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llvm-project/llvm/lib/Target/ARM/MCTargetDesc/ARMAddressingModes.h

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//===-- ARMAddressingModes.h - ARM Addressing Modes -------------*- C++ -*-===//
//
// The LLVM Compiler Infrastructure
//
// This file is distributed under the University of Illinois Open Source
// License. See LICENSE.TXT for details.
//
//===----------------------------------------------------------------------===//
//
// This file contains the ARM addressing mode implementation stuff.
//
//===----------------------------------------------------------------------===//
#ifndef LLVM_TARGET_ARM_ARMADDRESSINGMODES_H
#define LLVM_TARGET_ARM_ARMADDRESSINGMODES_H
#include "llvm/ADT/APFloat.h"
#include "llvm/ADT/APInt.h"
#include "llvm/Support/ErrorHandling.h"
#include "llvm/Support/MathExtras.h"
#include <cassert>
namespace llvm {
/// ARM_AM - ARM Addressing Mode Stuff
namespace ARM_AM {
enum ShiftOpc {
no_shift = 0,
asr,
lsl,
lsr,
ror,
rrx
};
enum AddrOpc {
sub = 0,
add
};
static inline const char *getAddrOpcStr(AddrOpc Op) {
return Op == sub ? "-" : "";
}
static inline const char *getShiftOpcStr(ShiftOpc Op) {
switch (Op) {
default: llvm_unreachable("Unknown shift opc!");
case ARM_AM::asr: return "asr";
case ARM_AM::lsl: return "lsl";
case ARM_AM::lsr: return "lsr";
case ARM_AM::ror: return "ror";
case ARM_AM::rrx: return "rrx";
}
}
static inline unsigned getShiftOpcEncoding(ShiftOpc Op) {
switch (Op) {
default: llvm_unreachable("Unknown shift opc!");
case ARM_AM::asr: return 2;
case ARM_AM::lsl: return 0;
case ARM_AM::lsr: return 1;
case ARM_AM::ror: return 3;
}
}
enum AMSubMode {
bad_am_submode = 0,
ia,
ib,
da,
db
};
static inline const char *getAMSubModeStr(AMSubMode Mode) {
switch (Mode) {
default: llvm_unreachable("Unknown addressing sub-mode!");
case ARM_AM::ia: return "ia";
case ARM_AM::ib: return "ib";
case ARM_AM::da: return "da";
case ARM_AM::db: return "db";
}
}
/// rotr32 - Rotate a 32-bit unsigned value right by a specified # bits.
///
static inline unsigned rotr32(unsigned Val, unsigned Amt) {
assert(Amt < 32 && "Invalid rotate amount");
return (Val >> Amt) | (Val << ((32-Amt)&31));
}
/// rotl32 - Rotate a 32-bit unsigned value left by a specified # bits.
///
static inline unsigned rotl32(unsigned Val, unsigned Amt) {
assert(Amt < 32 && "Invalid rotate amount");
return (Val << Amt) | (Val >> ((32-Amt)&31));
}
//===--------------------------------------------------------------------===//
// Addressing Mode #1: shift_operand with registers
//===--------------------------------------------------------------------===//
//
// This 'addressing mode' is used for arithmetic instructions. It can
// represent things like:
// reg
// reg [asr|lsl|lsr|ror|rrx] reg
// reg [asr|lsl|lsr|ror|rrx] imm
//
// This is stored three operands [rega, regb, opc]. The first is the base
// reg, the second is the shift amount (or reg0 if not present or imm). The
// third operand encodes the shift opcode and the imm if a reg isn't present.
//
static inline unsigned getSORegOpc(ShiftOpc ShOp, unsigned Imm) {
return ShOp | (Imm << 3);
}
static inline unsigned getSORegOffset(unsigned Op) {
return Op >> 3;
}
static inline ShiftOpc getSORegShOp(unsigned Op) {
return (ShiftOpc)(Op & 7);
}
/// getSOImmValImm - Given an encoded imm field for the reg/imm form, return
/// the 8-bit imm value.
static inline unsigned getSOImmValImm(unsigned Imm) {
return Imm & 0xFF;
}
/// getSOImmValRot - Given an encoded imm field for the reg/imm form, return
/// the rotate amount.
