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replaced integer RNG with smaller and faster routine.
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@ -229,44 +229,32 @@ _divisor .word 0
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.pend
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.pend
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randbyte = randword ; -- 8 bit pseudo random number generator into A (by just reusing randword)
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randword .proc
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randword .proc
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; -- 16 bit pseudo random number generator into AY
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; -- 16 bit pseudo random number generator into AY
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; default seed = $00c2 $1137
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; rand64k ;Factors of 65535: 3 5 17 257
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; routine from https://codebase64.org/doku.php?id=base:x_abc_random_number_generator_8_16_bit
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lda sr1+1
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inc x1
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asl a
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clc
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asl a
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x1=*+1
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eor sr1+1
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lda #$00 ;x1
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asl a
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c1=*+1
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eor sr1+1
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eor #$c2 ;c1
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asl a
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a1=*+1
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asl a
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eor #$11 ;a1
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eor sr1+1
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sta a1
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asl a
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b1=*+1
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rol sr1 ;shift this left, "random" bit comes from low
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adc #$37 ;b1
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rol sr1+1
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sta b1
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; rand32k ;Factors of 32767: 7 31 151 are independent and can be combined
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lsr a
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lda sr2+1
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eor a1
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asl a
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adc c1
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eor sr2+1
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sta c1
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asl a
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ldy b1
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asl a
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ror sr2 ;shift this right, random bit comes from high - nicer when eor with sr1
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rol sr2+1
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lda sr1+1 ;can be left out
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eor sr2+1 ;if you dont use
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tay ;y as suggested
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lda sr1 ;mix up lowbytes of SR1
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eor sr2 ;and SR2 to combine both
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rts
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rts
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sr1 .word $a55a
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sr2 .word $7653
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.pend
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.pend
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randbyte = randword ; -- 8 bit pseudo random number generator into A (by just reusing randword)
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; ----------- optimized multiplications (stack) : ---------
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; ----------- optimized multiplications (stack) : ---------
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stack_mul_byte_3 .proc
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stack_mul_byte_3 .proc
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@ -84,14 +84,14 @@ _sinecosR8 .char trunc(127.0 * sin(range(180+45) * rad(360.0/180.0)))
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}
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}
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asmsub rndseed(uword seed1 @AY, uword seed2 @R0) clobbers(A,Y) {
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asmsub rndseed(uword seed1 @AY, uword seed2 @R0) clobbers(A,Y) {
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; -- reset the pseudo RNG's seed values. Defaults are: $a55a, $7653.
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; -- set new pseudo RNG's seed values. Defaults are: $00c2, $1137
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%asm {{
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%asm {{
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sta math.randword.sr1
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sta math.randword.x1
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sty math.randword.sr1+1
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sty math.randword.c1
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lda cx16.r0L
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lda cx16.r0L
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ldy cx16.r0H
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sta math.randword.a1
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sta math.randword.sr2
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lda cx16.r0H
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sty math.randword.sr2+1
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sta math.randword.b1
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rts
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rts
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}}
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}}
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}
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}
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