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[/] [eco32/] [trunk/] [stdalone/] [dactest/] [dactest.s] - Blame information for rev 232

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;
; dactest.s -- play samples
;
 
        .set    dba,0xF0500000          ; DAC base address
        .set    tos,0xC0020000          ; top of stack
 
        ; get some addresses listed in the load map
        .export start
        .export main
        .export out
 
        ; these labels are defined in the data file
        .import samples
        .import endsmpl
 
        ; minimal execution environment
start:
        add     $29,$0,tos               ; setup stack
        jal     main                    ; do useful work
start1:
        j       start1                  ; halt by looping
 
        ; main program
main:
        sub     $29,$29,12              ; create stack frame
        stw     $31,$29,0                ; save return register
        stw     $16,$29,4               ; save register variable
        stw     $17,$29,8               ; save register variable
        add     $16,$0,samples           ; pointer to samples
        add     $17,$0,endsmpl           ; pointer to end of samples
loop:
        ldw     $4,$16,0         ; get sample
        jal     out                     ; output to DAC
        add     $16,$16,4               ; bump pointer
        bne     $16,$17,loop            ; next sample
stop:
        ldw     $31,$29,0                ; restore return register
        ldw     $16,$29,4               ; restore register variable
        add     $29,$29,12              ; release stack frame
        jr      $31                     ; return
 
        ; output a sample (2 * 16 bit) to the DAC
out:
        add     $8,$0,dba                ; set I/O base address
out1:
        ldw     $9,$8,0                  ; get DAC status
        and     $9,$9,1                 ; value needed?
        beq     $9,$0,out1               ; no - wait
        stw     $4,$8,0                  ; send sample
        jr      $31                     ; return

Line No.	Rev	Author	Line
1	232	hellwig	`;`
2			`; dactest.s -- play samples`
3			`;`
4
5			`.set dba,0xF0500000 ; DAC base address`
6			`.set tos,0xC0020000 ; top of stack`
7
8			`; get some addresses listed in the load map`
9			`.export start`
10			`.export main`
11			`.export out`
12
13			`; these labels are defined in the data file`
14			`.import samples`
15			`.import endsmpl`
16
17			`; minimal execution environment`
18			`start:`
19			`add $29,$0,tos ; setup stack`
20			`jal main ; do useful work`
21			`start1:`
22			`j start1 ; halt by looping`
23
24			`; main program`
25			`main:`
26			`sub $29,$29,12 ; create stack frame`
27			`stw $31,$29,0 ; save return register`
28			`stw $16,$29,4 ; save register variable`
29			`stw $17,$29,8 ; save register variable`
30			`add $16,$0,samples ; pointer to samples`
31			`add $17,$0,endsmpl ; pointer to end of samples`
32			`loop:`
33			`ldw $4,$16,0 ; get sample`
34			`jal out ; output to DAC`
35			`add $16,$16,4 ; bump pointer`
36			`bne $16,$17,loop ; next sample`
37			`stop:`
38			`ldw $31,$29,0 ; restore return register`
39			`ldw $16,$29,4 ; restore register variable`
40			`add $29,$29,12 ; release stack frame`
41			`jr $31 ; return`
42
43			`; output a sample (2 * 16 bit) to the DAC`
44			`out:`
45			`add $8,$0,dba ; set I/O base address`
46			`out1:`
47			`ldw $9,$8,0 ; get DAC status`
48			`and $9,$9,1 ; value needed?`
49			`beq $9,$0,out1 ; no - wait`
50			`stw $4,$8,0 ; send sample`
51			`jr $31 ; return`

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[/] [eco32/] [trunk/] [stdalone/] [dactest/] [dactest.s] - Blame information for rev 232