static inline unsigned getSOImmValRot(unsigned Imm) {
return (Imm >> 8) * 2;
}
/// getSOImmValRotate - Try to handle Imm with an immediate shifter operand,
/// computing the rotate amount to use. If this immediate value cannot be
/// handled with a single shifter-op, determine a good rotate amount that will
/// take a maximal chunk of bits out of the immediate.
static inline unsigned getSOImmValRotate(unsigned Imm) {
// 8-bit (or less) immediates are trivially shifter_operands with a rotate
// of zero.
if ((Imm & ~255U) == 0) return 0;
// Use CTZ to compute the rotate amount.
unsigned TZ = CountTrailingZeros_32(Imm);
// Rotate amount must be even. Something like 0x200 must be rotated 8 bits,
// not 9.
unsigned RotAmt = TZ & ~1;
// If we can handle this spread, return it.
if ((rotr32(Imm, RotAmt) & ~255U) == 0)
return (32-RotAmt)&31; // HW rotates right, not left.
// For values like 0xF000000F, we should ignore the low 6 bits, then
// retry the hunt.
if (Imm & 63U) {
unsigned TZ2 = CountTrailingZeros_32(Imm & ~63U);
unsigned RotAmt2 = TZ2 & ~1;
if ((rotr32(Imm, RotAmt2) & ~255U) == 0)
return (32-RotAmt2)&31; // HW rotates right, not left.
}
// Otherwise, we have no way to cover this span of bits with a single
// shifter_op immediate. Return a chunk of bits that will be useful to
// handle.
return (32-RotAmt)&31; // HW rotates right, not left.
}
/// getSOImmVal - Given a 32-bit immediate, if it is something that can fit
/// into an shifter_operand immediate operand, return the 12-bit encoding for
/// it. If not, return -1.
static inline int getSOImmVal(unsigned Arg) {
// 8-bit (or less) immediates are trivially shifter_operands with a rotate
// of zero.
if ((Arg & ~255U) == 0) return Arg;
unsigned RotAmt = getSOImmValRotate(Arg);
// If this cannot be handled with a single shifter_op, bail out.
if (rotr32(~255U, RotAmt) & Arg)
return -1;
// Encode this correctly.
return rotl32(Arg, RotAmt) | ((RotAmt>>1) << 8);
}
/// isSOImmTwoPartVal - Return true if the specified value can be obtained by
/// or'ing together two SOImmVal's.
static inline bool isSOImmTwoPartVal(unsigned V) {
// If this can be handled with a single shifter_op, bail out.
V = rotr32(~255U, getSOImmValRotate(V)) & V;
if (V == 0)
return false;
// If this can be handled with two shifter_op's, accept.
V = rotr32(~255U, getSOImmValRotate(V)) & V;
return V == 0;
}
/// getSOImmTwoPartFirst - If V is a value that satisfies isSOImmTwoPartVal,
/// return the first chunk of it.
static inline unsigned getSOImmTwoPartFirst(unsigned V) {
return rotr32(255U, getSOImmValRotate(V)) & V;
}
/// getSOImmTwoPartSecond - If V is a value that satisfies isSOImmTwoPartVal,
/// return the second chunk of it.
static inline unsigned getSOImmTwoPartSecond(unsigned V) {
// Mask out the first hunk.
V = rotr32(~255U, getSOImmValRotate(V)) & V;
// Take what's left.
assert(V == (rotr32(255U, getSOImmValRotate(V)) & V));
return V;
}
/// getThumbImmValShift - Try to handle Imm with a 8-bit immediate followed
/// by a left shift. Returns the shift amount to use.
static inline unsigned getThumbImmValShift(unsigned Imm) {
// 8-bit (or less) immediates are trivially immediate operand with a shift
// of zero.
if ((Imm & ~255U) == 0) return 0;
// Use CTZ to compute the shift amount.
return CountTrailingZeros_32(Imm);
}
/// isThumbImmShiftedVal - Return true if the specified value can be obtained
/// by left shifting a 8-bit immediate.
static inline bool isThumbImmShiftedVal(unsigned V) {
// If this can be handled with
V = (~255U << getThumbImmValShift(V)) & V;
return V == 0;
}
/// getThumbImm16ValShift - Try to handle Imm with a 16-bit immediate followed
/// by a left shift. Returns the shift amount to use.
