fpms 操作 字型慣例
if (PR[qp]) {
fp_check_target_register;
if (tmp_isrcode = fp_reg_disabled(f1, f2, f3, f4))
disabled_fp_register_fault(tmp_isrcode, 0);

if (fp_is_natval([f2]) || fp_is_natval(FR[f3]) || fp_is_natval(FR[f4])) {
FR[f1] = NATVAL;
fp_update_psr(f1);
} else {
tmp_default_result_pair = fpms_fpnma_exception_fault_check(f2,f3, f4,
sf, &tmp_fp_env);
if (fp_raise_fault(tmp_fp_env))
fp_exception_fault(fp_decode_fault(tmp_fp_env));

if (fp_is_nan_or_inf(tmp_default_result_pair.hi)) {
tmp_res_hi = fp_single(tmp_default_result_pair.hi);
} else {
tmp_res = fp_mul(fp_reg_read_hi(f3), fp_reg_read_hi(f4));
if (f2 != 0) {
tmp_sub = fp_reg_read_hi(f2);
tmp_sub.sign = !tmp_sub.sign;
tmp_res = fp_add(tmp_res, tmp_sub, tmp_fp_env);
}
tmp_res_hi = fp_ieee_round_sp(tmp_res, HIGH, &tmp_fp_env);
}

if (fp_is_nan_or_inf(tmp_default_result_pair.lo)) {
tmp_res_lo = fp_single(tmp_default_result_pair.lo);
} else {
tmp_res = fp_mul(fp_reg_read_lo(f3), fp_reg_read_lo(f4));
if (f2 != 0) {
tmp_sub = fp_reg_read_lo(f2);
tmp_sub.sign = !tmp_sub.sign;
tmp_res = fp_add(tmp_res, tmp_sub, tmp_fp_env);
}
tmp_res_lo = fp_ieee_round_sp(tmp_res, LOW, &tmp_fp_env);
}

FR[f1].significand = fp_concatenate(tmp_res_hi, tmp_res_lo);
FR[f1].exponent = FP_INTEGER_EXP;
FR[f1].sign = FP_SIGN_POSITIVE;

fp_update_fpsr(sf, tmp_fp_env);
fp_update_psr(f1);
if (fp_raise_traps(tmp_fp_env))
fp_exception_trap(fp_decode_trap(tmp_fp_env));
}
}