Implement the relocate origin feature of the Type 30 display. #7
Description
The Type 30 display has a little know and little used feature that allows the coordinate origin to be relocated. From the PDP-35-2 INSTRUCTION MANUAL:
The dpy instruction (73cb07) causes one point to be displayed on the scope. AC [0-9] specifies the X coordinate and IO [0-9] gives the Y coordinate. AC and IO remain unchanged after the dpу instruction. The three "b" bits control the brightness -- 4 is visible to photomultiplier tubes only, 7 is barely visible in a dark room, 0 1s normal, and 3 is brightest. The "c" bits contro1 the centering. O makes the origin in the center of the scope. 1 puts it at the center of the bottom edge. 2 makes the origin be half way up the left edge, while 3 puts it at the lower left corner.
Not sure if these "c bits" applied to all Type 30 Displays. For sure this feature is used in the "snowflake_sa-100.bin" demo.