asm 中的未知注册名称

Question

我有像这样使用 asm 的代码：

static inline void fft_run(void) {
  // store registers so they dont get clobbered
  // avr-gcc requires r2:r17,r28:r29, and r1 cleared
  asm volatile (
  "push r2 \n"
  "push r3 \n"
  "push r4 \n"
  "push r5 \n"
  "push r6 \n"
  );

我遇到了这个错误，如何解决？

unknown register name 'r5' in 'asm'
unknown register name 'r4' in 'asm'
unknown register name 'r3' in 'asm'
unknown register name 'r2' in 'asm'
unknown register name 'r1' in 'asm'
unknown register name 'r0' in 'asm'