static inline unsigned getThumbImm16ValShift(unsigned Imm) {
// 16-bit (or less) immediates are trivially immediate operand with a shift
// of zero.
if ((Imm & ~65535U) == 0) return 0;
// Use CTZ to compute the shift amount.
return CountTrailingZeros_32(Imm);
}
/// isThumbImm16ShiftedVal - Return true if the specified value can be
/// obtained by left shifting a 16-bit immediate.
static inline bool isThumbImm16ShiftedVal(unsigned V) {
// If this can be handled with
V = (~65535U << getThumbImm16ValShift(V)) & V;
return V == 0;
}
/// getThumbImmNonShiftedVal - If V is a value that satisfies
/// isThumbImmShiftedVal, return the non-shiftd value.
static inline unsigned getThumbImmNonShiftedVal(unsigned V) {
return V >> getThumbImmValShift(V);
}
/// getT2SOImmValSplat - Return the 12-bit encoded representation
/// if the specified value can be obtained by splatting the low 8 bits
/// into every other byte or every byte of a 32-bit value. i.e.,
/// 00000000 00000000 00000000 abcdefgh control = 0
/// 00000000 abcdefgh 00000000 abcdefgh control = 1
/// abcdefgh 00000000 abcdefgh 00000000 control = 2
/// abcdefgh abcdefgh abcdefgh abcdefgh control = 3
/// Return -1 if none of the above apply.
/// See ARM Reference Manual A6.3.2.
static inline int getT2SOImmValSplatVal(unsigned V) {
unsigned u, Vs, Imm;
// control = 0
if ((V & 0xffffff00) == 0)
return V;
// If the value is zeroes in the first byte, just shift those off
Vs = ((V & 0xff) == 0) ? V >> 8 : V;
// Any passing value only has 8 bits of payload, splatted across the word
Imm = Vs & 0xff;
// Likewise, any passing values have the payload splatted into the 3rd byte
u = Imm | (Imm << 16);
// control = 1 or 2
if (Vs == u)
return (((Vs == V) ? 1 : 2) << 8) | Imm;
// control = 3
if (Vs == (u | (u << 8)))
return (3 << 8) | Imm;
return -1;
}
/// getT2SOImmValRotateVal - Return the 12-bit encoded representation if the
/// specified value is a rotated 8-bit value. Return -1 if no rotation
/// encoding is possible.
/// See ARM Reference Manual A6.3.2.
static inline int getT2SOImmValRotateVal(unsigned V) {
unsigned RotAmt = CountLeadingZeros_32(V);
if (RotAmt >= 24)
return -1;
// If 'Arg' can be handled with a single shifter_op return the value.
if ((rotr32(0xff000000U, RotAmt) & V) == V)
return (rotr32(V, 24 - RotAmt) & 0x7f) | ((RotAmt + 8) << 7);
return -1;
}
/// getT2SOImmVal - Given a 32-bit immediate, if it is something that can fit
/// into a Thumb-2 shifter_operand immediate operand, return the 12-bit
/// encoding for it. If not, return -1.
/// See ARM Reference Manual A6.3.2.
static inline int getT2SOImmVal(unsigned Arg) {
// If 'Arg' is an 8-bit splat, then get the encoded value.
int Splat = getT2SOImmValSplatVal(Arg);
if (Splat != -1)
return Splat;
// If 'Arg' can be handled with a single shifter_op return the value.
int Rot = getT2SOImmValRotateVal(Arg);
if (Rot != -1)
return Rot;
return -1;
}
static inline unsigned getT2SOImmValRotate(unsigned V) {
if ((V & ~255U) == 0) return 0;
// Use CTZ to compute the rotate amount.
unsigned RotAmt = CountTrailingZeros_32(V);
return (32 - RotAmt) & 31;
}
static inline bool isT2SOImmTwoPartVal (unsigned Imm) {
unsigned V = Imm;
// Passing values can be any combination of splat values and shifter
// values. If this can be handled with a single shifter or splat, bail
// out. Those should be handled directly, not with a two-part val.
if (getT2SOImmValSplatVal(V) != -1)
return false;
V = rotr32 (~255U, getT2SOImmValRotate(V)) & V;
if (V == 0)
return false;
// If this can be handled as an immediate, accept.
if (getT2SOImmVal(V) != -1) return true;
// Likewise, try masking out a splat value first.
