Question

此汇编代码：

cmp [Variable1], 10
jae AlternateBlock
call SomeFunction
jmp AfterIfBlock
cmp [Variable1], 345
jne AfterIfBlock
call SomeOtherFunction

等于这个C代码？：

if (variable1 >= 10)
{
    goto AlternateBlock;
    SomeFunction();
    goto AfterIfBlock;
}
else if (Variable1 != 345)
{
    goto AfterIfBlock;
    SomeOtherFunction();
}

Answer 1

更简洁：

if( variable1 < 10 ) {
  SomeFunction();
} else if( variable1 == 345 ) {
  SomeOtherFunction()
}

说明：

cmp [Variable1], 10
jae AlternateBlock     ; if variable1 is >= 10 then go to alternate block
call SomeFunction      ; else fall through and call SomeFunction(). ie. when variable1 < 10
jmp AfterIfBlock       ; prevent falling through to next conditional
cmp [Variable1], 345
jne AfterIfBlock       ; if variable1 is not equal to 345 then jump to afterifblock
call SomeOtherFunction ; else fall through to call SomeOtherFunction

如果您需要一些时间来理解它，您应该看到它在语义上等同于C代码。也许这有帮助。

cmp [Variable1], 10
jb @f
call SomeFunction
jmp end
  @@:
cmp [Variable1], 345
jnz end
call SomeOtherFunction
  end:

Answer 2

不，它可能更像是这样：

if (variable1 < 10)
    SomeFunction();
else if (Variable1 == 345)
    SomeOtherFunction();

但是你没有在汇编程序中包含标签，所以我不能确定。我认为标签是这样的：

    cmp [Variable1], 10
    jae AlternateBlock
    call SomeFunction
    jmp AfterIfBlock
@@AlternateBlock:
    cmp [Variable1], 345
    jne AfterIfBlock
    call SomeOtherFunction
@@AfterIfBlock:

Answer 3

不，不是。如果variable1小于10，汇编代码将调用SomeFunction，而C代码则不会，它将跳转到AlternateBlock

汇编到C代码

3 个答案: