Assembly printf在masm32中打印字符时出错

这是我第一次在这里写作。。。我试着解释我的问题！ 我用masm32编写了这段代码

.586
.model flat
.data

mess db "digita un carattere    ",0
res db "x = %c",10,0

.data?
salva db ?

.code
extern _printf:proc
extern _scanf:proc

_funzione proc
;pre
push ebp
mov ebp,esp
push ebx
push edi
push esi

mov eax, offset mess
push eax
call _printf ;puting out the message
mov eax, offset salva
push eax
mov eax, offset res
push eax
call _scanf ;taking the char and saving it in "salva"
add esp,12
xor eax,eax
mov eax,offset salva
push eax
mov eax, offset res
push eax
call _printf ;printing the char
add esp,8

;post
pop esi
pop edi
pop ebx
pop ebp

ret
_funzione endp
end

当我编译它时，输出是：

我不明白为什么printf不打印scanf读过的字符（'y'）。。。

---

请帮帮我

printf和scanf的格式字符串非常不同。仅控制输入，

scanf

不输出内容（仅回显输入字符）

scanf

只会产生一个错误，即

resdb“x=%c”，10,0

。添加一行

scanf_res db“%c”，0

并将

mov eax，offset res

更改为

mov eax，offset scanf_res

resdb“x=%c”，10,0

要求推送一个直接值，而不是字符串的偏移量。将

mov eax，offset salva

更改为

mov al，salva

.586
.model flat
.data

mess db "digita un carattere    ",0
scanf_res db "%c",0
res db "x = %c",10,0

.data?
salva db ?

.code
extern _printf:proc
extern _scanf:proc
extern _fflush:proc

_funzione proc
;pre
push ebp
mov ebp,esp
push ebx
push edi
push esi

mov eax, offset mess
push eax
call _printf ;puting out the message
mov eax, offset salva
push eax
mov eax, offset scanf_res
push eax
call _scanf ;taking the char and saving it in "salva"
add esp,12

xor eax,eax
mov al, salva
push eax
mov eax, offset res
push eax
call _printf ;printing the char
add esp,8

;post
pop esi
pop edi
pop ebx
pop ebp

ret
_funzione endp
end

---

printf

和

scanf

的格式字符串非常不同。仅控制输入，

scanf

不输出内容（仅回显输入字符）

scanf

只会产生一个错误，即

resdb“x=%c”，10,0

。添加一行

scanf_res db“%c”，0

并将

mov eax，offset res

更改为

mov eax，offset scanf_res

resdb“x=%c”，10,0

要求推送一个直接值，而不是字符串的偏移量。将

mov eax，offset salva

更改为

mov al，salva

.586
.model flat
.data

mess db "digita un carattere    ",0
scanf_res db "%c",0
res db "x = %c",10,0

.data?
salva db ?

.code
extern _printf:proc
extern _scanf:proc
extern _fflush:proc

_funzione proc
;pre
push ebp
mov ebp,esp
push ebx
push edi
push esi

mov eax, offset mess
push eax
call _printf ;puting out the message
mov eax, offset salva
push eax
mov eax, offset scanf_res
push eax
call _scanf ;taking the char and saving it in "salva"
add esp,12

xor eax,eax
mov al, salva
push eax
mov eax, offset res
push eax
call _printf ;printing the char
add esp,8

;post
pop esi
pop edi
pop ebx
pop ebp

ret
_funzione endp
end