chore: use bitfield library

src/cpu.zig

@@ -1,7 +1,11 @@
 const std = @import("std");
 const util = @import("util.zig");
+const bitfield = @import("util/bitfield.zig");
+
 const Bus = @import("bus.zig").Bus;
 const Scheduler = @import("scheduler.zig").Scheduler;
+const Bitfield = bitfield.Bitfield;
+const Bit = bitfield.Bit;
 
 const comptimeDataProcessing = @import("cpu/data_processing.zig").comptimeDataProcessing;
 const comptimeSingleDataTransfer = @import("cpu/single_data_transfer.zig").comptimeSingleDataTransfer;
@@ -21,7 +25,7 @@ pub const Arm7tdmi = struct {
             .r = [_]u32{0x00} ** 16,
             .sch = scheduler,
             .bus = bus,
-            .cpsr = .{ .inner = 0x0000_00DF },
+            .cpsr = .{ .val = 0x0000_00DF },
         };
     }
 
@@ -52,20 +56,20 @@ fn armIdx(opcode: u32) u12 {
 fn checkCond(cpsr: *const CPSR, opcode: u32) bool {
     // TODO: Should I implement an enum?
     return switch (@truncate(u4, opcode >> 28)) {
-        0x0 => cpsr.z(), // EQ - Equal
-        0x1 => !cpsr.z(), // NEQ - Not equal
-        0x2 => cpsr.c(), // CS - Unsigned higher or same
-        0x3 => !cpsr.c(), // CC - Unsigned lower
-        0x4 => cpsr.n(), // MI - Negative
-        0x5 => !cpsr.n(), // PL - Positive or zero
-        0x6 => cpsr.v(), // VS - Overflow
-        0x7 => !cpsr.v(), // VC - No overflow
-        0x8 => cpsr.c() and !cpsr.z(), // HI - unsigned higher
-        0x9 => !cpsr.c() and cpsr.z(), // LS - unsigned lower or same
-        0xA => cpsr.n() == cpsr.v(), // GE - Greater or equal
-        0xB => cpsr.n() != cpsr.v(), // LT - Less than
-        0xC => !cpsr.z() and (cpsr.n() == cpsr.z()), // GT - Greater than
-        0xD => cpsr.z() or (cpsr.n() != cpsr.v()), // LE - Less than or equal
+        0x0 => cpsr.z.read(), // EQ - Equal
+        0x1 => !cpsr.z.read(), // NEQ - Not equal
+        0x2 => cpsr.c.read(), // CS - Unsigned higher or same
+        0x3 => !cpsr.c.read(), // CC - Unsigned lower
+        0x4 => cpsr.n.read(), // MI - Negative
+        0x5 => !cpsr.n.read(), // PL - Positive or zero
+        0x6 => cpsr.v.read(), // VS - Overflow
+        0x7 => !cpsr.v.read(), // VC - No overflow
+        0x8 => cpsr.c.read() and !cpsr.z.read(), // HI - unsigned higher
+        0x9 => !cpsr.c.read() and cpsr.z.read(), // LS - unsigned lower or same
+        0xA => cpsr.n.read() == cpsr.v.read(), // GE - Greater or equal
+        0xB => cpsr.n.read() != cpsr.v.read(), // LT - Less than
+        0xC => !cpsr.z.read() and (cpsr.n.read() == cpsr.z.read()), // GT - Greater than
+        0xD => cpsr.z.read() or (cpsr.n.read() != cpsr.v.read()), // LE - Less than or equal
         0xE => true, // AL - Always
         0xF => std.debug.panic("0xF is a reserved condition field", .{}),
     };
@@ -117,79 +121,16 @@ fn populate() [0x1000]InstrFn {
     };
 }
 
-const CPSR = struct {
-    inner: u32,
-
-    pub fn n(self: *const @This()) bool {
-        return self.inner >> 31 & 1 == 1;
-    }
-
-    pub fn setN(self: *@This(), set: bool) void {
-        self.setBit(31, set);
-    }
-
-    pub fn z(self: *const @This()) bool {
-        return self.inner >> 30 & 1 == 1;
-    }
-
-    pub fn setZ(self: *@This(), set: bool) void {
-        self.setBit(30, set);
-    }
-
-    pub fn c(self: *const @This()) bool {
-        return self.inner >> 29 & 1 == 1;
-    }
-
-    pub fn setC(self: *@This(), set: bool) void {
-        self.setBit(29, set);
-    }
-
-    pub fn v(self: *const @This()) bool {
-        return self.inner >> 28 & 1 == 1;
-    }
-
-    pub fn setV(self: *@This(), set: bool) void {
-        self.setBit(28, set);
-    }
-
-    pub fn i(self: *const @This()) bool {
-        return self.inner >> 7 & 1 == 1;
-    }
-
-    pub fn setI(self: *@This(), set: bool) void {
-        self.setBit(7, set);
-    }
-
-    pub fn f(self: *const @This()) bool {
-        return self.inner >> 6 & 1 == 1;
-    }
-
-    pub fn setF(self: *@This(), set: bool) void {
-        self.setBit(6, set);
-    }
-
-    pub fn t(self: *const @This()) bool {
-        return self.inner >> 5 & 1 == 1;
-    }
-
-    pub fn setT(self: *@This(), set: bool) void {
-        self.setBit(5, set);
-    }
-
-    pub fn mode(self: *const @This()) Mode {
-        return self.inner & 0x1F;
-    }
-
-    pub fn setMode(_: *@This(), _: Mode) void {
-        std.debug.panic("TODO: Implement set_mode for CPSR", .{});
-    }
-
-    fn setBit(self: *@This(), comptime bit: usize, set: bool) void {
-        const set_val = @as(u32, @boolToInt(set)) << bit;
-        const mask = ~(@as(u32, 1) << bit);
-
-        self.inner = (self.inner & mask) | set_val;
-    }
+const CPSR = extern union {
+    mode: Bitfield(u32, 0, 5),
+    t: Bit(u32, 5),
+    f: Bit(u32, 6),
+    i: Bit(u32, 7),
+    v: Bit(u32, 28),
+    c: Bit(u32, 29),
+    z: Bit(u32, 30),
+    n: Bit(u32, 31),
+    val: u32,
 };
 
 const Mode = enum(u5) {