我正在尝试编写一个使用x86 32位系统调用的程序。它应该建立一个结构数组，要求用户输入结构x和y。感谢之前的评论，我相信我现在能够获得填充结构的输入，但我似乎无法打印它们。有人能帮我推一下吗?
我知道输入需要修改以打印正确的数字，但是PrintDec函数应该考虑到这一点。我用: 编译nasm -f elf Lab_14.asm -o Lab_14.o and gcc -m32 -g -lc Lab_14.o -o Lab_14
这是我的代码和我当前结果的屏幕截图
; Lab_14_Data_Structure
STRUC Point ;define Point structure
.x: resb 4 ;reserve 4 bytes for x coordinate
.y: resb 4 ;reserve 4 bytes for y coordinate
.size:
ENDSTRUC
section .data
msg1: db "Set the x and y coordinates of the five points",10,0
msg1Len: equ $-msg1
msg2: db "Printing the X and Y coordinates for all points",10,0
msg2Len: equ $-msg2
msg3: db "X = ",10,0
msg3Len: equ $-msg3
msg4: db "Y = ",10,0
msg4Len: equ $-msg4
msg5: db "Program completed successfully. Goodbye",10,0
msg5Len: equ $-msg5
counter: dd 5; keep track of how many input cycles are left
;declaring an instrance of Point structure and initalize its fields
P:ISTRUC Point
AT Point.x, dd 0
AT Point.y, dd 0
IEND
section .bss
PtArr: resb Point.size*5 ;reserve place for five structures
ArrCount: equ ($-PtArr)/Point.size ;five structures
section .text
global main
extern printf
main:
;start stack
push ebp
mov ebp, esp
mov ecx, ArrCount ;count of array structures(5)
mov esi, PtArr ;points to beginning of array
mov ecx, msg1
mov edx, msg1Len
call PString
Input:
; get number from user to place in structures
mov ecx, msg3
mov edx, msg3Len
Call PString
mov eax, 3
mov ebx, 0
lea ecx, [esi+Point.x]
mov edx, 4
int 80h
mov ecx, msg4
mov edx, msg4Len
Call PString
mov eax, 3
mov ebx, 0
lea ecx, [esi+Point.y]
mov edx, 4
int 80h
add esi, Point.size ;move to next structure in array
dec DWORD[counter]
cmp DWORD[counter], 0
jne Input
mov ecx, ArrCount ;count of array structures(5)
mov esi, PtArr ;points to beginning of array
mov DWORD[counter], 5 ;reset counter
PrintArray:
mov eax, [esi+Point.x]
call printDec
call println
mov eax, [esi+Point.y]
call printDec
call println
add esi, Point.size
dec DWORD[counter]
cmp DWORD[counter], 0
jne PrintArray
Exit:
mov ecx, msg5
mov edx, msg5Len
call PString
mov esp, ebp
pop ebp
ret
;mov eax, 1
;mov ebx, 0
;int 80h
printDec:
section .bss
decstr resb 10
ct1 resd 1
section .text
pusha
mov dword[ct1], 0
mov edi, decstr
add edi, 9
xor edx, edx
WhileNotZero:
mov ebx, 10
div ebx
add edx, '0'
mov byte[edi], dl
dec edi
inc dword[ct1]
xor edx, edx
cmp eax, 0
jne WhileNotZero
inc edi
mov ecx, edi
mov edx, [ct1]
mov eax, 4
mov ebx, 1
int 80h
popa
ret
println:
section .data
nl db "",10
section .text
Pusha
mov ecx, nl
mov edx, 1
mov eax, 4
mov ebx, 1
int 80h
popa
ret
PString:
;save register values
pusha
mov eax, 4
mov ebx, 1
int 80h
;restore old register values
popa
ret
错误#1:您已经将counter定义为字节内存变量，但稍后在代码中将其视为DWORD。
counter: db 5; keep track of how many input cycles are left
...
dec DWORD[counter]
错误# 2:内核函数read期望第二个参数(在ECX中传递)指向目标缓冲区，但相反，您从PtArr中加载ECX和零。
mov eax, 3 ; Kernel function `sys_read`
mov ebx, 0 ; File descriptor STDIN_FILENO=0
mov ecx, DWORD[esi+Point.x] ; That is wrong!
LEA ECX,[ESI+Point.x] ; Load its address instead.
mov edx, 4 ; Size of Point.x=4
int 80h ; Invoke kernel
错误# 3:从键盘输入的坐标将输入的数字存储为十进制数字。例如，当您设置x坐标为1时，Point.x中的第一个字节将是0x31。你应该读入值到一个临时缓冲区，将数字转换为二进制，然后才将其存储到数组中。