Generate noise on PSX (Sony Playstation 1) without any samples

spu_noise.asm

; Generate noise with slow attack and decay/release on PSX (Sony Playstation 1). MIPS R3000
; (sounds like ocean waves). No samples used.
;
; by Frog (frog@enlight.ru)

        org $80010000
            
        lui r27,$1F80           ; I/O base
	


	      li r8,$ea30	; 1100000100110000 enable noise (no adpcm)
        sh r8,$1DAA(r27)        ; SPU_CONTROL

        li r8,$3fff             ; master volume = 011111111111111

        sh r8,$1d80(r27)        ; master volume left
        sh r8,$1d82(r27)        ; master volume right



        li r8,$1010		; SPU buffer address

        sh r8,$1C06(r27)        ; set SPU buffer address 

        li r8,$3fff             ; volume = 011111111111111

        sh r8,$1C00(r27)        ; volume left
        sh r8,$1C02(r27)        ; volume right
	

	      li r8,$bf3f		; 1011111100111111
        sh r8,$1c08(r27)        ; SPU_CH_ADSR1

	      li r8,$cfff		; 1100111111111111
        sh r8,$1c0a(r27)        ; SPU_CH_ADSR2

	      li r8,1
        sh r8,$1d94(r27)        ; SPU_NOISE_MODE1

	      li r8,1
        sh r8,$1d88(r27)        ; SPU_KEY_ON1

;	      jr ra
;	      nop

        loop:	j	loop