endianness

How do I swap endian-ness (byte order) of a variable in javascript

陌路散爱 提交于 2019-11-27 11:18:55
问题 I am receiving and sending a decimal representation of two little endian numbers. I would like to: shift one variable 8 bits left OR them shift a variable number of bits create 2 8 bit numbers representing the first and second half of the 16 bit number. javascript (according to https://developer.mozilla.org/en/JavaScript/Reference/Operators/Bitwise_Operators) uses big endian representation when shifting... endianness is a bit foreign to me (I am only 90 percent sure that my outlined steps are

Can endianness refer to bits order in a byte?

て烟熏妆下的殇ゞ 提交于 2019-11-27 10:08:07
问题 I'm reading "Learning Core Audio: A Hands-On Guide to Audio Programming for Mac and iOS" by Chris Adamson and at one point the author describes big-endian as: the high bits of a byte or word are numerically more significant than the lower ones. However, until now I though the problem of big-little endian only applies to byte order and not bit order. One byte has the same bit order (left to right) no matter if we're talking about little endian or big endian systems. Am I wrong? Is the author

Floating point Endianness?

假装没事ソ 提交于 2019-11-27 08:49:06
I'm writing a client and a server for a realtime offshore simulator, and, as I have to send a lot of data through a socket, I'm using binary data to maximize the ammount of data I can send. I already know about integers endianness, and how to use htonl and ntohl to circumvent endianness issues, but my application, as almost all simulation software, deals with a lot of floats. My question is: Is there some issue of endianness whean dealing with binary formats of floating point numbers? I know that all the machines where my code will run use IEEE implementation of floating points, but is there

Detecting Endianness

元气小坏坏 提交于 2019-11-27 08:39:34
I'm currently trying to create a C source code which properly handles I/O whatever the endianness of the target system. I've selected "little endian" as my I/O convention, which means that, for big endian CPU, I need to convert data while writing or reading. Conversion is not the issue. The problem I face is to detect endianness, preferably at compile time (since CPU do not change endianness in the middle of execution...). Up to now, I've been using this : #if __BYTE_ORDER__ == __ORDER_LITTLE_ENDIAN__ ... #else ... #endif It's documented as a GCC pre-defined macro, and Visual seems to

Convert Little Endian to Big Endian

半城伤御伤魂 提交于 2019-11-27 07:17:43
I just want to ask if my method is correct to convert from little endian to big endian, just to make sure if I understand the difference. I have a number which is stored in little-endian, here are the binary and hex representations of the number: ‭0001 0010 0011 0100 0101 0110 0111 1000‬ ‭12345678‬ In big-endian format I believe the bytes should be swapped, like this: 1000 0111 0110 0101 0100 0011 0010 0001 ‭87654321 Is this correct? Also, the code below attempts to do this but fails. Is there anything obviously wrong or can I optimize something? If the code is bad for this conversion can you

How do I convert an array of floats to a byte[] and back?

。_饼干妹妹 提交于 2019-11-27 07:12:58
I have an array of Floats that need to be converted to a byte array and back to a float[]... can anyone help me do this correctly? I'm working with the bitConverter class and found myself stuck trying to append the results. The reason I'm doing this is so I can save runtime values into a IO Stream. The target storage is Azure Page blobs in case that matters. I don't care about what endian this is stored in, as long as it input matches the output. static byte[] ConvertFloatToByteArray(float[] floats) { byte[] ret = new byte[floats.Length * 4];// a single float is 4 bytes/32 bits for (int i = 0;

Why is x86 little endian?

≯℡__Kan透↙ 提交于 2019-11-27 06:48:28
A real question that I've been asking myself lately is what design choices brought about x86 being a little endian architecture instead of a big endian architecture? Largely, for the same reason you start at the least significant digit (the right end) when you add—because carries propagate toward the more significant digits. Putting the least significant byte first allows the processor to get started on the add after having read only the first byte of an offset. After you've done enough assembly coding and debugging you may come to the conclusion that it's not little endian that's the strange

Little vs Big Endianess: How to interpret the test

痞子三分冷 提交于 2019-11-27 06:48:16
问题 So I'm writing a program to test the endianess of a machine and print it. I understand the difference between little and big endian, however, from what I've found online, I don't understand why these tests show the endianess of a machine. This is what I've found online. What does *(char *)&x mean and how does it equaling one prove that a machine is Little-Endian? int x = 1; if (*(char *)&x == 1) { printf("Little-Endian\n"); } else { printf("Big-Endian\n"); } 回答1: If we split into different

How does this program work?

不打扰是莪最后的温柔 提交于 2019-11-27 06:31:20
#include <stdio.h> int main() { float a = 1234.5f; printf("%d\n", a); return 0; } It displays a 0 !! How is that possible? What is the reasoning? I have deliberately put a %d in the printf statement to study the behaviour of printf . That's because %d expects an int but you've provided a float. Use %e / %f / %g to print the float. On why 0 is printed: The floating point number is converted to double before sending to printf . The number 1234.5 in double representation in little endian is 00 00 00 00 00 4A 93 40 A %d consumes a 32-bit integer, so a zero is printed. (As a test, you could printf(

Types of endianness

房东的猫 提交于 2019-11-27 05:26:16
问题 What is the difference between the following types of endianness? byte (8b) invariant big and little endianness half-word (16b) invariant big and little endianness word (32b) invariant big and little endianness double-word (64b) invariant big and little endianness Are there other types/variations? 回答1: There are two approaches to endian mapping: address invariance and data invariance . Address Invariance In this type of mapping, the address of bytes is always preserved between big and little.