Build Levels

Build levels in DevCPC determine which 8BP library features are included in your compiled program. Choosing the right build level is crucial for optimizing memory usage and ensuring your game has enough BASIC memory available.

What Are Build Levels?

The 8BP library for Amstrad CPC includes multiple features for game development: sprite handling, scrolling, layouts, pseudo-3D rendering, and more. Not all games need all features, so DevCPC allows you to select a build level that includes only what you need.

Higher build levels (4 = least features) free up more BASIC memory by excluding unused 8BP commands.

The 5 Build Levels

Level 0: Full Featured

All 8BP functionality included. Use when you need everything or aren’t sure yet.Memory: 23599 bytes
Size: 19120 bytes

Level 1: Maze Games

Layout and collision features for maze-style games.Memory: 24999 bytes
Size: 17620 bytes

Level 2: Scrolling Games

Map-to-sprite and update features for scrolling games.Memory: 24799 bytes
Size: 17820 bytes

Level 3: Pseudo-3D Games

3D rendering features for pseudo-3D games.Memory: 23999 bytes
Size: 18620 bytes

Level 4: Basic Features

Core sprite features only. Maximum memory available.Memory: 25299 bytes
Size: 17320 bytes

Detailed Build Level Comparison

Features Table
Memory Breakdown
Command Reference

Level	Description	MEMORY Value	Library Size	Available Commands
0	All functionalities	23599	19120 bytes	`\|LAYOUT`, `\|COLAY`, `\|MAP2SP`, `\|UMA`, `\|3D`
1	Maze games	24999	17620 bytes	`\|LAYOUT`, `\|COLAY`
2	Scrolling games	24799	17820 bytes	`\|MAP2SP`, `\|UMA`
3	Pseudo-3D games	23999	18620 bytes	`\|3D`
4	Basic (no scroll/layout)	25299	17320 bytes	Core sprite commands only

Memory Distribution

The MEMORY value defines the upper limit of BASIC’s memory space:

CPC Memory Layout:
┌──────────────────┐ &FFFF
│  System ROM      │
├──────────────────┤
│  8BP Library     │ ← Size varies by BUILD_LEVEL
├──────────────────┤ ← MEMORY value (23599-25299)
│  Your BASIC      │
│  Program         │
├──────────────────┤
│  Screen Memory   │ &C000
├──────────────────┤
│  Lower RAM       │
└──────────────────┘ &0000

Example for Level 0:

MEMORY 23599 = BASIC can use up to address 23599
8BP library loads at 23600-42719 (19120 bytes)

Example for Level 4:

MEMORY 25299 = BASIC can use up to address 25299
8BP library loads at 25300-42619 (17320 bytes)
+1700 more bytes for your BASIC program!

8BP Commands by Level

Level 0: All Commands

Includes every 8BP command:

Layout System: |LAYOUT, |COLAY, collision detection
Map-to-Sprite: |MAP2SP, automatic sprite generation from maps
Update Management: |UMA, efficient sprite updates
Pseudo-3D: |3D, 3D rendering routines
Core Sprites: |SETUPSP, |PRINTSP, |SPRITE, etc.
Music & FX: Sound and music commands

Level 1: Maze Game Commands

Optimized for grid-based games:

|LAYOUT - Define and manage tile-based layouts
|COLAY - Collision detection with layout
Core sprite commands - Basic sprite handling

Use for: Pac-Man style games, tile-based puzzles, dungeon crawlers

Level 2: Scrolling Commands

Optimized for scrolling games:

|MAP2SP - Convert map tiles to sprites dynamically
|UMA - Update manager for efficient redraws
Core sprite commands - Basic sprite handling

Use for: Platformers, shoot ‘em ups, side-scrollers

Level 3: Pseudo-3D Commands

Optimized for 3D games:

|3D - Pseudo-3D rendering routines
Core sprite commands - Basic sprite handling

Use for: Racing games, flight simulators, 3D maze games

Level 4: Core Commands Only

Basic sprite functionality:

|SETUPSP - Initialize sprite system
|PRINTSP - Print sprites
|SPRITE - Define sprites
|MOVE - Move sprites
Music commands - Sound and music

Use for: Simple arcade games, demos, music playersDoes NOT include: Layouts, maps, scrolling, or 3D

How to Choose Your Build Level

Use this decision tree to select the optimal build level:

Analyze Your Game Requirements

List all the 8BP features your game needs:

Tile-based layouts? → Consider Level 1
Scrolling maps? → Consider Level 2
3D graphics? → Consider Level 3
Simple sprites only? → Consider Level 4
Not sure yet? → Use Level 0

Check Memory Requirements

Estimate how much BASIC memory your game logic needs:

Large BASIC programs → Choose higher build levels (more memory)
Small BASIC, complex 8BP → Level 0 is fine

Set BUILD_LEVEL in devcpc.conf

# Example: Scrolling platformer game
BUILD_LEVEL=2

Update MEMORY in Your BASIC Loader

REM Match MEMORY to your BUILD_LEVEL
MEMORY 24799  ' For BUILD_LEVEL=2
LOAD"8BP2.bin"
CALL &6B78

Configuration Example

In devcpc.conf:

PROJECT_NAME="platformer"

# Choose build level based on your needs
BUILD_LEVEL=2

# Rest of configuration...
ASM_PATH="asm/make_all_platformer.asm"
BASIC_PATH="bas"

In Your BASIC Loader (bas/loader.bas):

REM Platformer Game Loader
MODE 0
MEMORY 24799: REM For BUILD_LEVEL 2
LOAD"8BP2.bin"
CALL &6B78
REM Your game initialization here

The MEMORY value in your BASIC program must match the BUILD_LEVEL in devcpc.conf. Mismatches can cause crashes or memory corruption.

