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https://opencores.org/ocsvn/eco32/eco32/trunk
Subversion Repositories eco32
[/] [eco32/] [tags/] [eco32-0.26/] [stdalone/] [dactest/] [dactest.s] - Rev 314
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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
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