aver/vm/
opcode.rs

1// Aver VM bytecode opcodes.
2//
3// Stack-based: operands are pushed/popped from the operand stack.
4// Variable-width encoding: opcode (1 byte) + operands (0-3 bytes).
5
6// -- Stack / locals ----------------------------------------------------------
7
8/// No-op, used as padding after superinstruction fusion.
9pub const NOP: u8 = 0x00;
10
11/// Push `stack[bp + slot]` onto the operand stack.
12pub const LOAD_LOCAL: u8 = 0x01; // slot:u8
13
14/// Pop top and store into `stack[bp + slot]`.
15pub const STORE_LOCAL: u8 = 0x02; // slot:u8
16
17/// Push `constants[idx]` onto the operand stack.
18pub const LOAD_CONST: u8 = 0x03; // idx:u16
19
20/// Push `globals[idx]` onto the operand stack.
21pub const LOAD_GLOBAL: u8 = 0x04; // idx:u16
22
23/// Pop top and store into `globals[idx]`.
24pub const STORE_GLOBAL: u8 = 0x0A; // idx:u16
25
26/// Discard the top value.
27pub const POP: u8 = 0x05;
28
29/// Duplicate the top value.
30pub const DUP: u8 = 0x06;
31
32/// Push `NanValue::UNIT`.
33pub const LOAD_UNIT: u8 = 0x07;
34
35/// Push `NanValue::TRUE`.
36pub const LOAD_TRUE: u8 = 0x08;
37
38/// Push `NanValue::FALSE`.
39pub const LOAD_FALSE: u8 = 0x09;
40
41// -- Arithmetic --------------------------------------------------------------
42
43/// Pop b, pop a, push a + b.
44pub const ADD: u8 = 0x10;
45
46/// Pop b, pop a, push a - b.
47pub const SUB: u8 = 0x11;
48
49/// Pop b, pop a, push a * b.
50pub const MUL: u8 = 0x12;
51
52/// Pop b, pop a, push a / b.
53pub const DIV: u8 = 0x13;
54
55/// Pop b, pop a, push a % b.
56pub const MOD: u8 = 0x14;
57
58/// Pop a, push -a.
59pub const NEG: u8 = 0x15;
60
61/// Pop a, push !a (boolean not).
62pub const NOT: u8 = 0x16;
63
64// -- Comparison --------------------------------------------------------------
65
66/// Pop b, pop a, push a == b.
67pub const EQ: u8 = 0x20;
68
69/// Pop b, pop a, push a < b.
70pub const LT: u8 = 0x21;
71
72/// Pop b, pop a, push a > b.
73pub const GT: u8 = 0x22;
74
75// -- String ------------------------------------------------------------------
76
77/// Pop b, pop a, push str(a) ++ str(b).
78pub const CONCAT: u8 = 0x28;
79
80// -- Control flow ------------------------------------------------------------
81
82/// Unconditional relative jump: ip += offset.
83pub const JUMP: u8 = 0x30; // offset:i16
84
85/// Pop top, if falsy: ip += offset.
86pub const JUMP_IF_FALSE: u8 = 0x31; // offset:i16
87
88// -- Calls -------------------------------------------------------------------
89
90/// Call a known function by id. Args already on stack.
91pub const CALL_KNOWN: u8 = 0x40; // fn_id:u16, argc:u8
92
93/// Call a function value on the stack (under args).
94pub const CALL_VALUE: u8 = 0x41; // argc:u8
95
96/// Call a builtin service function.
97pub const CALL_BUILTIN: u8 = 0x42; // symbol_id:u32, argc:u8
98
99/// Self tail-call: reuse current frame with new args.
100pub const TAIL_CALL_SELF: u8 = 0x43; // argc:u8
101
102/// Mutual tail-call to a known function: reuse frame, switch target.
103pub const TAIL_CALL_KNOWN: u8 = 0x44; // fn_id:u16, argc:u8
104
105/// Return top of stack to caller.
106pub const RETURN: u8 = 0x50;
107
108// -- Structured values -------------------------------------------------------
109
110/// Push Nil (empty cons list).
111pub const LIST_NIL: u8 = 0x60;
112
113/// Pop tail, pop head, push Cons(head, tail).
114pub const LIST_CONS: u8 = 0x61;
115
116/// Pop `count` items, build cons list from them (first item = head), push list.
117pub const LIST_NEW: u8 = 0x62; // count:u8
118
119/// Pop `count` field values, push a new record with `type_id`.
