cos_generate.asm

DSP系统入门与实践源代码

******************************************************************
***********余弦发生器程序******************************
**************************************************


              .mmregs
              .def    cos_generate,_c_int00
              .def    end_of_cose
              .def    d_cos_delay1,d_cos_delay2,d_theta,d_cosx
d_cos_delay1  .usect  "cos_vars",1
d_cos_delay2  .usect  "cos_vers",1 
d_theta       .usect  "cos_vers",1
d_cosx        .usect  "cos_vers",1


k_cos_delay_1 .set  06602h
k_cos_delay_2 .set  064d8h 
k_cos_theta   .set  07f83h
k_2           .set  2h
k_256         .set  256


COSDATA       .usect   "cos_data",256



              .text
_c_int00:
              SSBX  FRCT
              STM   #COSDATA,ar5
              NOP
              STM   #600h,SP
              LD    #d_cos_delay1,DP
              
               
                
                 
              STM   #d_cos_delay1,ar3
              STM   #d_theta,ar4
              RPTZ  A,#3h
              STL   A,*ar3+
              
              
              
              STM   #1,ar0
              STM   #d_cosx,ar2
              STM   #k_2,BK
              STM   #k_256-1,BRC
           
              STM   #d_cos_delay1,ar3
              ST    #k_cos_delay_1,*ar3+
              ST    #k_cos_delay_2,*ar3
              STM   #d_cos_delay1,ar3
              ST    #k_cos_theta,d_cosx
              
              
cos_generate:
              RPTB  end_of_cose
              MPY   *ar2,*ar3+0%,A
              SUB   *ar3,15,A
              SFTA  A,1,A
              STH   A,*ar3
              MVDD  *ar3,*ar5+
end_of_cose:  nop
              B     cos_generate 
cosend:       .end