Emerson MVME147 Manuel D’Utilisation
Interface Rules for the SCSI Firmware
5-13
5
* RESTORE REGISTERS FOR SCSI ROUTINE
* The driver must restore the registers the SCSI firmware has used.
* A3 is pointing to a list of the registers to restore.
* The following code is for 68010 or newer processor and could be more
* efficient if more advanced processor as 68020, 68030 is used.
* Entry: A3 = Pointer to register list of registers to
*
restore.
* Exit: Back to caller.
RESTORE_REG:
MOVE.L #14,D0 Number of longwords to move
= 15.
ADDA.L #60,A3 Start from bottom
of register
list.
RSTRLOOP MOVE.L -(A3),-(SP) Store on the stack
for MOVEM
instruction.
DBRA D0,RSTRLOOP
MOVEM.L (SP)+,D0-D7/A0-A6 Restore registers.
REST_OUT RTS
END
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Interface Rules for a Single Caller
You can use the same rules as provided for multiple callers. By doing so, a
second or third caller may later be added without the necessity of modifying
the initial caller routine. By using the rules for multiple callers, a user also
expects the firmware to do more work than would otherwise have to be done
second or third caller may later be added without the necessity of modifying
the initial caller routine. By using the rules for multiple callers, a user also
expects the firmware to do more work than would otherwise have to be done