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Diffstat (limited to 'disas/libvixl/a64/instructions-a64.cc')
-rw-r--r-- | disas/libvixl/a64/instructions-a64.cc | 238 |
1 files changed, 238 insertions, 0 deletions
diff --git a/disas/libvixl/a64/instructions-a64.cc b/disas/libvixl/a64/instructions-a64.cc new file mode 100644 index 0000000000..e87fa3acce --- /dev/null +++ b/disas/libvixl/a64/instructions-a64.cc @@ -0,0 +1,238 @@ +// Copyright 2013, ARM Limited +// All rights reserved. +// +// Redistribution and use in source and binary forms, with or without +// modification, are permitted provided that the following conditions are met: +// +// * Redistributions of source code must retain the above copyright notice, +// this list of conditions and the following disclaimer. +// * Redistributions in binary form must reproduce the above copyright notice, +// this list of conditions and the following disclaimer in the documentation +// and/or other materials provided with the distribution. +// * Neither the name of ARM Limited nor the names of its contributors may be +// used to endorse or promote products derived from this software without +// specific prior written permission. +// +// THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS CONTRIBUTORS "AS IS" AND +// ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED +// WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE +// DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR CONTRIBUTORS BE LIABLE +// FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL +// DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR +// SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER +// CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, +// OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE +// OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. + +#include "a64/instructions-a64.h" +#include "a64/assembler-a64.h" + +namespace vixl { + + +static uint64_t RotateRight(uint64_t value, + unsigned int rotate, + unsigned int width) { + ASSERT(width <= 64); + rotate &= 63; + return ((value & ((1UL << rotate) - 1UL)) << (width - rotate)) | + (value >> rotate); +} + + +static uint64_t RepeatBitsAcrossReg(unsigned reg_size, + uint64_t value, + unsigned width) { + ASSERT((width == 2) || (width == 4) || (width == 8) || (width == 16) || + (width == 32)); + ASSERT((reg_size == kWRegSize) || (reg_size == kXRegSize)); + uint64_t result = value & ((1UL << width) - 1UL); + for (unsigned i = width; i < reg_size; i *= 2) { + result |= (result << i); + } + return result; +} + + +// Logical immediates can't encode zero, so a return value of zero is used to +// indicate a failure case. Specifically, where the constraints on imm_s are +// not met. +uint64_t Instruction::ImmLogical() { + unsigned reg_size = SixtyFourBits() ? kXRegSize : kWRegSize; + int64_t n = BitN(); + int64_t imm_s = ImmSetBits(); + int64_t imm_r = ImmRotate(); + + // An integer is constructed from the n, imm_s and imm_r bits according to + // the following table: + // + // N imms immr size S R + // 1 ssssss rrrrrr 64 UInt(ssssss) UInt(rrrrrr) + // 0 0sssss xrrrrr 32 UInt(sssss) UInt(rrrrr) + // 0 10ssss xxrrrr 16 UInt(ssss) UInt(rrrr) + // 0 110sss xxxrrr 8 UInt(sss) UInt(rrr) + // 0 1110ss xxxxrr 4 UInt(ss) UInt(rr) + // 0 11110s xxxxxr 2 UInt(s) UInt(r) + // (s bits must not be all set) + // + // A pattern is constructed of size bits, where the least significant S+1 + // bits are set. The pattern is rotated right by R, and repeated across a + // 32 or 64-bit value, depending on destination register width. + // + + if (n == 1) { + if (imm_s == 0x3F) { + return 0; + } + uint64_t bits = (1UL << (imm_s + 1)) - 1; + return RotateRight(bits, imm_r, 