addition

adding the components of an SSE register

风流意气都作罢 提交于 2019-12-05 10:47:39
问题 I want to add the four components of an SSE register to get a single float. This is how I do it now: float a[4]; _mm_storeu_ps(a, foo128); float x = a[0] + a[1] + a[2] + a[3]; Is there an SSE instruction that directly achieves this? 回答1: You could probably use the HADDPS SSE3 instruction, or its compiler intrinsic _mm_hadd_ps , For example, see http://msdn.microsoft.com/en-us/library/yd9wecaa(v=vs.80).aspx If you have two registers v1 and v2 : v = _mm_hadd_ps(v1, v2); v = _mm_hadd_ps(v, v);

What happens if you remove the space between the + and ++ operators?

偶尔善良 提交于 2019-12-05 05:13:15
EDIT 1 DISCLAIMER: I know that +++ is not really an operator but the + and ++ operators without a space. I also know that there's no reason to use this; this question is just out of curiosity. So, I'm interested to see if the space between + and ++var is required in Java. Here is my test code: int i = 0; System.out.println(i); i = i +++i; System.out.println(i); This prints out: 0 1 which works as I would expect, just as if there were a space between the first and second + . Then, I tried it with string concatenation: String s1 = "s " + ++i; System.out.println(s1); // String s2 = "s " +++i;

Why is number + string a string in javascript?

你离开我真会死。 提交于 2019-12-05 00:44:10
Sort of trying out some quirks in javascript: First I did console.log("5" + 1); This prints 51, this is normal right, both number and string have a + operator, but since string is the first variable it will convert 1 to a string. Now when I did this: console.log(1 + "5") I expected output to be 6, as I thought it would convert string to a number. However, the magic output was 15. Could anyone more experienced in javascript brighten this up for me? Quoting ECMAScript spec The Addition operator ( + ) section : If Type(lprim) is String or Type(rprim) is String, then Return the String that is the

Sum of previous two numbers entered

ぐ巨炮叔叔 提交于 2019-12-04 19:46:42
I am working a simple beginner loop program, where i am trying to get an integer input from the user and calculate the sum. I have a simple menu in which the user can select one of for options, the first being inputting a number and second showing the sum of the last two numbers entered. So i need the program to add the previous two entered numbers together. so if the user selects option 1, they can enter a number and then be returned to the menu where they have to select option 1 again to enter another. option 2 should then calculate the sum and return the value.now lets say the user enters a

Signed saturated add of 64-bit ints?

吃可爱长大的小学妹 提交于 2019-12-04 17:50:51
问题 I'm looking for some C code for signed saturated 64-bit addition that compiles to efficient x86-64 code with the gcc optimizer. Portable code would be ideal, although an asm solution could be used if necessary. static const int64 kint64max = 0x7fffffffffffffffll; static const int64 kint64min = 0x8000000000000000ll; int64 signed_saturated_add(int64 x, int64 y) { bool x_is_negative = (x & kint64min) != 0; bool y_is_negative = (y & kint64min) != 0; int64 sum = x+y; bool sum_is_negative = (sum &

Typescript : Trying the addition of two variables but get the concatenation of the two

≡放荡痞女 提交于 2019-12-04 17:14:29
问题 I have three variable in my Typescript class : A:number; B:number; C:number; in another part of the class i try to make the addition of the two variable A and B : this.C = this.A+this.B; // A =20 and B = 50; and I display C in the html template <span>{{C}}</span> My problem is, instead of getting the addition of the TWO variable (20+50=70) i get the concatenation (2050)!! Can someone help me please ? UPDATE : Here is the exact code portion that cause problem : goTo(page:number,type:script) {

Create method which checks if x + y will overflow using bitwise operations

巧了我就是萌 提交于 2019-12-04 17:12:21
I need to create a method in C using bitwise operations which checks if x + y will overflow or not. I can only use a maximum of 20 of the following operations; ! ~ & ^ | + << >> Keep in mind I have to test for both negative and positive numbers. I've tried several times to make it work. Is my logic sound? I'm going by: if (x + y) is less than x, then it has overflowed. Based on that logic, I wrote this; int addOK(int x, int y) { int sum = x + y; int nx = ((~x) + 1); int check = (sum + nx)>>31; return !check; } Thank you! This should work, but it doesn't use only bitwise operator, but it work

Adding numbers within a vector in r

微笑、不失礼 提交于 2019-12-04 04:57:48
问题 I have a vector v<-c(1,2,3) I need add the numbers in the vector in the following fashion 1,1+2,1+2+3 producing a second vector v1<-c(1,3,6) This is probably quite simple...but I am a bit stuck. 回答1: Use the cumulative sum function: cumsum(v) #[1] 1 3 6 来源: https://stackoverflow.com/questions/12114127/adding-numbers-within-a-vector-in-r

adding the components of an SSE register

烂漫一生 提交于 2019-12-04 00:29:44
I want to add the four components of an SSE register to get a single float. This is how I do it now: float a[4]; _mm_storeu_ps(a, foo128); float x = a[0] + a[1] + a[2] + a[3]; Is there an SSE instruction that directly achieves this? You could probably use the HADDPS SSE3 instruction, or its compiler intrinsic _mm_hadd_ps , For example, see http://msdn.microsoft.com/en-us/library/yd9wecaa(v=vs.80).aspx If you have two registers v1 and v2 : v = _mm_hadd_ps(v1, v2); v = _mm_hadd_ps(v, v); Now, v[0] contains the sum of v1's components, and v[1] contains the sum of v2's components. If you want your

Non-restoring division algorithm

一曲冷凌霜 提交于 2019-12-03 06:53:12
Does anyone know the steps for dividing unsigned binary integers using non-restoring division? It's hard to find any good sources online. i.e if A = 101110 and B = 010111 how do we find A divided by B in non-restoring division? What do the registers look like in each step? Thanks! (My answer is a little late-reply. But I hope it will be useful for future visitors) Algorithm for Non-restoring division is given in below image : In this problem, Dividend (A) = 101110, ie 46, and Divisor (B) = 010111, ie 23. Initialization : Set Register A = Dividend = 000000 Set Register Q = Dividend = 101110 (