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llvm-mirror/lib/Target/M68k/M68kInstrFormats.td
Ricky Taylor 51b479815c [M68k] Introduce DReg bead
This is required in order to determine during disassembly whether a
Reg bead without associated DA bead is referring to a data register.

Differential Revision: https://reviews.llvm.org/D98534
2021-03-19 11:44:53 +00:00

372 lines
16 KiB
TableGen

//=== M68kInstrFormats.td - M68k Instruction Formats ---*- tablegen -*-===//
// The LLVM Compiler Infrastructure
// 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
//===----------------------------------------------------------------------===//
///
/// \file
/// This file contains M68k instruction formats.
///
/// Since M68k has quite a lot memory addressing modes there are more
/// instruction prefixes than just i, r and m:
/// TSF Since Form Letter Description
/// 00 M68000 Dn or An r any register
/// 01 M68000 Dn d data register direct
/// 02 M68000 An a address register direct
/// 03 M68000 (An) j address register indirect
/// 04 M68000 (An)+ o address register indirect with postincrement
/// 05 M68000 -(An) e address register indirect with predecrement
/// 06 M68000 (i,An) p address register indirect with displacement
/// 10 M68000 (i,An,Xn.L) f address register indirect with index and scale = 1
/// 07 M68000 (i,An,Xn.W) F address register indirect with index and scale = 1
/// 12 M68020 (i,An,Xn.L,SCALE) g address register indirect with index
/// 11 M68020 (i,An,Xn.W,SCALE) G address register indirect with index
/// 14 M68020 ([bd,An],Xn.L,SCALE,od) u memory indirect postindexed mode
/// 13 M68020 ([bd,An],Xn.W,SCALE,od) U memory indirect postindexed mode
/// 16 M68020 ([bd,An,Xn.L,SCALE],od) v memory indirect preindexed mode
/// 15 M68020 ([bd,An,Xn.W,SCALE],od) V memory indirect preindexed mode
/// 20 M68000 abs.L b absolute long address
/// 17 M68000 abs.W B absolute short address
/// 21 M68000 (i,PC) q program counter with displacement
/// 23 M68000 (i,PC,Xn.L) k program counter with index and scale = 1
/// 22 M68000 (i,PC,Xn.W) K program counter with index and scale = 1
/// 25 M68020 (i,PC,Xn.L,SCALE) l program counter with index
/// 24 M68020 (i,PC,Xn.W,SCALE) L program counter with index
/// 27 M68020 ([bd,PC],Xn.L,SCALE,od) x program counter memory indirect postindexed mode
/// 26 M68020 ([bd,PC],Xn.W,SCALE,od) X program counter memory indirect postindexed mode
/// 31 M68020 ([bd,PC,Xn.L,SCALE],od) y program counter memory indirect preindexed mode
/// 30 M68020 ([bd,PC,Xn.W,SCALE],od) Y program counter memory indirect preindexed mode
/// 32 M68000 #immediate i immediate data
///
/// NOTE that long form is always lowercase, word variants are capitalized
///
/// Operand can be qualified with size where appropriate to force a particular
/// instruction encoding, e.g.:
/// (i8,An,Xn.W) f8 1 extension word
/// (i16,An,Xn.W) f16 2 extension words
/// (i32,An,Xn.W) f32 3 extension words
///
/// Form without size qualifier will adapt to operand size automatically, e.g.:
/// (i,An,Xn.W) f 1, 2 or 3 extension words
///
/// Some forms already imply a particular size of their operands, e.g.:
/// (i,An) p 1 extension word and i is 16bit
///
/// Operand order follows x86 Intel order(destination before source), e.g.:
/// MOV8df MOVE (4,A0,D0), D1
///
/// Number after instruction mnemonics determines the size of the data
///
//===----------------------------------------------------------------------===//
/// ??? Is it possible to use this stuff for disassembling?
/// NOTE 1: In case of conditional beads(DA, DAReg), cond part is able to
/// consume any bit, though a more general instructions must be chosen, e.g.
