Add NES building and adapt example functions

LibMultiSpacc/neslib/memfill.s

@@ -0,0 +1,49 @@
+
+.importzp TEMP
+.import popa, popax
+.include "zpvars.inc"
+.export _memfill
+
+;void __fastcall__ memfill(void *dst,unsigned char value,unsigned int len);
+
+_memfill:
+
+	sta <LEN
+	stx <LEN+1
+	jsr popa
+	sta <TEMP
+	jsr popax
+	sta <DST
+	stx <DST+1
+
+	ldx #0
+
+@1:
+
+	lda <LEN+1
+	beq @2
+	jsr @3
+	dec <LEN+1
+	inc <DST+1
+	jmp @1
+
+@2:
+
+	ldx <LEN
+	beq @5
+
+@3:
+
+	ldy #0
+	lda <TEMP
+
+@4:
+
+	sta (DST),y
+	iny
+	dex
+	bne @4
+
+@5:
+
+	rts