C-将字节的las三位与一个字节合并

Question

Lets say I have this byte in binary: f= 01010111, then I'll do this: f<<3 so Im expecting: 10111000, at this point Im going to have another byte, lets say the other one is 10111001 and I want to attach them so the result is 1011110111001. Basiclly, what I want is that the last three bits from the first byte to get swap for the second byte.

I have no idea how can I do this, can you help me please?

Thanks!

Answer 1

How about this?

uint8_t f = 0x57; // 0b01010111
f <<= 3;          // now 10111000
uint8_t g = 0xB9; // 0b10111001
uint16_t out = (f << 5) | g;
printf("0x%04X\n", out);

> 0x17B9          // 0b1011110111001

I don't understand the intermediate << 3 but I'm assuming it's part of your application.