Routines
Prev: 624D Up: Map Next: 625C
6253: Multiply HL By Four
Used by the routines at OffsetBlipLeft, OffsetBlipDown, LocateRadarBlip and CollisionCup.
Used to convert a distance (in doubled map units) into radar pixels, which are then found in H.
Input
HL Value
Output
HL Value multiplied by 04
MultiplyHLByFour 6253 LD B,$02 Set the shift counter to 02.
MultiplyHLByFour_Loop 6255 RL L Rotate HL left by one place.
6257 RL H
6259 DJNZ MultiplyHLByFour_Loop Decrease the shift counter by one and loop back to MultiplyHLByFour_Loop until both shifts have been done.
625B RET Return.
Prev: 624D Up: Map Next: 625C