Diamond Mesh

Author: Dr. Lutz Bellmann
Category: Christmas Challenge
System: Commodore SX-64
Language: Assembler (Turbo Macro Pro v1.2)
Len source code: dunno, Windows says the text file has 1250bytes; the code is 73 lines including comments and blank lines
Len exe file:    119 bytes
Len code only:   117 bytes
Instructions:
Simply open the "vccc23-lutz.prg" in Vice (C64 or SX-64) and run "sys4096".
Description:
The program divides the picture into diagonals. Two loops go around the figure from left to right and use a plot-like routine to set the cursor and
use the chrout routine of the kernal to put the stars. One loop for diagonals from left to right the other from right to left. 
Comments:
This was a quick shot, so this is not heavily optimized. I just had a lot of fun handtyping the program on my real SX-64. Perfect evening job for just before christmas. Keep it up!
I included the Assembler file for TMP as well.
; VINTAGE COMPUTING CHRISTMAS
; CHALLENGE 2023 (VC3 2023)
; DR. LUTZ BELLMANN

; ------------------------------------

CINT     = $FF81
CHROUT   = $FFD2
SCR      = $E56C
YPOS     = $D6
XPOS     = $D3

         *= $1000
         JSR CINT
         LDX #0
L0       LDA XOORDV,X
         STA XPOS
         LDA YOORDV,X
         STA YPOS
         STX $FF
         JSR LV
         LDX $FF
         INX
         CPX #VXLEN
         BNE L0
         LDX #0
L1       LDA XOORDB,X
         STA XPOS
         LDA YOORDB,X
         STA YPOS
         STX $FF
         JSR LB
         LDX $FF
         INX
         CPX #BXLEN
         BNE L1
         RTS

LV       JSR PRT
         INC YPOS
         LDA #19
         CMP XPOS
         BEQ LEXV
         CMP YPOS
         BNE LV
LEXV     RTS

LB       JSR PRT
         INC YPOS
         DEC XPOS
         DEC XPOS
         LDA #$FF
         CMP XPOS
         BEQ LEXB
         LDA #19
         CMP YPOS
         BNE LB
LEXB     RTS

PRT      JSR SCR
         LDA #"*"
         JSR CHROUT
         RTS

XOORDV   .BYTE 0,0,0
XOORDB   .BYTE 3,9,15
VXLEN    = *-XOORDV
         .BYTE 18,18,18
BXLEN    = *-XOORDB
YOORDV   .BYTE 15,9,3
YOORDB   .BYTE 0,0,0
VYLEN    = *-YOORDV
         .BYTE 3,9,15