Build Level Binary Names

Each build level produces a uniquely named binary:

BUILD_LEVEL	Binary Name	Load From BASIC
0	`8BP0.bin`	`LOAD"8BP0.bin"`
1	`8BP1.bin`	`LOAD"8BP1.bin"`
2	`8BP2.bin`	`LOAD"8BP2.bin"`
3	`8BP3.bin`	`LOAD"8BP3.bin"`
4	`8BP4.bin`	`LOAD"8BP4.bin"`

DevCPC automatically sets the ASSEMBLING_OPTION variable in your ASM file based on BUILD_LEVEL.

Switching Build Levels

You can change build levels at any time:

# 1. Edit devcpc.conf
BUILD_LEVEL=4  # Change to level 4

# 2. Update your BASIC loader
# Change MEMORY and binary name to match

# 3. Clean and rebuild
devcpc clean
devcpc build

Memory Limit Verification

During build, DevCPC automatically checks:

Graphics Memory Limit

Limit: _END_GRAPH < 42040Ensures sprite and graphics data don’t overflow into system memory.

✓ Graphics limit respected (40152 < 42040)

C Code Memory Limit

Limit: C_CODE_LOC + size < 23999Ensures C code doesn’t overwrite the 8BP library.

✓ C code memory OK (20000 + 3500 = 23500 < 23999)

Build Output Messages

When you run devcpc build, you’ll see:

═══════════════════════════════════════
  Compilar Proyecto: my_game
═══════════════════════════════════════

ℹ Build Level: 2 (Juegos con scroll)
ℹ Memoria BASIC: MEMORY 24799

✓ Compilación exitosa
✓ Límite de gráficos respetado (< 42040)

Best Practices

Start with Level 0

Begin development with Level 0 to access all features, then optimize later.

Match MEMORY Values

Always ensure your BASIC MEMORY statement matches the build level.

Test After Switching

Run devcpc validate and test thoroughly when changing build levels.

Document Your Choice

Add comments in devcpc.conf explaining why you chose a specific level.

Common Issues

Error: Command not found (|MAP2SP)

Problem: Your code uses a command not available in your build level.Solution: Either:

Change to Level 0 or Level 2 (includes |MAP2SP)
Remove the unsupported command from your code

Program crashes on load

Problem: MEMORY value doesn’t match BUILD_LEVEL.Solution: Check your BASIC loader:

' BUILD_LEVEL=2 requires:
MEMORY 24799
LOAD"8BP2.bin"

Not enough BASIC memory

Problem: Large BASIC program hitting memory limits.Solution: Use a higher build level:

Level 0 (23599) → Level 4 (25299) = +1700 bytes
Remove unused 8BP features

Next Steps

Configuration Guide

Learn how to configure BUILD_LEVEL and other settings

Project Structure

Understand where build outputs are stored

Getting Started

Core Concepts

Guides

Advanced

Tools

What Are Build Levels?

The 5 Build Levels

Level 0: Full Featured

Level 1: Maze Games

Level 2: Scrolling Games

Level 3: Pseudo-3D Games

Level 4: Basic Features

Detailed Build Level Comparison

Memory Distribution

8BP Commands by Level

How to Choose Your Build Level

Configuration Example

In devcpc.conf:

In Your BASIC Loader (bas/loader.bas):

Build Level Binary Names

Switching Build Levels

Memory Limit Verification

Build Output Messages

Best Practices

Start with Level 0

Match MEMORY Values

Test After Switching

Document Your Choice

Common Issues

Next Steps

Configuration Guide

Project Structure

Build docs developers (and LLMs) love

Getting Started

Core Concepts

Guides

Advanced

Tools

​What Are Build Levels?

​The 5 Build Levels

Level 0: Full Featured

Level 1: Maze Games

Level 2: Scrolling Games

Level 3: Pseudo-3D Games

Level 4: Basic Features

​Detailed Build Level Comparison

​Memory Distribution

​8BP Commands by Level

​How to Choose Your Build Level

​Configuration Example

​In devcpc.conf:

​In Your BASIC Loader (bas/loader.bas):

​Build Level Binary Names

​Switching Build Levels

​Memory Limit Verification

​Build Output Messages

​Best Practices

Start with Level 0

Match MEMORY Values

Test After Switching

Document Your Choice

​Common Issues

​Next Steps

Configuration Guide

Project Structure

Build docs developers (and LLMs) love

What Are Build Levels?

The 5 Build Levels

Detailed Build Level Comparison

Memory Distribution

8BP Commands by Level

How to Choose Your Build Level

Configuration Example

In devcpc.conf:

In Your BASIC Loader (bas/loader.bas):

Build Level Binary Names

Switching Build Levels

Memory Limit Verification

Build Output Messages

Best Practices

Common Issues

Next Steps