Программирование

[parallelno]

нашел еще парочку интересных псевдо рандомайзеров

; 16-bit xorshift pseudorandom number generator
; returns   hl = pseudorandom number
; corrupts   a
; http://www.retroprogramming.com/2017/07/xorshift-pseudorandom-numbers-in-z80.html?m=1

Random:
			lxi h, 1       ; seed must not be 0
			mov a,h
			rar
			mov a,l
			rar
			xra h
			mov h,a
			mov a,l
			rar
			mov a,h
			rar
			xra l
			mov l,a
			xra h
			mov h,a
			shld Random+1		; 116
			ret

; Fast RND
;
; An 8-bit pseudo-random number generator,
; using a similar method to the Spectrum ROM,
; - without the overhead of the Spectrum ROM.
;
; R = random number seed
; an integer in the range [1, 256]
;
; R -> (33*R) mod 257
;
; S = R - 1
; an 8-bit unsigned integer. 256 period
; http://www.z80.info/pseudo-random.txt
Random:			
			mvi a, 34
			mov l, a
			rrc
			rrc
			rrc
			xri $1f
			add l
			sbi 255
			sta Random+1		; 64
			ret

; returns pseudo random 8 bit number in A. Only affects A.
; By Lee Davison. 256 period
; https://philpem.me.uk/leeedavison/z80/prng/index.html
Random:
			mvi a, 1	; get seed. must not be zero
			ani	$B8	; mask non feedback bits
			stc			; set carry
			jpo	no_clr	; skip clear if odd
			cmc			; complement carry (clear it)
no_clr:
			lda Random+1	; get seed back
			ral			; rotate carry into byte
			sta Random+1	; save back for next prn	; 72
			ret