chore: make use of comptime control flow when working with tuples

src/core/bus/dma.zig

@@ -335,10 +335,10 @@ fn DmaController(comptime id: u2) type {
 }
 
 pub fn pollDmaOnBlank(bus: *Bus, comptime kind: DmaKind) void {
-    bus.dma[0].poll(kind);
+    comptime var i: usize = 0;
-    bus.dma[1].poll(kind);
+    inline while (i < 4) : (i += 1) {
-    bus.dma[2].poll(kind);
+        bus.dma[i].poll(kind);
-    bus.dma[3].poll(kind);
+    }
 }
 
 const Adjustment = enum(u2) {

src/core/bus/io.zig

@@ -72,7 +72,7 @@ pub fn read(bus: *const Bus, comptime T: type, address: u32) ?T {
             0x0400_0200 => @as(u32, bus.io.irq.raw) << 16 | bus.io.ie.raw,
             0x0400_0204 => bus.io.waitcnt.raw,
             0x0400_0208 => @boolToInt(bus.io.ime),
-
+            0x0400_0300 => @enumToInt(bus.io.postflg),
             else => util.io.read.undef(T, log, "Tried to perform a {} read to 0x{X:0>8}", .{ T, address }),
         },
         u16 => switch (address) {
@@ -100,10 +100,11 @@ pub fn read(bus: *const Bus, comptime T: type, address: u32) ?T {
             // Interrupts
             0x0400_0200 => bus.io.ie.raw,
             0x0400_0202 => bus.io.irq.raw,
-            0x0400_0204 => @truncate(T, bus.io.waitcnt.raw),
+            0x0400_0204 => bus.io.waitcnt.raw,
             0x0400_0206 => null,
             0x0400_0208 => @boolToInt(bus.io.ime),
             0x0400_020A => null,
+            0x0400_0300 => @enumToInt(bus.io.postflg),
             else => util.io.read.undef(T, log, "Tried to perform a {} read to 0x{X:0>8}", .{ T, address }),
         },
         u8 => return switch (address) {
@@ -135,7 +136,6 @@ pub fn read(bus: *const Bus, comptime T: type, address: u32) ?T {
             0x0400_0206, 0x0400_0207 => null,
             0x0400_0208, 0x0400_0209 => @truncate(T, @as(u16, @boolToInt(bus.io.ime)) >> getHalf(@truncate(u8, address))),
             0x0400_020A, 0x0400_020B => null,
-
             0x0400_0300 => @enumToInt(bus.io.postflg),
             else => util.io.read.undef(T, log, "Tried to perform a {} read to 0x{X:0>8}", .{ T, address }),
         },
@@ -183,8 +183,12 @@ pub fn write(bus: *Bus, comptime T: type, address: u32, value: T) void {
 
             // Interrupts
             0x0400_0200 => bus.io.setIrqs(value),
-            0x0400_0204 => bus.io.waitcnt.raw = value,
+            0x0400_0204 => bus.io.waitcnt.raw = @truncate(u16, value),
             0x0400_0208 => bus.io.ime = value & 1 == 1,
+            0x0400_0300 => {
+                bus.io.postflg = @intToEnum(PostFlag, value & 1);
+                bus.io.haltcnt = if (value >> 15 & 1 == 0) .Halt else @panic("TODO: Implement STOP");
+            },
             else => util.io.write.undef(log, "Tried to write 0x{X:0>8}{} to 0x{X:0>8}", .{ value, T, address }),
         },
         u16 => switch (address) {
@@ -228,7 +232,10 @@ pub fn write(bus: *Bus, comptime T: type, address: u32, value: T) void {
             0x0400_0206 => {},
             0x0400_0208 => bus.io.ime = value & 1 == 1,
             0x0400_020A => {},
-
+            0x0400_0300 => {
+                bus.io.postflg = @intToEnum(PostFlag, value & 1);
+                bus.io.haltcnt = if (value >> 15 & 1 == 0) .Halt else @panic("TODO: Implement STOP");
+            },
             else => util.io.write.undef(log, "Tried to write 0x{X:0>4}{} to 0x{X:0>8}", .{ value, T, address }),
         },
         u8 => switch (address) {
@@ -262,7 +269,7 @@ pub fn write(bus: *Bus, comptime T: type, address: u32, value: T) void {
             0x0400_0209 => {},
             0x0400_020A, 0x0400_020B => {},
 
-            0x0400_0300 => bus.io.postflg = std.meta.intToEnum(PostFlag, value & 1) catch unreachable,
+            0x0400_0300 => bus.io.postflg = @intToEnum(PostFlag, value & 1),
             0x0400_0301 => bus.io.haltcnt = if (value >> 7 & 1 == 0) .Halt else std.debug.panic("TODO: Implement STOP", .{}),
 