64); + } else { + if ((imm_s >> 1) == 0x1F) { + return 0; + } + for (int width = 0x20; width >= 0x2; width >>= 1) { + if ((imm_s & width) == 0) { + int mask = width - 1; + if ((imm_s & mask) == mask) { + return 0; + } + uint64_t bits = (1UL << ((imm_s & mask) + 1)) - 1; + return RepeatBitsAcrossReg(reg_size, + RotateRight(bits, imm_r & mask, width), + width); + } + } + } + UNREACHABLE(); + return 0; +} + + +float Instruction::ImmFP32() { + // ImmFP: abcdefgh (8 bits) + // Single: aBbb.bbbc.defg.h000.0000.0000.0000.0000 (32 bits) + // where B is b ^ 1 + uint32_t bits = ImmFP(); + uint32_t bit7 = (bits >> 7) & 0x1; + uint32_t bit6 = (bits >> 6) & 0x1; + uint32_t bit5_to_0 = bits & 0x3f; + uint32_t result = (bit7 << 31) | ((32 - bit6) << 25) | (bit5_to_0 << 19); + + return rawbits_to_float(result); +} + + +double Instruction::ImmFP64() { + // ImmFP: abcdefgh (8 bits) + // Double: aBbb.bbbb.bbcd.efgh.0000.0000.0000.0000 + // 0000.0000.0000.0000.0000.0000.0000.0000 (64 bits) + // where B is b ^ 1 + uint32_t bits = ImmFP(); + uint64_t bit7 = (bits >> 7) & 0x1; + uint64_t bit6 = (bits >> 6) & 0x1; + uint64_t bit5_to_0 = bits & 0x3f; + uint64_t result = (bit7 << 63) | ((256 - bit6) << 54) | (bit5_to_0 << 48); + + return rawbits_to_double(result); +} + + +LSDataSize CalcLSPairDataSize(LoadStorePairOp op) { + switch (op) { + case STP_x: + case LDP_x: + case STP_d: + case LDP_d: return LSDoubleWord; + default: return LSWord; + } +} + + +Instruction* Instruction::ImmPCOffsetTarget() { + ptrdiff_t offset; + if (IsPCRelAddressing()) { + // PC-relative addressing. Only ADR is supported. + offset = ImmPCRel(); + } else { + // All PC-relative branches. + ASSERT(BranchType() != UnknownBranchType); + // Relative branch offsets are instruction-size-aligned. + offset = ImmBranch() << kInstructionSizeLog2; + } + return this + offset; +} + + +inline int Instruction::ImmBranch() const { + switch (BranchType()) { + case CondBranchType: return ImmCondBranch(); + case UncondBranchType: return ImmUncondBranch(); + case CompareBranchType: return ImmCmpBranch(); + case TestBranchType: return ImmTestBranch(); + default: UNREACHABLE(); + } + return 0; +} + + +void Instruction::SetImmPCOffsetTarget(Instruction* target) { + if (IsPCRelAddressing()) { + SetPCRelImmTarget(target); + } else { + SetBranchImmTarget(target); + } +} + + +void Instruction::SetPCRelImmTarget(Instruction* target) { + // ADRP is not supported, so 'this' must point to an ADR instruction. + ASSERT(Mask(PCRelAddressingMask) == ADR); + + Instr imm = Assembler::ImmPCRelAddress(target - this); + + SetInstructionBits(Mask(~ImmPCRel_mask) | imm); +} + + +void Instruction::SetBranchImmTarget(Instruction* target) { + ASSERT(((target - this) & 3) == 0); + Instr branch_imm = 0; + uint32_t imm_mask = 0; + int offset = (target - this) >> kInstructionSizeLog2; + switch (BranchType()) { + case CondBranchType: { + branch_imm = Assembler::ImmCondBranch(offset); + imm_mask = ImmCondBranch_mask; + break; + } + case UncondBranchType: { + branch_imm = Assembler::ImmUncondBranch(offset); + imm_mask = ImmUncondBranch_mask; + break; + } + case CompareBranchType: { + branch_imm = Assembler::ImmCmpBranch(offset); + imm_mask = ImmCmpBranch_mask; + break; + } + case TestBranchType: { + branch_imm = Assembler::ImmTestBranch(offset); + imm_mask = ImmTestBranch_mask; + break; + } + default: UNREACHABLE(); + } + SetInstructionBits(Mask(~imm_mask) | branch_imm); +} + + +void Instruction::SetImmLLiteral(Instruction* source) { + ASSERT(((source - this) & 3) == 0); + int offset = (source - this) >> kLiteralEntrySizeLog2; + Instr imm = Assembler::ImmLLiteral(offset); + Instr mask = ImmLLiteral_mask; + + SetInstructionBits(Mask(~mask) | imm); +} +} // namespace vixl + |