gcc 的嵌入汇编, 可以参考库里的例子.
上一个计算 CRC16 的例程, 来自 include\util\crc16.h
static __inline__ uint16_t
_crc16_update(uint16_t __crc, uint8_t __data)
{
uint8_t __tmp;
uint16_t __ret;
__asm__ __volatile__ (
"eor %A0,%2" "\n\t"
"mov %1,%A0" "\n\t"
"swap %1" "\n\t"
"eor %1,%A0" "\n\t"
"mov __tmp_reg__,%1" "\n\t"
"lsr %1" "\n\t"
"lsr %1" "\n\t"
"eor %1,__tmp_reg__" "\n\t"
"mov __tmp_reg__,%1" "\n\t"
"lsr %1" "\n\t"
"eor %1,__tmp_reg__" "\n\t"
"andi %1,0x07" "\n\t"
"mov __tmp_reg__,%A0" "\n\t"
"mov %A0,%B0" "\n\t"
"lsr %1" "\n\t"
"ror __tmp_reg__" "\n\t"
"ror %1" "\n\t"
"mov %B0,__tmp_reg__" "\n\t"
"eor %A0,%1" "\n\t"
"lsr __tmp_reg__" "\n\t"
"ror %1" "\n\t"
"eor %B0,__tmp_reg__" "\n\t"
"eor %A0,%1"
: "=r" (__ret), "=d" (__tmp)
: "r" (__data), "0" (__crc)
: "r0"
);
return __ret;
}
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