www.pudn.com > ScriptsSample.zip > GENSCSI.SS

; /*--------------------------------------------------*/ 
; /*                                                  */ 
; /* 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)