replaced integer RNG with smaller and faster routine.

compiler/res/prog8lib/math.asm

@@ -229,44 +229,32 @@ _divisor	.word 0
 		.pend
 
 
-randbyte = randword    ; -- 8 bit pseudo random number generator into A (by just reusing randword)
-
 randword	.proc
 	; -- 16 bit pseudo random number generator into AY
-
+	;    default seed = $00c2 $1137
-		; rand64k       ;Factors of 65535: 3 5 17 257
+        ;    routine from https://codebase64.org/doku.php?id=base:x_abc_random_number_generator_8_16_bit
-		lda sr1+1
+		inc x1
-		asl a
+		clc
-		asl a
+x1=*+1
-		eor sr1+1
+		lda #$00	;x1
-		asl a
+c1=*+1
-		eor sr1+1
+		eor #$c2	;c1
-		asl a
+a1=*+1
-		asl a
+		eor #$11	;a1
-		eor sr1+1
+		sta a1
-		asl a
+b1=*+1
-		rol sr1         ;shift this left, "random" bit comes from low
+		adc #$37	;b1
-		rol sr1+1
+		sta b1
-		; rand32k       ;Factors of 32767: 7 31 151 are independent and can be combined
+		lsr a
-		lda sr2+1
+		eor a1
-		asl a
+		adc c1
-		eor sr2+1
+		sta c1
-		asl a
+		ldy b1
-		asl a
-		ror sr2         ;shift this right, random bit comes from high - nicer when eor with sr1
-		rol sr2+1
-		lda sr1+1         ;can be left out
-		eor sr2+1         ;if you dont use
-		tay               ;y as suggested
-		lda sr1           ;mix up lowbytes of SR1
-		eor sr2           ;and SR2 to combine both
 		rts
-
-sr1     	.word $a55a
-sr2     	.word $7653
-
 		.pend
 
+randbyte = randword    ; -- 8 bit pseudo random number generator into A (by just reusing randword)
+
 
 ; ----------- optimized multiplications (stack) : ---------
 stack_mul_byte_3	.proc

compiler/res/prog8lib/math.p8

@@ -84,14 +84,14 @@ _sinecosR8	.char  trunc(127.0 * sin(range(180+45) * rad(360.0/180.0)))
     }
 
     asmsub rndseed(uword seed1 @AY, uword seed2 @R0) clobbers(A,Y) {
-        ; -- reset the pseudo RNG's seed values. Defaults are: $a55a, $7653.
+        ; -- set new pseudo RNG's seed values. Defaults are: $00c2, $1137
         %asm {{
-            sta  math.randword.sr1
+            sta  math.randword.x1
-            sty  math.randword.sr1+1
+            sty  math.randword.c1
             lda  cx16.r0L
-            ldy  cx16.r0H
+            sta  math.randword.a1
-            sta  math.randword.sr2
+            lda  cx16.r0H
-            sty  math.randword.sr2+1
+            sta  math.randword.b1
             rts
         }}
     }