Christmas Tree - Revision history

Wil: /* Remarkable Entries */ added shortest BASIC entry for C64

2023-01-07T16:40:21Z

‎Remarkable Entries: added shortest BASIC entry for C64

Wil: /* The challenge */

2023-01-01T22:48:15Z

‎The challenge

Wil: /* Winning Entries */

2023-01-01T22:44:47Z

‎Winning Entries

Wil: /* Winning entry for C64 */

2023-01-01T22:44:34Z

‎Winning entry for C64

Serato: Added 33 byte C64 version

2022-01-01T10:42:15Z

Added 33 byte C64 version

Serato: Added 34 byte C64 version

2021-12-31T23:15:11Z

Added 34 byte C64 version

Serato: Added 35-byte C64 version

2021-12-30T08:12:27Z

Added 35-byte C64 version

GeirS: Added creation date of version

2021-12-30T00:19:40Z

Added creation date of version

GeirS: Replaced semicolon with hash for better formatting of comments

2021-12-29T13:00:30Z

Replaced semicolon with hash for better formatting of comments

GeirS: Added 35 byte Plus/4 version

2021-12-29T10:20:02Z

Added 35 byte Plus/4 version

← Older revision		Revision as of 16:40, 7 January 2023
Line 116:		Line 116:

	b - The BASIC interpreter leaves the line number in the zero page word at $39, so by setting the line number in the basic header to the address of the table, "LAX ($39),y" can be used for the table access.</nowiki>		b - The BASIC interpreter leaves the line number in the zero page word at $39, so by setting the line number in the basic header to the address of the table, "LAX ($39),y" can be used for the table access.</nowiki>
		+
		+	=== Shortest BASIC entry for C64 ===
		+
		+	While BASIC programs seem to have a structural disadvantage for this kind of challenge, some entries in the spirit of oneliners are remarkably compact.
		+	The shortest BASIC entry for the C64 was submitted by Wil with 68 bytes of source code length.
		+
		+	<syntaxhighlight lang="basic">
		+	0dA-1,,1,2,,2,4,6,1,4,7,10,,:rEw:?sP18-w);:fOk=-2tow+w:?"*";:nE:?:gO
		+	</syntaxhighlight>
		+
		+	Expanded source code as produced by LIST:
		+
		+	<syntaxhighlight lang="basic">
		+	0 data-1,,1,2,,2,4,6,1,4,7,10,,:readw:printspc(18-w);:fork=-2tow+w:print"*";:next:print:goto
		+	</syntaxhighlight>

	==Optimized post-deadline versions==		==Optimized post-deadline versions==

@@ Line 22: / Line 22: @@
 * calculate stars using a formula
 * save amount of stars within data
 Do to the trunk of the tree, the second type was more efficient.
 ==Remarkable Entries==
 === Shortest DOS version ===

@@ Line 23: / Line 23: @@
 * save amount of stars within data
 Do to the trunk of the tree, the second type was more efficient.
-==Winning Entries==
+==Remarkable Entries==
 === Shortest DOS version ===
 The shortest DOS version with 44 bytes came from Hellmood:

@@ Line 45: / Line 45: @@
 d:db 2,2,12,9,6,3,8,6,4,2,4,3,2,1
 </syntaxhighlight>
-=== Winning entry for C64 ===
+=== Overall winning entry (C64) ===
 The shortest entry overall was for the C64 and was submitted by Serato with only 37 bytes:
 <syntaxhighlight lang="6502">

@@ Line 252: / Line 252: @@
 		lax (tape1),y
 		bne --
 		rts
 end

@@ Line 210: / Line 210: @@
 		!byte -3
 ;		!byte -1
 </syntaxhighlight>
 ===32 bytes version for ZX Spectrum===

@@ Line 198: / Line 198: @@
 The following optimized version for the Commodore Plus/4 was created after the deadline:
 <syntaxhighlight lang="6502tasm">
-# Plus/4 Christmas Tree by GeirS
+# Plus/4 Christmas Tree by GeirS, 2021-12-29
 # Assemble using 64tass (replace hash with semicolon first, except for 'lda #$2a')

@@ Line 198: / Line 198: @@
 The following optimized version for the Commodore Plus/4 was created after the deadline:
 <syntaxhighlight lang="6502tasm">
-; Plus/4 Christmas Tree by GeirS
+# Plus/4 Christmas Tree by GeirS
-; Assemble using 64tass
+# Assemble using 64tass (replace hash with semicolon first, except for 'lda #$2a')
-BtmRow		= $0c00+$28*$18	; Address of bottom screen row
+BtmRow		= $0c00+$28*$18	# Address of bottom screen row
-Screen		= BtmRow-$6c	; Adjustment for ($100-$28)/2
+Screen		= BtmRow-$6c	# Adjustment for ($100-$28)/2
-ScrollUp	= $da89			; KERNAL routine to scroll screen upwards
+ScrollUp	= $da89			# KERNAL routine to scroll screen upwards
-VarTab		= $2d			; Pointer: Start of BASIC variables
+VarTab		= $2d			# Pointer: Start of BASIC variables
-			* = $1001		; Load address
+			* = $1001		# Load address
-; BASIC stub
+# BASIC stub
 			.word (NextLine),0
 			.null $9e,format("%4d", Start)
@@ Line 214: / Line 214: @@
 			.word 0
-; Code and data (35 bytes total)
+# Code and data (35 bytes total)
 RowLoop
-			lsr				; Calculate screen offset
+			lsr				# Calculate screen offset
 			tay
-			lda #$2a		; Asterisk character
+			lda #$2a		# Asterisk character
 CharLoop
-			sta Screen,y	; Put char in bottom screen row
+			sta Screen,y	# Put char in bottom screen row
 			iny
 			inx
-			bne CharLoop	; Loop for all chars
+			bne CharLoop	# Loop for all chars
 Start
-			jsr ScrollUp	; Scroll the screen upwards (x=0 after)
+			jsr ScrollUp	# Scroll the screen upwards (x=0 after)
-			dec VarTab		; Adjust address of char count to use next
+			dec VarTab		# Adjust address of char count to use next
-			lax (VarTab,x)	; Load char count into both a and x
+			lax (VarTab,x)	# Load char count into both a and x
-			bmi RowLoop		; Loop while not done
+			bmi RowLoop		# Loop while not done
 			rts
-; Asterisk counts (negative values to optimize the code)
+# Asterisk counts (negative values to optimize the code)
 			.char -3,-3,-23,-17,-11,-5,-15,-11,-7,-3,-7,-5,-3,-1
 </syntaxhighlight>

@@ Line 193: / Line 193: @@
 	jr	start
 end
 </syntaxhighlight>