cos.asm

来自「fir的c语言程序」· 汇编 代码 · 共 50 行

       .title    "cos.asm"
       .mmregs
       .def      _cosX
     
       .data          
Ctab:  .word   -585   ;1/(7*8)
       .word   -1092
       .word   -2371
       
       .bss    coef2,3
       .bss    temp2,1
       
       .global xx
       .global cosX
       .global input
       
       .text
_cosX: ld     #0x7fff,16,B
       
       stm    #xx,ar3
       stm    #temp2,ar5
       
       stm    #coef2,ar1
       mvmm   ar1,ar2
       mvmm   ar2,ar4
       rpt    #2
       mvpd   Ctab,*ar1+
              
       ;stm    #2,brc
       ;rptb   init-1
       mpy    *ar2,*ar3,A
       sth    A,*ar2+ 
       mpy    *ar2,*ar3,A
       sth    A,*ar2+
       mpy    *ar2,*ar3,A
       sth    A,*ar2+
       
init:  add    *ar4,16,B,A
       sth    A,*ar5
       mac    *ar5,*ar4+,B,A
       sth    A,*ar5
       mac    *ar5,*ar4+,B,A
       sth    A,*ar5      
       mpy    *ar3,*ar5,A
       sfta   A,-1,A              ; *(-1/2)
       neg    A
       add    A,B
       sth    B,@cosX
       ret
       .end