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https://github.com/TomHarte/CLK.git
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Rearrange class for clarity.
This commit is contained in:
Thomas Harte
parent
f9d98ed219
commit
a30cad5e8a
@ -655,11 +655,141 @@ class DataPointer {
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template<bool is_32bit> class Instruction {
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public:
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Operation operation() const {
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using DisplacementT = typename std::conditional<is_32bit, int32_t, int16_t>::type;
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using ImmediateT = typename std::conditional<is_32bit, uint32_t, uint16_t>::type;
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using AddressT = ImmediateT;
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constexpr Instruction() noexcept {}
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constexpr Instruction(Operation operation) noexcept :
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Instruction(operation, Source::None, Source::None, ScaleIndexBase(), false, AddressSize::b16, Source::None, DataSize::None, 0, 0) {}
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constexpr Instruction(
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Operation operation,
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Source source,
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Source destination,
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ScaleIndexBase sib,
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bool lock,
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AddressSize address_size,
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Source segment_override,
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DataSize data_size,
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DisplacementT displacement,
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ImmediateT operand) noexcept :
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operation_(operation),
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mem_exts_source_(uint8_t(
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(int(address_size) << 7) |
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(displacement ? 0x40 : 0x00) |
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(operand ? 0x20 : 0x00) |
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int(source) |
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(source == Source::Indirect ? (uint8_t(sib) & 7) : 0)
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)),
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source_data_dest_sib_(uint16_t(
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(int(data_size) << 14) |
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(lock ? (1 << 13) : 0) |
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((uint8_t(sib) & 0xf8) << 2) |
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int(destination) |
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(destination == Source::Indirect ? (uint8_t(sib) & 7) : 0)
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)) {
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// Decisions on whether to include operand, displacement and/or size extension words
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// have implicitly been made in the int packing above; honour them here.
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int extension = 0;
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if(has_operand()) {
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extensions_[extension] = operand;
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++extension;
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}
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if(has_displacement()) {
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extensions_[extension] = ImmediateT(displacement);
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++extension;
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}
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// Patch in a fully-resolved segment.
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Source segment = segment_override;
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if(segment == Source::None) segment = this->source().default_segment();
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if(segment == Source::None) segment = this->destination().default_segment();
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if(segment == Source::None) segment = Source::DS;
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source_data_dest_sib_ |= (int(segment)&7) << 10;
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}
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/// @returns The number of bytes used for meaningful content within this class. A receiver must use at least @c sizeof(Instruction) bytes
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/// to store an @c Instruction but is permitted to reuse the trailing sizeof(Instruction) - packing_size() for any purpose it likes. Teleologically,
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/// this allows a denser packing of instructions into containers.
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constexpr size_t packing_size() const {
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return
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offsetof(Instruction<is_32bit>, extensions_) +
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(has_displacement() + has_operand()) * sizeof(ImmediateT);
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}
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/// @returns The @c Operation performed by this instruction.
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constexpr Operation operation() const {
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return operation_;
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}
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bool operator ==(const Instruction<is_32bit> &rhs) const {
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/// @returns A @c DataPointer describing the 'destination' of this instruction, conventionally the first operand in Intel-syntax assembly.
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constexpr DataPointer destination() const {
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return DataPointer(
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Source(source_data_dest_sib_ & sib_masks[(source_data_dest_sib_ >> 3) & 3]),
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((source_data_dest_sib_ >> 2) & 0xf8) | (source_data_dest_sib_ & 0x07)
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);
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}
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/// @returns A @c DataPointer describing the 'source' of this instruction, conventionally the second operand in Intel-syntax assembly.
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constexpr DataPointer source() const {
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return DataPointer(
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Source(mem_exts_source_ & sib_masks[(mem_exts_source_ >> 3) & 3]),
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((source_data_dest_sib_ >> 2) & 0xf8) | (mem_exts_source_ & 0x07)
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);
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}
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/// @returns @c true if the lock prefix was present on this instruction; @c false otherwise.
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constexpr bool lock() const {
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return source_data_dest_sib_ & (1 << 13);
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}
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/// @returns The address size for this instruction; will always be 16-bit for instructions decoded by a 16-bit decoder but can be 16- or 32-bit for
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/// instructions decoded by a 32-bit decoder, depending on the program's use of the address size prefix byte.
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constexpr AddressSize address_size() const {
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return AddressSize(mem_exts_source_ >> 7);
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}
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/// @returns The segment that should be used for data fetches if this operation accepts segment overrides.
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constexpr Source data_segment() const {
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return Source(
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int(Source::ES) +
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((source_data_dest_sib_ >> 10) & 7)
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);
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}
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/// @returns The data size of this operation — e.g. `MOV AX, BX` has a data size of `::Word` but `MOV EAX, EBX` has a data size of
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/// `::DWord`. This value is guaranteed never to be `DataSize::None` even for operations such as `CLI` that don't have operands and operate
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/// on data that is not a byte, word or double word.
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constexpr DataSize operation_size() const {
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return DataSize(source_data_dest_sib_ >> 14);
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}
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/// @returns The immediate value provided with this instruction, if any. E.g. `ADD AX, 23h` has the operand `23h`.
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constexpr ImmediateT operand() const {
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const ImmediateT ops[] = {0, operand_extension()};
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return ops[has_operand()];
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}
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/// @returns The immediate segment value provided with this instruction, if any. Relevant for far calls and jumps; e.g. `JMP 1234h:5678h` will
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/// have a segment value of `1234h`.
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constexpr uint16_t segment() const {
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return uint16_t(operand());
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}
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/// @returns The offset provided with this instruction, if any. E.g. `MOV AX, [es:1998h]` has an offset of `1998h`.