V = Imm;
if (getT2SOImmValSplatVal(V & 0xff00ff00U) != -1)
V &= ~0xff00ff00U;
else if (getT2SOImmValSplatVal(V & 0x00ff00ffU) != -1)
V &= ~0x00ff00ffU;
// If what's left can be handled as an immediate, accept.
if (getT2SOImmVal(V) != -1) return true;
// Otherwise, do not accept.
return false;
}
static inline unsigned getT2SOImmTwoPartFirst(unsigned Imm) {
assert (isT2SOImmTwoPartVal(Imm) &&
"Immedate cannot be encoded as two part immediate!");
// Try a shifter operand as one part
unsigned V = rotr32 (~255, getT2SOImmValRotate(Imm)) & Imm;
// If the rest is encodable as an immediate, then return it.
if (getT2SOImmVal(V) != -1) return V;
// Try masking out a splat value first.
if (getT2SOImmValSplatVal(Imm & 0xff00ff00U) != -1)
return Imm & 0xff00ff00U;
// The other splat is all that's left as an option.
assert (getT2SOImmValSplatVal(Imm & 0x00ff00ffU) != -1);
return Imm & 0x00ff00ffU;
}
static inline unsigned getT2SOImmTwoPartSecond(unsigned Imm) {
// Mask out the first hunk
Imm ^= getT2SOImmTwoPartFirst(Imm);
// Return what's left
assert (getT2SOImmVal(Imm) != -1 &&
"Unable to encode second part of T2 two part SO immediate");
return Imm;
}
//===--------------------------------------------------------------------===//
// Addressing Mode #2
//===--------------------------------------------------------------------===//
//
// This is used for most simple load/store instructions.
//
// addrmode2 := reg +/- reg shop imm
// addrmode2 := reg +/- imm12
//
// The first operand is always a Reg. The second operand is a reg if in
// reg/reg form, otherwise it's reg#0. The third field encodes the operation
// in bit 12, the immediate in bits 0-11, and the shift op in 13-15. The
// fourth operand 16-17 encodes the index mode.
//
// If this addressing mode is a frame index (before prolog/epilog insertion
// and code rewriting), this operand will have the form: FI#, reg0, <offs>
// with no shift amount for the frame offset.
//
static inline unsigned getAM2Opc(AddrOpc Opc, unsigned Imm12, ShiftOpc SO,
unsigned IdxMode = 0) {
assert(Imm12 < (1 << 12) && "Imm too large!");
bool isSub = Opc == sub;
return Imm12 | ((int)isSub << 12) | (SO << 13) | (IdxMode << 16) ;
}
static inline unsigned getAM2Offset(unsigned AM2Opc) {
return AM2Opc & ((1 << 12)-1);
}
static inline AddrOpc getAM2Op(unsigned AM2Opc) {
return ((AM2Opc >> 12) & 1) ? sub : add;
}
static inline ShiftOpc getAM2ShiftOpc(unsigned AM2Opc) {
return (ShiftOpc)((AM2Opc >> 13) & 7);
}
static inline unsigned getAM2IdxMode(unsigned AM2Opc) {
return (AM2Opc >> 16);
}
//===--------------------------------------------------------------------===//
// Addressing Mode #3
//===--------------------------------------------------------------------===//
//
// This is used for sign-extending loads, and load/store-pair instructions.
//
// addrmode3 := reg +/- reg
// addrmode3 := reg +/- imm8
//
// The first operand is always a Reg. The second operand is a reg if in
// reg/reg form, otherwise it's reg#0. The third field encodes the operation
// in bit 8, the immediate in bits 0-7. The fourth operand 9-10 encodes the
// index mode.
