Add NES building and adapt example functions

LibMultiSpacc/neslib/rand.s

@@ -0,0 +1,71 @@
+
+.segment "ZEROPAGE"
+
+RAND_SEED: 		.res 2
+
+.segment "CODE"
+.export _rand8,_rand16,_set_rand
+.exportzp RAND_SEED
+
+;unsigned char __fastcall__ rand8(void);
+;Galois random generator, found somewhere
+;out: A random number 0..255
+
+rand1:
+
+	lda <RAND_SEED
+	beq @z1
+	asl a
+	bcc @1
+@z1:	eor #$cf
+
+@1:
+
+	sta <RAND_SEED
+	rts
+
+rand2:
+
+	lda <RAND_SEED+1
+	beq @z2
+	asl a
+	bcc @1
+@z2:	eor #$d7
+
+@1:
+
+	sta <RAND_SEED+1
+	rts
+
+_rand8:
+
+	jsr rand1
+	jsr rand2
+	adc <RAND_SEED
+	ldx #$00
+	rts
+
+
+
+;unsigned int __fastcall__ rand16(void);
+
+_rand16:
+
+	jsr rand1
+	tax
+	jsr rand2
+
+	rts
+
+
+;void __fastcall__ set_rand(unsigned char seed);
+
+_set_rand:
+	ora #1
+	sta <RAND_SEED
+	stx <RAND_SEED+1
+
+	rts
+
+
+