Knight Lore: Routine at B9CC

B9CC: Choose a walking guard's next heading

Used by the routine at upd_30_31_158_159.

Bits 0 and 1 of +13 are the heading, and the handler for each is in guard_NSEW_tbl. Each one returns the deltas for carrying on the same way, or, if the last move was blocked along that heading's axis, the deltas for the next heading and a step on of the heading bits.

Input
HL	on exit, the new dY (H) and dX (L)

move_guard_wizard_NSEW

B9CC

LD BC,guard_NSEW_tbl

jump on bits 0 and 1 of +13

B9CF

LD A,(IX+$0D)

B9D2

AND $03

B9D4

LD L,A

B9D5

JP jump_to_tbl_entry