1//===-- AVRInstPrinter.cpp - Convert AVR MCInst to assembly syntax --------===//
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// This class prints an AVR MCInst to a .s file.
10//
11//===----------------------------------------------------------------------===//
12
13#include "AVRInstPrinter.h"
14
15#include "MCTargetDesc/AVRMCTargetDesc.h"
16
17#include "llvm/MC/MCExpr.h"
18#include "llvm/MC/MCInst.h"
19#include "llvm/MC/MCInstrDesc.h"
20#include "llvm/MC/MCInstrInfo.h"
21#include "llvm/MC/MCRegisterInfo.h"
22#include "llvm/Support/ErrorHandling.h"
23#include "llvm/Support/FormattedStream.h"
24
25#include <cstring>
26
27#define DEBUG_TYPE "asm-printer"
28
29namespace llvm {
30
31// Include the auto-generated portion of the assembly writer.
32#define PRINT_ALIAS_INSTR
33#include "AVRGenAsmWriter.inc"
34
35void AVRInstPrinter::printInst(const MCInst *MI, uint64_t Address,
36                               StringRef Annot, const MCSubtargetInfo &STI,
37                               raw_ostream &O) {
38  unsigned Opcode = MI->getOpcode();
39
40  // First handle load and store instructions with postinc or predec
41  // of the form "ld reg, X+".
42  // TODO: We should be able to rewrite this using TableGen data.
43  switch (Opcode) {
44  case AVR::LDRdPtr:
45  case AVR::LDRdPtrPi:
46  case AVR::LDRdPtrPd:
47    O << "\tld\t";
48    printOperand(MI, 0, O);
49    O << ", ";
50
51    if (Opcode == AVR::LDRdPtrPd)
52      O << '-';
53
54    printOperand(MI, 1, O);
55
56    if (Opcode == AVR::LDRdPtrPi)
57      O << '+';
58    break;
59  case AVR::STPtrRr:
60    O << "\tst\t";
61    printOperand(MI, 0, O);
62    O << ", ";
63    printOperand(MI, 1, O);
64    break;
65  case AVR::STPtrPiRr:
66  case AVR::STPtrPdRr:
67    O << "\tst\t";
68
69    if (Opcode == AVR::STPtrPdRr)
70      O << '-';
71
72    printOperand(MI, 1, O);
73
74    if (Opcode == AVR::STPtrPiRr)
75      O << '+';
76
77    O << ", ";
78    printOperand(MI, 2, O);
79    break;
80  default:
81    if (!printAliasInstr(MI, O))
82      printInstruction(MI, Address, O);
83
84    printAnnotation(O, Annot);
85    break;
86  }
87}
88
89const char *AVRInstPrinter::getPrettyRegisterName(unsigned RegNum,
90                                                  MCRegisterInfo const &MRI) {
91  // GCC prints register pairs by just printing the lower register
92  // If the register contains a subregister, print it instead
93  if (MRI.getNumSubRegIndices() > 0) {
94    unsigned RegLoNum = MRI.getSubReg(RegNum, AVR::sub_lo);
95    RegNum = (RegLoNum != AVR::NoRegister) ? RegLoNum : RegNum;
96  }
97
98  return getRegisterName(RegNum);
99}
100
101void AVRInstPrinter::printOperand(const MCInst *MI, unsigned OpNo,
102                                  raw_ostream &O) {
103  const MCOperand &Op = MI->getOperand(OpNo);
104  const MCOperandInfo &MOI = this->MII.get(MI->getOpcode()).OpInfo[OpNo];
105
106  if (Op.isReg()) {
107    bool isPtrReg = (MOI.RegClass == AVR::PTRREGSRegClassID) ||
108                    (MOI.RegClass == AVR::PTRDISPREGSRegClassID) ||
109                    (MOI.RegClass == AVR::ZREGRegClassID);
110
111    if (isPtrReg) {
112      O << getRegisterName(Op.getReg(), AVR::ptr);
113    } else {
114      O << getPrettyRegisterName(Op.getReg(), MRI);
115    }
116  } else if (Op.isImm()) {
117    O << Op.getImm();
118  } else {
119    assert(Op.isExpr() && "Unknown operand kind in printOperand");
120    O << *Op.getExpr();
121  }
122}
123
124/// This is used to print an immediate value that ends up
125/// being encoded as a pc-relative value.
126void AVRInstPrinter::printPCRelImm(const MCInst *MI, unsigned OpNo,
127                                   raw_ostream &O) {
128  const MCOperand &Op = MI->getOperand(OpNo);
129
130  if (Op.isImm()) {
131    int64_t Imm = Op.getImm();
132    O << '.';
133
134    // Print a position sign if needed.
135    // Negative values have their sign printed automatically.
136    if (Imm >= 0)
137      O << '+';
138
139    O << Imm;
140  } else {
141    assert(Op.isExpr() && "Unknown pcrel immediate operand");
142    O << *Op.getExpr();
143  }
144}
145
146void AVRInstPrinter::printMemri(const MCInst *MI, unsigned OpNo,
147                                raw_ostream &O) {
148  assert(MI->getOperand(OpNo).isReg() && "Expected a register for the first operand");
149
150  const MCOperand &OffsetOp = MI->getOperand(OpNo + 1);
151
152  // Print the register.
153  printOperand(MI, OpNo, O);
154
155  // Print the {+,-}offset.
156  if (OffsetOp.isImm()) {
157    int64_t Offset = OffsetOp.getImm();
158
159    if (Offset >= 0)
160      O << '+';
161
162    O << Offset;
163  } else if (OffsetOp.isExpr()) {
164    O << *OffsetOp.getExpr();
165  } else {
166    llvm_unreachable("unknown type for offset");
167  }
168}
169
170} // end of namespace llvm
171
172