x86 - about assembly CF(Carry) and OF(Overflow) flag -


It is known that the CF indicates that an unsigned out carrying and o signed overflow so between an assembly and a signed data What does the assembly program differentiate because it is a sequence of bits only? (For information type through extra memory storage, or through positional information or other?) And can these two flags be used for each other?

The difference is that what instructions are used to manipulate data, the data itself No. Modern computers (since about 1970) use the representation of integer data, called complementary of two, in which both the signed and unsigned numbers have the same and subtraction functions.

  • The difference in representation is the meaning given to the most important bit (also called sine bit ) for unsigned numbers too big means Positive number is; For signed numbers it means that very large negative numbers (negative numbers with a big full value)

  • Different instructions can use different interpretations of the same bit. For example, there are two signed and unsigned multi-directional instructions on large machines. With 'at least' instructions machines can have both taste and signed sign.

  • The off (overflow flag) indicates whether the most important bit result in carrying one is to separate it from the most important bits of the argument. If the numbers are defined as unsigned, the overflow flag is irrelevant, but if they are interpreted as signature, it means, for example, two big positive numbers were added and the result was negative.

  • The CF (carry flag) states that a little word was completely done (like in bit 33 or bit 65) if the numbers are defined as unsigned , Then the flag means that the excess overflow occurs, and the result is too big to fit the machine word. Overflow flag is irrelevant.

The answer to your question is that there are several ways to sign the data signed in the assembly code:

    • < Li> It can either select signed or unsigned multiplication and split instructions.
  • This can select a signed or unsigned correct change (signed copies high bit, unsigned poly in zero).

Comments

Post a Comment

Popular posts from this blog

python - Overriding the save method in Django ModelForm -

I'm having trouble overriding a ModelForm save method. I get this error I'm: Exception type: TypeErier Exception Value: Save () found an unexpected keyword argument 'committed' My intentions include a form 3 fields Submit several values ​​for, then create an object for each combination of those areas, and to save each object file models.py class collarsult type (models.Model): id = model. AutoField (db_column = 'icontact_result_code_type_id', primary_key = true) callResult = models.ForeignKey ( 'CallResult', db_column = 'icontact_result_code_id') campaign = models.ForeignKey ( 'campaign', db_column = 'icampaign_id') CALLTYPE = models.ForeignKey ( 'CALLTYPE', db_column = 'icall_type_id') agent = models.BooleanField (db_column = 'bagent', default = true) teamLeader = models.BooleanField (db_column = 'bTeamLeader', default = true) active = models.BooleanField (db_column = Django.form...
Read more

html - CSS autoheight, but fit content to height of div -

I have a div in which there are three children- div in the left and middle div: float: left while true: float: true because it is my layout Actually will spoil, I've used ClearFix Hack: .cf {zoom: 1; }. Cf: First,. Cf: {content: ""; Display: Table; }. Cf: After {clear: both; } It still works, but I want to be the right div an indicator. So it should fill 100% of the parent unit of height. How can I complete this? PS is the full code: & Lt; / Div & gt; & Lt; Div class = "mobile_content" & gt; & Lt; H5 & gt; {{Data.titel}} & lt; / H5> & Lt; Table & gt; & Lt; TR & gt; & Lt; Th & gt; Komponist: & lt; / Th & gt; & Lt; TD & gt; {{Data.komponist}} & lt; / TD & gt; & Lt; / TR & gt; & Lt; TR & gt; & Lt; Th & gt; Instrument: & lt; / Th & gt; & Lt; TD & gt; {{Data.instrumente}} & lt; / TD & gt; & Lt; / TR & gt;...
Read more

qt - How to prevent QAudioInput from automatically boosting the master volume to 100%? -

I have been trying to use Qt5 multimedia to record audio with QAudioInput, however, when I see If QAudioInput is started, it increases the master volume of my sound device to 100%. How can I prevent QAudioInput from changing the master volume? My current development platform is Linux with PalsAdio (with flat audio disabled). How can I use QAudioInput : QAudioDeviceInfo device_info = QAudioDeviceInfo :: defaultInputDevice (); QAudio format format; Format.setSampleRate (44100); Format.setChannelCount (1); Format.setSampleSize (16); Format.setCodec ("Audio / PCM"); Format.setSampleType (QAudioFormat :: SignedInt); Format.setByteOrder (QAudioFormat :: LittleEndian); Std :: cout & lt; & Lt; Device_info.deviceName (). ToUtf8 (). ConstData () & lt; & Lt; Std :: endl; QAudioInput * default_device = new QAudioInput (device_info, format); QIODevice * default_io_device = default_device-> Start (); a QAudioInput.setVolume () method is not you I ...
Read more