removed fastrnd8() because it was hilariously bad, just use rnd()

compiler/res/prog8lib/cx16/gfx2.p8

@@ -573,6 +573,7 @@ _done
                     }
                 }
             }
+            ; TODO mode 2,3
             4 -> {
                 ; lores 256c
                 void addr_mul_24_for_lores_256c(y, x)      ; 24 bits result is in r0 and r1L (highest byte)

compiler/res/prog8lib/math.asm

@@ -244,25 +244,6 @@ randseed	.proc
 		.pend
 
 
-fast_randbyte	.proc
-	; -- fast but bad 8-bit pseudo random number generator into A
-		lda  _seed
-		beq  _eor
-		asl  a
-		beq  _done	; if the input was $80, skip the EOR
-		bcc  _done
-_eor		eor  #$1d	; xor with magic value see below for possible values
-_done		sta  _seed
-		rts
-
-_seed		.byte  $3a
-
-		; possible 'magic' eor bytes are:
-		; $1d, $2b, $2d, $4d, $5f, $63, $65, $69
-		; $71, $87, $8d, $a9, $c3, $cf, $e7, $f5
-
-		.pend
-
 randbyte        .proc
 	; -- 8 bit pseudo random number generator into A (by just reusing randword)
 		jmp  randword
@@ -271,45 +252,37 @@ randbyte        .proc
 randword	.proc
 	; -- 16 bit pseudo random number generator into AY
 
-magic_eor = $3f1d
+		; rand64k       ;Factors of 65535: 3 5 17 257
-		; possible magic eor words are:
+		lda sr1+1
-		; $3f1d, $3f81, $3fa5, $3fc5, $4075, $409d, $40cd, $4109
+		asl a
- 		; $413f, $414b, $4153, $4159, $4193, $4199, $41af, $41bb
+		asl a
+		eor sr1+1
+		asl a
+		eor sr1+1
+		asl a
+		asl a
+		eor sr1+1
+		asl a
+		rol sr1         ;shift this left, "random" bit comes from low
+		rol sr1+1
+		; rand32k       ;Factors of 32767: 7 31 151 are independent and can be combined
+		lda sr2+1
+		asl a
+		eor sr2+1
+		asl a
+		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
 
-		lda  _seed
+sr1     	.word $a55a
-		beq  _lowZero	; $0000 and $8000 are special values to test for
+sr2     	.word $7653
 
- 		; Do a normal shift
-		asl  _seed
-		lda  _seed+1
-		rol  a
-		bcc  _noEor
-
-_doEor		; high byte is in A
-		eor  #>magic_eor
-  		sta  _seed+1
-  		lda  _seed
-  		eor  #<magic_eor
-  		sta  _seed
-  		ldy  _seed+1
-  		rts
-
-_lowZero	lda  _seed+1
-		beq  _doEor	; High byte is also zero, so apply the EOR
-				; For speed, you could store 'magic' into 'seed' directly
-				; instead of running the EORs
-
- 		; wasn't zero, check for $8000
-		asl  a
-		beq  _noEor	; if $00 is left after the shift, then it was $80
-		bcs  _doEor	; else, do the EOR based on the carry bit as usual
-
-_noEor		sta  _seed+1
-		tay
-		lda  _seed
- 		rts
-
-_seed		.word	$2c9e
 		.pend
 
 

compiler/res/prog8lib/prog8_funcs.asm

@@ -387,14 +387,6 @@ func_sqrt16_into_A	.proc
 		rts
 		.pend
 
-func_fastrnd8_stack	.proc
-	; -- put a random ubyte on the estack (using fast but bad RNG)
-		jsr  math.fast_randbyte
-		sta  P8ESTACK_LO,x
-		dex
-		rts
-		.pend
-
 func_rnd_stack	.proc
 	; -- put a random ubyte on the estack
 		jsr  math.randbyte

compiler/src/prog8/compiler/functions/BuiltinFunctions.kt

@@ -138,7 +138,6 @@ private val functionSignatures: List<FSignature> = listOf(
     FSignature("peekw"       , true, listOf(FParam("address", setOf(DataType.UWORD))), DataType.UWORD),
     FSignature("poke"        , false, listOf(FParam("address", setOf(DataType.UWORD)), FParam("value", setOf(DataType.UBYTE))), null),
     FSignature("pokew"       , false, listOf(FParam("address", setOf(DataType.UWORD)), FParam("value", setOf(DataType.UWORD))), null),
-    FSignature("fastrnd8"    , false, emptyList(), DataType.UBYTE),
     FSignature("rnd"         , false, emptyList(), DataType.UBYTE),
     FSignature("rndw"        , false, emptyList(), DataType.UWORD),
     FSignature("rndf"        , false, emptyList(), DataType.FLOAT),

