cos.asm

C5000系列DSP上实现正弦波发生器的源代码

			.mmregs
			.def cosx,d_xc , d_cosx
cosx:  
            .data
table_c     .word 0x0249
            .word 0x0444
            .word 0x0aab
            .word 0x4000
            
d_coef_c    .usect "coef_c" ,4
d_xc        .usect "cos_vars" , 1
d_squr_xc   .usect "cos_vars" , 1
d_temp_c    .usect "cos_vars" , 1
d_cosx      .usect "cos_vars" , 1
c_1_c       .usect "cos_vars" , 1
       
            .text
            SSBX  FRCT
            STM #d_coef_c , AR5
            RPT #3
            MVPD #table_c ,*AR5+
            STM #d_coef_c , AR3
            STM #d_xc ,AR2
            STM #c_1_c , AR4
            ST #7FFFh , c_1_c
            SQUR *AR2+ , A
            ST A , *AR2
            ||LD *AR4 , B
            MASR *AR2+ , *AR3+ , B , A
            MPYA A  
            STH A , *AR2
            MASR *AR2- , *AR3+ , B ,A
            MPYA *AR2+
            ST B ,*AR2
            ||LD *AR4 ,B 
            MASR *AR2- , *AR3+ , B , A
            SFTA A ,-1 , A   
            NEG A
            MPYA *AR2+
            MAR *AR2+
            RETD 
            ADD *AR4 , 16 , B                                              
            STH B ,*AR2