/// d -> r, a -> r
//===----------------------------------------------------------------------===//
// Encoding primitives
//===----------------------------------------------------------------------===//
class MxBead<bits<4> type, bit b4 = 0, bit b5 = 0, bit b6 = 0, bit b7 = 0> {
bits<8> Value = 0b00000000;
let Value{3-0} = type;
let Value{4} = b4;
let Value{5} = b5;
let Value{6} = b6;
let Value{7} = b7;
}
/// System beads, allow to control beading flow
def MxBeadTerm : MxBead<0x0, 0, 0, 0, 0>;
def MxBeadIgnore : MxBead<0x0, 1, 0, 0, 0>;
/// Add plain bit to the instruction
class MxBead1Bit <bits<1> b> : MxBead<0x1, b>;
class MxBead2Bits <bits<2> b> : MxBead<0x2, b{0}, b{1}>;
class MxBead3Bits <bits<3> b> : MxBead<0x3, b{0}, b{1}, b{2}>;
class MxBead4Bits <bits<4> b> : MxBead<0x4, b{0}, b{1}, b{2}, b{3}>;
/// bits<3> o - operand number
/// bit a - use alternative, used to select index register or
/// outer displacement/immediate
/// suffix NP means non-padded
class MxBeadDAReg <bits<3> o, bit a = 0> : MxBead<0x5, o{0}, o{1}, o{2}, a>;
class MxBeadDA <bits<3> o, bit a = 0> : MxBead<0x6, o{0}, o{1}, o{2}, a>;
class MxBeadReg <bits<3> o, bit a = 0> : MxBead<0x7, o{0}, o{1}, o{2}, a>;
class MxBeadDReg <bits<3> o, bit a = 0> : MxBead<0x8, o{0}, o{1}, o{2}, a>;
class MxBead8Disp <bits<3> o, bit a = 0> : MxBead<0x9, o{0}, o{1}, o{2}, a>;
/// Add Immediate to the instruction. 8-bit version is padded with zeros to fit
/// the word.
class MxBead8Imm <bits<3> o, bit a = 0> : MxBead<0xA, o{0}, o{1}, o{2}, a>;
class MxBead16Imm <bits<3> o, bit a = 0> : MxBead<0xB, o{0}, o{1}, o{2}, a>;
class MxBead32Imm <bits<3> o, bit a = 0> : MxBead<0xC, o{0}, o{1}, o{2}, a>;
/// Encodes an immediate 0-7(alt. 1-8) into 3 bit field
class MxBead3Imm <bits<3> o, bit a = 0> : MxBead<0xD, o{0}, o{1}, o{2}, a>;
class MxEncoding<MxBead n0 = MxBeadTerm, MxBead n1 = MxBeadTerm,
MxBead n2 = MxBeadTerm, MxBead n3 = MxBeadTerm,
MxBead n4 = MxBeadTerm, MxBead n5 = MxBeadTerm,
MxBead n6 = MxBeadTerm, MxBead n7 = MxBeadTerm,
MxBead n8 = MxBeadTerm, MxBead n9 = MxBeadTerm,
MxBead n10 = MxBeadTerm, MxBead n11 = MxBeadTerm,
MxBead n12 = MxBeadTerm, MxBead n13 = MxBeadTerm,
MxBead n14 = MxBeadTerm, MxBead n15 = MxBeadTerm,
MxBead n16 = MxBeadTerm, MxBead n17 = MxBeadTerm,
MxBead n18 = MxBeadTerm, MxBead n19 = MxBeadTerm,
MxBead n20 = MxBeadTerm, MxBead n21 = MxBeadTerm,
MxBead n22 = MxBeadTerm, MxBead n23 = MxBeadTerm> {
bits <192> Value;
let Value{7-0} = n0.Value;
let Value{15-8} = n1.Value;
let Value{23-16} = n2.Value;
let Value{31-24} = n3.Value;
let Value{39-32} = n4.Value;
let Value{47-40} = n5.Value;
let Value{55-48} = n6.Value;
let Value{63-56} = n7.Value;
let Value{71-64} = n8.Value;
let Value{79-72} = n9.Value;
let Value{87-80} = n10.Value;
let Value{95-88} = n11.Value;
let Value{103-96} = n12.Value;
let Value{111-104} = n13.Value;
let Value{119-112} = n14.Value;
let Value{127-120} = n15.Value;
let Value{135-128} = n16.Value;
let Value{143-136} = n17.Value;
let Value{151-144} = n18.Value;
let Value{159-152} = n19.Value;
let Value{167-160} = n20.Value;
let Value{175-168} = n21.Value;
let Value{183-176} = n22.Value;
let Value{191-184} = n23.Value;
}
class MxEncFixed<bits<16> value> : MxEncoding {
let Value{7-0} = MxBead4Bits<value{3-0}>.Value;
let Value{15-8} = MxBead4Bits<value{7-4}>.Value;
let Value{23-16} = MxBead4Bits<value{11-8}>.Value;
let Value{31-24} = MxBead4Bits<value{15-12}>.Value;
}
//===----------------------------------------------------------------------===//
// Encoding composites
//
// These must be lowered to MxEncoding by instr specific wrappers
//
// HERE BE DRAGONS...
