我是汇编语言的新手，我的课程基于MASM。我的目标是从用户输入中获取数组的索引。
.data
myDates BYTE 1,2,3,4,5,6,7,8,9,10,11,12
.code
main PROC
Month:
mov edi, ecx ; edi = ecx copy counter
mov edx, OFFSET disMonth ; edx = disMonth
call WriteString ; write ax
call ReadInt ; eax = user input
cmp eax, 12 ; no, is eax > 12
JA ErrorMonth ; yes, jmp to ErrorMonth
cmp eax, 0 ; no, is eax > 0
JA CalMonth ; yes, jmp to CalMonth
ErrorMonth:
mov edx, OFFSET errMsg ; edx = errMsg
call WriteString ; display edx
jmp Month ; jmp back to Month
CalMonth:
; calculating (m + 9) % 12
add eax, 9 ; eax += 9
mov edx, 0 ; edx = 0
mov ecx, 12 ; ecx = 12
div ecx ; eax = Q & edx = R
mov ebx, edx ; ebx = edx *Month Storage*
Day:
mov edx, OFFSET disDay ; edx = disDay
call WriteString ; write edx
call ReadInt ; eax = user input
mov ebp, eax ; ebp = eax *Day Storage*
movzx eax, monthDate[ebx - 1]
call WriteInt
cmp ebp, eax ; is ebp > eax
JA ErrorDay ; jmp to ErrorDay
jmp Year ; jmp to Year
如果ebx == 12由于某种原因输出为9而不是12.但是当我用11替换ebx - 1时，它会按照它应该打印12。有什么我想念的吗？