120pub const RECORD_NEW: u8 = 0x63; // type_id:u16, count:u8
121
122/// Pop record, push `fields[field_idx]` (compile-time resolved index).
123pub const RECORD_GET: u8 = 0x64; // field_idx:u8
124
125/// Pop record, lookup field by interned field symbol, push value.
126pub const RECORD_GET_NAMED: u8 = 0x67; // field_symbol_id:u32
127
128/// Pop `count` field values, push a new variant.
129pub const VARIANT_NEW: u8 = 0x65; // type_id:u16, variant_id:u16, count:u8
130
131/// Pop value, push wrapped value. kind: 0=Ok, 1=Err, 2=Some.
132pub const WRAP: u8 = 0x66; // kind:u8
133
134/// Pop `count` items, build a tuple from them, push tuple.
135pub const TUPLE_NEW: u8 = 0x68; // count:u8
136
137/// Update selected fields on a record, preserving the rest from the base value.
138/// Stack: [..., base_record, update_0, ..., update_n-1] -> [..., updated_record]
139pub const RECORD_UPDATE: u8 = 0x69; // type_id:u16, count:u8, field_idx[count]:u8
140
141/// Propagate `Result.Err` to caller or unwrap `Result.Ok` in place.
142pub const PROPAGATE_ERR: u8 = 0x6A;
143
144/// Pop list, push its length as Int.
145pub const LIST_LEN: u8 = 0x6B;
146
147// 0x6C and 0x6D were LIST_GET and LIST_APPEND — removed.
148
149/// Pop list, pop value, push prepended list.
150pub const LIST_PREPEND: u8 = 0x6E;
151
152// 0x6F was LIST_GET_MATCH — removed.
153
154// -- Pattern matching --------------------------------------------------------
155
156/// Peek top: if NaN tag != expected, ip += fail_offset.
157pub const MATCH_TAG: u8 = 0x70; // expected_tag:u8, fail_offset:i16
158
159/// Peek top (must be variant): if variant_id != expected, ip += fail_offset.
160pub const MATCH_VARIANT: u8 = 0x71; // ctor_id:u16, fail_offset:i16
161
162/// Peek top: if not wrapper of `kind`, ip += fail_offset.
163/// If matches, replace top with inner value (unwrap in-place).
164/// kind: 0=Ok, 1=Err, 2=Some.
165pub const MATCH_UNWRAP: u8 = 0x72; // kind:u8, fail_offset:i16
166
167/// Peek top: if not Nil, ip += fail_offset.
168pub const MATCH_NIL: u8 = 0x73; // fail_offset:i16
169
170/// Peek top: if Nil (not a cons), ip += fail_offset.
171pub const MATCH_CONS: u8 = 0x74; // fail_offset:i16
172
173/// Pop cons cell, push tail then push head.
174pub const LIST_HEAD_TAIL: u8 = 0x75;
175
176/// Peek top (record/variant), push `fields[field_idx]` (non-destructive).
177pub const EXTRACT_FIELD: u8 = 0x76; // field_idx:u8
178
179/// Peek top: if not a tuple of `count` items, ip += fail_offset.
180pub const MATCH_TUPLE: u8 = 0x78; // count:u8, fail_offset:i16
181
182/// Peek top tuple, push `items[item_idx]` (non-destructive).
183pub const EXTRACT_TUPLE_ITEM: u8 = 0x79; // item_idx:u8
184
185/// Non-exhaustive match error at source line.
186pub const MATCH_FAIL: u8 = 0x77; // line:u16
187
188/// Unified prefix/exact dispatch on NanValue bits.
189///
190/// Encoding:
191///   MATCH_DISPATCH count:u8 default_offset:i16
192///     [(kind:u8, expected:u64, offset:i16) × count]
193///
194/// kind=0: exact match  — `val.bits() == expected`
195/// kind=1: tag match    — `(val.bits() & TAG_MASK_FULL) == expected`
196///   where TAG_MASK_FULL = 0xFFFF_C000_0000_0000 (QNAN 14 bits + tag 4 bits)
197///
198/// Pops subject. Scans entries in order; first match wins → ip += offset.
199/// No match → ip += default_offset.
200/// All offsets are relative to the end of the full instruction.
201pub const MATCH_DISPATCH: u8 = 0x7A;
202
203/// Like MATCH_DISPATCH but every entry carries an inline result instead
204/// of a jump offset.  When an entry matches, the result is pushed directly
205/// onto the stack and the match body is skipped entirely.
206///
207/// Encoding:
208///   MATCH_DISPATCH_CONST count:u8 default_offset:i16
209///     [(kind:u8, expected:u64, result:u64) × count]
210///
211/// Hit → pop subject, push result NanValue.
