From e63111ea98bc1b5b55e99e197e75736350169840 Mon Sep 17 00:00:00 2001
From: pingu <nor@acorneroftheweb.com>
Date: Mon, 30 Mar 2026 13:10:23 +0200
Subject: [PATCH] No more const where it is not needed

---
 src/GB/CPU.hs | 26 +++++++++++++-------------
 1 file changed, 13 insertions(+), 13 deletions(-)

diff --git a/src/GB/CPU.hs b/src/GB/CPU.hs
index 4eb07f3..5d3d00e 100644
--- a/src/GB/CPU.hs
+++ b/src/GB/CPU.hs
@@ -108,12 +108,12 @@ execute cpu = \case
                      H -> cpu ^. registers . h
                      L -> cpu ^. registers . l
                    (newValue, newFlags) = add (cpu ^. registers . a) value $ _c && cpu ^. registers . flags . carry in
-            cpu & registers . a %~ const newValue & registers . flags %~ const newFlags
+            cpu & registers . a .~ newValue & registers . flags .~ newFlags
   AddHL _c -> let value = fetch cpu . getHL $ cpu ^. registers
                   (newValue, newFlags) = add (cpu ^. registers . a) value $ _c && cpu ^. registers . flags . carry in
-           cpu & registers . a %~ const newValue & registers . flags %~ const newFlags
+           cpu & registers . a .~ newValue & registers . flags .~ newFlags
   AddN value _c -> let (newValue, newFlags) = add (cpu ^. registers . a) value $ _c && cpu ^. registers .flags . carry in
-                cpu & registers . a %~ const newValue & registers . flags %~ const newFlags
+                cpu & registers . a .~ newValue & registers . flags .~ newFlags
   SubR t _c -> let value = case t of
                      A -> cpu ^. registers . a
                      B -> cpu ^. registers . b
@@ -123,12 +123,12 @@ execute cpu = \case
                      H -> cpu ^. registers . h
                      L -> cpu ^. registers . l
                    (newValue, newFlags) = sub (cpu ^. registers . a) value $ _c && cpu ^. registers . flags . carry in
-            cpu & registers . a %~ const newValue & registers . flags %~ const newFlags
+            cpu & registers . a .~ newValue & registers . flags .~ newFlags
   SubHL _c -> let value = fetch cpu . getHL $ cpu ^. registers
                   (newValue, newFlags) = sub (cpu ^. registers . a) value $ _c && cpu ^. registers . flags . carry in
-           cpu & registers . a %~ const newValue & registers . flags %~ const newFlags
+           cpu & registers . a .~ newValue & registers . flags .~ newFlags
   SubN value _c -> let (newValue, newFlags) = sub (cpu ^. registers . a) value $ _c && cpu ^. registers .flags . carry in
-                cpu & registers . a %~ const newValue & registers . flags %~ const newFlags
+                cpu & registers . a .~ newValue & registers . flags .~ newFlags
   CpR t _c -> let value = case t of
                      A -> cpu ^. registers . a
                      B -> cpu ^. registers . b
@@ -138,12 +138,12 @@ execute cpu = \case
                      H -> cpu ^. registers . h
                      L -> cpu ^. registers . l
                   (_, newFlags) = sub (cpu ^. registers . a) value $ _c && cpu ^. registers . flags . carry in
-            cpu & registers . flags %~ const newFlags
+            cpu & registers . flags .~ newFlags
   CpHL _c -> let value = fetch cpu . getHL $ cpu ^. registers
                  (_, newFlags) = sub (cpu ^. registers . a) value $ _c && cpu ^. registers . flags . carry in
-           cpu & registers . flags %~ const newFlags
+           cpu & registers . flags .~ newFlags
   CpN value _c -> let (_, newFlags) = sub (cpu ^. registers . a) value $ _c && cpu ^. registers .flags . carry in
-                cpu & registers . flags %~ const newFlags
+                cpu & registers . flags .~ newFlags
   IncR t -> let (target, target') = case t of
                      A -> (a,a)
                      B -> (b,b)
@@ -153,11 +153,11 @@ execute cpu = \case
                      H -> (h,h)
                      L -> (l,l)
                 (value, newFlags) = add (cpu ^. registers . target) 1 False in
-            cpu & registers . target' %~ const value & registers . flags %~ const newFlags
+            cpu & registers . target' .~ value & registers . flags .~ newFlags
   IncHL -> let target = getHL $ cpu ^. registers
                value = fetch cpu target
                (newValue, newFlags) = add value 1 False in
-            cpu & bus %~ (flip V.update $ V.singleton (fromIntegral target, newValue)) & registers . flags %~ const newFlags
+            cpu & bus %~ (flip V.update $ V.singleton (fromIntegral target, newValue)) & registers . flags .~ newFlags
   DecR t -> let (target, target') = case t of
                      A -> (a,a)
                      B -> (b,b)
@@ -167,11 +167,11 @@ execute cpu = \case
                      H -> (h,h)
                      L -> (l,l)
                 (value, newFlags) = sub (cpu ^. registers . target) 1 False in
-            cpu & registers . target' %~ const value & registers . flags %~ const newFlags
+            cpu & registers . target' .~ value & registers . flags .~ newFlags
   DecHL -> let target = getHL $ cpu ^. registers
                value = fetch cpu target
                (newValue, newFlags) = sub value 1 False in
-            cpu & bus %~ (flip V.update $ V.singleton (fromIntegral target, newValue)) & registers . flags %~ const newFlags
+            cpu & bus %~ (flip V.update $ V.singleton (fromIntegral target, newValue)) & registers . flags .~ newFlags
   where
     add :: Word8 -> Word8 -> Bool -> (Word8, FlagRegister)
     add o n _c = let new        = o + n + if _c then 1 else 0