compiler/src/prog8/compiler/target/cpu6502/codegen/BuiltinFunctionsAsmGen.kt

@@ -52,7 +52,7 @@ internal class BuiltinFunctionsAsmGen(private val program: Program, private val
             "ln", "log2", "sqrt", "rad",
             "deg", "round", "floor", "ceil",
             "rndf" -> funcVariousFloatFuncs(fcall, func, resultToStack, resultRegister, sscope)
-            "fastrnd8", "rnd", "rndw" -> funcRnd(func, resultToStack, resultRegister, sscope)
+            "rnd", "rndw" -> funcRnd(func, resultToStack, resultRegister, sscope)
             "sqrt16" -> funcSqrt16(fcall, func, resultToStack, resultRegister, sscope)
             "rol" -> funcRol(fcall)
             "rol2" -> funcRol2(fcall)
@@ -1115,14 +1115,6 @@ internal class BuiltinFunctionsAsmGen(private val program: Program, private val
 
     private fun funcRnd(func: FSignature, resultToStack: Boolean, resultRegister: RegisterOrPair?, scope: Subroutine?) {
         when(func.name) {
-            "fastrnd8" -> {
-                if(resultToStack)
-                    asmgen.out("  jsr  prog8_lib.func_fastrnd8_stack")
-                else {
-                    asmgen.out("  jsr  math.fast_randbyte")
-                    assignAsmGen.assignRegisterByte(AsmAssignTarget.fromRegisters(resultRegister ?: RegisterOrPair.A, scope, program, asmgen), CpuRegister.A)
-                }
-            }
             "rnd" -> {
                 if(resultToStack)
                     asmgen.out("  jsr  prog8_lib.func_rnd_stack")

docs/source/programming.rst

@@ -845,9 +845,6 @@ rndw()
 rndf()
     returns a pseudo-random float between 0.0 and 1.0
 
-fastrnd8()
-    returns a pseudo-random byte from 0..255 (using a fast but not very good rng)
-
 rol(x)
     Rotate the bits in x (byte or word) one position to the left.
     This uses the CPU's rotate semantics: bit 0 will be set to the current value of the Carry flag,

examples/balloonflight.p8

@@ -42,7 +42,7 @@ main {
                 active_height--
                 upwards = false
             } else {
-                target_height = 8 + fastrnd8() % 16
+                target_height = 8 + rnd() % 16
                 if upwards
                     mountain = 233
                 else
@@ -57,7 +57,7 @@ main {
             txt.scroll_left(true)
 
             ; float the balloon
-            if fastrnd8() & %10000
+            if rnd() & %10000
                 c64.SPXY[1] ++
             else
                 c64.SPXY[1] --
@@ -71,10 +71,10 @@ main {
                 txt.setcc(39, yy, 160, 8)        ; draw mountain
             }
 
-            yy = fastrnd8()
+            yy = rnd()
             if yy > 100 {
                 ; draw a star
-                txt.setcc(39, yy % (active_height-1), '.', fastrnd8())
+                txt.setcc(39, yy % (active_height-1), '.', rnd())
             }
 
             if yy > 200 {
@@ -85,7 +85,7 @@ main {
                     tree = 88
                 else if yy & %00100000 != 0
                     tree = 65
-                if fastrnd8() > 130
+                if rnd() > 130
                     treecolor = 13
                 txt.setcc(39, active_height, tree, treecolor)
             }

examples/balls.p8

@@ -24,12 +24,11 @@ main {
         ; Setup Starting Ball Positions
         ubyte lp
         for lp in 0 to ballCount-1 {
-            BX[lp] = fastrnd8() % txt.DEFAULT_WIDTH
+            BX[lp] = rnd() % txt.DEFAULT_WIDTH
-            BY[lp] = fastrnd8() % txt.DEFAULT_HEIGHT
+            BY[lp] = rnd() % txt.DEFAULT_HEIGHT
-            BC[lp] = fastrnd8() & 15
+            BC[lp] = rnd() & 15
-            DX[lp] = fastrnd8() & 1
+            DX[lp] = rnd() & 1
-            DY[lp] = fastrnd8() & 1
+            DY[lp] = rnd() & 1
-            void fastrnd8()
         }
 
