feat: add hardware breakpoints

src/State.zig

@@ -0,0 +1,68 @@
+const std = @import("std");
+
+hw_bkpt: HwBkpt = .{},
+
+const HwBkpt = struct {
+    const log = std.log.scoped(.HwBkpt);
+
+    list: [2]?Bkpt = .{ null, null },
+
+    pub fn isHit(self: *const @This(), addr: u32) bool {
+        for (self.list) |bkpt_opt| {
+            if (bkpt_opt == null) continue;
+            const bkpt = bkpt_opt.?;
+
+            if (bkpt.addr == addr) return true;
+        }
+
+        return false;
+    }
+
+    pub fn add(self: *@This(), addr: u32, kind: u32) !void {
+        for (self.list) |*bkpt_opt| {
+            if (bkpt_opt.* != null) {
+                const bkpt = bkpt_opt.*.?;
+                if (bkpt.addr == addr) return; // makes this fn indempotent
+
+                continue;
+            }
+
+            bkpt_opt.* = .{ .addr = addr, .kind = try Bkpt.Kind.from(u32, kind) };
+            log.debug("Added Breakpoint at 0x{X:0>8}", .{addr});
+
+            return;
+        }
+
+        return error.OutOfSpace;
+    }
+
+    pub fn remove(self: *@This(), addr: u32) void {
+        for (self.list) |*bkpt_opt| {
+            if (bkpt_opt.* == null) continue;
+            const bkpt = bkpt_opt.*.?; // FIXME: bkpt_opt.?.addr works though?
+
+            log.debug("Removed Breakpoint at 0x{X:0>8}", .{addr});
+            if (bkpt.addr == addr) bkpt_opt.* = null;
+        }
+    }
+};
+
+const Bkpt = struct {
+    addr: u32,
+    kind: Kind,
+
+    const Kind = enum(u3) {
+        Arm = 2,
+        Thumb = 4,
+
+        pub fn from(comptime T: type, num: T) !@This() {
+            comptime std.debug.assert(@typeInfo(T) == .Int);
+
+            return switch (num) {
+                2 => .Arm,
+                4 => .Thumb,
+                else => error.UnknownBkptKind,
+            };
+        }
+    };
+};