What does this assembler code implement?

Question

assembler

The task is to determine what the given code does. Please tell me, it's really bad with assembler.
Initial conditions:
addr - address of initial values
​​var1 - unsigned number, variable
var2, var3 - variables for storing the result
Program text:

JMP     (label4)
label1:
  MOV.B   &var1,R15
  RLA.W   R15
  TST.W   addr(R15)
  JGE     (label2)
  INC.B   &var2
  JMP     (label3)
label2:
  MOV.B   &var1,R15
  RLA.W   R15
  CMP.W   #1,addr(R15)
  JL      (label3)
  INC.B   &var3
label3:
  INC.B   &var1
label4:
  MOV.B   &var1,R15
  RLA.W   R15
  TST.W   addr(R15)
  JNE     (label1)