Making It Yours

The game works. Now make it yours.

This unit teaches the attribute system by having you change it. You won’t just read about bits and colours - you’ll modify them and see the results. By the end, you’ll understand exactly how the Spectrum’s colour system works because you’ll have bent it to your will.

Run It

Assemble and run:

pasmonext --tapbas inkwar.asm inkwar.tap

This doesn’t look like the previous versions. The board is cyan instead of white. There’s a yellow border around it. The screen border is blue (because it’s Player 2’s turn). The cursor is bright white, not flashing.

Same game, completely different feel.

The Customisation Section

All the visual changes come from one section at the top of the code:

This is your control panel. Change these values, reassemble, and see the difference immediately.

Understanding the Attribute Byte

Let’s decode %01101000 (the cyan cell):

%01101000
 │└┬┘└┬┘
 │ │  └── INK: 000 = black (0)
 │ └───── PAPER: 101 = cyan (5)
 └─────── BRIGHT: 1 = yes, FLASH: 0 = no

The attribute byte packs four pieces of information into 8 bits:

Building Attribute Values

To create an attribute byte, work backwards:

1. Choose your PAPER colour (0-7)
2. Choose your INK colour (0-7)
3. Decide on BRIGHT (add 64 if yes)
4. Decide on FLASH (add 128 if yes)

Example: Bright yellow paper, blue ink

• PAPER = 6 (yellow) → bits 5-3 = 110
• INK = 1 (blue) → bits 2-0 = 001
• BRIGHT = yes → bit 6 = 1
• FLASH = no → bit 7 = 0

Result: %01110001 = 113 decimal

Example: Flashing green paper, white ink

• PAPER = 4 (green) → bits 5-3 = 100
• INK = 7 (white) → bits 2-0 = 111
• BRIGHT = no → bit 6 = 0
• FLASH = yes → bit 7 = 1

Result: %10100111 = 167 decimal

Try This: Change the Board Colour

Edit EMPTY_ATTR to try different colours:

; Bright green board
EMPTY_ATTR  equ     %01100000       ; Green paper (4), black ink

; Bright magenta board
EMPTY_ATTR  equ     %01011000       ; Magenta paper (3), black ink

; Yellow board with blue ink
EMPTY_ATTR  equ     %01110001       ; Yellow paper (6), blue ink (1)

Reassemble after each change. Watch the board transform.

The Visible Border

In Units 1 and 2, the border around the board was invisible - black on black. Now we draw it explicitly:

The border is one row above, one row below, and one column on each side of the 8×8 playing area. We draw it as a rectangle of yellow cells.

Try This: Change the Border Colour

; Red border
BORDER_ATTR equ     %01010000       ; Red paper (2)

; White border
BORDER_ATTR equ     %01111000       ; White paper (7)

; Flashing border (dramatic!)
BORDER_ATTR equ     %11110000       ; Flash + Bright + Yellow

Dynamic Screen Border

The screen border (the area outside the main display) changes colour based on whose turn it is:

This is different from attribute memory. The screen border is set by outputting a value (0-7) to port $FE:

            ld      a, 2            ; Red
            out     ($fe), a        ; Set border

The border colour gives immediate visual feedback about game state.

Try This: Different Turn Colours

; Green for P1, Cyan for P2
P1_BORDER   equ     4               ; Green
P2_BORDER   equ     5               ; Cyan

; Yellow for P1, Magenta for P2
P1_BORDER   equ     6               ; Yellow
P2_BORDER   equ     3               ; Magenta

The Cursor: Flash vs Bright

The original cursor used FLASH (bit 7):

CURSOR_ATTR equ     %10111000       ; Flash + white paper

The FLASH attribute alternates the cell between normal and inverted colours every 16 frames (about 0.32 seconds). It’s automatic - the hardware does it.

The new cursor uses BRIGHT instead:

CURSOR_ATTR equ     %01111000       ; Bright + white paper (no flash)

BRIGHT makes colours more vivid. The cursor now stands out by being brighter than surrounding cells, rather than flashing.

Which do you prefer? Try both.

The Colour Palette

Here’s the complete Spectrum palette:

Note that “white” only exists as bright 7. Normal 7 is actually grey.

The Complete Code

Challenge: Create Your Theme

Design a complete colour scheme:

1. Choose a board colour that looks good
2. Choose a contrasting border colour
3. Pick screen border colours that clearly indicate whose turn it is
4. Decide between flash and bright for the cursor
5. Make sure player colours (red/blue) still stand out

Document your choices in comments. Share your theme.

What You’ve Learnt

• Attribute byte format - FBPPPIII: flash, bright, paper, ink packed into 8 bits
• Calculating attributes - Shift paper left 3, add ink, optionally add 64 (bright) or 128 (flash)
• Screen border - OUT ($FE), A sets the border to colours 0-7
• FLASH vs BRIGHT - Flash alternates automatically; bright intensifies colours
• Colour palette - 8 colours × 2 brightness levels, but black stays black

What’s Next

In Unit 4, we’ll add score and turn display - text on screen showing whose turn it is and how many cells each player controls.

What Changed