24531904_j

スタティ ック ・ レジスタとローテー ト ・ レジスタを 1 つずつ指定するのは、 CFM.rrb.fr
の値が予測可能な値 (0 など ) になる と きに限られる。
操作 : if (PR[qp]) {
size = single_form ? 8 : 16;
speculative = (fldtype == ‘s’ || fldtype == ‘sa’);
advanced = (fldtype == ‘a’ || fldtype == ‘sa’);
check_clear = (fldtype == ‘c.clr’);
check_no_clear = (fldtype == ‘c.nc’);
check = check_clear || check_no_clear;
itype = READ;
if (speculative) itype |= SPEC;
if (advanced) itype |= ADVANCE;
if (fp_reg_bank_conflict(f1, f2))
illegal_operation_fault();
if (base_update_form)
check_target_register(r 3 );
fp_check_target_register(f 1 );
fp_check_target_register(f 2 );
if (tmp_isrcode = fp_reg_disabled(f 1, f 2, 0, 0))
disabled_fp_register_fault(tmp_isrcode, itype);
if (!speculative && GR[r 3].nat) // fault on NaT address
register_nat_consumption_fault(itype);
defer = speculative && (GR[r 3].nat || PSR.ed);// defer exception if spec
if (check && alat_cmp(FLOAT, f 1 )) { // no load on ldfp.c & ALAT hit
if (check_clear) // remove entry on ldfp.c.clr
alat_inval_single_entry(FLOAT, f 1 );
} else {
if (!defer) {
paddr = tlb_translate(GR[r 3 ], size, itype, PSR.cpl, &mattr,
&defer);
spontaneous_deferral(paddr, size, UM.be, mattr, UNORDERED,
ldhint, &defer);
if (!defer)
mem_read_pair(&f1_val, &f2_val, paddr, size, UM.be,
mattr, UNORDERED, ldhint);
}
if (check_clear || advanced) // remove any old ALAT entry
alat_inval_single_entry(FLOAT, f 1 );
if (speculative && defer) {
FR[f 1 ] = NATVAL;
FR[f 2 ] = NATVAL;
} else if (advanced && !speculative && defer) {
FR[f 1 ] = (integer_form ? FP_INT_ZERO : FP_ZERO);
FR[f 2 ] = (integer_form ? FP_INT_ZERO : FP_ZERO);
} else { // execute load normally
FR[f 1 ] = fp_mem_to_fr_format(f1_val, size/2, integer_form);
FR[f 2 ] = fp_mem_to_fr_format(f2_val, size/2, integer_form);
}
if ((check_no_clear || advanced) && ma_is_speculative(mattr))
// add entry to ALAT
alat_write(FLOAT, f 1, paddr, size);
3:144 第 3 巻 : 命令リファレンス
ldfp