             0x0400_0410 => log.debug("Wrote 0x{X:0>2} to the common yet undocumented 0x{X:0>8}", .{ value, address }),
@@ -602,16 +609,16 @@ pub const SoundBias = extern union {
 
 /// Read / Write
 pub const WaitControl = extern union {
-    sram_cnt: Bitfield(u32, 0, 2),
+    sram_cnt: Bitfield(u16, 0, 2),
-    s0_first: Bitfield(u32, 2, 2),
+    s0_first: Bitfield(u16, 2, 2),
-    s0_second: Bit(u32, 4),
+    s0_second: Bit(u16, 4),
-    s1_first: Bitfield(u32, 5, 2),
+    s1_first: Bitfield(u16, 5, 2),
-    s1_second: Bit(u32, 7),
+    s1_second: Bit(u16, 7),
-    s2_first: Bitfield(u32, 8, 2),
+    s2_first: Bitfield(u16, 8, 2),
-    s2_second: Bit(u32, 10),
+    s2_second: Bit(u16, 10),
-    phi_out: Bitfield(u32, 11, 2),
+    phi_out: Bitfield(u16, 11, 2),
 
-    prefetch_enable: Bit(u32, 14),
+    prefetch_enable: Bit(u16, 14),
-    pak_kind: Bit(u32, 15),
+    pak_kind: Bit(u16, 15),
-    raw: u32,
+    raw: u16,
 };

src/core/bus/timer.zig

@@ -190,19 +190,15 @@ fn Timer(comptime id: u2) type {
 
             // Perform Cascade Behaviour
             switch (id) {
-                0 => if (cpu.bus.tim[1].cnt.cascade.read()) {
+                inline 0, 1, 2 => |idx| {
-                    cpu.bus.tim[1]._counter +%= 1;
+                    const next = idx + 1;
-                    if (cpu.bus.tim[1]._counter == 0) cpu.bus.tim[1].onTimerExpire(cpu, late);
+
+                    if (cpu.bus.tim[next].cnt.cascade.read()) {
+                        cpu.bus.tim[next]._counter +%= 1;
+                        if (cpu.bus.tim[next]._counter == 0) cpu.bus.tim[next].onTimerExpire(cpu, late);
+                    }
                 },
-                1 => if (cpu.bus.tim[2].cnt.cascade.read()) {
+                3 => {}, // THere is no timer for TIM3 to cascade to
-                    cpu.bus.tim[2]._counter +%= 1;
-                    if (cpu.bus.tim[2]._counter == 0) cpu.bus.tim[2].onTimerExpire(cpu, late);
-                },
-                2 => if (cpu.bus.tim[3].cnt.cascade.read()) {
-                    cpu.bus.tim[3]._counter +%= 1;
-                    if (cpu.bus.tim[3]._counter == 0) cpu.bus.tim[3].onTimerExpire(cpu, late);
-                },
-                3 => {}, // There is no Timer for TIM3 to "cascade" to,
             }
 
             // Reschedule Timer if we're not cascading

src/core/cpu.zig

@@ -455,29 +455,12 @@ pub const Arm7tdmi = struct {
     }
 
     pub fn stepDmaTransfer(self: *Self) bool {
-        const dma0 = &self.bus.dma[0];
+        comptime var i: usize = 0;
-        const dma1 = &self.bus.dma[1];
+        inline while (i < 4) : (i += 1) {
-        const dma2 = &self.bus.dma[2];
+            if (self.bus.dma[i].in_progress) {
-        const dma3 = &self.bus.dma[3];
+                self.bus.dma[i].step(self);
-
+                return true;
-        if (dma0.in_progress) {
+            }
-            dma0.step(self);
-            return true;
-        }
-
-        if (dma1.in_progress) {
-            dma1.step(self);
-            return true;
-        }
-
-        if (dma2.in_progress) {
-            dma2.step(self);
-            return true;
-        }
-
-        if (dma3.in_progress) {
-            dma3.step(self);
-            return true;
         }
 
         return false;

src/core/scheduler.zig

@@ -46,10 +46,7 @@ pub const Scheduler = struct {
                 },
                 .TimerOverflow => |id| {
                     switch (id) {
-                        0 => cpu.bus.tim[0].onTimerExpire(cpu, late),
+                        inline 0...3 => |idx| cpu.bus.tim[idx].onTimerExpire(cpu, late),
-                        1 => cpu.bus.tim[1].onTimerExpire(cpu, late),
-                        2 => cpu.bus.tim[2].onTimerExpire(cpu, late),
-                        3 => cpu.bus.tim[3].onTimerExpire(cpu, late),
                     }
                 },
                 .ApuChannel => |id| {