36 lines
445 B
C
36 lines
445 B
C
|
#include "u.h"
|
||
|
|
#include "libc.h"
|
||
|
|
|
||
|
|
int
|
||
|
|
tas(long *x)
|
||
|
|
{
|
||
|
|
int v, t, i = 1;
|
||
|
|
|
||
|
|
#if ARMv5
|
||
|
|
__asm__(
|
||
|
|
"swp %0, %1, [%2]"
|
||
|
|
: "=&r" (v)
|
||
|
|
: "r" (1), "r" (x)
|
||
|
|
: "memory"
|
||
|
|
);
|
||
|
|
#else
|
||
|
|
__asm__ (
|
||
|
|
"1: ldrex %0, [%2]\n"
|
||
|
|
" strex %1, %3, [%2]\n"
|
||
|
|
" teq %1, #0\n"
|
||
|
|
" bne 1b"
|
||
|
|
: "=&r" (v), "=&r" (t)
|
||
|
|
: "r" (x), "r" (i)
|
||
|
|
: "cc");
|
||
|
|
#endif
|
||
|
|
switch(v) {
|
||
|
|
case 0:
|
||
|
|
case 1:
|
||
|
|
return v;
|
||
|
|
default:
|
||
|
|
print("canlock: corrupted 0x%lux\n", v);
|
||
|
|
return 1;
|
||
|
|
}
|
||
|
|
}
|
||
|
|
|