The format of the execute form of the TRKADDR SETCYL
macro is:
>>-+-------+--TRKADDR--SETCYL--+-,cchh--+--,REG=(rega)---------><
'-label-' '-,(reg)-'
Stores the cylinder number from the register to the 28-bits in
the cchh and sets H to 0 (0cccCCCC to CCCCccc0). Destroys the register.