程，该程序使用定义的函数打印变量，并在末尾添加一行新行。sprintLF调用sprint，sprint反过来打印rax中设置了适当系统调用的内容。返回时，sprintLF用0Ah更新rax的换行代码，然后将其推送到堆栈中，并将rax重新分配到堆栈地址0Ah，然后再次调用sprint，将换行代码写入stdout。下面是我在gdb中调试sprint的所有代码，这些代码显示所有正确的寄存器都存储了与系统调用4相关的值，我不知道为什么变量字符串被成功打印，而换行符没有被打印 呼叫代码Linux 新行字节0Ah被x86_64系统调用打印程序忽略,linux,assembly,stack,x86-64,system-calls,Linux,Assembly,Stack,X86 64,System Calls,在创建NASM x86_64程序时，我遵循了一个简单的教程，该程序使用定义的函数打印变量，并在末尾添加一行新行。sprintLF调用sprint，sprint反过来打印rax中设置了适当系统调用的内容。返回时，sprintLF用0Ah更新rax的换行代码，然后将其推送到堆栈中，并将rax重新分配到堆栈地址0Ah，然后再次调用sprint，将换行代码写入stdout。下面是我在gdb中调试sprint的所有代码，这些代码显示所有正确的寄存器都存储了与系统调用4相关的值，我不知道为什么变量字符串被成
;; Hello World Program (Externam file include)
;; Compile with: nasm -f elf64 helloworld-if.asm
;; Link with ld helloworld-if.o -o helloworld-if
;; Run with ./helloworld-inc
%include 'function.asm' ; include our external file
SECTION .data
msg1 db 'Hello, brave new world!', 0h ;our first message string add null terminating byte
msg2 db 'This is how we recycle in NASM.', 0h ; our second message string add null terminating byte
SECTION .text
global _start
_start:
mov rax, msg1 ; mov the address of our first message string into RAX
call sprintLF ; call our string printing function
mov rax, msg2 ; move the address of our second message string into RAX
call sprintLF ; call our string printing function
call quit ; call our quit function
; -------------------------------------------------------------------------------------------------------------------
; int slen(String message)
; String length calculation function
slen: ; this is our first function declaration
push rbx ; push the value in RBX onto the stack to preserve it while we use RBX in this function
mov rbx, rax ; move this address in RAX into RBX ( Both point to the same segment in memory)
nextchar:
cmp byte [rax], 0 ; this is the same as lesson 3
jz finished
inc rax
jmp nextchar
finished:
sub rax, rbx
pop rbx ; pop the value on the stack back into RBX
ret ; return to where the function was called
;; ---------------------------------------------------------------------------------------------------------
;; void sprint(String message)
;; String printing function
sprint:
push rdx
push rcx
push rbx
push rax
call slen
mov rdx, rax
pop rax
mov rcx, rax
mov rbx, 1
mov rax, 4
int 80h
pop rbx
pop rcx
pop rdx
ret
;; ----------------------------------------------------------------------------------------------------------
;; void sprintLF(String message)
;; String printing with line feed function
sprintLF:
call sprint
push rax ; push rax onto the stack to preserve it while we use the rax register in this function
mov rax, 0Ah ; push 0Ah into rax, 0Ah is the ascii character for a linefeed
push rax ; push the linefeede onto the stack so we can get the address
mov rax, rsp ; move the address of the current stack pointer into rax for sprint -> because write requires a memory address
call sprint ; call our sprint function
pop rax ; restore out linefeed character from the stack
pop rax ; return to our program
ret
;; -----------------------------------------------------------------------------------------------------------
;; void exit()
;; Exit program restore resources
quit:
mov rbx, 0
mov rax, 1
int 80h
ret
nasm -f elf64 helloworld-if.asm
ld helloworld-if.o -o hellworld-if
./hellworld-if
Hello, brave new world!This is how we recycle in NASM.
在另一个程序中，我尝试在将参数放入堆栈后打印参数，同样的情况也会发生，因此我只能猜测系统调用不喜欢从堆栈中获取其值，但我是汇编新手，这让我感到困惑。您一直在尝试将使用
int0x80int 0x80int 0x80int0x80mov-rax时，rspsprintint 0x80syscallsyscallsys\u writesprintsyscallsprint:
push r11 ; R11 and RCX are clobbered by syscall as well
push rcx
push rdx
push rsi
push rdi
push rax
call slen
mov rdx, rax ; RDX = number of characters to print
pop rax
mov rsi, rax ; RSI = address of characters to print
mov rdi, 1 ; RDI = file descriptor (1=STDOUT)
mov rax, 1 ; System call number 1 = sys_write
syscall ; 64-bit system call (rather than int 0x80)
pop rdi
pop rsi
pop rdx
pop rcx
pop r11
ret
注意：您应该使用Ryan Chapman的表作为指导，将所有
int 0x80syscallint 0x80