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[/] [eco32/] [trunk/] [hwtests/] [dsptest/] [start.s] - Blame information for rev 235

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Line No. Rev Author Line
1 14 hellwig
;
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; start.s -- startup and support routines
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;
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        .set    dmapaddr,0xC0000000     ; base of directly mapped addresses
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        .set    stacktop,0xC0400000     ; monitor stack is at top of memory
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        .set    PSW,0                    ; reg # of PSW
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        .set    TLB_INDEX,1             ; reg # of TLB Index
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        .set    TLB_ENTRY_HI,2          ; reg # of TLB EntryHi
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        .set    TLB_ENTRY_LO,3          ; reg # of TLB EntryLo
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        .set    TLB_ENTRIES,32          ; number of TLB entries
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;***************************************************************
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        .import _ecode
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        .import _edata
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        .import _ebss
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        .import serinit
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        .import ser0in
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        .import ser0out
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        .import main
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        .export _bcode
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        .export _bdata
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        .export _bbss
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        .export cin
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        .export cout
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        .export getTLB_HI
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        .export getTLB_LO
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        .export setTLB
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        .export wrtRndTLB
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        .export probeTLB
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        .export wait
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;***************************************************************
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        .code
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_bcode:
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        .data
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_bdata:
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        .bss
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_bbss:
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;***************************************************************
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        .code
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        .align  4
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reset:
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        j       start
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interrupt:
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        j       interrupt
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userMiss:
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        j       userMiss
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;***************************************************************
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        .code
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        .align  4
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cin:
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        j       ser0in
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cout:
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        j       ser0out
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;***************************************************************
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        .code
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        .align  4
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start:
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        ; force CPU into a defined state
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        mvts    $0,PSW                   ; disable interrupts and user mode
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        ; initialize TLB
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        mvts    $0,TLB_ENTRY_LO          ; invalidate all TLB entries
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        add     $8,$0,dmapaddr           ; by impossible virtual page number
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        add     $9,$0,$0
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        add     $10,$0,TLB_ENTRIES
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tlbloop:
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        mvts    $8,TLB_ENTRY_HI
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        mvts    $9,TLB_INDEX
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        tbwi
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        add     $8,$8,0x1000            ; all entries must be different
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        add     $9,$9,1
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        bne     $9,$10,tlbloop
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        ; copy data segment
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        add     $10,$0,_bdata            ; lowest dst addr to be written to
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        add     $8,$0,_edata             ; one above the top dst addr
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        sub     $9,$8,$10               ; $9 = size of data segment
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        add     $9,$9,_ecode            ; data is waiting right after code
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        j       cpytest
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cpyloop:
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        ldw     $11,$9,0         ; src addr in $9
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        stw     $11,$8,0         ; dst addr in $8
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cpytest:
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        sub     $8,$8,4                 ; downward
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        sub     $9,$9,4
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        bgeu    $8,$10,cpyloop
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        ; clear bss segment
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        add     $8,$0,_bbss              ; start with first word of bss
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        add     $9,$0,_ebss              ; this is one above the top
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        j       clrtest
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clrloop:
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        stw     $0,$8,0                   ; dst addr in $8
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        add     $8,$8,4                 ; upward
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clrtest:
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        bltu    $8,$9,clrloop
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        ; now do some useful work
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        add     $29,$0,stacktop          ; setup monitor stack
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        jal     serinit                 ; init serial interface
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        jal     main                    ; enter command loop
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        ; main should never return
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        j       start                   ; just to be sure...
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;***************************************************************
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        ; Word getTLB_HI(int index)
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getTLB_HI:
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        mvts    $4,TLB_INDEX
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        tbri
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        mvfs    $2,TLB_ENTRY_HI
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        jr      $31
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        ; Word getTLB_LO(int index)
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getTLB_LO:
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        mvts    $4,TLB_INDEX
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        tbri
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        mvfs    $2,TLB_ENTRY_LO
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        jr      $31
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        ; void setTLB(int index, Word entryHi, Word entryLo)
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setTLB:
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        mvts    $4,TLB_INDEX
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        mvts    $5,TLB_ENTRY_HI
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        mvts    $6,TLB_ENTRY_LO
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        tbwi
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        jr      $31
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        ; void wrtRndTLB(Word entryHi, Word entryLo)
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wrtRndTLB:
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        mvts    $4,TLB_ENTRY_HI
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        mvts    $5,TLB_ENTRY_LO
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        tbwr
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        jr      $31
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        ; Word probeTLB(Word entryHi)
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probeTLB:
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        mvts    $4,TLB_ENTRY_HI
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        tbs
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        mvfs    $2,TLB_INDEX
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        jr      $31
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        ; void wait(int n)
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wait:
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        j       wait2
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wait1:
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        add     $4,$4,$0
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        sub     $4,$4,1
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wait2:
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        bne     $4,$0,wait1
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        jr      $31

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