MSP430.cpp
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//===- MSP430.cpp ---------------------------------------------------------===//
//
// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
// See https://llvm.org/LICENSE.txt for license information.
// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
//
//===----------------------------------------------------------------------===//
//
// The MSP430 is a 16-bit microcontroller RISC architecture. The instruction set
// has only 27 core instructions orthogonally augmented with a variety
// of addressing modes for source and destination operands. Entire address space
// of MSP430 is 64KB (the extended MSP430X architecture is not considered here).
// A typical MSP430 MCU has several kilobytes of RAM and ROM, plenty
// of peripherals and is generally optimized for a low power consumption.
//
//===----------------------------------------------------------------------===//
#include "InputFiles.h"
#include "Symbols.h"
#include "Target.h"
#include "lld/Common/ErrorHandler.h"
#include "llvm/Object/ELF.h"
#include "llvm/Support/Endian.h"
using namespace llvm;
using namespace llvm::object;
using namespace llvm::support::endian;
using namespace llvm::ELF;
using namespace lld;
using namespace lld::elf;
namespace {
class MSP430 final : public TargetInfo {
public:
MSP430();
RelExpr getRelExpr(RelType type, const Symbol &s,
const uint8_t *loc) const override;
void relocate(uint8_t *loc, const Relocation &rel,
uint64_t val) const override;
};
} // namespace
MSP430::MSP430() {
// mov.b #0, r3
trapInstr = {0x43, 0x43, 0x43, 0x43};
}
RelExpr MSP430::getRelExpr(RelType type, const Symbol &s,
const uint8_t *loc) const {
switch (type) {
case R_MSP430_10_PCREL:
case R_MSP430_16_PCREL:
case R_MSP430_16_PCREL_BYTE:
case R_MSP430_2X_PCREL:
case R_MSP430_RL_PCREL:
case R_MSP430_SYM_DIFF:
return R_PC;
default:
return R_ABS;
}
}
void MSP430::relocate(uint8_t *loc, const Relocation &rel, uint64_t val) const {
switch (rel.type) {
case R_MSP430_8:
checkIntUInt(loc, val, 8, rel);
*loc = val;
break;
case R_MSP430_16:
case R_MSP430_16_PCREL:
case R_MSP430_16_BYTE:
case R_MSP430_16_PCREL_BYTE:
checkIntUInt(loc, val, 16, rel);
write16le(loc, val);
break;
case R_MSP430_32:
checkIntUInt(loc, val, 32, rel);
write32le(loc, val);
break;
case R_MSP430_10_PCREL: {
int16_t offset = ((int16_t)val >> 1) - 1;
checkInt(loc, offset, 10, rel);
write16le(loc, (read16le(loc) & 0xFC00) | (offset & 0x3FF));
break;
}
default:
error(getErrorLocation(loc) + "unrecognized relocation " +
toString(rel.type));
}
}
TargetInfo *elf::getMSP430TargetInfo() {
static MSP430 target;
return ⌖
}