Files
Odin/core/rexcode/isa/ppc/reloc.odin
Brendan Punsky 95df04fbe1 rexcode: re-house ISA packages under core:rexcode/isa/<arch>
Move all ten ISA packages (x86, arm32, arm64, mips, riscv, ppc, ppc_vle,
rsp, mos6502, mos65816) from core/rexcode/<arch> to core/rexcode/isa/<arch>,
so the import pattern is now `import "core:rexcode/isa/x86"`. The shared
core stays at core:rexcode/isa.

Mechanical: relative `import "../isa"` / "../../isa" -> absolute
"core:rexcode/isa" (the only path that survives the move; the "../" and
"../.." self/generated imports move with their packages). build.lua now
builds paths as <root>/isa/<name>; stale `cd <arch>` hints in the verify
tools and the doc.odin paths updated.

WASM stays at core/rexcode/wasm for now -- it is an IR, not an ISA, and
will move under the forthcoming core:rexcode/ir once that layer lands.

All 10 arches gen/builders/check/test green; import core:rexcode/isa/x86
verified working; wasm still compiles.
2026-06-18 19:03:27 -04:00

37 lines
1.3 KiB
Odin

// rexcode · Brendan Punsky (dotbmp@github), original author
package rexcode_ppc
// =============================================================================
// PowerPC RELOCATIONS
// =============================================================================
//
// PowerPC has two PC-relative branch forms in the base ISA:
//
// * I-form b/bl/ba/bla: 24-bit signed << 2 (±32MB)
// * B-form bc/bca/bcl/bcla: 14-bit signed << 2 (±32KB) with BO/BI fixed
//
// Power ISA 3.1 prefixed PC-relative loads/stores extend the displacement
// to 34 bits via the prefix word's R=1 form, but those are normally encoded
// via the prefixed-immediate path, not via relocations.
//
// PC for PowerPC is the address of the current instruction (not pc+8 like
// ARM). The resolver subtracts the current offset.
Relocation_Type :: enum u8 {
NONE = 0,
BRANCH_I_24, // I-form: LI (24-bit signed << 2 at bits 2..25 LSB)
BRANCH_B_14, // B-form: BD (14-bit signed << 2 at bits 2..15 LSB)
PREFIXED_34, // Power ISA 3.1: 34-bit signed at IMM18(prefix)||D(suffix)
}
Relocation :: struct #packed {
offset: u32, // byte offset into code buffer
label_id: u32,
addend: i32,
type: Relocation_Type,
size: u8, // 4 (base) or 8 (prefixed)
inst_idx: u16,
}
#assert(size_of(Relocation) == 16)