Please help me find/remember this game!

[Madkao]

I vaguely remember a PC game (likely IBM AT-5051 but I am not sure) that I used to play at my friend's house back in the early 80s in Taiwan. (probably 1983-1985). The game is monochrome. I remember the character in the game runs from the left of the screen to the right and can shoot a boomerang. The only image I can really remember is a there is an Eagle coming down from the top right corner to attack the player and I have to get across the screen in a safe manner. Then the next screen will load up with a different challenge (kind of like pitfall I think). I want to say that the game has a medieval setting and somehow I remember it being called "the king's sword" or something like that. I know this is a long shot but maybe someone can help me find this game. Thanks!