piot1.asm

来自「DSP学习讲座」· 汇编 代码 · 共 117 行

;
;  Copyright 2001 by Texas Instruments Incorporated.
;  All rights reserved. Property of Texas Instruments Incorporated.
;  Restricted rights to use, duplicate or disclose this code are
;  granted through contract.
;  
;
; "@(#) DSP/BIOS 4.60.22 12-07-01 (barracuda-j15)"
;
;  ======== echo_asm.s62 ========
;
;  C-callable interface to assembly language utility functions for the
;  volume example.


       
		.global startp
        .text



;
;  ======== _load ========
;  This function simulates a load on the DSP by executing N * loopCount
;  instructions, where loopCount is the input parameter to load().
;
;      void _load(int loopCount)
;
;  The loop is using 8 instructions. One instruction for sub, nop and
;  b, plus nop 5. The extra nop added after sub is to make the number
;  of instructions in the loop a power of 2.
;
               
startp:
	    mvk.s2  0x0000,b0 ;loop counter
	    mvkh.s2 0x0001,b0
	    
	    mvk.s2  0x0001,b1
	    mvkh.s2 0x00000000,b1;initial output data
	    
	    mvk.s2 0x0001,b3 ;increment quantity
	    mvkh.s2 0x00000000,b3	   
	    
	    mvk.s2  0x00000004,b2 ;output address
	    mvkh.s2 0xb0000000,b2
	    nop
	    nop
	    mvk.s2  0x00000000,b5 ;input address
	    mvkh.s2 0xb0000000,b5 
	    
	    nop
	    nop
	    nop
loop1:  ldw.d2 *b5, b4	
		nop
		nop
		stw b1, *b2
		nop
		nop 3
		mvk.s1  0x00001004,a1 ;loop count delayt
	    mvkh.s1 0x00050000,a1
		nop
		nop
dlt1:	sub a1,1,a1
    	nop
		nop
		nop
  [a1]  b.s1 dlt1		
		nop
		nop
		nop
		nop
		nop
		nop
        add b1,b3,b1
        nop
        nop
        sub b0,1,b0
        nop 
        nop
  [b0]  b.s2 loop1 
  		nop  	
  		nop
  		nop
  		nop
  		nop   		
  		nop
  		nop    
	    b startp
	    nop
	    nop
	    nop
	    nop 
	    nop
	    nop
	    nop
	    nop
	    
        mv a4, b0               ; use b0 as loop counter
  [!b0] b lend  
        mvk 0x1000,b1
        mpy b1,b0,b0
        nop
        shru b0,3,b0            ; (loop counter)= (# loops)/8 

loop:
        sub b0,1,b0
        nop
   [b0] b loop
        nop 5

lend:   b b3
        nop 5                   ; return
        
        .end