Status: Work in Progress Version: 0.1.0 Language: C++17

V4-std is a device-independent standard library for the V4 Forth VM, providing portable hardware abstraction through the Device Descriptor Table (DDT) mechanism. Write once, run on any V4-supported platform.

• Device Descriptor Table (DDT): Hardware abstraction via table-driven device enumeration
• SYS Call Architecture: Standardized syscall interface (0x0100-0x0FFF range)
• Portable Forth Words: Standard word library that works across all platforms
• Zero Dependencies: No dynamic allocation, no exceptions, no RTTI
• Modern C++17: Type-safe APIs with std::span, constexpr, etc.
• Multi-Platform: Linux, macOS, Windows, ESP32-C6, and more

• LED: Digital output (status indicators, user LEDs)
• Button: Digital input (user buttons, switches)
• Timer: Millisecond/microsecond timing, delays
• UART: Serial communication (console, debugging)
• More coming soon: I2C, SPI, ADC, PWM, Display, Storage

cmake -B build -DCMAKE_BUILD_TYPE=Release
cmake --build build
ctest --test-dir build

\ led-hello.fth - Portable LED blink
: hello
  ." V4-std LED Demo" cr
  button-wait
  3 blink ;

S" led" cap? if
  S" button" cap? if
    hello
  else
    ." No button available" cr
  then
then

Forth Application (led-hello.fth)
        ↓
V4-std Words (led-on, button?, ms)
        ↓
SYS Calls (0x0120, 0x0140, 0x0162)
        ↓
SYS Handlers (sys_led_on, sys_button_read)
        ↓
DDT (Device Descriptor Table)
        ↓
Platform Provider (ESP32-C6, etc.)
        ↓
V4-hal (Hardware Abstraction Layer)

V4-std/
├── include/v4std/       # Public headers
├── src/                 # Implementation
├── tests/               # Unit tests
├── forth/               # Forth word definitions
├── examples/            # Example programs
└── docs/                # Documentation

#include "v4std/ddt.hpp"
#include "v4std/sys_handlers.hpp"

// Set DDT provider
v4std::Ddt::set_provider(&my_platform_provider);

// Register SYS handlers
v4std::register_all_sys_handlers(vm);

See V4-runtime/bsp/esp32c6/components/v4_std/ for platform integration.

• Repository structure
• DDT type definitions
• DDT search API
• SYS call definitions
• LED SYS handlers
• Button SYS handlers
• Timer SYS handlers
• Forth word library
• ESP32-C6 integration
• Documentation

This project adheres to C++17 embedded coding standards:

• No exceptions (-fno-exceptions)
• No RTTI (-fno-rtti)
• No dynamic allocation
• Fixed-size arrays and std::span

Dual-licensed under MIT OR Apache-2.0.

• V4 Project
• V4-engine
• V4-hal
• V4-link