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//===----------------------------------------------------------------------===//
10
11//===----------------------------------------------------------------------===//
12// AVR Return Value Calling Convention
13//===----------------------------------------------------------------------===//
14
15def RetCC_AVR : CallingConv
16<[
17  // i8 is returned in R24.
18  CCIfType<[i8], CCAssignToReg<[R24]>>,
19
20  // i16 are returned in R25:R24, R23:R22, R21:R20 and R19:R18.
21  CCIfType<[i16], CCAssignToReg<[R25R24, R23R22, R21R20, R19R18]>>
22]>;
23
24// Special return value calling convention for runtime functions.
25def RetCC_AVR_BUILTIN : CallingConv
26<[
27  CCIfType<[i8], CCAssignToReg<[R24,R25]>>,
28  CCIfType<[i16], CCAssignToReg<[R23R22, R25R24]>>
29]>;
30
31//===----------------------------------------------------------------------===//
32// AVR Argument Calling Conventions
33//===----------------------------------------------------------------------===//
34
35// The calling conventions are implemented in custom C++ code
36
37// Calling convention for variadic functions.
38def ArgCC_AVR_Vararg : CallingConv
39<[
40  // i16 are always passed through the stack with an alignment of 1.
41  CCAssignToStack<2, 1>
42]>;
43
44// Special argument calling convention for
45// division runtime functions.
46def ArgCC_AVR_BUILTIN_DIV : CallingConv
47<[
48  CCIfType<[i8], CCAssignToReg<[R24,R22]>>,
49  CCIfType<[i16], CCAssignToReg<[R25R24, R23R22]>>
50]>;
51
52//===----------------------------------------------------------------------===//
53// Callee-saved register lists.
54//===----------------------------------------------------------------------===//
55
56def CSR_Normal : CalleeSavedRegs<(add R29, R28, (sequence "R%u", 17, 2))>;
57def CSR_Interrupts : CalleeSavedRegs<(add (sequence "R%u", 31, 0))>;
58