212/// Miss → pop subject, ip += default_offset (execute default arm body).
213///
214/// Emitted when ALL dispatchable arms have constant bodies (literals).
215pub const MATCH_DISPATCH_CONST: u8 = 0x7B;
216
217/// Tail-call self for thin frames: no arena finalization needed.
218/// The compiler emits this instead of TAIL_CALL_SELF when the function
219/// is known to be "thin" (no heap allocations within the frame).
220/// Skips finalize_frame_locals_for_tail_call entirely — just copies
221/// args in-place and resets ip.
222pub const TAIL_CALL_SELF_THIN: u8 = 0x45; // argc:u8
223
224/// Inline Option.withDefault: pop default, pop option → push inner or default.
225/// Stack: [option, default] → [result]
226/// If option is Some → push unwrapped inner value.
227/// If option is None → push default.
228pub const UNWRAP_OR: u8 = 0x7C;
229
230/// Inline Result.withDefault: pop default, pop result → push inner or default.
231/// Stack: [result, default] → [value]
232/// If result is Ok → push unwrapped inner value.
233/// If result is Err → push default.
234pub const UNWRAP_RESULT_OR: u8 = 0x7D;
235
236/// Frameless call to a leaf+thin+args-only function.
237/// No CallFrame is pushed — just saves (fn_id, ip) in the dispatch loop,
238/// sets bp to the args already on stack, and jumps to the target.
239/// On RETURN, restores the caller's state directly.
240/// Format: fn_id:u16, argc:u8 (same as CALL_KNOWN).
241pub const CALL_LEAF: u8 = 0x7E;
242
243// ─── Superinstructions ──────────────────────────────────────
244
245/// Push two locals in one dispatch. Format: slot_a:u8, slot_b:u8.
246pub const LOAD_LOCAL_2: u8 = 0x80;
247
248/// Push one local + one constant in one dispatch. Format: slot:u8, const_idx:u16.
249pub const LOAD_LOCAL_CONST: u8 = 0x81;
250
251/// Inline Vector.get: pop index, pop vector → push Option (Some/None).
252/// Stack: [vector, index] → [option]
253pub const VECTOR_GET: u8 = 0x82;
254
255/// Fused Vector.get + Option.withDefault: pop default, pop index, pop vector → push value.
256/// Stack: [vector, index, default] → [value]
257/// Combines CALL_BUILTIN(Vector.get) + LOAD_CONST + UNWRAP_OR into one opcode.
258pub const VECTOR_GET_OR: u8 = 0x83;
259
260/// Inline Vector.set: pop value, pop index, pop vector → push Option<Vector>.
261/// Stack: [vector, index, value] → [option_vector]
262pub const VECTOR_SET: u8 = 0x84;
263
264/// Opcode name for debug/disassembly.
265pub fn opcode_name(op: u8) -> &'static str {
266    match op {
267        LOAD_LOCAL => "LOAD_LOCAL",
268        STORE_LOCAL => "STORE_LOCAL",
269        LOAD_CONST => "LOAD_CONST",
270        LOAD_GLOBAL => "LOAD_GLOBAL",
271        POP => "POP",
272        DUP => "DUP",
273        LOAD_UNIT => "LOAD_UNIT",
274        LOAD_TRUE => "LOAD_TRUE",
275        LOAD_FALSE => "LOAD_FALSE",
276        ADD => "ADD",
277        SUB => "SUB",
278        MUL => "MUL",
279        DIV => "DIV",
280        MOD => "MOD",
281        NEG => "NEG",
282        NOT => "NOT",
283        EQ => "EQ",
284        LT => "LT",
285        GT => "GT",
286        CONCAT => "CONCAT",
287        JUMP => "JUMP",
288        JUMP_IF_FALSE => "JUMP_IF_FALSE",
289        CALL_KNOWN => "CALL_KNOWN",
290        CALL_VALUE => "CALL_VALUE",
291        CALL_BUILTIN => "CALL_BUILTIN",
292        TAIL_CALL_SELF => "TAIL_CALL_SELF",
293        TAIL_CALL_KNOWN => "TAIL_CALL_KNOWN",
294        RETURN => "RETURN",
295        LIST_NIL => "LIST_NIL",
