Files
Odin/core/rexcode/mos6502/instructions.odin
Flāvius a4f08f8307 Load rexcode encode/decode tables from committed binary blobs
Each ISA's hand-written ENCODING_TABLE (the single source of truth) now lives
in a per-arch tablegen/ metaprogram that flattens it and serializes committed
binary blobs; the library #loads those into @(rodata) at compile time rather
than compiling a table body. No arch keeps encoding_table.odin or
decoding_tables.odin -- only a generated tables.odin loader and tables/*.bin.

* Two-stage, type-checked pipeline: tablegen Stage A emits human-readable
  generated Odin, which compiles and serializes the blobs in Stage B.
* encode() goes through encoding_forms(m); decoders are unchanged apart from
  x86's flattened 2-D index. Decode tables are byte-identical to the old ones.
* build.lua: a LuaJIT driver for the metaprograms, validations, and tests,
  with cross-platform gating and a clear report.
* Docs refreshed; the obsolete forward-looking plan in cross_arch_design.md
  trimmed to what was actually built.
* Attribution headers added to all rexcode source files; the generators emit
  them so generated files keep them.
2026-06-15 07:43:29 -04:00

99 lines
3.3 KiB
Odin

// rexcode · Brendan Punsky (dotbmp@github), original author
package rexcode_mos6502
// =============================================================================
// INSTRUCTION
// =============================================================================
//
// Up to 3 operands per instruction (only the HuC6280 block-transfer ops
// actually use all three; the rest top out at two).
Instruction_Flags :: bit_field u8 {
_: u8 | 8,
}
Instruction :: struct #packed {
ops: [3]Operand `fmt:"v,operand_count"`, // 48 bytes
mnemonic: Mnemonic, // 2
operand_count: u8, // 1
flags: Instruction_Flags, // 1
length: u8, // 1 (filled by decoder; 1..7)
_: [3]u8, // 3
}
#assert(size_of(Instruction) == 56)
// =============================================================================
// Builders (mirror the contract: shape spelled out, comma-separated)
// =============================================================================
@(require_results)
inst_none :: #force_inline proc "contextless" (m: Mnemonic) -> Instruction {
return Instruction{mnemonic = m, operand_count = 0, length = 1}
}
@(require_results)
inst_a :: #force_inline proc "contextless" (m: Mnemonic) -> Instruction {
// Explicit accumulator (e.g. `ROL A`). Encodes to 1 byte (opcode only)
// and counts as 1 operand for the matcher.
return Instruction{
mnemonic = m, operand_count = 1, length = 1,
ops = {op_reg(A), {}, {}},
}
}
@(require_results)
inst_i :: #force_inline proc "contextless" (m: Mnemonic, imm: i64) -> Instruction {
return Instruction{
mnemonic = m, operand_count = 1, length = 2,
ops = {op_imm8(imm), {}, {}},
}
}
@(require_results)
inst_m :: #force_inline proc "contextless" (m: Mnemonic, mm: Memory) -> Instruction {
return Instruction{
mnemonic = m, operand_count = 1, length = 0, // filled by encoder
ops = {op_mem(mm), {}, {}},
}
}
@(require_results)
inst_rel :: #force_inline proc "contextless" (m: Mnemonic, label_id: u32) -> Instruction {
return Instruction{
mnemonic = m, operand_count = 1, length = 2,
ops = {op_label(label_id, 1), {}, {}},
}
}
// BBR/BBS: zero-page byte + relative branch (3-byte encoding).
@(require_results)
inst_zp_rel :: #force_inline proc "contextless" (m: Mnemonic, zp: u8, label_id: u32) -> Instruction {
return Instruction{
mnemonic = m, operand_count = 2, length = 3,
ops = {op_zp(zp), op_label(label_id, 1), {}},
}
}
// HuC6280 TST # imm, addr (3 or 4 bytes depending on addressing mode).
@(require_results)
inst_tst :: #force_inline proc "contextless" (m: Mnemonic, imm: i64, mm: Memory) -> Instruction {
return Instruction{
mnemonic = m, operand_count = 2, length = 0,
ops = {op_imm8(imm), op_mem(mm), {}},
}
}
// HuC6280 block transfer: src, dst, length (7-byte encoding).
@(require_results)
inst_block :: #force_inline proc "contextless" (m: Mnemonic, src, dst, length_val: u16) -> Instruction {
return Instruction{
mnemonic = m, operand_count = 3, length = 7,
ops = {
Operand{immediate = i64(src), kind = .IMMEDIATE, size = 2},
Operand{immediate = i64(dst), kind = .IMMEDIATE, size = 2},
Operand{immediate = i64(length_val), kind = .IMMEDIATE, size = 2},
},
}
}