//===----------------------------------------------------------------------===//
class MxEncByte<bits<8> value> : MxEncoding {
MxBead4Bits LO = MxBead4Bits<value{3-0}>;
MxBead4Bits HI = MxBead4Bits<value{7-4}>;
}
def MxEncEmpty : MxEncoding;
/// M68k Standard Effective Address layout:
///
/// :-------------------:
/// | 5 4 3 | 2 1 0 |
/// | mode | reg |
/// :-------------------:
///
/// If the EA is a direct register mode, bits 4 and 5 are 0, and the register
/// number will be encoded in bit 0 - 3. Since the first address register's
/// (A0) register number is 8, we can easily tell data registers from
/// address registers by only inspecting bit 3 (i.e. if bit 3 is set, it's an
/// address register).
///
///
/// But MOVE instruction uses reversed layout for destination EA:
///
/// :-------------------:
/// | 5 4 3 | 2 1 0 |
/// | reg | mode |
/// :-------------------:
///
/// And this complicates things a bit because the DA bit is now separated from
/// the register and we have to encode those separately using MxBeadDA<opN>
///
class MxEncEA<MxBead reg, MxBead mode, MxBead da = MxBeadIgnore> {
MxBead Reg = reg;
MxBead Mode = mode;
MxBead DA = da;
}
// FIXME: Is there a way to factorize the addressing mode suffix (i.e.
// 'r', 'd', 'a' etc.) and use something like multiclass to replace?
def MxEncEAr_0: MxEncEA<MxBeadDAReg<0>, MxBead2Bits<0b00>>;
def MxEncEAd_0: MxEncEA<MxBeadDReg<0>, MxBead2Bits<0b00>, MxBead1Bit<0>>;
def MxEncEAa_0: MxEncEA<MxBeadReg<0>, MxBead2Bits<0b00>, MxBead1Bit<1>>;
def MxEncEAj_0: MxEncEA<MxBeadReg<0>, MxBead2Bits<0b01>, MxBead1Bit<0>>;
def MxEncEAo_0: MxEncEA<MxBeadReg<0>, MxBead2Bits<0b01>, MxBead1Bit<1>>;
def MxEncEAe_0: MxEncEA<MxBeadReg<0>, MxBead2Bits<0b10>, MxBead1Bit<0>>;
def MxEncEAp_0: MxEncEA<MxBeadReg<0>, MxBead2Bits<0b10>, MxBead1Bit<1>>;
def MxEncEAf_0: MxEncEA<MxBeadReg<0>, MxBead2Bits<0b11>, MxBead1Bit<0>>;
def MxEncEAa_0_reflected : MxEncEA<MxBeadReg<0>, MxBead3Bits<0b001>>;
def MxEncEAr_0_reflected : MxEncEA<MxBeadReg<0>, MxBead2Bits<0b00>, MxBeadDA<0>>;
def MxEncEAr_1: MxEncEA<MxBeadDAReg<1>, MxBead2Bits<0b00>>;
def MxEncEAd_1: MxEncEA<MxBeadDReg<1>, MxBead2Bits<0b00>, MxBead1Bit<0>>;
def MxEncEAa_1: MxEncEA<MxBeadReg<1>, MxBead2Bits<0b00>, MxBead1Bit<1>>;
def MxEncEAj_1: MxEncEA<MxBeadReg<1>, MxBead2Bits<0b01>, MxBead1Bit<0>>;
def MxEncEAo_1: MxEncEA<MxBeadReg<1>, MxBead2Bits<0b01>, MxBead1Bit<1>>;
def MxEncEAe_1: MxEncEA<MxBeadReg<1>, MxBead2Bits<0b10>, MxBead1Bit<0>>;
