Files
Odin/core/rexcode/riscv/operands.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

75 lines
2.5 KiB
Odin

// rexcode · Brendan Punsky (dotbmp@github), original author
package rexcode_riscv
// =============================================================================
// RISC-V OPERANDS
// =============================================================================
//
// Same kind-tagged shape as the other arches. Memory is a single
// `(base GPR, signed 12-bit displacement)` pair -- RISC-V's only
// addressing mode is `disp12(base)`, with no index register, no scale,
// and no PC-relative form (PC-rel work is done by AUIPC + add/load pairs).
//
// RELATIVE operands cover both 13-bit branches (B-type) and 21-bit
// jumps (J-type); the encoding form's Operand_Encoding tells the
// encoder which scatter pattern to apply.
Operand_Kind :: enum u8 {
NONE,
REGISTER,
IMMEDIATE,
MEMORY,
RELATIVE,
}
Memory :: struct #packed {
base: Register, // GPR base
_: u16,
disp: i32, // sign-extended 12-bit displacement
}
#assert(size_of(Memory) == 8)
@(require_results)
mem :: #force_inline proc "contextless" (base: Register, disp: i32) -> Memory {
return Memory{base = base, disp = disp}
}
Operand :: struct #packed {
using _: struct #raw_union {
reg: Register, // REGISTER (int or FP)
mem: Memory,
immediate: i64,
relative: i64, // label id pre-resolution; byte offset post
},
kind: Operand_Kind,
size: u8,
_: [6]u8,
}
#assert(size_of(Operand) == 16)
@(require_results)
op_reg :: #force_inline proc "contextless" (r: Register) -> Operand { return Operand{reg = r, kind = .REGISTER, size = 4} }
@(require_results)
op_imm :: #force_inline proc "contextless" (v: i64, size: u8) -> Operand { return Operand{immediate = v, kind = .IMMEDIATE, size = size} }
@(require_results)
op_mem :: #force_inline proc "contextless" (m: Memory) -> Operand { return Operand{mem = m, kind = .MEMORY, size = 4} }
@(require_results)
op_label :: #force_inline proc "contextless" (label_id: u32, size: u8 = 2) -> Operand {
return Operand{relative = i64(label_id), kind = .RELATIVE, size = size}
}
@(require_results)
op_rel_offset :: #force_inline proc "contextless" (off: i64) -> Operand {
return Operand{relative = off, kind = .RELATIVE, size = 2}
}
// Typed constructors
@(require_results)
op_gpr :: #force_inline proc "contextless" (g: GPR) -> Operand {
return Operand{reg = Register(REG_GPR | u16(g)), kind = .REGISTER, size = 4}
}
@(require_results)
op_fpr :: #force_inline proc "contextless" (f: FPR) -> Operand {
return Operand{reg = Register(REG_FPR | u16(f)), kind = .REGISTER, size = 4}
}