genscsi.ss

scsi脚本文件(scripts)编程例子

; /*--------------------------------------------------*/
; /*                                                  */
; /* Module GENSCSI.SS                                */
; /*                                                  */
; /* SCRIPTS routines for generic SCSI operations.    */
; /*                                                  */
; /* Adapted from Symbios Logic                       */
; /*    Software Development Kit                      */
; /*                                                  */
; /* Project: A Programmer's Guide to SCSI            */
; /* Copyright (C) 1997, Brian Sawert.                */
; /* All rights reserved.                             */
; /*                                                  */
; /*--------------------------------------------------*/


; /*--------------------------------------------------*/
; /*                                                  */
; /* This script is a generic skeleton for issuing    */
; /* SCSI commands. It handles arbitration, message   */
; /* in and out, status and data in.                  */
; /*                                                  */
; /* Uses table indirect mode for command, data, and  */
; /* other buffers.                                   */
; /*                                                  */
; /*--------------------------------------------------*/


;---------- set architecture for 53C825
ARCH 825


;---------- set constant values
ABSOLUTE err_cmd_complete =      0x00000000
ABSOLUTE err_not_msgout =        0x00000001
ABSOLUTE err_bad_reselect =      0x00000002
ABSOLUTE err_bad_phase =         0x00000004


;---------- set up table definitions
TABLE table0 \
   scsi_id = ID {0x33, 0x00, 0x00, 0x00}, \
	msgout_buf = {0x80, 0x00}, \
	cmd_buf = {0x00, 0x00, 0x00, 0x00, 0x00, 0x00}, \
	stat_buf = ??, \
	msgin_buf = 2 {??}, \
   exmsgin_buf = 4 {??} \
	datain_buf = 0x40 {??}


;---------- entry point for general SCSI script
ENTRY start_scsi


PROC GEN_SCRIPT:

;---------- start SCSI target selection
start_scsi:

; select device from encoded SCSI ID
; set ATN for message out after select
SELECT ATN FROM scsi_id, REL(bad_reselect)

;---------- send identify message
; exit if not message out phase
INT err_not_msgout, WHEN NOT MSG_OUT

; send identify message
MOVE FROM msgout_buf, WHEN MSG_OUT
JUMP REL(handle_phase)

;---------- send SCSI command
send_cmd:

; send command block to target
MOVE FROM cmd_buf, WHEN CMD
JUMP REL(handle_phase)

;---------- get SCSI status
get_status:

; read status byte from data bus
MOVE FROM stat_buf, WHEN STATUS
JUMP REL(handle_phase)

;---------- get SCSI message input
get_msgin:

; read message byte from data bus
MOVE FROM msgin_buf, WHEN MSG_IN
CLEAR ACK

; handle Command Complete message
JUMP REL(cmd_complete), IF 0x00

; handle Disconnect message
JUMP REL(wait_disconnect), IF 0x04

; handle extended message
JUMP REL(ext_msgin), IF 0x01
JUMP REL(handle_phase)

;---------- handle extended message
ext_msgin:

; read extended message from data bus
MOVE FROM exmsgin_buf, WHEN MSG_IN
CLEAR ACK
JUMP REL(handle_phase)

;---------- get data input
get_datain:

; read data from bus
MOVE FROM datain_buf, WHEN DATA_IN
JUMP REL(handle_phase)

;---------- handle SCSI phases
handle_phase:

; jump to appropriate handler for phase
JUMP REL(get_status), WHEN STATUS
JUMP REL(get_msgin), WHEN MSG_IN
JUMP REL(get_datain), WHEN DATA_IN
JUMP REL(send_cmd), WHEN COMMAND
; unhandled phase
INT err_bad_phase

;---------- SCSI command execution complete
cmd_complete:

; command complete - wait for disconnect
MOVE SCNTL2 & 0x7F to SCNTL2
CLEAR ACK
WAIT DISCONNECT
INT err_cmd_complete

;---------- handle invalid select or reselect
bad_reselect:

; unhandled reselect
INT err_bad_reselect

;---------- handle disconnect before reselect
wait_disconnect:

MOVE SCNTL2 & 0x7F to SCNTL2
CLEAR ACK
WAIT DISCONNECT

; clear DMA and SCSI fifos
MOVE CTEST3 | 0x04 to CTEST3
MOVE STEST3 | 0x02 to STEST3

; wait for reselect
WAIT RESELECT REL(bad_reselect)

; expect identify message
MOVE FROM msgin_buf, WHEN MSG_IN
CLEAR ACK

; shortcut to update sync and wide options
SELECT FROM scsi_id, REL(handle_phase)