def MxEncEAp_1: MxEncEA<MxBeadReg<1>, MxBead2Bits<0b10>, MxBead1Bit<1>>;
def MxEncEAf_1: MxEncEA<MxBeadReg<1>, MxBead2Bits<0b11>, MxBead1Bit<0>>;
def MxEncEAr_2: MxEncEA<MxBeadDAReg<2>, MxBead2Bits<0b00>>;
def MxEncEAd_2: MxEncEA<MxBeadDReg<2>, MxBead2Bits<0b00>, MxBead1Bit<0>>;
def MxEncEAa_2: MxEncEA<MxBeadReg<2>, MxBead2Bits<0b00>, MxBead1Bit<1>>;
def MxEncEAj_2: MxEncEA<MxBeadReg<2>, MxBead2Bits<0b01>, MxBead1Bit<0>>;
def MxEncEAo_2: MxEncEA<MxBeadReg<2>, MxBead2Bits<0b01>, MxBead1Bit<1>>;
def MxEncEAe_2: MxEncEA<MxBeadReg<2>, MxBead2Bits<0b10>, MxBead1Bit<0>>;
def MxEncEAp_2: MxEncEA<MxBeadReg<2>, MxBead2Bits<0b10>, MxBead1Bit<1>>;
def MxEncEAf_2: MxEncEA<MxBeadReg<2>, MxBead2Bits<0b11>, MxBead1Bit<0>>;
def MxEncEAb : MxEncEA<MxBead3Bits<0b001>, MxBead2Bits<0b11>, MxBead1Bit<1>>;
def MxEncEAq : MxEncEA<MxBead3Bits<0b010>, MxBead2Bits<0b11>, MxBead1Bit<1>>;
def MxEncEAk : MxEncEA<MxBead3Bits<0b011>, MxBead2Bits<0b11>, MxBead1Bit<1>>;
def MxEncEAi : MxEncEA<MxBead3Bits<0b100>, MxBead2Bits<0b11>, MxBead1Bit<1>>;
// Allows you to specify each bit of opcode
class MxEncOpMode<MxBead b0, MxBead b1 = MxBeadIgnore, MxBead b2 = MxBeadIgnore> {
MxBead B0 = b0;
MxBead B1 = b1;
MxBead B2 = b2;
}
// op EA, Dn
def MxOpMode8dEA : MxEncOpMode<MxBead3Bits<0b000>>;
def MxOpMode16dEA : MxEncOpMode<MxBead3Bits<0b001>>;
def MxOpMode32dEA : MxEncOpMode<MxBead3Bits<0b010>>;
// op EA, An
def MxOpMode16aEA : MxEncOpMode<MxBead3Bits<0b110>>;
def MxOpMode32aEA : MxEncOpMode<MxBead3Bits<0b111>>;
// op EA, Rn
// As you might noticed this guy is special... Since M68k differentiates
// between Data and Address registers we required to use different OPMODE codes
// for Address registers DST operands. One way of dealing with it is to use
// separate tablegen instructions, but in this case it would force Register
// Allocator to use specific Register Classes and eventually will lead to
// superfluous moves. Another approach is to use reg-variadic encoding which will
// change OPMODE base on Register Class used. Luckily, all the bits that differ go
// from 0 to 1 and can be encoded with MxBeadDA.
// Basically, if the register used is of Data type these encodings will be
// the same as MxOpMode{16,32}dEA above and used with regular instructions(e.g. ADD,
// SUB), but if the register is of Address type the appropriate bits will flip and
// the instructions become of *A type(e.g ADDA, SUBA).
