twos-complement

Do we ignore overflow in Two's Complement

…衆ロ難τιáo~ 提交于 2019-12-02 13:59:26
问题 I'm trying to wrap my head around overflow within twos complement for example say I'm trying to take away these two binary numbers: 1111 1000 0100 - 010 111 001 000 I convert the 2nd binary number to it's two complement equivalent and then simply add it but I noticed it resulted in an overflow of 1, do I simply ignore the overflow? or is there a rule I must follow 1111 1000 0100 + 1010 0011 1000 = (1) 1001 1011 1100 回答1: Short answer: if you are performing arithmetic on fixed-width binary

Struct variable doesn't changed by assignment

守給你的承諾、 提交于 2019-12-02 13:22:44
struct st { int a1 : 3; int a2 : 2; int a3 : 1; } void main(void) { x.a3 = -1; if (x.a3 == -1) printf("TRUE\n"); else printf("FALSE\n"); x.a3 = 1; if (x.a3 == 1) printf("TRUE\n"); else printf("FALSE\n"); } In case, 'x.a3 = -1;' First if is TRUE . But, why 'x.a3 = 1' doesn't changed in second if ? It's still x.a3 = -1. And If I type 'x.a3 = 1;' in first if, it still x.a3 = = 1 !! It doesn't changed! Debug Result in XCode The problem is, a signed 1 bit variable can hold only two values, -1 and 0 (Read about Two's complement ). It is not sufficient to hold a value of 1 (+ 1 , to be exact). To

Finding how many bits it takes to represent a 2's complement using only bitwise functions

情到浓时终转凉″ 提交于 2019-12-02 13:03:41
We can assume an int is 32 bits in 2's compliment The only Legal operators are: ! ~ & ^ | + << >> At this point i am using brute force int a=0x01; x=(x+1)>>1; //(have tried with just x instead of x+1 as well) a = a+(!(!x)); ... with the last 2 statements repeated 32 times. This adds 1 to a everytime x is shifted one place and != 0 for all 32 bits Using the test compiler it says my method fails on test case 0x7FFFFFFF (a 0 followed by 31 1's) and says this number requires 32 bits to represent. I dont see why this isnt 31 (which my method computes) Can anyone explain why? And what i need to

Interpreting signed and unsigned numbers

ぐ巨炮叔叔 提交于 2019-12-02 09:15:02
the teacher told us that a binary number, for examle 1000 0001, have 2 meanings. one is represent -127 (signed), which is from -127 to 127 and the another is a unsigned number , from 0 to 256 If I have a number in binary, for example 1000 0001 , the calculator shows only the signed number (-127). how can I know what is the unsigned number that this binary number represent? A signed and an unsigned number have exactly the same bits ! In your calculator, you can display as hex (0xff). It's up to you whether you want to interpret the hex digits and "signed" or "unsigned". In x86 assembler, you

reversing two's complement for 18bit int

让人想犯罪 __ 提交于 2019-12-02 08:55:38
I have an 18 bit integer that is in two's complement and I'd like to convert it to a signed number so I can better use it. On the platform I'm using, ints are 4 bytes (i.e. 32 bits). Based on this post: Convert Raw 14 bit Two's Complement to Signed 16 bit Integer I tried the following to convert the number: using SomeType = uint64_t; SomeType largeNum = 0x32020e6ed2006400; int twosCompNum = (largeNum & 0x3FFFF); int regularNum = (int) ((twosCompNum << 14) / 8192); I shifted the number left 14 places to get the sign bit as the most significant bit and then divided by 8192 (in binary, it's 1

sign extend 1-bit 2's complement number?

假装没事ソ 提交于 2019-12-02 07:42:20
问题 I am a student and I am writing a function in C to sign extend a given bit field. I'm working with 32 bits. I looked this answer up on Google but didn't find what I was looking for. I'm writing function that returns the twos complemnt representation of one or more consecutive bits pulled from a 32 int. The leftmost bit is the sign bit. What do I return if I pull a single bit? How do you represent a single bit as a signed twos complment number? 回答1: It doesn't make much sense to talk a 1-bit

Do we ignore overflow in Two's Complement

心已入冬 提交于 2019-12-02 07:23:17
I'm trying to wrap my head around overflow within twos complement for example say I'm trying to take away these two binary numbers: 1111 1000 0100 - 010 111 001 000 I convert the 2nd binary number to it's two complement equivalent and then simply add it but I noticed it resulted in an overflow of 1, do I simply ignore the overflow? or is there a rule I must follow 1111 1000 0100 + 1010 0011 1000 = (1) 1001 1011 1100 Short answer: if you are performing arithmetic on fixed-width binary numbers, using two's complement representation for negative numbers, then yes, you ignore the one-bit overflow.

Assembly MASM Dealing with Negative Integers

可紊 提交于 2019-12-02 04:48:48
问题 I was instructed to write a program in assembly that will carry out the following arithmetic: ((A + B) / C) * ((D - A) + E) I've succeeded in doing this when no negative values come into to play, but suppose A = 5, B = 4, C = 3, D = 2, and E = 1. This gives us ((5 + 4) / 3) * ((2 - 5) + 1) or -6. this is where I need help. I've done some research, and have found 2's compliment to be a solution, but I'm not sure to implement it into my code. If someone could help me, I'd be very grateful!

Whats the highest and the lowest integer for representing signed numbers in two's complement in 5 bits?

守給你的承諾、 提交于 2019-12-02 01:06:54
问题 I understand how binary works and I can calculate binary to decimal, but I'm lost around signed numbers. I have found a calculator that does the conversion. But I'm not sure how to find the maximum and the minumum number or convert if a binary number is not given, and question in StackO seems to be about converting specific numbers or doesn't include signed numbers to a specific bit. The specific question is: We have only 5 bits for representing signed numbers in two's complement: What is the

What is the maximum and minimum values can be represented with 5-digit number? in 2's complement representation

白昼怎懂夜的黑 提交于 2019-12-01 08:57:21
问题 What is the maximum and minimum values can be represented with 5-digit number that is assuming 2's complement representation? do I find the the min and maximum value of 5-digit numbers, which are 00000 and I'm not sure what the max is. Then convert to two's complement? This sounds stupid, but it's the only one I can come up with... my last question is: What is the minimum register length in a processor required to store values between –EA(base16) and 24(base16) assuming they are stores using