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304 lines
8.9 KiB
C++
304 lines
8.9 KiB
C++
//
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// Instruction.hpp
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// Clock Signal
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//
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// Created by Thomas Harte on 15/01/21.
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// Copyright © 2021 Thomas Harte. All rights reserved.
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//
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#ifndef InstructionSets_x86_Instruction_h
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#define InstructionSets_x86_Instruction_h
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#include <cstdint>
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namespace InstructionSet {
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namespace x86 {
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/*
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Operations are documented below to establish expectations as to which
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instruction fields will be meaningful for each; this is a work-in-progress
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and may currently contain errors in the opcode descriptions — especially
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where implicit register dependencies are afoot.
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*/
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enum class Operation: uint8_t {
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Invalid,
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/// ASCII adjust after addition; source will be AL and destination will be AX.
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AAA,
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/// ASCII adjust before division; destination will be AX and source will be a multiplier.
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AAD,
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/// ASCII adjust after multiplication; destination will be AX and source will be a divider.
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AAM,
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/// ASCII adjust after subtraction; source will be AL and destination will be AX.
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AAS,
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/// Decimal adjust after addition; source and destination will be AL.
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DAA,
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/// Decimal adjust after subtraction; source and destination will be AL.
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DAS,
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/// Convert byte into word; source will be AL, destination will be AH.
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CBW,
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/// Convert word to double word; source will be AX and destination will be DX.
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CWD,
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/// Escape, for a coprocessor; perform the bus cycles necessary to read the source and destination and perform a NOP.
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ESC,
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/// Stops the processor until the next interrupt is fired.
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HLT,
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/// Waits until the WAIT input is asserted; if an interrupt occurs then it is serviced but returns to the WAIT.
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WAIT,
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/// Add with carry; source, destination, operand and displacement will be populated appropriately.
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ADC,
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/// Add; source, destination, operand and displacement will be populated appropriately.
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ADD,
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/// Subtract with borrow; source, destination, operand and displacement will be populated appropriately.
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SBB,
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/// Subtract; source, destination, operand and displacement will be populated appropriately.
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SUB,
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/// Unsigned multiply; multiplies the source value by AX or AL, storing the result in DX:AX or AX.
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MUL,
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/// Signed multiply; multiplies the source value by AX or AL, storing the result in DX:AX or AX.
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IMUL,
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/// Unsigned divide; divide the source value by AX or AL, storing the quotient in AL and the remainder in AH.
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DIV,
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/// Signed divide; divide the source value by AX or AL, storing the quotient in AL and the remainder in AH.
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IDIV,
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/// Increment; source, destination, operand and displacement will be populated appropriately.
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INC,
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/// Decrement; source, destination, operand and displacement will be populated appropriately.
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DEC,
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/// Reads from the port specified by source to the destination.
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IN,
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/// Writes from the port specified by destination from the source.
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OUT,
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// Various jumps; see the displacement to calculate targets.
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JO, JNO, JB, JNB, JE, JNE, JBE, JNBE,
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JS, JNS, JP, JNP, JL, JNL, JLE, JNLE,
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/// Far call; see the segment() and offset() fields.
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CALLF,
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/// Displacement call; followed by a 16-bit operand providing a call offset.
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CALLD,
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/// Near call.
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CALLN,
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/// Return from interrupt.
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IRET,
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/// Near return; if source is not ::None then it will be an ::Immediate indicating how many additional bytes to remove from the stack.
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RETF,
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/// Far return; if source is not ::None then it will be an ::Immediate indicating how many additional bytes to remove from the stack.
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RETN,
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/// Near jump; if an operand is not ::None then it gives an absolute destination; otherwise see the displacement.
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JMPN,
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/// Far jump to the indicated segment and offset.
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JMPF,
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/// Relative jump performed only if CX = 0; see the displacement.
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JPCX,
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/// Generates a software interrupt of the level stated in the operand.
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INT,
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/// Generates a software interrupt of level 3.
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INT3,
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/// Generates a software interrupt of level 4 if overflow is set.
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INTO,
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/// Load status flags to AH.
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LAHF,
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/// Load status flags from AH.
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SAHF,
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/// Load a segment and offset from the source into DS and the destination.
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LDS,
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/// Load a segment and offset from the source into ES and the destination.
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LES,
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/// Computes the effective address of the source and loads it into the destination.
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LEA,
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/// Compare [bytes or words, per operation size]; source and destination implied to be DS:[SI] and ES:[DI].
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CMPS,
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/// Load string; reads from DS:SI into AL or AX, subject to segment override.
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LODS,
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/// Move string; moves a byte or word from DS:SI to ES:DI. If a segment override is provided, it overrides the the source.
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MOVS,
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/// Scan string; reads a byte or word from DS:SI and compares it to AL or AX.
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SCAS,
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/// Store string; store AL or AX to ES:DI.
