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Diffstat (limited to 'lib/Target/ARM/ARMAddressingModes.h')
| -rw-r--r-- | lib/Target/ARM/ARMAddressingModes.h | 394 |
1 files changed, 394 insertions, 0 deletions
diff --git a/lib/Target/ARM/ARMAddressingModes.h b/lib/Target/ARM/ARMAddressingModes.h new file mode 100644 index 0000000..6d9b9ee --- /dev/null +++ b/lib/Target/ARM/ARMAddressingModes.h @@ -0,0 +1,394 @@ +//===- 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/CodeGen/SelectionDAGNodes.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 { + add = '+', sub = '-' + }; + + static inline const char *getShiftOpcStr(ShiftOpc Op) { + switch (Op) { + default: assert(0 && "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 ShiftOpc getShiftOpcForNode(SDValue N) { + switch (N.getOpcode()) { + default: return ARM_AM::no_shift; + case ISD::SHL: return ARM_AM::lsl; + case ISD::SRL: return ARM_AM::lsr; + case ISD::SRA: return ARM_AM::asr; + case ISD::ROTR: return ARM_AM::ror; + //case ISD::ROTL: // Only if imm -> turn into ROTR. + // Can't handle RRX here, because it would require folding a flag into + // the addressing mode. :( This causes us to miss certain things. + //case ARMISD::RRX: return ARM_AM::rrx; + } + } + + enum AMSubMode { + bad_am_submode = 0, + ia, + ib, + da, + db + }; + + static inline const char *getAMSubModeStr(AMSubMode Mode) { + switch (Mode) { + default: assert(0 && "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"; + } + } + + static inline const char *getAMSubModeAltStr(AMSubMode Mode, bool isLD) { + switch (Mode) { + default: assert(0 && "Unknown addressing sub-mode!"); + case ARM_AM::ia: return isLD ? "fd" : "ea"; + case ARM_AM::ib: return isLD ? "ed" : "fa"; + case ARM_AM::da: return isLD ? "fa" : "ed"; + case ARM_AM::db: return isLD ? "ea" : "fd"; + } + } + + /// 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 skip the first run of ones, then + // retry the hunt. + if (Imm & 1) { + unsigned TrailingOnes = CountTrailingZeros_32(~Imm); + if (TrailingOnes != 32) { // Avoid overflow on 0xFFFFFFFF + // Restart the search for a high-order bit after the initial seconds of + // ones. + unsigned TZ2 = CountTrailingZeros_32(Imm & ~((1 << TrailingOnes)-1)); + + // Rotate amount must be even. + unsigned RotAmt2 = TZ2 & ~1; + + // If this fits, use it. + if (RotAmt2 != 32 && (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; + } + + /// getThumbImmNonShiftedVal - If V is a value that satisfies + /// isThumbImmShiftedVal, return the non-shiftd value. + static inline unsigned getThumbImmNonShiftedVal(unsigned V) { + return V >> getThumbImmValShift(V); + } + + //===--------------------------------------------------------------------===// + // 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. + // + // 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) { + assert(Imm12 < (1 << 12) && "Imm too large!"); + bool isSub = Opc == sub; + return Imm12 | ((int)isSub << 12) | (SO << 13); + } + 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); + } + + + //===--------------------------------------------------------------------===// + // 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. + + /// getAM3Opc - This function encodes the addrmode3 opc field. + static inline unsigned getAM3Opc(AddrOpc Opc, unsigned char Offset) { + bool isSub = Opc == sub; + return ((int)isSub << 8) | Offset; + } + static inline unsigned char getAM3Offset(unsigned AM3Opc) { + return AM3Opc & 0xFF; + } + static inline AddrOpc getAM3Op(unsigned AM3Opc) { + return ((AM3Opc >> 8) & 1) ? sub : add; + } + + //===--------------------------------------------------------------------===// + // 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 + // + // If the 4th bit (writeback)is set, then the base register is updated after + // the memory transfer. + + static inline AMSubMode getAM4SubMode(unsigned Mode) { + return (AMSubMode)(Mode & 0x7); + } + + static inline unsigned getAM4ModeImm(AMSubMode SubMode, bool WB = false) { + return (int)SubMode | ((int)WB << 3); + } + + static inline bool getAM4WBFlag(unsigned Mode) { + return (Mode >> 3) & 1; + } + + //===--------------------------------------------------------------------===// + // 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 third field encodes the operation + // in bit 8, the immediate in bits 0-7. + // + // This can also be used for FP load/store multiple ops. The third field encodes + // writeback mode in bit 8, the number of registers (or 2 times the number of + // registers for DPR ops) in bits 0-7. In addition, bit 9-11 encodes one of the + // following two sub-modes: + // + // IA - Increment after + // DB - Decrement before + + /// 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; + } + + /// getAM5Opc - This function encodes the addrmode5 opc field for FLDM and + /// FSTM instructions. + static inline unsigned getAM5Opc(AMSubMode SubMode, bool WB, + unsigned char Offset) { + assert((SubMode == ia || SubMode == db) && + "Illegal addressing mode 5 sub-mode!"); + return ((int)SubMode << 9) | ((int)WB << 8) | Offset; + } + static inline AMSubMode getAM5SubMode(unsigned AM5Opc) { + return (AMSubMode)((AM5Opc >> 9) & 0x7); + } + static inline bool getAM5WBFlag(unsigned AM5Opc) { + return ((AM5Opc >> 8) & 1); + } + +} // end namespace ARM_AM +} // end namespace llvm + +#endif + |
