SGS ATES Z80, Instruction Set, Page: 215 / 273

~R
NZ,
Opera t io n:
If
Z
=
1 ,
c ontinu e
If Z
=
0, PC
+ -
PC + e
I
0 :
a
> :
a :
0 : 0 : 0 : 0
I
2 0
I. , :
: e - 2 : : : •.
I
T h is i n s tr uc t io n p r o v i d es fo r co nditi o n a l br a n c hin g t o
ot h er seg m e nt s of a pr og r a m d e p e ndin g o n t h e r es ults o f
a tes t on t h e Ze r o Fl ag . I f th e f l ag i s e q u a l t o a '0',
the va l ue of t h e di s pl ace m e nt e is a dd ed t o th e P r og r a m
Coun t er (PC) a nd th e n ex t i n s tru c t io n i s f e t c h e d f r om
t he loca t io n des i g n a t e d b y th e n e w co nt e n ts o f t h e P C.
The j u mp is meas ur e d f r o m th e a ddr ess of th e i n s tru c t ion
opc o de a nd h a s a r a n ge of - 1 26 t o +1 29 b y t es . T h e
asse mbl e r ca l cu l a t es the d i s p l a ccm( ' nt (. and a u t om a ti ca ll y adj u st s
f o r th e t w i ce in C I'( ' m c n L ed P C .
If t h e Ze r o Flag i s e qu a l t o a
' 1',
th e next in s tru c t ion
to be exec ut ed is t a k e n f r o m th e l oca ti o n f o ll o w i n g th is
instr u c t io n .
The Ze r o F l ag i s r e s e t a nd it i s r e q ui r e d t o jump b ac k 4
locatio n s f r om 4 80 . T h e asse mbl y l ang u ag e s t a t e m e nt i s: