utl_loop.s54

来自「使用在TI 系列dsk5402 的很多可用例子」· S54 代码 · 共 55 行

;
;  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.s54 ========
;  C-callable interface to assembly language utility functions for the
;  echo example.
;

    .mmregs

    .global _UTL_loop

    .text

N       .set    1000

;
;  ======== _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)
;
;  true execution time: ?? + N * (loop count)
;
_UTL_loop:
        sub     #1, a
        stlm    a, ar4          ; ar4 = loopCount - 1
        ld      #(N/4-2), a     ; a = (N / 4) - 2
loop:   
        stlm    a,brc           ; initialize count register for block rpt
        nop
        nop
        rptb    $1
        nop
        nop
        nop
$1      nop
        banz    loop, *ar4-

        .if __far_mode      ; -mf flag will assemble far mode return opcode
        fret
    .else
        ret
    .endif

    
    .end