1 files changed, 27 insertions, 0 deletions
diff --git a/src/lib/trap.zig b/src/lib/trap.zig
index 4460cfd..99db8ba 100644
--- a/src/lib/trap.zig
+++ b/src/lib/trap.zig
@@ -8,4 +8,31 @@ pub const Frame = extern struct {
     satp: usize, // Offset: 512
     stack_pointer: *allowzero u8, // Offset: 520
     hart_id: usize, // Offset: 528
+
+    pub fn setReturnValue(self: *Frame, value: anytype) void {
+        switch (@typeInfo(@TypeOf(value))) {
+            .ErrorUnion => self.returnErrorUnion(value),
+            .ErrorSet => self.returnError(value),
+            else => self.returnValue(value),
+        }
+    }
+
+    fn returnErrorUnion(self: *Frame, error_union: anytype) void {
+        if (error_union) |value| {
+            self.returnValue(value);
+        } else |err| {
+            self.returnError(err);
+        }
+    }
+
+    fn returnError(self: *Frame, err: anyerror) void {
+        self.general_purpose_registers[11] = @intFromError(err);
+    }
+
+    fn returnValue(self: *Frame, value: anytype) void {
+        self.general_purpose_registers[11] = 0;
+        if (@typeInfo(@TypeOf(value)) != .Void) {
+            self.general_purpose_registers[10] = @bitCast(value);
+        }
+    }
 };