请问各位大侠，下边这段程序是什么意思？
//Generate Pointer to Drive Outputs
OPN #iDriveIntfcDB
L DBNO
T #tDriveIntfcDBNum
LAR1 P##tOutputsPointer

L B#16#10 // 10 hex = S7 Data Type
T LB [AR1,P#0.0] // Transfer to Source pointer byte 0

L B#16#2 // 2 hex = byte data type
T LB [AR1,P#1.0] // Transfer to Source pointer byte 1

L 24 // How many bytes to move
T LW [AR1,P#2.0] // Transfer to Source pointer bytes 2-3

L #tDriveIntfcDBNum // Load DB Number
T LW [AR1,P#4.0] // Transfer to Source pointer bytes 4-5

L 172 // Load start address of data
SLD 3 // Shift data in AR1 3 bits to the left
T LD [AR1,P#6.0] // Trasfer to Source Pointer bytes 6-9

L B#16#84 // 84 hex = DB memory area
T LB [AR1,P#6.0] // Transfer to Source pointer byte 6

//Transfer Outputs From Drive Interface DB To Local Copy
CALL SFC 20
SRCBLK :=#tOutputsPointer
RET_VAL:=#tRet
DSTBLK :=#tDriveIntfc.Output