1//===- MSP430.cpp ---------------------------------------------------------===//
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//
9// The MSP430 is a 16-bit microcontroller RISC architecture. The instruction set
10// has only 27 core instructions orthogonally augmented with a variety
11// of addressing modes for source and destination operands. Entire address space
12// of MSP430 is 64KB (the extended MSP430X architecture is not considered here).
13// A typical MSP430 MCU has several kilobytes of RAM and ROM, plenty
14// of peripherals and is generally optimized for a low power consumption.
15//
16//===----------------------------------------------------------------------===//
17
18#include "InputFiles.h"
19#include "Symbols.h"
20#include "Target.h"
21#include "lld/Common/ErrorHandler.h"
22#include "llvm/Object/ELF.h"
23#include "llvm/Support/Endian.h"
24
25using namespace llvm;
26using namespace llvm::object;
27using namespace llvm::support::endian;
28using namespace llvm::ELF;
29using namespace lld;
30using namespace lld::elf;
31
32namespace {
33class MSP430 final : public TargetInfo {
34public:
35  MSP430();
36  RelExpr getRelExpr(RelType type, const Symbol &s,
37                     const uint8_t *loc) const override;
38  void relocate(uint8_t *loc, const Relocation &rel,
39                uint64_t val) const override;
40};
41} // namespace
42
43MSP430::MSP430() {
44  // mov.b #0, r3
45  trapInstr = {0x43, 0x43, 0x43, 0x43};
46}
47
48RelExpr MSP430::getRelExpr(RelType type, const Symbol &s,
49                           const uint8_t *loc) const {
50  switch (type) {
51  case R_MSP430_10_PCREL:
52  case R_MSP430_16_PCREL:
53  case R_MSP430_16_PCREL_BYTE:
54  case R_MSP430_2X_PCREL:
55  case R_MSP430_RL_PCREL:
56  case R_MSP430_SYM_DIFF:
57    return R_PC;
58  default:
59    return R_ABS;
60  }
61}
62
63void MSP430::relocate(uint8_t *loc, const Relocation &rel, uint64_t val) const {
64  switch (rel.type) {
65  case R_MSP430_8:
66    checkIntUInt(loc, val, 8, rel);
67    *loc = val;
68    break;
69  case R_MSP430_16:
70  case R_MSP430_16_PCREL:
71  case R_MSP430_16_BYTE:
72  case R_MSP430_16_PCREL_BYTE:
73    checkIntUInt(loc, val, 16, rel);
74    write16le(loc, val);
75    break;
76  case R_MSP430_32:
77    checkIntUInt(loc, val, 32, rel);
78    write32le(loc, val);
79    break;
80  case R_MSP430_10_PCREL: {
81    int16_t offset = ((int16_t)val >> 1) - 1;
82    checkInt(loc, offset, 10, rel);
83    write16le(loc, (read16le(loc) & 0xFC00) | (offset & 0x3FF));
84    break;
85  }
86  default:
87    error(getErrorLocation(loc) + "unrecognized relocation " +
88          toString(rel.type));
89  }
90}
91
92TargetInfo *elf::getMSP430TargetInfo() {
93  static MSP430 target;
94  return ⌖
95}
96