From 90d5c19e0159776a2f45e7e56aad982885de7408 Mon Sep 17 00:00:00 2001
From: Rekai Musuka <rekai@musuka.dev>
Date: Thu, 29 Jun 2023 23:12:08 -0500
Subject: [PATCH] feat: implement debug i/o in Bus Interface

---
 src/lib.zig | 109 ++++++++++++++++++++++++++++++++++++++++++++++++----
 1 file changed, 102 insertions(+), 7 deletions(-)

diff --git a/src/lib.zig b/src/lib.zig
index cd73a37..fae4590 100644
--- a/src/lib.zig
+++ b/src/lib.zig
@@ -45,6 +45,14 @@ pub const Bus = struct {
         write16: *const fn (ptr: *anyopaque, address: u32, value: u16) void,
         write32: *const fn (ptr: *anyopaque, address: u32, value: u32) void,
 
+        dbg_read8: *const fn (ptr: *anyopaque, address: u32) u8,
+        dbg_read16: *const fn (ptr: *anyopaque, address: u32) u16,
+        dbg_read32: *const fn (ptr: *anyopaque, address: u32) u32,
+
+        dbg_write8: *const fn (ptr: *anyopaque, address: u32, value: u8) void,
+        dbg_write16: *const fn (ptr: *anyopaque, address: u32, value: u16) void,
+        dbg_write32: *const fn (ptr: *anyopaque, address: u32, value: u32) void,
+
         reset: *const fn (ptr: *anyopaque) void,
     };
 
@@ -89,6 +97,36 @@ pub const Bus = struct {
                 self.write(u32, address, value);
             }
 
+            fn dbgRead8(ptr: *anyopaque, address: u32) u8 {
+                const self = @ptrCast(P, @alignCast(alignment, ptr));
+                return self.dbgRead(u8, address);
+            }
+
+            fn dbgRead16(ptr: *anyopaque, address: u32) u16 {
+                const self = @ptrCast(P, @alignCast(alignment, ptr));
+                return self.dbgRead(u16, address);
+            }
+
+            fn dbgRead32(ptr: *anyopaque, address: u32) u32 {
+                const self = @ptrCast(P, @alignCast(alignment, ptr));
+                return self.dbgRead(u32, address);
+            }
+
+            fn dbgWrite8(ptr: *anyopaque, address: u32, value: u8) void {
+                const self = @ptrCast(P, @alignCast(alignment, ptr));
+                self.dbgWrite(u8, address, value);
+            }
+
+            fn dbgWrite16(ptr: *anyopaque, address: u32, value: u16) void {
+                const self = @ptrCast(P, @alignCast(alignment, ptr));
+                self.dbgWrite(u16, address, value);
+            }
+
+            fn dbgWrite32(ptr: *anyopaque, address: u32, value: u32) void {
+                const self = @ptrCast(P, @alignCast(alignment, ptr));
+                self.dbgWrite(u32, address, value);
+            }
+
             fn reset(ptr: *anyopaque) void {
                 const self = @ptrCast(P, @alignCast(alignment, ptr));
                 self.reset();
@@ -106,6 +144,14 @@ pub const Bus = struct {
                 .write16 = impl.write16,
                 .write32 = impl.write32,
 
+                .dbg_read8 = impl.dbgRead8,
+                .dbg_read16 = impl.dbgRead16,
+                .dbg_read32 = impl.dbgRead32,
+
+                .dbg_write8 = impl.dbgWrite8,
+                .dbg_write16 = impl.dbgWrite16,
+                .dbg_write32 = impl.dbgWrite32,
+
                 .reset = impl.reset,
             },
         };
@@ -130,16 +176,21 @@ pub const Bus = struct {
     }
 
     pub fn dbgRead(self: @This(), comptime T: type, address: u32) T {
-        _ = address;
-        _ = self;
-        @panic("TODO: Implement Debug Reads via Bus Interface");
+        return switch (T) {
+            u32 => self.vtable.dbg_read32(self.ptr, address),
+            u16 => self.vtable.dbg_read16(self.ptr, address),
+            u8 => self.vtable.dbg_read8(self.ptr, address),
+            else => @compileError("TODO: Fill this in"),
+        };
     }
 
     pub fn dbgWrite(self: @This(), comptime T: type, address: u32, value: T) void {
-        _ = self;
-        _ = value;
-        _ = address;
-        @panic("TODO: Implement Debug Writes via Bus Interface");
+        switch (T) {
+            u32 => self.vtable.dbg_write32(self.ptr, address, value),
+            u16 => self.vtable.dbg_write16(self.ptr, address, value),
+            u8 => self.vtable.dbg_write8(self.ptr, address, value),
+            else => @compileError("TODO: Fill this in"),
+        }
     }
 
     pub fn reset(self: @This()) void {
@@ -206,6 +257,17 @@ const ExampleBus = struct {
         _ = value;
         _ = address;
     }
+    pub fn dbgRead(self: *@This(), comptime T: type, address: u32) T {
+        _ = self;
+        _ = address;
+        return 0;
+    }
+
+    pub fn dbgWrite(self: *@This(), comptime T: type, address: u32, value: T) void {
+        _ = self;
+        _ = value;
+        _ = address;
+    }
 
     pub fn reset(self: *@This()) void {
         self._ = 0;
@@ -224,6 +286,38 @@ const ExampleScheduler = struct {
     }
 };
 
+test "create IBus" {
+    var bus_impl = ExampleBus{};
+    const iface = Bus.init(&bus_impl);
+    _ = iface;
+}
+
+test "call IBus reads" {
+    var bus_impl = ExampleBus{};
+    const iface = Bus.init(&bus_impl);
+
+    _ = iface.read(u32, 0x0000_0000);
+    _ = iface.read(u16, 0x0000_0000);
+    _ = iface.read(u8, 0x0000_0000);
+
+    _ = iface.dbgRead(u32, 0x0000_0000);
+    _ = iface.dbgRead(u16, 0x0000_0000);
+    _ = iface.dbgRead(u8, 0x0000_0000);
+}
+
+test "call IBus writes" {
+    var bus_impl = ExampleBus{};
+    const iface = Bus.init(&bus_impl);
+
+    _ = iface.write(u32, 0x0000_0000, 0x0000_0000);
+    _ = iface.write(u16, 0x0000_0000, 0x0000);
+    _ = iface.write(u8, 0x0000_0000, 0x00);
+
+    _ = iface.dbgWrite(u32, 0x0000_0000, 0x0000_0000);
+    _ = iface.dbgWrite(u16, 0x0000_0000, 0x0000);
+    _ = iface.dbgWrite(u8, 0x0000_0000, 0x00);
+}
+
 test "create ARMv4T interface" {
     var bus_impl = ExampleBus{};
     var scheduler_impl = ExampleScheduler{};
@@ -242,6 +336,7 @@ test "create ARMv4T interface" {
 
     icpu.reset();
     icpu.step();
+    // TODO: call icpu.panic()
 }
 
 test "create ARMv5TE interface" {