PPC中如何实现C以及汇编的远程调用

li32    r0, timer_init
mtspr   9, r0
bctrl

typedef int (*func_ptr)(int a,int b)

int max(int a, int b) {
return a>b?a:b;
}

main() {
func_ptr xxx;
xxx=max;  or  max=(func_ptr)0xffff0000;
(*xxx)(9,8);
}

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//declare before main()
// Function point that is used at the end of the program
// to jump to the address location stated by PROG_START_ADDR
#define PROG_START_ADDR 0x80180000
int (*func_ptr) ();
// declare after main()
// function point that is set to point to the address of
// PROG_START_ADDR
func_ptr = PROG_START_ADDR;
// jump to start execution code at the address
// PROG_START_ADDR
func_ptr();