ST Memory Map
colorptr
1 1 1 4 - 1 1 1 7 ( $ 4 5 A - $ 4 5 D )
If th is v alu e is n o n ze ro , th en a t th e n ex t v e rtica l blan k in te rru p t, th e tab le
of 16 co lo r v alu es th at s ta rt a t th e ad d re ss sto red h ere a r e lo ad ed in to th e
16 co lo r re g iste rs. If th is va lu e is ze ro , th e co lo r p alette is n o t ch a n g e d .
screenpt
1 1 1 8 - 1 1 2 1 ( $ 4 5 E - $ 4 6 1 )
If th is va lu e is n o n z ero , it is as su m ed to b e th e sta rtin g ad d res s fo r a n ew
32 K block o f d isp lay m em o ry , a n d th e p h y sic al scre en b ase a d d re ss w ill b e
ch an g e d acco rd in g ly , d u rin g th e n ex t v ertica l b lan k in terru p t.
__vbclock
1 1 2 2 - 1 1 2 5 ( $ 4 6 2 - $ 4 6 5 )
C o u n te r fo r th e n u m b er of ve rtica l b lan k in terru p ts th a t h av e ac tu ally be en
p ro ce sse d (n ot block ed b y vb lsem ).
__frclock
1 1 2 6 - 1 1 2 9 ( $ 4 6 6 - $ 4 6 9 )
T otal co u n t o f v ertic al b lan k in terru p ts. T his co u n t is u p d ate d re g ard le ss of
th e sta tu s of vb lsem .
hdv
_
init
1 1 3 0 - 1 1 3 3 ( $ 4 6 A - $ 4 6 D )
V ec to r to th e h ard d isk in itialization ro u tin e . A 0 in d icate s th at no h ard
disk is in stalle d .
swv
_
vec
1 1 3 4 - 1 1 3 7 ( $ 4 6 E - $ 4 7 1 )
V e c tor to th e ro u tin e th at th e s y ste m u se s w h en it d ete cts a m o n ito r
ch an g e (from m o n o ch ro m e to co lo r, o r v ice v e rs a ). T h is v ec to r initially
p o in ts to th e re se t h an d le r, so th e s ys te m r e se ts if th e u se r ch a n g es th e
m o n ito r.
hdv
__
bpb
1 1 3 8 - 1 1 4 1 ( $ 4 7 2 - $ 4 7 5 )
T h e v ec to r to th e ro u tin e to u se w h e n th e G e tb p b () ro u tin e req u ests infor
m a tio n a b o u t a h ard disk . T his ro u tin e is in sta lled w h en th e h ard d isk is
in itialized , a n d sh o u ld follo w th e callin g se q u en ce of th e n o rm al B IO S
G e tb p b () fu n ctio n. A v alu e of 0 is sto re d h ere if n o h a rd disk is atta ch ed .
397
To Next Page
Loading...
