Routines
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B1C7: Multiply by 8
This multiplies A by 8, returning the result in BC.
Used by the routines at bounds_check, spawn_character, vischar_move_x, vischar_move_y and get_next_drawable_itemstruct.
Input
A Argument.
Output
BC Result of (A << 3).
multiply_by_8 B1C7 LD B,$00 Set B to zero
B1C9 ADD A,A Double the input argument
B1CA RL B Merge the carry out from the doubling into B
B1CC ADD A,A Double it again
B1CD RL B
B1CF ADD A,A And double it again
B1D0 RL B
B1D2 LD C,A Move low part of result into C
B1D3 RET Return
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