utl_loop.s62

使用在dsp TI DSK6711中 很多ｃｏｎｔｒｏｌｌｅｒ 的例子

;
;  Copyright 2003 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.
;
;  @(#) XDAS 2.51.00 11-29-2003 (xdas-2.50.00.9)
;
;
;  ======== utl_loop.s62 ========
;  Simulate load on the DSP for the audio example.
;
;
        .global _UTL_loop

        .text

N       .set    1000            ; N must be evenly-divisible by 10

;
;  ======== _UTL_loop ========
;  This function simulates a load on the DSP by executing N * loopCount
;  instructions, where loopCount is the input parameter to UTL_loop().
;
;      void UTL_loop(int loopCount)
;
;  Actual instruction cycles: 6 + N * (loopCount)
;
;  Limitation: The code assumes that loopCount is at most 0xffff, so with 
;  N=1000 the maximum delay allowed is: 6 + 1000 * 65535 = 65,535,006 
;  instructions.  N can be increased if you need more cycles.

_UTL_loop:

        mvk (N/10),b0
        mpyu a4,b0,b0
        nop 4
loop:           
        sub b0,1,b0
        nop 3
 [b0]   b loop 
        nop 5

        b b3            
        nop 5
    
    .end