scene.org File Archive

File download

<root>­/­parties­/­2022­/­vccc22­/­christmas_star_challenge/hugodufortminimaliststar2.zip

File size:
65 519 bytes (63.98K)
File date:
2022-12-30 11:32:13
Download count:
all-time: 3

Preview

  • minimalist/ dir
  • minimalist/2022-12-26_11-44-25.png 55.47K
  • minimalist/2022-12-26_11-44-53.png 12.90K
  • minimalist/2022-12-26_11-45-13.png 5.16K
  • minimalist/file_id.diz.txt 1.19K
  • minimalist/star.asm 914B
  • minimalist/star.bin 89B

file_id.diz

<Name of Release>

Author: Hugo Dufort
Category: Christmas Challenge
System:   Tandy Color Computer
Language: 6809 assembler
Len source code: <# bytes>
Len exe file:    89
Len code only:   <# bytes> (valid for assembler only; length of executable without BASIC stub)
Instructions:
Use the VCC emulator (Color Computer 3 emulator)
Command line: vcc star.bin
Description:
Since the star is symmetrical, I have stored the upper half of it as bit masks, with 3 bytes per line.
The main program loops through these masks until it reaches the end address of the bit masks.
The loop symply calls the bit decoding subroutine 3 times per line.
The decoding subroutine shifts one bit to the left, 8 times. A counter going from 8 to 0 is stored in memory at an arbitrary address.
The decoding subroutine simply looks at the sign bit (bit 7 in register B) and displays either a star (#106) or a space (#96) character.
The program doesn't clear the screen, and unfortunately, since the COCO's low-resolution text screen is just 32x16, the last line of the star is not visible.
Comments:
Please disregard the previous entry (91 bytes long compiled code), as there was an unnecessary line of code left in.