296        LIST_CONS => "LIST_CONS",
297        LIST_NEW => "LIST_NEW",
298        RECORD_NEW => "RECORD_NEW",
299        STORE_GLOBAL => "STORE_GLOBAL",
300        RECORD_GET => "RECORD_GET",
301        RECORD_GET_NAMED => "RECORD_GET_NAMED",
302        VARIANT_NEW => "VARIANT_NEW",
303        WRAP => "WRAP",
304        TUPLE_NEW => "TUPLE_NEW",
305        RECORD_UPDATE => "RECORD_UPDATE",
306        PROPAGATE_ERR => "PROPAGATE_ERR",
307        LIST_LEN => "LIST_LEN",
308        LIST_PREPEND => "LIST_PREPEND",
309        MATCH_TAG => "MATCH_TAG",
310        MATCH_VARIANT => "MATCH_VARIANT",
311        MATCH_UNWRAP => "MATCH_UNWRAP",
312        MATCH_NIL => "MATCH_NIL",
313        MATCH_CONS => "MATCH_CONS",
314        LIST_HEAD_TAIL => "LIST_HEAD_TAIL",
315        EXTRACT_FIELD => "EXTRACT_FIELD",
316        MATCH_TUPLE => "MATCH_TUPLE",
317        EXTRACT_TUPLE_ITEM => "EXTRACT_TUPLE_ITEM",
318        MATCH_FAIL => "MATCH_FAIL",
319        MATCH_DISPATCH => "MATCH_DISPATCH",
320        MATCH_DISPATCH_CONST => "MATCH_DISPATCH_CONST",
321        TAIL_CALL_SELF_THIN => "TAIL_CALL_SELF_THIN",
322        UNWRAP_OR => "UNWRAP_OR",
323        UNWRAP_RESULT_OR => "UNWRAP_RESULT_OR",
324        CALL_LEAF => "CALL_LEAF",
325        LOAD_LOCAL_2 => "LOAD_LOCAL_2",
326        LOAD_LOCAL_CONST => "LOAD_LOCAL_CONST",
327        VECTOR_GET => "VECTOR_GET",
328        VECTOR_GET_OR => "VECTOR_GET_OR",
329        VECTOR_SET => "VECTOR_SET",
330        NOP => "NOP",
331        _ => "UNKNOWN",
332    }
333}
334
335/// Operand byte width after the opcode byte. Single source of truth —
336/// all bytecode traversal functions must use this.
337pub fn opcode_operand_width(op: u8, code: &[u8], ip: usize) -> usize {
338    match op {
339        // 0-byte (stack-only)
340        POP | DUP | LOAD_UNIT | LOAD_TRUE | LOAD_FALSE | ADD | SUB | MUL | DIV | MOD | NEG
341        | NOT | EQ | LT | GT | RETURN | PROPAGATE_ERR | LIST_HEAD_TAIL | LIST_NIL | LIST_CONS
342        | LIST_LEN | LIST_PREPEND | UNWRAP_OR | UNWRAP_RESULT_OR | CONCAT | VECTOR_GET
343        | VECTOR_SET | NOP => 0,
344
345        // 1-byte
346        LOAD_LOCAL | STORE_LOCAL | CALL_VALUE | RECORD_GET | EXTRACT_FIELD | EXTRACT_TUPLE_ITEM
347        | LIST_NEW | WRAP | TUPLE_NEW | TAIL_CALL_SELF | TAIL_CALL_SELF_THIN => 1,
348
349        // 2-byte (u16)
350        LOAD_CONST | LOAD_GLOBAL | STORE_GLOBAL | JUMP | JUMP_IF_FALSE | MATCH_FAIL | MATCH_NIL
351        | MATCH_CONS | LOAD_LOCAL_2 | VECTOR_GET_OR => 2,
352
353        // 3-byte
354        CALL_KNOWN | CALL_LEAF | MATCH_TAG | MATCH_UNWRAP | MATCH_TUPLE | RECORD_NEW
355        | LOAD_LOCAL_CONST => 3,
356
357        // 4-byte
358        MATCH_VARIANT | RECORD_GET_NAMED => 4,
359
360        // 5-byte
361        CALL_BUILTIN | VARIANT_NEW => 5,
362
363        // Variable-length
364        MATCH_DISPATCH | MATCH_DISPATCH_CONST => {
365            if ip < code.len() {
366                let count = code[ip] as usize;
367                let entry_size = if op == MATCH_DISPATCH { 11 } else { 17 };
368                3 + count * entry_size
369            } else {
370                0
371            }
372        }
373        RECORD_UPDATE => {
374            if ip + 2 < code.len() {
375                3 + code[ip + 2] as usize
376            } else {
377                0
378            }
379        }
380        _ => 0,
381    }
382}
aver/vm/opcode.rs

aver/vm/
opcode.rs
