1//===-- AVRCallingConv.td - Calling Conventions for AVR ----*- tablegen -*-===//
2//
3// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
4// See https://llvm.org/LICENSE.txt for license information.
5// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
6//
7//===----------------------------------------------------------------------===//
8// This describes the calling conventions for AVR architecture.
9// Normal functions use a special calling convention, solved in code.
10//===----------------------------------------------------------------------===//
11
12//===----------------------------------------------------------------------===//
13// AVR Return Value Calling Convention
14//===----------------------------------------------------------------------===//
15
16// Special return value calling convention for runtime functions.
17def RetCC_AVR_BUILTIN : CallingConv<[
18  CCIfType<[i8], CCAssignToReg<[R24, R25]>>,
19  CCIfType<[i16], CCAssignToReg<[R23R22, R25R24]>>
20]>;
21
22//===----------------------------------------------------------------------===//
23// AVR Argument Calling Conventions
24//===----------------------------------------------------------------------===//
25
26// The calling conventions are implemented in custom C++ code
27
28// Calling convention for variadic functions.
29def ArgCC_AVR_Vararg : CallingConv<[
30  // i8 are always passed through the stack with a byte slot and byte alignment.
31  CCIfType<[i8], CCAssignToStack<1, 1>>,
32  // i16 are always passed through the stack with an alignment of 1.
33  CCAssignToStack<2, 1>
34]>;
35
36//===----------------------------------------------------------------------===//
37// Callee-saved register lists.
38//===----------------------------------------------------------------------===//
39
40def CSR_Normal : CalleeSavedRegs<(add R29, R28, (sequence "R%u", 17, 2))>;
41def CSR_NormalTiny : CalleeSavedRegs<(add R29, R28, R19, R18)>;
42def CSR_Interrupts : CalleeSavedRegs<(add(sequence "R%u", 31, 2))>;
43def CSR_InterruptsTiny : CalleeSavedRegs<(add(sequence "R%u", 31, 18))>;
44