请问STM8S003引脚复用如何在程序中定义呢?

这个原理图中MCU_SWIM是烧录脚，但是和一个按键的输入IO口复用，然后我在stm8s_gpio.h和stm8s.h中均没有对复用功能的函数，然后应该怎么去定义这些复用功能，像STM32在stm32f10x.c中有定义 void GPIO_PinRemapConfig(uint32_t GPIO_Remap, FunctionalState NewState){
uint32_t tmp = 0x00, tmp1 = 0x00, tmpreg = 0x00, tmpmask = 0x00;

/* Check the parameters */
assert_param(IS_GPIO_REMAP(GPIO_Remap));
assert_param(IS_FUNCTIONAL_STATE(NewState));

if((GPIO_Remap 0x80000000) == 0x80000000)
{
tmpreg = AFIO->MAPR2;
}
else
{
tmpreg = AFIO->MAPR;
}

tmpmask = (GPIO_Remap DBGAFR_POSITION_MASK) >> 0x10;
tmp = GPIO_Remap LSB_MASK;

if ((GPIO_Remap (DBGAFR_LOCATION_MASK | DBGAFR_NUMBITS_MASK)) == (DBGAFR_LOCATION_MASK | DBGAFR_NUMBITS_MASK))
{
tmpreg = DBGAFR_SWJCFG_MASK;
AFIO->MAPR = DBGAFR_SWJCFG_MASK;
}
else if ((GPIO_Remap DBGAFR_NUMBITS_MASK) == DBGAFR_NUMBITS_MASK)
{
tmp1 = ((uint32_t)0x03) << tmpmask;
tmpreg = ~tmp1;
tmpreg |= ~DBGAFR_SWJCFG_MASK;
}
else
{
tmpreg = ~(tmp << ((GPIO_Remap >> 0x15)*0x10));
tmpreg |= ~DBGAFR_SWJCFG_MASK;
}

if (NewState != DISABLE)
{
tmpreg |= (tmp << ((GPIO_Remap >> 0x15)*0x10));
}

if((GPIO_Remap 0x80000000) == 0x80000000)
{
AFIO->MAPR2 = tmpreg;
}
else
{
AFIO->MAPR = tmpreg;
}
}
但是STM8S里面的标准库里面没有这样的复用功能重映射的函数定义改如何解？各位有没有遇到过这样的问题的?