Assembly 英特尔80368 32位汇编程序除法的奇怪结果

它被困在函数“prebroj”的无限循环中。它应该计算我的结果编号中有多少位数字，这样我可以稍后将其作为字符串返回，并在

%eax

变为0时退出。当我在调试器中运行它时，当我将我的数字（

%eax

）除以所需的基数（

%ecx

）以获得有多少位数字时，在除法后的某一点上，它会返回一个非常奇怪的数字到

%eax

，但

%edx

中的除法的其余部分仍然返回完全正常，即使

%eax

中的结果数字毫无意义。这是代码，它相当长，但我认为它可能有助于提供整个内容。问题循环位于第152行，靠近末端。我在它旁边放了一堆注释，这样更容易找到（唯一的问题是循环，我只是把整个程序放在最上面的注释中，以防相关，简短的程序描述）：

---

这是不归零edx的常见问题。阅读有关

div

工作原理的参考手册。您将看到它使用

edx

作为红利的前32位。如果你只有32位，你需要把它归零。它成功了，干杯！可能重复的Never use div！，始终将idiv与显式操作数一起使用。问题已解决。可能与、、等重复。

#unsigned saberi2 (char *num1, unsigned base1, char *num2, unsigned, base2, char *sum, unsigned *sum_length, unsigned sum_base);
#           8       12      16      20  24      28      32
#the subprogram is called from a c program and takes the first 2 numbers from args 1 and 3 as strings (to be converted), their respective bases from args 2 and 4, and returns the sum as a string at the address from arg 5
.text
.globl saberi2

saberi2:
pushl %ebp
movl %esp, %ebp
pushl %ebx
pushl %esi
subl $16, %esp          # -4(%ebp) i -8(%ebp) su prvi i drugi broj
movl $1, -8(%ebp)
movl $0, -12(%ebp)

prov_prvi:
movl 8(%ebp), %esi
movb (%esi), %bl
cmpb $'-', %bl
jne nm1
movl $-1, -8(%ebp)
incl %esi
jmp np1
nm1:
cmpb $'+', %bl
jne np1
incl %esi
np1:
movl $0, %eax
movl 12(%ebp), %ecx
cmpl $10, %ecx
ja preko10_1

ispod10_1:
movb (%esi), %bl
cmpb $0, %bl
je kraj1
subb $'0', %bl
cmpb $0, %bl
jl greska1
cmpb 12(%ebp), %bl
jg greska1
mull %ecx
movb %bl, -12(%ebp)
addl -12(%ebp), %eax
incl %esi
jmp ispod10_1

preko10_1:
movb (%esi), %bl
cmpb $0, %bl
je kraj1
subb $'0', %bl
cmpb $0, %bl
jl greska1
cmpb $9, %bl
jg slovo1
mull %ecx
movb %bl, -12(%ebp)
addl -12(%ebp), %eax
incl %esi
jmp preko10_1
slovo1:
subb $7, %bl            #17 je razmak od 0 do A
cmpb $10, %bl
jl greska1
cmpb 12(%ebp), %bl
jg greska1
mull %ecx
movb %bl, -12(%ebp)
addl -12(%ebp), %eax
incl %esi
jmp preko10_1

kraj1:
movl -8(%ebp), %ecx
mull %ecx
movl %eax, -4(%ebp)

prov_drugi:
movl 16(%ebp), %esi
movb (%esi), %bl
movl $1, -8(%ebp)
cmpb $'-', %bl
jne nm2
movl $-1, -8(%ebp)
incl %esi
jmp np2
nm2:
cmpb $'+', %bl
jne np2
incl %esi
np2:
movl $0, %eax
movl 20(%ebp), %ecx
cmpl $10, %ecx
ja preko10_2

ispod10_2:
movb (%esi), %bl
cmpb $0, %bl
je kraj2
subb $'0', %bl
cmpb $0, %bl
jb greska2
cmpb 20(%ebp), %bl
ja greska2
mull %ecx
movb %bl, -12(%ebp)
addl -12(%ebp), %eax
incl %esi
jmp ispod10_2

preko10_2:
movb (%esi), %bl
cmpb $0, %bl
je kraj2
subb $'0', %bl
cmpb $0, %bl
jl greska2
cmpb $9, %bl
jg slovo2
mull %ecx
movb %bl, -12(%ebp)
addl -12(%ebp), %eax
incl %esi
jmp preko10_2
slovo2:
subb $7, %bl            #17 je razmak od 0 do A
cmpb $10, %bl
jl greska2
cmpb 20(%ebp), %bl
jg greska2
mull %ecx
movb %bl, -12(%ebp)
addl -12(%ebp), %eax
incl %esi
jmp preko10_2

kraj2:
movl -8(%ebp), %ecx
mull %ecx
addl -4(%ebp), %eax
jo greska3

ispis:
movl 24(%ebp), %ebx     #ebx je adresa zbira
movl %eax, -4(%ebp)     #eax je zbir
movl $0, %esi           #esi je broj cifara zbira
movl 32(%ebp), %ecx     #ecx je baza zbira

prebroj:
cmpl $0, %eax           #brojanje cifara zbira
je unesi            #-----------------------------------------------
divl %ecx           #THIS IS THE LOOP-------------------------------
incl %esi           #-----------------------------------------------
movl %eax, -12(%ebp)
jmp prebroj

unesi:                  #unos cifara na adresu iz arg
movl %esi, 28(%ebp)
movl -4(%ebp), %eax
cmpl $0, %eax
jg nmi
movb $'-', (%ebx)
incl %esi
nmi:
movb $0, (%ebx, %esi, 1)
decl %esi
cmpl $10, %ecx
ja preko10_i

ispod10_i:
cmpl $0, %eax
je preende
divl %ecx
addb $'0', %dl
movb %dl, (%ebx, %esi, 1)
decl %esi
jmp ispod10_i

preko10_i:
cmpl $0, %eax
je preende
divl %ecx
cmpb $9, %dl
ja slovoi
addb $'0', %dl
movb %dl, (%ebx, %esi, 1)
decl %esi
jmp preko10_i
slovoi:
addb $55, %dl
movb %dl, (%ebx, %esi, 1)
decl %esi
jmp preko10_i

greska1:
movl $1, %eax
jmp ende

greska2:
movl $2, %eax
jmp ende

greska3:
movl $3, %eax
jmp ende

preende:
movl $0, %eax
ende:
popl %esi
popl %ebx
movl %ebp, %esp
popl %ebp
ret