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 "Symbols.h"
19#include "Target.h"
20#include "llvm/BinaryFormat/ELF.h"
21#include "llvm/Support/Endian.h"
22
23using namespace llvm;
24using namespace llvm::object;
25using namespace llvm::support::endian;
26using namespace llvm::ELF;
27using namespace lld;
28using namespace lld::elf;
29
30namespace {
31class MSP430 final : public TargetInfo {
32public:
33 MSP430(Ctx &);
34 RelExpr getRelExpr(RelType type, const Symbol &s,
35 const uint8_t *loc) const override;
36 void relocate(uint8_t *loc, const Relocation &rel,
37 uint64_t val) const override;
38};
39} // namespace
40
41MSP430::MSP430(Ctx &ctx) : TargetInfo(ctx) {
42 // mov.b #0, r3
43 trapInstr = {0x43, 0x43, 0x43, 0x43};
44}
45
46RelExpr MSP430::getRelExpr(RelType type, const Symbol &s,
47 const uint8_t *loc) const {
48 switch (type) {
49 case R_MSP430_10_PCREL:
50 case R_MSP430_16_PCREL:
51 case R_MSP430_16_PCREL_BYTE:
52 case R_MSP430_2X_PCREL:
53 case R_MSP430_RL_PCREL:
54 case R_MSP430_SYM_DIFF:
55 return R_PC;
56 default:
57 return R_ABS;
58 }
59}
60
61void MSP430::relocate(uint8_t *loc, const Relocation &rel, uint64_t val) const {
62 switch (rel.type) {
63 case R_MSP430_8:
64 checkIntUInt(ctx, loc, v: val, n: 8, rel);
65 *loc = val;
66 break;
67 case R_MSP430_16:
68 case R_MSP430_16_PCREL:
69 case R_MSP430_16_BYTE:
70 case R_MSP430_16_PCREL_BYTE:
71 checkIntUInt(ctx, loc, v: val, n: 16, rel);
72 write16le(P: loc, V: val);
73 break;
74 case R_MSP430_32:
75 checkIntUInt(ctx, loc, v: val, n: 32, rel);
76 write32le(P: loc, V: val);
77 break;
78 case R_MSP430_10_PCREL: {
79 int16_t offset = ((int16_t)val >> 1) - 1;
80 checkInt(ctx, loc, v: offset, n: 10, rel);
81 write16le(P: loc, V: (read16le(P: loc) & 0xFC00) | (offset & 0x3FF));
82 break;
83 }
84 default:
85 Err(ctx) << getErrorLoc(ctx, loc) << "unrecognized relocation " << rel.type;
86 }
87}
88
89void elf::setMSP430TargetInfo(Ctx &ctx) { ctx.target.reset(p: new MSP430(ctx)); }
90