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<br />EX PLA NAiI Q N 0� R E� I STE RS *P'�e�'��er Functions as tlie program' addre�
<br />count�r. Provides continuity between individua
<br />steps of program by generating the addr�sses a;a
<br />which individual steps are coritained. Upvn'compte
<br />tion of each sequential step, count in P i� advance�
<br />by one to specify address of next step. Jurrip'ins�ruc
<br />tions clear P and enter new address ;in it: '; ;���
<br />*Index Registers, B'-B6 Provide modification i
<br />execution addresses in`program loops. Cont�nts of;'a
<br />Tndex_ Registcr can be advanced each pass;'throug
<br />j a lo��p, with an e.xit initiated on a given thresholc
<br />*A�-Register Principal arithmetic register. I'unc- ' `
<br />tions as a 48-bit accumulator in most arithmetic Altc ��ate approach allo�vs an Index. �.eg�ster to ;�
<br />bperatians. Quantity zero represented by a binary
<br />p�eset, then reduced by one count each pass throug
<br />� the program—with an exit after �zero.
<br />zero in each stage. Contents of A may be shifted -
<br />� either tb�the right or left. Shifting may involve only Storage Address Registers, S'=S� Represei
<br />;the contents of A or may include tlie contents of Q. even and odd 16,384-word memory unrts r�spei
<br />�� Leftmost sign bit extended on shifts to right; bits tively. Receive addresses of instruetions from P an
<br />� + :;shifted oi�' the right end of A or Q are dropped. Left adclresses of operands from U2: ��_-,
<br />�, `., ,sliifts are circular, with lower order bits being_re- Storage Restorafion Registe�s, Z'-Z� ' Represe�i
<br />placed by higher order bits. Mulfiiply, divide, and
<br />;�',� eve.n and odd 16, 384-word memory units respei
<br />r} ` floating p�int instrucfions are sequenced operations tivcly. Hold the 48-bit word to be written in a v�
<br />� �'
<br /><< invalving bot h A a�d Q. storage location.
<br />�� � *Q-Register Assists accumulator in performing ��
<br />R-Register Functions as exchange register 'fi
<br />{�,�, ' more complicaled arithmetic aperations. Used with transmission involving B-Index Registers. Used; i
<br />� A�o perform double precision arithmetic. Q may be
<br />`� �t aclvancing or reducing count in a given B�Registe
<br />'��F' �-shifted �•ight or left, singly or in conjunction with A. During scvcral insfructions, used to 4ount repefiiti�
<br />ti;,; Q.also contains mask, in logical aperatian. ` ° `�
<br />, f4 ,: operations. � usecl with fioating point �nstru�tioi
<br />`� `�: " program; �ontrol Regi�ter, U� Holds program step in performing arithmetic operations ori the c�cp�
<br />��'� `wliile the two.instructions cantained in it are exccut- nent or eharacteristic.
<br />`° ;ed. The 48-bit instruction word taken from storage .'
<br />�{ ' X-Regi�ter An exchan�;e anci' auxil�ary arithixi
<br />� location specified uy P and entered in U', the upper tic registe��. All input-ou��put data passe� �hrougl� :
<br />�;� Y instruction being executed first. Execution of lower � -: ;,s;
<br />s�ts, , •
<br />�� �� �_ ;instructio� follows, except when upper instruction Externa! Funetion R�g�sier, 0° ` Used for e.
<br />�s�� �� j, :�s a, jump or when it p�•ovicics for conditional skip- changing cantrol infarmation with' inr�ut outpi
<br />� y` � in ; of low�r ins�:ruction. equipmcnt.
<br />P � �,
<br />�,, { �' ` ; ; :
<br />k��,y'p`h .� ' ': ,Auxil,i�iry Program Control R�gi�ter, U' An ac- t�utput Register�, 0' fhrough t�'' .'UL through'
<br />����x4,6r Y + ..',. ' . . � . .- . � . e -- . .
<br />�4�.,,�.x�� , `,�umulator' used: irr the inodifica�ion of execution used for output kiuH'er operatio�is where; datat�
<br />,, ;
<br />�,��� j = , ..
<br />��,w,, ,;� address of current instruction. This modification trans�7�i�t�d at spe�d of input; output �qu�.pmer
<br />��`i1�°� �
<br />J -4c c ^ � , . , , ; . � ..
<br />[��� ;� ,, '� �onsists o#' `addin� �contents of a�; Xndex Register: to Wlier� high-speed transfer is�rec�uireci, nutpi��` tr�%r.
<br />� f�'` 4 : ex�cutian address of current instruction. fer operations carried out via Q�. :,
<br />F��''+� `4 "it S
<br />���JK`�: , ,.., *O��ralional Regfsters �_��
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<br />c �i� ;a rf :�r
<br />r��'+ `t�„ r , �
<br />��fi� t
<br />3��� ;. . ,` c
<br />�4C��� 1 � •�;:
<br />��`��.,�27v'a°� lv 1 � _ . � �� '2
<br />.i y
<br />> rn t � ��+ c
<br />� i � 4 St
<br />� ��'' _�4 , ��a a ,� � ,��r�;
<br />�T�x���� i' f_s i� i . iy" 4 r1 ��, �
<br />.�' t � � r � � 4,
<br />��� �y� s� k
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<br />i} z�`�1 31��11 .t u y�� i: �\ 1� � � � r 4h,r/v�j�
<br />��<<', F t� � � . e i � �� t 1 t�w�'' �i- ttF� Y1F��� i�'�1
<br />���,�`.i,���::?�riS� �i�. <,��w_, r'�, .. �. � � �4�. ,. .,. _ „ ,. .. ,. .., . , . i � . � , .. , . .. . . . , , � . `._.� ,... �`,t � .� �'::� ., v .�.ln.�'''.,.. i�U.�vtr,�,:�`�1
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