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[/] [eco32/] [trunk/] [monitor/] [monitor/] [common/] [dskser.s] - Blame information for rev 317

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Line No. Rev Author Line
1 59 hellwig
;
2 182 hellwig
; dskser.s -- disk made available by serial interface
3 59 hellwig
;
4
 
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;***************************************************************
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        .export dskinitser              ; initialize disk
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        .export dskcapser               ; determine disk capacity
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        .export dskioser                ; do disk I/O
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11
        .import ser1in
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        .import ser1out
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        .import ser1inchk
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        .import puts
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        ; constants for communication with disk server
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        .set    SYN,0x16                ; to initiate the three-way handshake
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        .set    ACK,0x06                ; acknowledgement for handshake
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        .set    RESULT_OK,0x00          ; server successfully executed cmd
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                                        ; everything else means error
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        .set    WAIT_DELAY,800000       ; count for delay loop
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24
;***************************************************************
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        .code
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        .align  4
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29 184 hellwig
dskinitser:
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        jr      $31
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32 182 hellwig
dskcapser:
33 59 hellwig
        sub     $29,$29,16
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        stw     $16,$29,0
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        stw     $17,$29,4
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        stw     $18,$29,8
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        stw     $31,$29,12
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        add     $4,$0,trymsg             ; say what we are doing
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        jal     puts
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        add     $18,$0,$0         ; capacity == 0 if disk not present
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        add     $16,$0,10                ; 10 tries to get a connection
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handshake1:
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        sub     $16,$16,1
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        add     $4,$0,SYN
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        jal     ser1out                 ; send SYN
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        add     $17,$0,WAIT_DELAY        ; wait for ACK
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handshake2:
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        sub     $17,$17,1
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        jal     ser1inchk
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        bne     $2,$0,handshake3
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        bne     $17,$0,handshake2
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        add     $4,$0,timeoutmsg
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        jal     puts
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        bne     $16,$0,handshake1
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        add     $4,$0,frustratedmsg
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        jal     puts
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        j       dskcapx
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handshake3:
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        jal     ser1in
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        add     $8,$0,ACK
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        bne     $2,$8,dskcapx
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        ; we got an ACK so we return it
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        add     $4,$0,ACK
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        jal     ser1out
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        ; ask it for its capacity
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        add     $4,$0,'c'
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        jal     ser1out                 ; request
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        jal     ser1in                  ; first byte of response
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        bne     $2,$0,dskcapx            ; exit if error
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        ; all is well and the server will give us the capacity
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        add     $16,$0,4         ; 4 bytes to read
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dskcap1:
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        sll     $18,$18,8
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        jal     ser1in
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        or      $18,$18,$2              ; most significant byte first
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        sub     $16,$16,1
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        bne     $16,$0,dskcap1
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        ; return value is in $18
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dskcapx:
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        add     $2,$0,$18
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        ldw     $16,$29,0
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        ldw     $17,$29,4
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        ldw     $18,$29,8
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        ldw     $31,$29,12
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        add     $29,$29,16
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        jr      $31
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        .data
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        .align  4
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trymsg:
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        .byte   "Trying to connect to disk server..."
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        .byte   0x0A, 0
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timeoutmsg:
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        .byte   "Request timed out..."
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        .byte   0x0A, 0
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frustratedmsg:
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        .byte   "Unable to establish connection to disk server."
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        .byte   0x0A, 0
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        .code
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        .align  4
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109 182 hellwig
dskioser:
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        sub     $29,$29,24
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        stw     $16,$29,0
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        stw     $17,$29,4
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        stw     $18,$29,8
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        stw     $19,$29,12
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        stw     $20,$29,16
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        stw     $31,$29,20
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        add     $16,$0,$4                ; command
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        add     $17,$0,$5                ; start at sector
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        add     $8,$0,0xc0000000
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        or      $18,$8,$6               ; memory address (logicalized)
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        add     $19,$0,$7                ; number of sectors
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        ; switch over command
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        add     $8,$0,'r'
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        beq     $8,$16,dskior           ; read
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        add     $8,$0,'w'
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        beq     $8,$16,dskiow           ; write
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        ; unknown command
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        add     $2,$0,1                  ; value != 0 signifies error
130 182 hellwig
        j       dskiox
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        ; read from disk
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dskior:
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dskior1:                                ; loop over number of sectors
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        beq     $19,$0,dskiorsuc ; successful return
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        sub     $19,$19,1
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        ; read a sector
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        add     $4,$0,'r'
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        jal     ser1out
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        ; send sector number
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        add     $20,$0,32                ; 4 bytes
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dskior2:
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        sub     $20,$20,8
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        slr     $4,$17,$20
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        and     $4,$4,0xff
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        jal     ser1out
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        bne     $20,$0,dskior2
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        add     $17,$17,1
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        ; get answer
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        jal     ser1in
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        bne     $2,$0,dskiox             ; $2 != 0 so we use it as return code
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        ; read data
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        add     $20,$0,512
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dskior3:
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        sub     $20,$20,1
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        jal     ser1in
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        stb     $2,$18,0
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        add     $18,$18,1
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        bne     $20,$0,dskior3
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        j       dskior1
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dskiorsuc:
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        add     $2,$0,$0
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        j       dskiox
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        ; write to disk
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dskiow:
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dskiow1:                                ; loop over number of sectors
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        beq     $19,$0,dskiowsuc ; successful return
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        sub     $19,$19,1
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        ; write a sector
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        add     $4,$0,'w'
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        jal     ser1out
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        ; send sector number
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        add     $20,$0,32                ; 4 bytes
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dskiow2:
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        sub     $20,$20,8
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        slr     $4,$17,$20
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        and     $4,$4,0xff
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        jal     ser1out
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        bne     $20,$0,dskiow2
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        add     $17,$17,1
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        ; write data
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        add     $20,$0,512
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dskiow3:
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        sub     $20,$20,1
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        ldbu    $4,$18,0
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        jal     ser1out
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        add     $18,$18,1
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        bne     $20,$0,dskiow3
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        ; get answer
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        jal     ser1in
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        bne     $2,$0,dskiox
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        j       dskiow1
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dskiowsuc:
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        add     $2,$0,$0
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dskiox:
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        ldw     $16,$29,0
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        ldw     $17,$29,4
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        ldw     $18,$29,8
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        ldw     $19,$29,12
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        ldw     $20,$29,16
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        ldw     $31,$29,20
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        add     $29,$29,24
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        jr      $31

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