pcm1.asm

来自「智能玩具实际文件」· 汇编 代码 · 共 46 行

;================================================================;
; PCM Speech Subroutine
;================================================================;
          .area   pcmvari(data)

M_sphptr::      .ds     3
M_stopbit::	.ds	1
M_pcmdata::	.ds	1

          .area   pcmlibrary(code)
          
.Pcm_Play::
	lda	M_sphptr+2	
	sta	r_tpp
        lda     M_sphptr+1
        sta     r_tph
        lda     M_sphptr
        sta     r_tpl
        inca
        sta     M_sphptr
        lda     #00h
        addc    M_sphptr+1
        sta     M_sphptr+1
        lda	#00h
        addc	M_sphptr+2
        sta	M_sphptr+2
        
loop_rom_ready:        
        lda	r_op1			;if data rom grand than 64k
        anda	#10000000b		;program must detect OP1[7]
        brz	loop_rom_ready		;or add 5us delay in program
  
        ldv
        xora    #0xFF
        brz     10$
        xora    #0xFF
        sta     M_pcmdata
        ret
10$:
        lda     #0xFF
        sta     M_stopbit
        ret