// SPDX-License-Identifier: CC-BY-SA-4.0
// SPDX-FileCopyrightText: 2024-2026 hyperpolymath (Jonathan D.A. Jewell <j.d.a.jewell@open.ac.uk>)
= AffineScript Backend Analysis: Coprocessor Support

== Executive Summary

*Current State:* AffineScript has basic WASM backend support but *NO
dedicated coprocessor backends* for audio, I/O, NPU, TPU, GPU, math,
physics, FPGA, crypto, or vector operations.

*What Exists:* - ✅ Basic WASM code generation (lib/codegen.ml) - ✅
WASI runtime support (lib/wasi++_++runtime.ml) - ✅ FFI layer
(runtime/src/ffi.rs) - ✅ Memory management (runtime/src/alloc.rs) - ✅
Basic I/O operations (print, println)

*What’s Missing:* - ❌ Audio coprocessor backend - ❌ GPU compute
backend - ❌ NPU/TPU acceleration - ❌ Physics engine integration - ❌
FPGA acceleration - ❌ Cryptographic acceleration - ❌ Vector/SIMD
optimization - ❌ Math coprocessor utilization

'''''

== Detailed Analysis

=== 1. Current Backend Architecture

*WASM Backend (lib/codegen.ml):* - Targets WebAssembly 1.0 (MVP) - Basic
arithmetic operations - Memory management via linear memory - Function
calls and control flow - No SIMD or vector instructions - No
multithreading support

*WASI Runtime (lib/wasi++_++runtime.ml):* - fd++_++write for
stdout/stderr - Basic string and integer printing - No file I/O,
networking, or system calls - No hardware acceleration

*FFI Layer (runtime/src/ffi.rs):* - Host function callbacks - String
interop - JavaScript bindings (stubbed) - WASI bindings (stubbed) - No
coprocessor-specific FFI

=== 2. Coprocessor Support Status

==== Audio Processing

* *Status:* ❌ Not implemented
* *Current:* Basic print/println only
* *Missing:* Audio buffers, DSP operations, real-time processing
* *Files:* No audio-specific modules

==== GPU Compute

* *Status:* ❌ Not implemented
* *Current:* CPU-only WASM execution
* *Missing:* WebGPU bindings, compute shaders, GPU memory management
* *Files:* No GPU-related code

==== NPU/TPU Acceleration

* *Status:* ❌ Not implemented
* *Current:* No neural network support
* *Missing:* Tensor operations, NPU instruction sets, model loading
* *Files:* No AI/ML modules

==== Physics Engine

* *Status:* ❌ Not implemented
* *Current:* No physics calculations
* *Missing:* Collision detection, rigid body dynamics, physics
simulation
* *Files:* No physics-related code

==== FPGA Acceleration

* *Status:* ❌ Not implemented
* *Current:* No hardware acceleration
* *Missing:* FPGA bitstream generation, hardware description
* *Files:* No FPGA-related modules

==== Cryptographic Acceleration

* *Status:* ❌ Not implemented
* *Current:* No crypto operations
* *Missing:* Hash functions, encryption, digital signatures
* *Files:* No crypto modules

==== Vector/SIMD Operations

* *Status:* ❌ Not implemented
* *Current:* Scalar operations only
* *Missing:* SIMD instructions, vectorized math, parallel operations
* *Files:* No vector optimization

==== Math Coprocessor

* *Status:* ❌ Not implemented
* *Current:* Basic arithmetic in WASM
* *Missing:* High-precision math, transcendental functions, numerical
optimization
* *Files:* No math library

=== 3. Backend vs Kernel Distinction

*Current Backends:* - These are *compilation targets* (WASM) - They
generate code for execution - No runtime optimization or
hardware-specific code

*Missing Kernels:* - No specialized computation kernels - No
hardware-optimized routines - No domain-specific libraries - No
acceleration frameworks

=== 4. What Would Be Needed

==== For Audio Backend:

[source,rust]
----
// Example: Audio coprocessor backend (missing)
pub mod audio {
    pub fn init_device(sample_rate: u32, channels: u8) -> AudioDevice;
    pub fn create_buffer(samples: &[f32]) -> AudioBuffer;
    pub fn play_buffer(device: &AudioDevice, buffer: &AudioBuffer);
    pub fn apply_effect(buffer: &mut AudioBuffer, effect: AudioEffect);
}
----

==== For GPU Backend:

[source,rust]
----
// Example: GPU compute backend (missing)
pub mod gpu {
    pub fn init_context() -> GPUContext;
    pub fn create_shader(source: &str) -> GPUShader;
    pub fn dispatch_compute(context: &GPUContext, shader: &GPUShader, workgroups: (u32, u32, u32));
    pub fn read_buffer(buffer: &GPUBuffer) -> Vec<u8>;
}
----

==== For Vector Backend:

[source,ocaml]
----
(* Example: Vector optimization backend (missing) *)
module Vector = struct
  let simd_add : float array -> float array -> float array
  let simd_mul : float array -> float array -> float array
  let simd_dot : float array -> float array -> float
  let simd_normalize : float array -> float array
end
----

=== 5. Recommendations

==== Short-Term (Alpha-1):

* ✅ Document current limitations
* ✅ Focus on core language stability
* ✅ Complete basic WASM backend
* ✅ Implement WASI file I/O

==== Medium-Term (Beta):

* 🔄 Add WASM SIMD support
* 🔄 Implement basic audio via Web Audio API
* 🔄 Add WebGPU bindings for browser GPU
* 🔄 Implement vector math library

==== Long-Term (1.0{plus}):

* 🚀 Dedicated audio DSP backend
* 🚀 GPU compute backend
* 🚀 NPU/TPU acceleration
* 🚀 Physics engine integration
* 🚀 Cryptographic acceleration
* 🚀 FPGA backend

'''''

== Conclusion

AffineScript currently has *basic backend support only* - enough to
compile to WASM and run simple programs, but *no coprocessor-specific
backends or kernels*. All the mentioned coprocessor support (audio, GPU,
NPU, physics, FPGA, crypto, vector) would need to be implemented from
scratch.

The current architecture is designed to be extensible, with the FFI
layer providing a foundation for future coprocessor integration, but
none of these advanced backends exist yet.

*Priority for Alpha-1:* Focus on core language features and basic WASM
backend. Coprocessor support should be planned for future releases (Beta
and beyond).
