Interface Rules for the SCSI Firmware
MOVE.W 2(A2),D0 | STATUS WORD TO D0. |
| |
BTST | #15,D0 | FINAL/INTERMEDIATE | STATUS? |
BEQ | FINALSTAT | IF 0, THE RETURN IS A FINAL ONE. | |
******************************************************************
************
*THE FOLLOWING CODE CHECKS ALL ALLOWED INTERMEDIATE RETURN CODES.
*
CMP.B #$02,D0 WAITING FOR AN INTERRUPT? (BUS CLEAR) IF <EQ> THEN
BRA RET_OUT NO NEW COMMANDS TO SEND BECAUSE NO QUEUING
NECESSARY
*FOR MULTIPLE CALLERS, THE SCSI FIRMWARE QUEUES COMMANDS WHEN THE BUS IS
*BUSY.
*BECAUSE OF THIS REASON, NO COMMAND QUEUING IS NECESSARY IN THE DRIVER. IF
*THERE IS NO QUEUING IN THE DRIVER, THE DRIVER WILL NOT HAVE A NEW COMMAND
*TO SEND WHENEVER AN INTERMEDIATE OR FINAL RETURN OCCURS. THE COMMANDS ARE
*ALWAYS SENT AS THEY ARRIVE TO THE DRIVER.
*’RET_INT’ is the user’s code to handle the return from interrupt process.
ENDI
CMP.B #$04,D0 | MESSAGE INTERPRETATION? |
IF <EQ> THEN |
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BSR INTERPRET | INTERPRET IS A MESSAGE INTERPRETATION |
ROUTINE |
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BRA RET_INT |
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ENDI |
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CMP.B #$06,D0 | COMMAND RECEIVED FOR THE TARGET? |
IF <EQ> THEN |
|
BSR SERVCMD | SERVCMD IS TARGET ROLE COMMAND SERVICE |
ROUTINE |
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BRA RET_INT |
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ENDI |
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5 |
