Page 392 - FUNDAMENTALS OF COMPUTER

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392 Fundamentals of Computers NPP

(r ) (r )
1
2
 r and r can be any 8-bit registers. · r VWm r H$moB© ^r 8-{~Q> a{OñQ>a hmo gH$Vo h¢&
1 2 1 2
e.g. XCHG AL, CH
Contents of AL and CH are exchanged. AL VWm CH Ho$ H§$Q>|Q²>g EŠgM|O hmo JE h¢&
 r and r both can be 16-bit General register; · r VWm r XmoZm| 16-{~Q> OZac a{OñQ>a hmo gH$Vo
1 2 1 2
h¢,
e.g. XCHG AX, SI.
 Neither r nor r can be segment register. · Z Vmo r Am¡a Zm hr r goJ_|Q> a{OñQ>a hmo gH$Vo h¢&
1
2
1
2
XCHG m,r: Exchange contents of memory XCHG m,r: _o_moar cmoHo$eZ m VWm a{OñQ>a r Ho$
location m and contents of register r. H§$Q>|Q²>g EŠgM|O H$a|& AWm©V² XCHG [BX], AL
e.g. XCHG [BX], AL

 Register r cannot be segment register. · a{OñQ>a r goJ_|Q> a{OñQ>a Zht hmo gH$Vm&
 The segment register for physical address · DS _| {\${OH$c ES´>og H¡$ëŠ`ycoeZ hoVw goJ_|Q> a{OñQ>a
calculation is DS. h¡&

 No flags are affected with XCHG instr- · XCHG B§ñQ´>ŠeZ Ho$ gmW H$moB© ^r âc¡J A\o$ŠQ> Zht
uction. hmoJm&
 XCHG r, m can also be executed in the · XCHG r, m Bgr àH$ma EŠOrŠ`yQ> {H$E Om gH|$Jo&
same way.
5.4.2 Data Manipulation Instructions 5.4.2 S>mQ>m ‘o{ZnwboeZ BÝñQ´>³eÝg
ADD r , r : Add the contents of register r 1 ADD r , r : a{OñQ>a r VWm r Ho$ H$ÝQ>oÝQ²>g H$mo
2
1
1
2
2
1
and r and put the result in register r . Omo‹S>| VWm n[aUm_ H$mo a{OñQ>a r _| aI|&
1
2
1
(r ) (r ) + (r )
1
2
1
 r and r can be any 8-bit registers or · r VWm r H$moB© ^r 8-{~Q> `m 16-{~Q> a{OñQ>a hmo
1
2
1
2
16-bit register. gH$Vo h¢&
 Neither r nor r can be segment registers. · Z Vmo r Am¡a Z hr r goJ_oÝQ> a{OñQ>a hmo gH$Vo h¢&
1 2 1 2
e.g. ADD AL, BL
ADD AX, BX
ADD AX, SI
 Contents of r remain unchanged. · r Ho$ H$ÝQ>oÝQ> An[ad{V©V ahVo h¢&
2
2
ADD m, r: Contents of register r and the ADD m, r: a{OñQ>a r Ho$ H$ÝQ>oÝQ> VWm S>mQ>m goJ_oÝQ>
memory m in Data segment are added and _| _o_moar m Omo‹S>o OmVo h¢ VWm n[aUm_ H$mo _o_moar _| aIm
result is placed in the memory. Only Effective
address is specified in the instruction. The de- OmVm h¡& Ho$dc à^mdr ES´>og H$mo hr BÝñQ´>ŠeZ _| {ZYm©[aV