Page 394 - FUNDAMENTALS OF COMPUTER

NPP

394 Fundamentals of Computers NPP

r → (r ) + (r ) + CF
1
1
2
ADC r , data (r ) (r ) + data + CF
1
1
1
ADC m data (m) [m] + data + CF
1
INC r: Increment contents of register r by INC r: a{OñQ>a r Ho$ H$ÝQ>oÝQ²>g H$mo 1 ~‹T>mVm h¡ VWm
one and place the result in the same register. n[aUm_ H$mo Cgr a{OñQ>a _| aIVm h¡&
(r) (r) + 1
 Register r can be any 8-bit or 16-bit general · a{OñQ>a r H$moB© ^r 8 {~Q> `m 16 {~Q> a{OñQ>a hmo
Register. gH$Vm h¡&
 Register r can not be a segment register. · a{OñQ>a r EH$ goJ_oÝQ> a{OñQ>a Zht hmo gH$Vm h¡&
 CF (carry flag) is not affected. · CF (Ho$ar âcoJ) à^m{dV Zht hmoVm h¡&
INC m: Increment contents of memory m INC m: S>mQ>m goJ_oÝQ> _| _o_moar m Ho$ H$ÝQ>oÝQ²>g _|
in data segment and place the result in the d¥{Õ H$aVm h¡ VWm n[aUm_ H$mo Cgr ñWmZ _| aIVm h¡&
same location.
Assembler Directives can be used to indi- Agoå~ca S>mBaopŠQ>ìg `h g§Ho$V H$aZo Ho$ {cE Cn`moJ
cate whether memory points to a byte (single {H$`o Om gH$Vo h¢ {H$ Š`m _o_moar EH$ ~mBQ> (qgJc cmoHo$eZ)
location) or a word (two locations).
`m EH$ dS>© (Qy> cmoHo$eÝg) H$m g§Ho$V H$aVr h¡&
e.g. INC BYTE PTR [BX]
BYTE PTR is an assembler directive BYTE PTR EH$ Agoå~ca S>mBaopŠQ>d h¡ Omo g§Ho$V
which indicates that the memory location in H$aVm h¡ {H$ ñŠd¡`a ~«oHo$Q> _| _o_moar cmoHo$eZ EH$ ~mBQ> H$mo
square bracket points to a byte which is to be
incremented by 1 and the result must be placed B§{JV H$aVm h¡ {Ogo 1 ~‹T>m`m OmZm h¡ VWm [aOëQ> H$mo
in the same location. Cgr ñWmZ _| aIZm hmoVm h¡&
Consider following instruction: {ZåZ{c{IV BÝñQ´>ŠeZ na {dMma H$a|:
INC WORD PTR [BX]
WORD PTR is an Assembler Directive WORD PTR EH$ Agoå~ca S>mBaopŠQ>d h¡ Omo g§Ho$V
which indicates that the memory location in H$aVm h¡ {H$ ñŠd¡`a ~«oHo$Q> _| _o_moar cmoHo$eZ EH$ 16 {~Q>
square bracket points to a 16-bit word or
two bytes. This word is placed at effective dS>© `m Xmo ~mBQ> H$mo B§{JV H$aVm h¡& `h dS>© EH$ à^mdr
address [BX] and [BX + 1]. This word is to ES´>og [BX] VWm [BX +1] na aIm OmVm h¡& `h dS>© 1
be incre-mented by 1 and the result must be BÝH«$s_oÝQ> {H$`m OmZm h¡ VWm n[aUm_ H$mo Cgr ñWmZ na
placed in the same location. Default segment
register is DS. aIZm hmoVm h¡& {S>\$m°ëQ> goJ_oÝQ> a{OñQ>a DS h¡&
DEC r: Decrement contents of register r by DEC r: a{OñQ>a r Ho$ H$ÝQ>oÝQ²>g H$mo 1 KQ>mVm h¡
1 and place the result in the same register. Reg- VWm n[aUm_ H$mo Cgr a{OñQ>a _| aIVm h¡& a{OñQ>a r
ister r can be any 8-bit or 16-bit register except
segment register. goJ_oÝQ> a{OñQ>a H$mo N>mo‹S>H$a H$moB© ^r 8 {~Q> `m 16 {~Q>
a{OñQ>a hmo gH$Vm h¡&
(r) (r) 1
 CF is not affected.  CF à^m{dV Zht hmoVm h¡&