Ðåôåðàòû. Ñèñòåìû àäðåñàöèè â Ìèíè- è ÌèêpîÝÂÌ

Äî îïåðàöèè CLRB @(R5)+

                                                                        R5 = 00001000 

                                                          (00001000) = 000000AC          (R5)

                                                         (000000AC) = 0A                      (00001000)

Ïîñëå...

                                                                        R5 = 00001004           <——  óâåëè÷èëîñü íà 4

                                                          (00001000) = 000000AC

                                                         (000000AC) = 00                       <——  0

 ðåçóëüòàòå âûïîëíåíèÿ ýòîé êîìàíäû ñîäåðæèìîå ÿ÷åéêè 000000AC, àäðåñ êîòîðîé cîäåðæàëñÿ â ÿ÷åéêå 00001000, íà êîòîðóþ óêàçûâàë ðåãèñòð R5 îáíóëèëîñü, à çíà÷åíèå ðåãèñòðà R5 óâåëè÷èëîñü íà 4.

   


2.6  ÐÅÆÈÌ ÑÌÅÙÅÍÈß


             ýòîì ðåæèìå ñîäåðæèìîå âûáðàííîãî ðåãèñòðà ñêëàäûâàåòñÿ ñ ñîäåðæèìûì áàéòà, ñëîâà èëè äâîéíîãî ñëîâà, ñëåäóþùåãî íåïîñðåäñòâåííî çà ñïåöèôèêàòîðîì îïåðàíäà. Ïîëó÷åííàÿ ñóììà ÿâëÿåòñÿ àäðåñîì îïåðàíäà. Ìíåìîíèêè íà àññåìáëåðå äëÿ 3åõ ñëó÷àåâ èìåþò âèä: B^X(Rn), W^X(Rn), L^X(Rn), ãäå X ñìåùåíèå, îòíîñèòåëüíî (Rn). Âîçìîæíîñòü çàäàâàòü ðàçìåðíîñòü ñìåùåíèÿ ïðåäóñìîòðåíà äëÿ ýêîíîìèè ïàìÿòè.

            Ðàññìîòðèì ýòîò ñïîñîá àäðåñàöèè íà ïðèìåðå êîìàíäû CLRB B^2(R4), êîòîðàÿ î÷èñòèò 3èé áàéò áàéòîâîãî ìàññèâà, àäðåñ êîòîðîãî ñîäåðæèòñÿ â ðåãèñòðå R5. Åå ìàøèííîå ïðåäñòàâëåíèå âûãëÿäèò êàê 94 A4 02, ãäå 94 - êîä îïåðàöèè, A4 - ðåãèñòð R4 è ñìåùåíèå ïðåäñòàâëåíî áàéòîì ( äëÿ ñëîâà è äâîéíîãî ñëîâà áûëî áû C4 è E4 ñîîòâåòñòâåííî, à òðåòüå ïîëå ïðåäñòàâëÿëî áû ñìåùåíèå êàê ñëîâî èëè äâîéíîå ñëîâî ),  à 02 ñîáñòâåííî ñìåùåíèå, ïðåäñòàâëåííîå â âèäå áàéòà.


Äî îïåðàöèè CLRB B^2(R4)

                                                                        R4 = 00001000

                                                          (00001000) = 00                       (R4)

                                                          (00001001) = 01

                                                          (00001002) = 02                       (R4)+2


Ïîñëå...

                                                                        R4 = 00001000

                                                          (00001000) = 00                       (R4)

                                                          (00001001) = 01

                                                          (00001002) = 00                       <—— 0


 ðåçóëüòàòå âûïîëíåíèÿ êîìàíäû äåéñòâèòåëüíî ïðîèçîøëî î÷èùåíèå ÿ÷åéêè 00001002, çàäàííîé íà÷àëüíûì àäðåñîì 00001000 è ñìåùåíèåì 2. Ýòîò ðåæèì àäðåñàöèè ïîçâîëÿåò ëåãêî îáðàùàòüñÿ ê îòäåëüíûì ýëåìåíòàì ìàññèâîâ, ÷òî î÷åíü óäîáíî.



2.7  ÊÎÑÂÅÍÍÛÉ ÐÅÆÈÌ ÑÌÅÙÅÍÈß


             ýòîì ðåæèìå ñîäåðæèìîå âûáðàííîãî ðåãèñòðà ñêëàäûâàåòñÿ ñî ñìåùåíèåì ( áàéò, ñëîâî èëè äâîéíîå ñëîâî ñëåäóþùåå íåïîñðåäñòâåííî çà ñïåöèôèêàòîðîì  îïåðàíäà ) è ïîëó÷åííàÿ ñóììà ðàññìàòðèâàåòñÿ êàê àäðåñ äâîéíîãî ñëîâà, êîòîðîå ÿâëÿåòñÿ àäðåñîì îïåðàíäà. Ìíåìîíè÷åñêîå ïðåäñòàâëåíèå íà àññåìáëåðå @B^X(Rn), @W^X(Rn) è @L^X(Rn) äëÿ ñìåùåíèÿ X â áàéò, ñëîâî èëè äâîéíîå ñëîâî ñîîòâåòñòâåííî. Rn - ýòî ðåãèñòð,èñïîëüçóåìûé â äàííîì ñïîñîáå àäðåñàöèè.

Ñòðàíèöû: 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20



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