def MxOpMode16rEA : MxEncOpMode<MxBead1Bit<1>, MxBeadDA<0>, MxBead1Bit<0>>;
def MxOpMode32rEA : MxEncOpMode<MxBeadDA<0>, MxBead1Bit<1>, MxBeadDA<0>>;
// op Dn, EA
def MxOpMode8EAd : MxEncOpMode<MxBead3Bits<0b100>>;
def MxOpMode16EAd : MxEncOpMode<MxBead3Bits<0b101>>;
def MxOpMode32EAd : MxEncOpMode<MxBead3Bits<0b110>>;
// Represents two types of extension word:
// - Imm extension word
// - Brief extension word
class MxEncExt<MxBead imm = MxBeadIgnore, MxBead b8 = MxBeadIgnore,
MxBead scale = MxBeadIgnore, MxBead wl = MxBeadIgnore,
MxBead daReg = MxBeadIgnore> {
MxBead Imm = imm;
MxBead B8 = b8;
MxBead Scale = scale;
MxBead WL = wl;
MxBead DAReg = daReg;
}
def MxExtEmpty : MxEncExt;
// These handle encoding of displacement fields, absolute addresses and
// immediate values, since encoding for these categories is mainly the same,
// with exception of some weird immediates.
def MxExtI8_0 : MxEncExt<MxBead8Imm<0>>;
def MxExtI16_0 : MxEncExt<MxBead16Imm<0>>;
def MxExtI32_0 : MxEncExt<MxBead32Imm<0>>;
def MxExtI8_1 : MxEncExt<MxBead8Imm<1>>;
def MxExtI16_1 : MxEncExt<MxBead16Imm<1>>;
def MxExtI32_1 : MxEncExt<MxBead32Imm<1>>;
def MxExtI8_2 : MxEncExt<MxBead8Imm<2>>;
def MxExtI16_2 : MxEncExt<MxBead16Imm<2>>;
def MxExtI32_2 : MxEncExt<MxBead32Imm<2>>;
// NOTE They are all using Long Xn
def MxExtBrief_0 : MxEncExt<MxBead8Disp<0>, MxBead1Bit<0b0>,
MxBead2Bits<0b00>, MxBead1Bit<1>,
MxBeadDAReg<0, 1>>;
def MxExtBrief_1 : MxEncExt<MxBead8Disp<1>, MxBead1Bit<0b0>,
MxBead2Bits<0b00>, MxBead1Bit<1>,
MxBeadDAReg<1, 1>>;
def MxExtBrief_2 : MxEncExt<MxBead8Disp<2>, MxBead1Bit<0b0>,
MxBead2Bits<0b00>, MxBead1Bit<1>,
MxBeadDAReg<2, 1>>;
def MxExtBrief_3 : MxEncExt<MxBead8Disp<3>, MxBead1Bit<0b0>,
MxBead2Bits<0b00>, MxBead1Bit<1>,
MxBeadDAReg<3, 1>>;
def MxExtBrief_4 : MxEncExt<MxBead8Disp<4>, MxBead1Bit<0b0>,
MxBead2Bits<0b00>, MxBead1Bit<1>,
MxBeadDAReg<4, 1>>;
class MxEncSize<bits<2> value> : MxBead2Bits<value>;
def MxEncSize8 : MxEncSize<0b00>;
def MxEncSize16 : MxEncSize<0b01>;
def MxEncSize32 : MxEncSize<0b10>;
def MxEncSize64 : MxEncSize<0b11>;
// M68k INSTRUCTION. Most instructions specify the location of an operand by
// using the effective address field in the operation word. The effective address
// is composed of two 3-bit fields: the mode field and the register field. The
// value in the mode field selects the different address modes. The register
// field contains the number of a register. The effective address field may
// require additional information to fully specify the operand. This additional
// information, called the effective address extension, is contained in the
// following word or words and is considered part of the instruction. The
// effective address modes are grouped into three categories: register direct,
// memory addressing, and special.
class MxInst<dag outs, dag ins,
string asmStr = "",
list<dag> pattern = [],
MxEncoding beads = MxEncEmpty,
InstrItinClass itin = NoItinerary>
: Instruction {
let Namespace = "M68k";
let OutOperandList = outs;
let InOperandList = ins;
let AsmString = asmStr;
let Pattern = pattern;
let Itinerary = itin;
// Byte stream
field bits<192> Beads = beads.Value;
// Number of bytes
let Size = 0;
let UseLogicalOperandMappings = 1;
}
// M68k PSEUDO INSTRUCTION
class MxPseudo<dag outs, dag ins, list<dag> pattern = []>
: MxInst<outs, ins, "; error: this should not be emitted", pattern> {
let isPseudo = 1;
}