         ; start clock

examples/sprites.p8

@@ -42,7 +42,7 @@ main {
         for i in 0 to 7 {
             c64.SPRPTR[i] = $0a00 / 64
             c64.SPXY[i*2] = 50+25*i
-            c64.SPXY[i*2+1] = fastrnd8()
+            c64.SPXY[i*2+1] = rnd()
         }
 
         c64.SPENA = 255                ; enable all sprites
@@ -60,7 +60,7 @@ irq {
         ubyte @zp i
         for i in 0 to 14 step 2 {
             c64.SPXY[i+1]--
-            ubyte @zp r = fastrnd8()
+            ubyte @zp r = rnd()
             if r>200
                 c64.SPXY[i]++
             else if r<40

examples/test.p8

@@ -1,29 +1,29 @@
 %import conv
 %import gfx2
+%import textio
 
 main {
 
     sub start() {
-        gfx2.screen_mode(1)     ; high res 4c
+        gfx2.screen_mode(1)     ; lo res
         gfx2.text_charset(3)
         gfx2.text(10, 10, 1, @"Hello!")
 
         c64.SETTIM(0,0,0)
 
+        ubyte yy
+        uword rw
 
-        repeat 2 {
+        ;413 jiffies (lores mono) / 480 jiffies (highres mono) / 368 jiffies (lores 256c) / 442 jiffies (lores 4c)
-            uword xx
+        repeat 50000 {
-            gfx2.monochrome_stipple(true)
+            rw = rndw()
-            for xx in 0 to 319 {
+            yy = (lsb(rw) & 127) + 20
-                gfx2.vertical_line(xx, 20, 200, 1)
+            gfx2.plot(msb(rw), yy, 1)
-            }
+        }
-            gfx2.monochrome_stipple(false)
+        repeat 50000 {
-            for xx in 0 to 319 {
+            rw = rndw()
-                gfx2.vertical_line(xx, 20, 200, 1)
+            yy = (lsb(rw) & 127) + 20
-            }
+            gfx2.plot(msb(rw), yy, 0)
-            for xx in 0 to 319 {
-                gfx2.vertical_line(xx, 20, 200, 0)
-            }
         }
 
         uword time = c64.RDTIM16()

syntax-files/IDEA/Prog8.xml

@@ -14,7 +14,7 @@
     <keywords keywords="&amp;;-&gt;;@;\$;and;as;asmsub;break;clobbers;do;downto;else;false;for;goto;if;if_cc;if_cs;if_eq;if_mi;if_ne;if_neg;if_nz;if_pl;if_pos;if_vc;if_vs;if_z;in;inline;not;or;repeat;return;romsub;step;sub;to;true;until;when;while;xor;~" ignore_case="false" />
     <keywords2 keywords="%address;%asm;%asmbinary;%asminclude;%breakpoint;%import;%launcher;%option;%output;%target;%zeropage;%zpreserved" />
     <keywords3 keywords="byte;const;float;str;struct;ubyte;uword;void;word;zp" />
-    <keywords4 keywords="abs;acos;all;any;asin;atan;avg;callfar;ceil;cmp;cos;cos16;cos16u;cos8;cos8u;deg;fastrnd8;floor;len;ln;log2;lsb;lsl;lsr;max;memory;min;mkword;msb;offsetof;peek;peekw;poke;pokew;rad;reverse;rnd;rndf;rndw;rol;rol2;ror;ror2;round;sgn;sin;sin16;sin16u;sin8;sin8u;sizeof;sort;sqrt;sqrt16;sum;swap;tan" />
+    <keywords4 keywords="abs;acos;all;any;asin;atan;avg;callfar;callrom;ceil;cmp;cos;cos16;cos16u;cos8;cos8u;deg;floor;len;ln;log2;lsb;lsl;lsr;max;memory;min;mkword;msb;offsetof;peek;peekw;poke;pokew;rad;reverse;rnd;rndf;rndw;rol;rol2;ror;ror2;round;sgn;sin;sin16;sin16u;sin8;sin8u;sizeof;sort;sqrt;sqrt16;sum;swap;tan" />
   </highlighting>
   <extensionMap>
     <mapping ext="p8" />

syntax-files/Vim/prog8_builtins.vim

@@ -16,7 +16,7 @@ syn keyword prog8BuiltInFunc any all len max min reverse sum sort
 
 " Miscellaneous functions
 syn keyword prog8BuiltInFunc cmp lsb msb mkword peek peekw poke pokew rnd rndw
-syn keyword prog8BuiltInFunc rndf fastrnd8 rol rol2 ror ror2 sizeof offsetof
+syn keyword prog8BuiltInFunc rndf rol rol2 ror ror2 sizeof offsetof
 syn keyword prog8BuiltInFunc swap memory callfar callrom