quirks.rs: Prepare screen_wrap quirk for future xochip compat

src/cpu/mode.rs

@@ -1,8 +1,9 @@
 //! Selects the memory behavior of the [super::CPU]
 //!
-//! Since [super::Quirks] implements [From<Mode>],
+//! Since [Quirks] implements [`From<Mode>`],
 //! this can be used to select the appropriate quirk-set
 
+use super::Quirks;
 use crate::error::Error;
 use std::str::FromStr;
 
@@ -12,7 +13,7 @@ pub enum Mode {
     /// VIP emulation mode
     #[default]
     Chip8,
-    /// Chip-48 emulation mode
+    /// Super Chip emulation mode
     SChip,
     /// XO-Chip emulation mode
     XOChip,
@@ -32,3 +33,20 @@ impl FromStr for Mode {
         }
     }
 }
+
+impl From<Mode> for Quirks {
+    fn from(value: Mode) -> Self {
+        match value {
+            Mode::Chip8 => false.into(),
+            Mode::SChip => true.into(),
+            Mode::XOChip => Self {
+                bin_ops: true,
+                shift: false,
+                draw_wait: true,
+                screen_wrap: true,
+                dma_inc: false,
+                stupid_jumps: false,
+            },
+        }
+    }
+}

src/cpu/quirks.rs

@@ -1,17 +1,21 @@
 //! Controls the [Quirks] behavior of the CPU on a granular level.
-use super::Mode;
+
-/// Controls the authenticity behavior of the CPU on a granular level.
+/// Controls the quirk behavior of the CPU on a granular level.
+///
+/// `false` is Cosmac-VIP-like behavior
 #[derive(Clone, Copy, Debug, PartialEq, Eq, PartialOrd, Ord, Hash)]
 pub struct Quirks {
-    /// Binary ops in `8xy`(`1`, `2`, `3`) shouldn't set vF to 0
+    /// Super Chip: Binary ops in `8xy`(`1`, `2`, `3`) shouldn't set vF to 0
     pub bin_ops: bool,
-    /// Shift ops in `8xy`(`6`, `E`) shouldn't source from vY instead of vX
+    /// Super Chip: Shift ops in `8xy`(`6`, `E`) shouldn't source from vY instead of vX
     pub shift: bool,
-    /// Draw operations shouldn't pause execution until the next timer tick
+    /// Super Chip: Draw operations shouldn't pause execution until the next timer tick
     pub draw_wait: bool,
-    /// DMA instructions `Fx55`/`Fx65` shouldn't change I to I + x + 1
+    /// XO-Chip:    Draw operations shouldn't wrap from the bottom of the screen to the top
+    pub screen_wrap: bool,
+    /// Super Chip: DMA instructions `Fx55`/`Fx65` shouldn't change I to I + x + 1
     pub dma_inc: bool,
-    /// Indexed jump instructions should go to `adr` + v`a` where `a` is high nibble of `adr`.
+    /// Super Chip: Indexed jump instructions should go to `adr` + v`a` where `a` is high nibble of `adr`.
     pub stupid_jumps: bool,
 }
 
@@ -22,6 +26,7 @@ impl From<bool> for Quirks {
                 bin_ops: true,
                 shift: true,
                 draw_wait: true,
+                screen_wrap: false,
                 dma_inc: true,
                 stupid_jumps: true,
             }
@@ -30,6 +35,7 @@ impl From<bool> for Quirks {
                 bin_ops: false,
                 shift: false,
                 draw_wait: false,
+                screen_wrap: false,
                 dma_inc: false,
                 stupid_jumps: false,
             }
@@ -37,22 +43,6 @@ impl From<bool> for Quirks {
     }
 }
 
-impl From<Mode> for Quirks {
-    fn from(value: Mode) -> Self {
-        match value {
-            Mode::Chip8 => false.into(),
-            Mode::SChip => true.into(),
-            Mode::XOChip => Self {
-                bin_ops: true,
-                shift: false,
-                draw_wait: true,
-                dma_inc: false,
-                stupid_jumps: false,
-            },
-        }
-    }
-}
-
 impl Default for Quirks {
     fn default() -> Self {
         Self::from(false)

src/cpu/tests.rs

@@ -13,7 +13,7 @@
 //! Some of these tests run >16M times, which is very silly
 
 use super::*;
-pub(self) use crate::{
+use crate::{
     bus,
     bus::{Bus, Region::*},
 };
@@ -674,9 +674,9 @@ mod i {
 /// - Random number generation
 /// - Drawing to the display
 mod io {
+    use super::*;
     use std::io::Write;
 
-    use super::*;
     /// Cxbb: Stores a random number & the provided byte into vX
     #[test]
     fn rand() {
@@ -712,6 +712,7 @@ mod io {
                     bin_ops: false,
                     shift: false,
                     draw_wait: false,
+                    screen_wrap: true,
                     dma_inc: false,
                     stupid_jumps: false,
                 },
@@ -727,6 +728,7 @@ mod io {
                     bin_ops: false,
                     shift: false,
                     draw_wait: true,
+                    screen_wrap: true,
                     dma_inc: false,
                     stupid_jumps: false,
                 },
@@ -740,6 +742,7 @@ mod io {
                     bin_ops: false,
                     shift: false,
                     draw_wait: true,
+                    screen_wrap: true,
                     dma_inc: false,
                     stupid_jumps: false,
                 },

tests/integration.rs

@@ -226,6 +226,7 @@ mod quirks {
                 bin_ops: true,
                 shift: true,
                 draw_wait: true,
+                screen_wrap: false,
                 dma_inc: true,
                 stupid_jumps: true,
             }
@@ -241,6 +242,7 @@ mod quirks {
                 bin_ops: false,
                 shift: false,
                 draw_wait: false,
+                screen_wrap: false,
                 dma_inc: false,
                 stupid_jumps: false,
             }
@@ -253,6 +255,7 @@ mod quirks {
             bin_ops: false,
             shift: true,
             draw_wait: false,
+            screen_wrap: false,
             dma_inc: true,
             stupid_jumps: false,
         };