blob: e20dd8dad829eabc9e4727024f5682b8213ac57e (
plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
|
module Fig.Emulator.GB.Component.RAM
( compWRAM
) where
import Fig.Prelude
import Prelude (fromIntegral)
import qualified Data.Vector as V
import qualified Data.Vector.Mutable as MV
import Data.Word (Word8)
import Fig.Emulator.GB.Bus
newtype RAMError = RAMError Text
deriving Show
instance Exception RAMError
instance Pretty RAMError where
pretty (RAMError b) = mconcat
[ "internal RAM error: "
, b
]
compWRAM :: (MonadIO m, MonadThrow m) => Addr -> Int -> Component m
compWRAM start size = Component
{ compState = V.replicate size 0 :: V.Vector Word8
, compMatches = \a ->
a >= start && a <= end
, compUpdate = \s _ -> pure s
, compWrite = \s ad v -> do
let offset = fromIntegral . unAddr $ ad - start
pure $ V.modify (\ms -> MV.write ms offset v) s
, compRead = \s ad -> do
let offset = fromIntegral . unAddr $ ad - start
case s V.!? offset of
Nothing -> throwM . RAMError $ mconcat
[ "address ", pretty ad, " out of bounds"
]
Just v -> pure v
}
where
end = start + Addr (fromIntegral (size - 1))
|
