luaur-code-gen 0.1.1

Native (A64/X64) code generation for Luau (Rust).
Documentation 
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use crate::enums::address_kind_a_64::AddressKindA64;
use crate::enums::kind_a_64::KindA64;
use crate::functions::emit_exit_code_gen_a_64::emit_exit_assembly_builder_a_64_bool;
use crate::functions::emit_update_base_emit_common_a_64::emit_update_base;
use crate::records::address_a_64::AddressA64;
use crate::records::assembly_builder_a_64::AssemblyBuilderA64;
use crate::records::label::Label;
use crate::records::register_a_64::RegisterA64;
use luaur_vm::records::call_info::CallInfo;
use luaur_vm::records::global_state::global_State;
use luaur_vm::records::lua_callbacks::LuaCallbacks;
use luaur_vm::records::lua_state::lua_State;

const fn reg(kind: KindA64, index: u8) -> RegisterA64 {
    RegisterA64 {
        bits: kind as u8 | (index << 3),
    }
}

const X0: RegisterA64 = reg(KindA64::x, 0);
const X1: RegisterA64 = reg(KindA64::x, 1);
const X2: RegisterA64 = reg(KindA64::x, 2);
const W0: RegisterA64 = reg(KindA64::w, 0);
const W1: RegisterA64 = reg(KindA64::w, 1);
const R_STATE: RegisterA64 = reg(KindA64::x, 19);
const R_BASE: RegisterA64 = reg(KindA64::x, 22);
const R_CODE: RegisterA64 = reg(KindA64::x, 24);

const SIZEOF_INSTRUCTION: u16 = 4;

fn mem(base: RegisterA64, data: i32) -> AddressA64 {
    AddressA64 {
        kind: AddressKindA64::imm,
        base,
        offset: RegisterA64::noreg,
        data,
    }
}

pub fn emit_interrupt(build: &mut AssemblyBuilderA64) {
    let mut skip = Label::default();

    build.mov_register_a_64_register_a_64(R_BASE, X1);

    build.ldr(
        X2,
        mem(R_STATE, core::mem::offset_of!(lua_State, global) as i32),
    );
    build.ldr(
        X2,
        mem(
            X2,
            (core::mem::offset_of!(global_State, cb)
                + core::mem::offset_of!(LuaCallbacks, interrupt)) as i32,
        ),
    );
    build.cbz(X2, &mut skip);

    build.add_register_a_64_register_a_64_register_a_64_i32(X0, R_CODE, X0, 0);
    build.ldr(
        X1,
        mem(R_STATE, core::mem::offset_of!(lua_State, ci) as i32),
    );
    build.str(X0, mem(X1, core::mem::offset_of!(CallInfo, savedpc) as i32));

    build.mov_register_a_64_register_a_64(X0, R_STATE);
    build.mov_register_a_64_i32(W1, -1);
    build.blr(X2);

    build.ldrb(
        W0,
        mem(R_STATE, core::mem::offset_of!(lua_State, status) as i32),
    );
    build.cbz(W0, &mut skip);

    build.ldr(
        X1,
        mem(R_STATE, core::mem::offset_of!(lua_State, ci) as i32),
    );
    build.ldr(X0, mem(X1, core::mem::offset_of!(CallInfo, savedpc) as i32));
    build.sub_register_a_64_register_a_64_u16(X0, X0, SIZEOF_INSTRUCTION);
    build.str(X0, mem(X1, core::mem::offset_of!(CallInfo, savedpc) as i32));

    emit_exit_assembly_builder_a_64_bool(build, false);

    build.set_label_label(&mut skip);

    build.mov_register_a_64_register_a_64(X0, R_BASE);
    emit_update_base(build);
    build.br(X0);
}