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constexpr ImmediateT offset() const {
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const ImmediateT offsets[] = {0, displacement_extension()};
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return offsets[has_displacement()];
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}
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/// @returns The displacement provided with this instruction `SUB AX, [SI+BP-23h]` has an offset of `-23h` and `JMP 19h`
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/// has an offset of `19h`.
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constexpr DisplacementT displacement() const {
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return DisplacementT(offset());
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}
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// Standard comparison operator.
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constexpr bool operator ==(const Instruction<is_32bit> &rhs) const {
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if( operation_ != rhs.operation_ ||
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mem_exts_source_ != rhs.mem_exts_source_ ||
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source_data_dest_sib_ != rhs.source_data_dest_sib_) {
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@ -676,10 +806,6 @@ template<bool is_32bit> class Instruction {
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return true;
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}
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using DisplacementT = typename std::conditional<is_32bit, int32_t, int16_t>::type;
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using ImmediateT = typename std::conditional<is_32bit, uint32_t, uint16_t>::type;
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using AddressT = ImmediateT;
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private:
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Operation operation_ = Operation::Invalid;
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@ -722,125 +848,12 @@ template<bool is_32bit> class Instruction {
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return extensions_[(mem_exts_source_ >> 5) & 1];
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}
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public:
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/// @returns The number of bytes used for meaningful content within this class. A receiver must use at least @c sizeof(Instruction) bytes
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/// to store an @c Instruction but is permitted to reuse the trailing sizeof(Instruction) - packing_size() for any purpose it likes. Teleologically,
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/// this allows a denser packing of instructions into containers.
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size_t packing_size() const {
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return
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offsetof(Instruction<is_32bit>, extensions_) +
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(has_displacement() + has_operand()) * sizeof(ImmediateT);
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}
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private:
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// A lookup table to help with stripping parts of the SIB that have been
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// hidden within the source/destination fields.
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static constexpr uint8_t sib_masks[] = {
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0x1f, 0x1f, 0x1f, 0x18
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};
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public:
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DataPointer source() const {
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return DataPointer(
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Source(mem_exts_source_ & sib_masks[(mem_exts_source_ >> 3) & 3]),
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((source_data_dest_sib_ >> 2) & 0xf8) | (mem_exts_source_ & 0x07)
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);
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}
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DataPointer destination() const {
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return DataPointer(
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Source(source_data_dest_sib_ & sib_masks[(source_data_dest_sib_ >> 3) & 3]),
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((source_data_dest_sib_ >> 2) & 0xf8) | (source_data_dest_sib_ & 0x07)
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);
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}
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bool lock() const {
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return source_data_dest_sib_ & (1 << 13);
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}
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AddressSize address_size() const {
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return AddressSize(mem_exts_source_ >> 7);
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}
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/// @returns @c Source::None if no segment is applicable; the segment to use for any
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/// memory-accessing source otherwise.
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Source data_segment() const {
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return Source(
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int(Source::ES) +
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((source_data_dest_sib_ >> 10) & 7)
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);
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}
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/// @returns The data size of this operation — e.g. `MOV AX, BX` has a data size of `::Word` but `MOV EAX, EBX` has a data size of
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/// `::DWord`. This value is guaranteed never to be `DataSize::None` even for operations such as `CLI` that don't have operands and operate
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/// on data that is not a byte, word or double word.
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DataSize operation_size() const {
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return DataSize(source_data_dest_sib_ >> 14);
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}
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ImmediateT operand() const {
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const ImmediateT ops[] = {0, operand_extension()};
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return ops[has_operand()];
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}
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DisplacementT displacement() const {
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return DisplacementT(offset());
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}
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uint16_t segment() const {
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return uint16_t(operand());
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}
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ImmediateT offset() const {
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const ImmediateT offsets[] = {0, displacement_extension()};
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return offsets[has_displacement()];
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}
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constexpr Instruction() noexcept {}
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constexpr Instruction(Operation operation) noexcept :
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Instruction(operation, Source::None, Source::None, ScaleIndexBase(), false, AddressSize::b16, Source::None, DataSize::None, 0, 0) {}
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constexpr Instruction(
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Operation operation,
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Source source,
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Source destination,
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ScaleIndexBase sib,
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bool lock,
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AddressSize address_size,
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Source segment_override,
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DataSize data_size,
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DisplacementT displacement,
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ImmediateT operand) noexcept :
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operation_(operation),
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mem_exts_source_(uint8_t(
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(int(address_size) << 7) |
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(displacement ? 0x40 : 0x00) |
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(operand ? 0x20 : 0x00) |
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int(source) |
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(source == Source::Indirect ? (uint8_t(sib) & 7) : 0)
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)),
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source_data_dest_sib_(uint16_t(
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(int(data_size) << 14) |
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(lock ? (1 << 13) : 0) |
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((uint8_t(sib) & 0xf8) << 2) |
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int(destination) |
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(destination == Source::Indirect ? (uint8_t(sib) & 7) : 0)
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))
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{
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// Decisions on whether to include operand, displacement and/or size extension words
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// have implicitly been made in the int packing above; honour them here.
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int extension = 0;
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if(has_operand()) {
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extensions_[extension] = operand;
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++extension;
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}
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if(has_displacement()) {
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extensions_[extension] = ImmediateT(displacement);
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++extension;
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}
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// Patch in a fully-resolved segment.
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Source segment = segment_override;
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if(segment == Source::None) segment = this->source().default_segment();
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if(segment == Source::None) segment = this->destination().default_segment();
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if(segment == Source::None) segment = Source::DS;
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source_data_dest_sib_ |= (int(segment)&7) << 10;
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}
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};
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static_assert(sizeof(Instruction<true>) <= 16);
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