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Get/Set Blitter Configuration
Blitmode()
T h is f u n c t i o n is u s e d to f in d o u t if a b l itt e r c h i p is a v a i la b l e , a n d w h e t h e r it
is b e i n g u s e d f o r d r a w i n g r o u t i n e s . If th e b l itt e r c h i p is p r e s e n t , th is f u n c
ti o n m a y a l s o b e u s e d to c h o o s e b e t w e e n h a r d w a r e b l itt in g o r s o f t w a r e
e m u l a t i o n m o d e .
C macro format
# d e f m e B l i t m o d e ( a ) x b i o s ( 6 4 ,a )
in t s t a t u s , v a l u e ;
s t a t u s =
B l i t m o d e ( v a l u e ) ;
Machine language format
v a l u e , - (s p )
m o v e . w
# 6 4 , - (s p )
m o v e . w
t r a p
# 1 4
a d d q .l
# 4 , s p
Inputs
v a l u e
w o r d
T h e b it v a l u e s f o r t h e v a l u e f la g a r e :
Bit Number
Function
0
S e t b lit m o d e
0 =
1 =
1 - 1 4
U n d e f i n e d , r e s e r v e d
1 5
M u s t b e 0
Results
DO
s t a t u s
w o r d
T h e s t a t u s b it v a l u e s a r e :
Bit Number
Description
0
C u r r e n t b lit m o d e
0 =
1 =
1
B lit te r c h i p a v a i la b i lity
0 =
1 =
2 - 1 4
U n d e f i n e d , r e s e r v e d
1 5
A 0 is a l w a y s r e t u r n e d
234
Blitmode
A b it f la g u s e d to s e t t h e b l itt e r c o n f i g u
r a t i o n . A v a l u e o f - 1
c h a n g e , t h e c o n f i g u r a t i o n .
U s e s o f t w a r e b lit r o u t i n e s
U s e b l itt e r h a r d w a r e
A b it fla g t h a t r e t u r n s t h e b litte r c o n f i g u r a t i o n a s it
s t o o d p r i o r to t h e s e t o p e r a t i o n .
U s i n g s o f t w a r e b lit r o u t i n e s
U s i n g b l itt e r h a r d w a r e
B lit te r c h i p n o t a v a i la b l e
B lit te r c h i p is in s t a lle d
Opcode = 64
is u s e d to r e a d , n o t
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