_X_A0
#define tf_a0 tf_reg[_X_A0]
#define PTRACE_REG_INTRV(r) (r)->r_reg[_X_A0]
tf->tf_reg[_X_A0 + _QUAD_LOWWORD] = (int32_t) tmp;
tf->tf_reg[_X_A0 + _QUAD_HIGHWORD] = tmp >> 32;