Routines
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B047: Reduce Velocity
Used by the routine at GamePlay_Start.
Moves a signed velocity towards zero by a given amount. It will not go past zero.
Input
A Velocity
B Amount to reduce the speed by
Output
A The new velocity
ReduceVelocity B047 AND A Jump to ReduceVelocity_Positive if the velocity is positive.
B048 JP P,ReduceVelocity_Positive
B04B ADD A,B Add the amount to reduce the velocity by to the negative velocity.
B04C RET NC Return if the velocity is still negative.
B04D XOR A Set the velocity to zero.
B04E RET Return.
ReduceVelocity_Positive B04F SUB B Subtract the amount to reduce the velocity by from the positive velocity.
B050 RET NC Return if the velocity is still positive.
B051 XOR A Set the velocity to zero.
B052 RET Return.
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