git: 9front

ref: d8b8993a8914c0fb4ed9bd60bdb0f85d0ce2e497
dir: /sys/src/cmd/unix/drawterm/win32-386/tas.c/

View raw version 
#include "u.h"
#include "libc.h"

int
tas(long *x)
{
	int     v;

	__asm__(	"movl   $1, %%eax\n\t"
			"xchgl  %%eax,(%%ecx)"
			: "=a" (v)
			: "c" (x)
	);
	switch(v) {
	case 0:
	case 1:
		return v;
	default:
		print("canlock: corrupted 0x%lux\n", v);
		return 1;
	}
}