/// getAM3Opc - This function encodes the addrmode3 opc field.
static inline unsigned getAM3Opc(AddrOpc Opc, unsigned char Offset,
unsigned IdxMode = 0) {
bool isSub = Opc == sub;
return ((int)isSub << 8) | Offset | (IdxMode << 9);
}
static inline unsigned char getAM3Offset(unsigned AM3Opc) {
return AM3Opc & 0xFF;
}
static inline AddrOpc getAM3Op(unsigned AM3Opc) {
return ((AM3Opc >> 8) & 1) ? sub : add;
}
static inline unsigned getAM3IdxMode(unsigned AM3Opc) {
return (AM3Opc >> 9);
}
//===--------------------------------------------------------------------===//
// Addressing Mode #4
//===--------------------------------------------------------------------===//
//
// This is used for load / store multiple instructions.
//
// addrmode4 := reg, <mode>
//
// The four modes are:
// IA - Increment after
// IB - Increment before
// DA - Decrement after
// DB - Decrement before
// For VFP instructions, only the IA and DB modes are valid.
static inline AMSubMode getAM4SubMode(unsigned Mode) {
return (AMSubMode)(Mode & 0x7);
}
static inline unsigned getAM4ModeImm(AMSubMode SubMode) {
return (int)SubMode;
}
//===--------------------------------------------------------------------===//
// Addressing Mode #5
//===--------------------------------------------------------------------===//
//
// This is used for coprocessor instructions, such as FP load/stores.
//
// addrmode5 := reg +/- imm8*4
//
// The first operand is always a Reg. The second operand encodes the
// operation in bit 8 and the immediate in bits 0-7.
/// getAM5Opc - This function encodes the addrmode5 opc field.
static inline unsigned getAM5Opc(AddrOpc Opc, unsigned char Offset) {
bool isSub = Opc == sub;
return ((int)isSub << 8) | Offset;
}
static inline unsigned char getAM5Offset(unsigned AM5Opc) {
return AM5Opc & 0xFF;
}
static inline AddrOpc getAM5Op(unsigned AM5Opc) {
return ((AM5Opc >> 8) & 1) ? sub : add;
}
//===--------------------------------------------------------------------===//
// Addressing Mode #6
//===--------------------------------------------------------------------===//
//
// This is used for NEON load / store instructions.
//
// addrmode6 := reg with optional alignment
//
// This is stored in two operands [regaddr, align]. The first is the
// address register. The second operand is the value of the alignment
// specifier in bytes or zero if no explicit alignment.
// Valid alignments depend on the specific instruction.
//===--------------------------------------------------------------------===//
// NEON Modified Immediates
//===--------------------------------------------------------------------===//
//
// Several NEON instructions (e.g., VMOV) take a "modified immediate"
// vector operand, where a small immediate encoded in the instruction
// specifies a full NEON vector value. These modified immediates are
// represented here as encoded integers. The low 8 bits hold the immediate
// value; bit 12 holds the "Op" field of the instruction, and bits 11-8 hold
// the "Cmode" field of the instruction. The interfaces below treat the
// Op and Cmode values as a single 5-bit value.
static inline unsigned createNEONModImm(unsigned OpCmode, unsigned Val) {
return (OpCmode << 8) | Val;
}
static inline unsigned getNEONModImmOpCmode(unsigned ModImm) {
return (ModImm >> 8) & 0x1f;
}
static inline unsigned getNEONModImmVal(unsigned ModImm) {
return ModImm & 0xff;
}
/// decodeNEONModImm - Decode a NEON modified immediate value into the
/// element value and the element size in bits. (If the element size is
/// smaller than the vector, it is splatted into all the elements.)
