linux/tile/get_error.c

/*
 * The standard tile calling convention returns the value (or negative
 * errno) in r0, and zero (or positive errno) in r1.
 * Until at least kernel 3.8, however, the r1 value is not reflected
 * in ptregs at this point, so we use r0 here.
 */
if (check_errno && is_negated_errno(tile_regs.regs[0])) {
	tcp->u_rval = -1;
	tcp->u_error = -tile_regs.regs[0];
} else {
	tcp->u_rval = tile_regs.regs[0];
}