2011年11月21日 · When 0x8000 is considered unsigned int, the negation will invert 16 bits, resulting in a representation 0x7FFF with type unsigned int; the cast will then zero-extend to a long value of 0x00007FFF. Look at H&S5, section 2.7.1 page 24ff. It is best to augment the constants with U, UL or L as appropriate.

2012年5月30日 · Without saying a specific system which is diverse, for example linux (even in android), general RTOS (nucleus, and the others, especially ARM linker section), they all use address 0x8000 as start address general program. such named as crt_begin.o, crt.o, etc located at 0x0 with loader exist in this area.

2016年3月22日 · Thanks and I've updated my question, I don't understand why it returns 0x8000 0000,why not return 0 or any other number – walle Commented Mar 22, 2016 at 5:59

2014年1月24日 · The statement v -= 0x8000 ; is identical to v = v - 0x8000 ; On the right-hand side, the int value v is implicitly cast to unsigned int , per the rules, the arithmetic operation is performed, yielding an rval that is an unsigned int .

2019年9月15日 · Doing & 0x8000 is a way to mask off (ignore) all of the bits except for the most significant bit. You can then check the result of this operation is != 0 and that will return true or false depending on if the key you passed in to the function was pressed down.

2020年5月5日 · Harassment is any behavior intended to disturb or upset a person or group of people. Threats include any threat of violence, or harm to another.

2019年7月5日 · C 11 6.3.1.3, for cast: Otherwise, if the new type is unsigned, the value is converted by repeatedly adding or subtracting one more than the maximum value that can be represented in the new type...

I would like to have a boolean event toggle when a key is pressed. Specifically, the 's' key. I have been pointed to the function GetKeyState(), which supposedly works under the Win32 API.

@anatolyg: But 0x8000 isn't negative. Either it can fit in an int, in which case 0x8000 > 0x7000 is done as a comparison of int, otherwise 0x8000 is an unsigned and 0x7000 is promoted to unsigned (no change of value) and the comparison is a …

2011年5月22日 · In hexadecimal, your number is 0x8000 which is 0x80 and 0x00. To get the low byte from the input, use low=input & 0xff and to get the high byte, use high=(input>>8) & 0xff. Get the input back from the low and high byes like so: input=low | (high<<8). Make sure the integer types you use are big enough to store these numbers.