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STOS,
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// Perform a possibly-conditional loop, decrementing CX. See the displacement.
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LOOP, LOOPE, LOOPNE,
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/// Loads the destination with the source.
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MOV,
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/// Negatives; source and destination point to the same thing, to negative.
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NEG,
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/// Logical NOT; source and destination point to the same thing, to negative.
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NOT,
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/// Logical AND; source, destination, operand and displacement will be populated appropriately.
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AND,
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/// Logical OR of source onto destination.
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OR,
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/// Logical XOR of source onto destination.
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XOR,
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/// NOP; no further fields.
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NOP,
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/// POP from the stack to destination.
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POP,
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/// POP from the stack to the flags register.
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POPF,
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/// PUSH the source to the stack.
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PUSH,
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/// PUSH the flags register to the stack.
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PUSHF,
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/// Rotate the destination left through carry the number of bits indicated by source.
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RCL,
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/// Rotate the destination right through carry the number of bits indicated by source.
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RCR,
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/// Rotate the destination left the number of bits indicated by source.
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ROL,
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/// Rotate the destination right the number of bits indicated by source.
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ROR,
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/// Arithmetic shift left the destination by the number of bits indicated by source.
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SAL,
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/// Arithmetic shift right the destination by the number of bits indicated by source.
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SAR,
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/// Logical shift right the destination by the number of bits indicated by source.
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SHR,
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/// Clear carry flag; no source or destination provided.
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CLC,
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/// Clear direction flag; no source or destination provided.
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CLD,
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/// Clear interrupt flag; no source or destination provided.
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CLI,
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/// Set carry flag.
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STC,
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/// Set decimal flag.
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STD,
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/// Set interrupt flag.
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STI,
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/// Complement carry flag; no source or destination provided.
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CMC,
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/// Compare; source, destination, operand and displacement will be populated appropriately.
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CMP,
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/// Sets flags based on the result of a logical AND of source and destination.
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TEST,
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/// Exchanges the contents of the source and destination.
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XCHG,
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/// Load AL with DS:[AL+BX].
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XLAT,
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};
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enum class Size: uint8_t {
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Implied = 0,
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Byte = 1,
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Word = 2,
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DWord = 4,
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};
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enum class Source: uint8_t {
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None,
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CS, DS, ES, SS,
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AL, AH, AX,
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BL, BH, BX,
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CL, CH, CX,
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DL, DH, DX,
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SI, DI,
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BP, SP,
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IndBXPlusSI,
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IndBXPlusDI,
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IndBPPlusSI,
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IndBPPlusDI,
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IndSI,
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IndDI,
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DirectAddress,
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IndBP,
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IndBX,
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Immediate
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};
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enum class Repetition: uint8_t {
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None, RepE, RepNE
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};
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class Instruction {
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public:
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Operation operation = Operation::Invalid;
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bool operator ==(const Instruction &rhs) const {
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return
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repetition_size_ == rhs.repetition_size_ &&
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sources_ == rhs.sources_ &&
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displacement_ == rhs.displacement_ &&
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operand_ == rhs.operand_;
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}
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private:
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// b0, b1: a Repetition;
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// b2+: operation size.
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uint8_t repetition_size_ = 0;
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// b0–b5: source;
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// b6–b11: destination;
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// b12–b14: segment override;
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// b15: lock.
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uint16_t sources_ = 0;
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// Unpackable fields.
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int16_t displacement_ = 0;
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uint16_t operand_ = 0; // ... or used to store a segment for far operations.
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public:
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Source source() const { return Source(sources_ & 0x3f); }
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Source destination() const { return Source((sources_ >> 6) & 0x3f); }
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bool lock() const { return sources_ & 0x8000; }
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Source segment_override() const { return Source((sources_ >> 12) & 7); }
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Repetition repetition() const { return Repetition(repetition_size_ & 3); }
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Size operation_size() const { return Size(repetition_size_ >> 2); }
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uint16_t segment() const { return uint16_t(operand_); }
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uint16_t offset() const { return uint16_t(displacement_); }
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int16_t displacement() const { return displacement_; }
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uint16_t operand() const { return operand_; }
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Instruction() noexcept {}
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Instruction(
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Operation operation,
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Source source,
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Source destination,
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bool lock,
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Source segment_override,
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Repetition repetition,
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Size operation_size,
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int16_t displacement,
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uint16_t operand) noexcept :
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operation(operation),
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repetition_size_(uint8_t((int(operation_size) << 2) | int(repetition))),
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sources_(uint16_t(
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int(source) |
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(int(destination) << 6) |
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(int(segment_override) << 12) |
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(int(lock) << 15)
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)),
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displacement_(displacement),
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operand_(operand) {}
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};
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static_assert(sizeof(Instruction) <= 8);
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}
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}
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#endif /* InstructionSets_x86_Instruction_h */
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