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instruction_encoding_examples.md

This file lists six ProXPL snippet examples and their emitted bytecode (hex) with annotated assembly.

  1. Hello World (print string) Source (pseudo-ProXPL):
  • print("Hello, World!")

Constants: 0: "Hello, World!" 1: "print" (native function reference name for test)

Bytecode (assembly): 0000: PUSH_CONST 0 0002: CALL AM_CONST const_idx=1 argc=1 0006: HALT

Hex bytes: 30 00 50 01 01 01 ff Explanation:

  • 0x30 (PUSH_CONST) + 0x00 (uleb128 const idx 0)
  • 0x50 (CALL), 0x01 (AM_CONST), 0x01 (uleb128 const idx 1), 0x01 (argc)
  • 0xFF HALT
  1. Simple Arithmetic Source:
  • a = 2 + 3 * 4

Compiled to registers:

  • consts: 0 -> 2, 1 -> 3, 2 -> 4 Assembly: 0000: PUSH_CONST 0 0002: PUSH_CONST 1 0004: PUSH_CONST 2 0006: CALL AM_CONST const_idx=... (for multiply) ; in simple compiled register model we'd use regs; example simplified: 0008: HALT

Hex (example compact): 30 00 30 01 30 02 FF

  1. Function Call (user function) Source: func add(x, y) { return x + y; } z = add(10, 20)

Example compiled:

  • function proto constant at const idx 2 Constants: 0: 10 1: 20 2:

Assembly: 0000: PUSH_CONST 0 0002: PUSH_CONST 1 0004: PUSH_CONST 2 0006: CALL AM_STACK idx=0 argc=2 000A: HALT

Hex (example): 30 00 30 01 30 02 50 03 02 ff Note: 0x03 used to denote AM_STACK here as an example, followed by stack index (0) encoded as uleb128, then argc 2.

  1. Loop (sum 1..N) Source: sum = 0 i = 1 while (i <= N) { sum = sum + i; i = i + 1; }

Assembly sketch: 0000: PUSH_CONST sum_init (0) 0002: STORE_REG r0 0004: PUSH_CONST i_init (1) 0006: STORE_REG r1 0008: JMP to_cond 0010: loop_body: 0010: LOAD_REG r2, r0 0012: LOAD_REG r3, r1 0014: ADD r2, r2, r3 0017: STORE_REG r0, r2 0020: LOAD_REG r3, r1 0022: PUSH_CONST 1 0024: ADD r3, r3, rX 0027: STORE_REG r1, r3 002A: to_cond: 002A: LOAD_REG r3, r1 002C: PUSH_CONST N 002E: LTE r3, r3, rConstN 0031: JMP_IF_TRUE offset_to_loop_body 0035: HALT

This shows use of reg operations and conditional jump (sleb128 offset).

  1. Conditional (if) Source: if (x > 0) { print("positive"); } else { print("non-positive"); }

Constants: 0: "positive" 1: "non-positive"

Assembly: 0000: LOAD_REG r0, r_x 0002: PUSH_CONST 0 0004: GT r1, r0, rConst0 0007: JMP_IF_FALSE offset_else 0009: PUSH_CONST 0 000B: CALL AM_CONST const_idx=print argc=1 000F: JMP offset_end 0011: else_label: 0011: PUSH_CONST 1 0013: CALL AM_CONST const_idx=print argc=1 0017: end: 0017: HALT

  1. Closure / Capture Source: func makeAdder(a) { return func(b) { return a + b; } } add5 = makeAdder(5) result = add5(10)

Example function proto layout:

  • Outer function proto contains inner function as a constant (function proto)
  • CLOSURE const_idx(inner_proto), upvalue_count=1, upvalue descriptors: (is_local=1, index_of_a)

Assembly (simplified): 0000: PUSH_CONST const_inner_proto 0002: CLOSURE const_idx=1 upvalue_count=1 [is_local=1, index=0] 0006: STORE_REG r0 ; store created closure 0008: PUSH_CONST 5 000A: CALL AM_REG reg=0 argc=1 000D: HALT

Notes

  • The hex sequences above are illustrative; actual emitted bytes will vary depending on exact LEB128 encodings and chosen addressing mode encodings.
  • Use the provided disassembler disasm.c to decode real binary chunks into readable assembly.