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d12ad11746
## Control Flow Opcodes - Implemented all 10 remaining stub control flow opcodes: block, loop, if, else, end, br, br_if, br_table, call, call_indirect - Rewrote return opcode to walk control stack and restore call frames - Fixed tick() hang: now halts when IP >= Limit ## Refactoring - Extracted WASM_HDR_MAGIC and CTRL_FRAME_* constants to wasm.types.constants.pas - Extracted push_control_frame, scan_forward, do_branch helpers to wasm.vm.control.pas - Updated wasm.parser.pas to reference constants via wasm.types.constants ## Tests - Added 9 new test units (25 tests): block, loop, if, end, br, br_if, br_table, call, call_indirect - Added E2E binary test: 115-byte handcrafted WASM binary exercising all control flow opcodes (2 functions, expected result=30) - All 425/425 tests passing
WASURO
A WebAssembly virtual machine for the Asuro operating system, written in Standard Pascal.
WASURO parses and executes WASM binaries directly in a bare-metal kernel environment — no runtime library, no classes, no heap manager beyond what the OS provides.
Architecture
src/
├── emu/ # OS emulation layer (types, console, memory, LEB128)
├── wasm/ # WASM Virtual Machine
│ ├── parser/ # WASM binary parser
│ │ └── sections/ # Section-specific parsers (type, function, export,
│ │ # code, global, memory, start, data, etc.)
│ ├── types/ # WASM type system, stack, and linear memory (heap)
│ ├── vm/ # VM tick loop and opcode jump table
│ └── test/ # Test suite
│ ├── infra/ # Stack, heap, LEB128 tests
│ ├── opcodes/ # Per-opcode test units
│ └── parsers/ # Per-section parser tests
└── project/ # Lazarus project files
Key components
- VM (
wasm.vm) — Tick-based execution loop dispatching opcodes through a 256-entry jump table. - Parser (
wasm.parser) — Validates the WASM magic/version header, then routes each binary section to its handler. - Stack (
wasm.types.stack) — Operand and control stacks supporting i32, i64, f32, f64 push/pop. - Heap (
wasm.types.heap) — Paged linear memory with read/write at 8/16/32/64-bit widths. - Emulation layer (
src/emu/) — Provides the sametypes,console,lmemorymanager, andleb128interfaces that exist in the real Asuro kernel, allowing development and testing on a host OS.
Implemented opcodes
| Category | Opcodes |
|---|---|
| Control | nop, unreachable, drop, select, return |
| Variables | local.get/set/tee, global.get/set |
| Constants | i32.const, i64.const, f32.const, f64.const |
| i32 Arithmetic | add, sub, mul, div_s/u, rem_s/u, clz, ctz, popcnt |
| i32 Bitwise | and, or, xor, shl, shr_s/u, rotl, rotr |
| i32 Comparison | eqz, eq, ne, lt_s/u, gt_s/u, le_s/u, ge_s/u |
| i64 Arithmetic | add, sub, mul, div_s/u, rem_s/u, clz, ctz, popcnt |
| i64 Bitwise | and, or, xor, shl, shr_s/u, rotl, rotr |
| i64 Comparison | eqz, eq, ne, lt_s/u, gt_s/u, le_s/u, ge_s/u |
| f32/f64 Comparison | eq, ne, lt, gt, le, ge |
| Memory Loads | i32/i64/f32/f64.load, sign/zero-extending variants (8/16/32-bit) |
| Memory Stores | i32/i64/f32/f64.store, narrowing variants (8/16/32-bit) |
| Memory Mgmt | memory.size, memory.grow |
Parsed sections
Type, Function, Export, Code, Global, Memory, Start, Data, Import (stub), Table (stub), Element (stub), Custom (stub).
Constraints
- Standard Pascal only — no runtime library, no classes.
- Kernel-compatible — all arithmetic (including
shr_s) uses manual implementations, no RTL intrinsics. - Emulation layer —
src/emu/mirrors the real Asuro kernel API; only these interfaces are available.
Requirements
- Free Pascal Compiler 3.2.2+ (x86_64-win64)
- Windows (build script is a
.batfile)
Building
# Normal build
build.bat
# Build with test suite
build.bat test
Output: bin\WASURO.exe
Testing
build.bat test
bin\WASURO.exe
Runs 374 tests across 108 test units. Exit code equals the number of failed tests (0 on success), making it CI/CD-friendly.
License
See repository for license details.