有没有办法在不使用进位标志或 RRX 的情况下在 ARM 汇编语言中对 32 位二进制整数进行位反转？

Question

In the normal way, we would have used LSLS, #1 instruction on the 32-bit binary number where the MSB will be kept in the carry and use RRX to push it back into another register in order to reverse the bits, and we will do this for 32 times.

But if we are not allowed to RRX specifically and any carry bits, is there another way to reverse the bits?

Answer 1

您已经标记了 Cortex m3（Arm V7-m 架构）和 cortex a8（Arm V7-a 架构），这两者都有rbit指令，可以反转 32 位寄存器中的位。