static inline uint64_t decodeNEONModImm(unsigned ModImm, unsigned &EltBits) {
unsigned OpCmode = getNEONModImmOpCmode(ModImm);
unsigned Imm8 = getNEONModImmVal(ModImm);
uint64_t Val = 0;
if (OpCmode == 0xe) {
// 8-bit vector elements
Val = Imm8;
EltBits = 8;
} else if ((OpCmode & 0xc) == 0x8) {
// 16-bit vector elements
unsigned ByteNum = (OpCmode & 0x6) >> 1;
Val = Imm8 << (8 * ByteNum);
EltBits = 16;
} else if ((OpCmode & 0x8) == 0) {
// 32-bit vector elements, zero with one byte set
unsigned ByteNum = (OpCmode & 0x6) >> 1;
Val = Imm8 << (8 * ByteNum);
EltBits = 32;
} else if ((OpCmode & 0xe) == 0xc) {
// 32-bit vector elements, one byte with low bits set
unsigned ByteNum = 1 + (OpCmode & 0x1);
Val = (Imm8 << (8 * ByteNum)) | (0xffff >> (8 * (2 - ByteNum)));
EltBits = 32;
} else if (OpCmode == 0x1e) {
// 64-bit vector elements
for (unsigned ByteNum = 0; ByteNum < 8; ++ByteNum) {
if ((ModImm >> ByteNum) & 1)
Val |= (uint64_t)0xff << (8 * ByteNum);
}
EltBits = 64;
} else {
llvm_unreachable("Unsupported NEON immediate");
}
return Val;
}
AMSubMode getLoadStoreMultipleSubMode(int Opcode);
//===--------------------------------------------------------------------===//
// Floating-point Immediates
//
static inline float getFPImmFloat(unsigned Imm) {
// We expect an 8-bit binary encoding of a floating-point number here.
union {
uint32_t I;
float F;
} FPUnion;
uint8_t Sign = (Imm >> 7) & 0x1;
uint8_t Exp = (Imm >> 4) & 0x7;
uint8_t Mantissa = Imm & 0xf;
// 8-bit FP iEEEE Float Encoding
// abcd efgh aBbbbbbc defgh000 00000000 00000000
//
// where B = NOT(b);
FPUnion.I = 0;
FPUnion.I |= Sign << 31;
FPUnion.I |= ((Exp & 0x4) != 0 ? 0 : 1) << 30;
FPUnion.I |= ((Exp & 0x4) != 0 ? 0x1f : 0) << 25;
FPUnion.I |= (Exp & 0x3) << 23;
FPUnion.I |= Mantissa << 19;
return FPUnion.F;
}
/// getFP32Imm - Return an 8-bit floating-point version of the 32-bit
/// floating-point value. If the value cannot be represented as an 8-bit
/// floating-point value, then return -1.
static inline int getFP32Imm(const APInt &Imm) {
uint32_t Sign = Imm.lshr(31).getZExtValue() & 1;
int32_t Exp = (Imm.lshr(23).getSExtValue() & 0xff) - 127; // -126 to 127
int64_t Mantissa = Imm.getZExtValue() & 0x7fffff; // 23 bits
// We can handle 4 bits of mantissa.
// mantissa = (16+UInt(e:f:g:h))/16.
if (Mantissa & 0x7ffff)
return -1;
Mantissa >>= 19;
if ((Mantissa & 0xf) != Mantissa)
return -1;
// We can handle 3 bits of exponent: exp == UInt(NOT(b):c:d)-3
if (Exp < -3 || Exp > 4)
return -1;
Exp = ((Exp+3) & 0x7) ^ 4;
return ((int)Sign << 7) | (Exp << 4) | Mantissa;
}
static inline int getFP32Imm(const APFloat &FPImm) {
return getFP32Imm(FPImm.bitcastToAPInt());
}
/// getFP64Imm - Return an 8-bit floating-point version of the 64-bit
/// floating-point value. If the value cannot be represented as an 8-bit
/// floating-point value, then return -1.
static inline int getFP64Imm(const APInt &Imm) {
uint64_t Sign = Imm.lshr(63).getZExtValue() & 1;
int64_t Exp = (Imm.lshr(52).getSExtValue() & 0x7ff) - 1023; // -1022 to 1023
uint64_t Mantissa = Imm.getZExtValue() & 0xfffffffffffffULL;
// We can handle 4 bits of mantissa.
// mantissa = (16+UInt(e:f:g:h))/16.
if (Mantissa & 0xffffffffffffULL)
return -1;
Mantissa >>= 48;
if ((Mantissa & 0xf) != Mantissa)
return -1;
// We can handle 3 bits of exponent: exp == UInt(NOT(b):c:d)-3
if (Exp < -3 || Exp > 4)
return -1;
Exp = ((Exp+3) & 0x7) ^ 4;
return ((int)Sign << 7) | (Exp << 4) | Mantissa;
}
static inline int getFP64Imm(const APFloat &FPImm) {
return getFP64Imm(FPImm.bitcastToAPInt());
}
} // end namespace ARM_AM
} // end namespace llvm
#endif
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