Developer Handbook¶

Instructions¶

class riscvmodel.insn.Instruction¶

Base class for instructions

This is the abstract base class for all instruction. They are derived via their instruction type.

decode(machinecode: int)¶

Decode a machine code and configure this instruction from it.

Parameters:	machinecode (int) – Machine code as 32-bit integer

execute(model: riscvmodel.model.State)¶

Execute this instruction

Execute the instruction on the given model

Parameters:	model – RISC-V core model
Returns:	nothing

randomize(variant: riscvmodel.variant.Variant)¶

Randomize this instruction

This function randomizes the instance of an instruction according to the given variant.

Parameters:	variant – RISC-V ISA variant
Returns:	nothing

class riscvmodel.insn.InstructionBType(rs1: int = None, rs2: int = None, imm: int = None)¶

B-type instructions encode branches. Branches have two source registers that are compared. They then change the program counter by the immediate value.

Parameters:	rs1 (int) – Source 1 for comparison rs2 (int) – Source 2 for comparison imm (int) – Immediate for branch destination address calculation (13-bit, signed, 16-bit aligned)

decode(machinecode: int)¶

Decode a machine code and configure this instruction from it.

Parameters:	machinecode (int) – Machine code as 32-bit integer

randomize(variant: riscvmodel.variant.Variant)¶

Randomize this instruction

This function randomizes the instance of an instruction according to the given variant.

Parameters:	variant – RISC-V ISA variant
Returns:	nothing

class riscvmodel.insn.InstructionCBType(rd: int = None, imm: int = None)¶

decode(machinecode: int)¶

Decode a machine code and configure this instruction from it.

Parameters:	machinecode (int) – Machine code as 32-bit integer

class riscvmodel.insn.InstructionCIType(rd: int = None, imm: int = None)¶

decode(machinecode: int)¶

Decode a machine code and configure this instruction from it.

Parameters:	machinecode (int) – Machine code as 32-bit integer

randomize(variant: riscvmodel.variant.Variant)¶

Randomize this instruction

This function randomizes the instance of an instruction according to the given variant.

Parameters:	variant – RISC-V ISA variant
Returns:	nothing

class riscvmodel.insn.InstructionCRType(rd: int = None, rs: int = None)¶

decode(machinecode: int)¶

Decode a machine code and configure this instruction from it.

Parameters:	machinecode (int) – Machine code as 32-bit integer

randomize(variant: riscvmodel.variant.Variant)¶

Randomize this instruction

This function randomizes the instance of an instruction according to the given variant.

Parameters:	variant – RISC-V ISA variant
Returns:	nothing

class riscvmodel.insn.InstructionCSSType(rs: int = None, imm: int = None)¶

randomize(variant: riscvmodel.variant.Variant)¶

Randomize this instruction

This function randomizes the instance of an instruction according to the given variant.

Parameters:	variant – RISC-V ISA variant
Returns:	nothing

class riscvmodel.insn.InstructionCType¶

class riscvmodel.insn.InstructionILType(rd: int = None, rs1: int = None, imm: int = None)¶

I-type instruction specialization for stores. The produce a different assembler than the base class

Parameters:	rd (int) – Destination register rs1 (int) – Source register 1 imm – 12-bit signed immediate

class riscvmodel.insn.InstructionISType(rd: int = None, rs1: int = None, shamt: int = None)¶

I-Type instruction specialization for shifts by immediate. The immediate differs here (5-bit unsigned).

Parameters:	rd (int) – Destination register rs1 (int) – Source register 1 imm (int) – 12-bit signed immediate

decode(machinecode: int)¶

Decode a machine code and configure this instruction from it.

Parameters:	machinecode (int) – Machine code as 32-bit integer

randomize(variant: riscvmodel.variant.Variant)¶

Randomize this instruction

This function randomizes the instance of an instruction according to the given variant.

Parameters:	variant – RISC-V ISA variant
Returns:	nothing

class riscvmodel.insn.InstructionIType(rd: int = None, rs1: int = None, imm: int = None)¶

I-type instructions are registers that use one source register and an immediate to produce a new value for the destination register.

Two specialization exist for this class: InstructionILType for load instructions and InstructionISType for instructions that shift by an immediate value.

Parameters:	rd (int) – Destination register rs1 (int) – Source register 1 imm (int) – 12-bit signed immediate

decode(machinecode: int)¶

Decode a machine code and configure this instruction from it.

Parameters:	machinecode (int) – Machine code as 32-bit integer

randomize(variant: riscvmodel.variant.Variant)¶

Randomize this instruction

This function randomizes the instance of an instruction according to the given variant.

Parameters:	variant – RISC-V ISA variant
Returns:	nothing

class riscvmodel.insn.InstructionJType(rd: int = None, imm: int = None)¶

J-type instruction are used for jump and link instructions.

Parameters:	rd (int) – Destination register imm (int) – Immediate for the jump (21-bit, signed, 16-bit aligned)

decode(machinecode: int)¶

Decode a machine code and configure this instruction from it.

Parameters:	machinecode (int) – Machine code as 32-bit integer

randomize(variant: riscvmodel.variant.Variant)¶

Randomize this instruction

This function randomizes the instance of an instruction according to the given variant.

Parameters:	variant – RISC-V ISA variant
Returns:	nothing

class riscvmodel.insn.InstructionRType(rd: int = None, rs1: int = None, rs2: int = None)¶

R-type instructions are 3-register instructions which use two source registers and write one output register.

Parameters:	rd (int) – Destination register rs1 (int) – Source register 1 rs2 (int) – Source register 2

decode(machinecode: int)¶

Decode a machine code and configure this instruction from it.

Parameters:	machinecode (int) – Machine code as 32-bit integer

randomize(variant: riscvmodel.variant.Variant)¶

Randomize this instruction

This function randomizes the instance of an instruction according to the given variant.

Parameters:	variant – RISC-V ISA variant
Returns:	nothing

class riscvmodel.insn.InstructionSType(rs1: int = None, rs2: int = None, imm: int = None)¶

S-type instructions are used for stores. They don’t have a destination register, but two source registers.

Parameters:	rs1 (int) – Source register for base address rs2 (int) – Source register for data imm (int) – Offset of store, for calculation of address relative to rs1

decode(machinecode: int)¶

Decode a machine code and configure this instruction from it.

Parameters:	machinecode (int) – Machine code as 32-bit integer

randomize(variant: riscvmodel.variant.Variant)¶

Randomize this instruction

This function randomizes the instance of an instruction according to the given variant.

Parameters:	variant – RISC-V ISA variant
Returns:	nothing

class riscvmodel.insn.InstructionUType(rd: int = None, imm: int = None)¶

U-type instructions are used for constant formation and set the upper bits of a register.

Parameters:	rd (int) – Destination register imm (int) – Immediate (20-bit, unsigned)

decode(machinecode: int)¶

Decode a machine code and configure this instruction from it.

Parameters:	machinecode (int) – Machine code as 32-bit integer

randomize(variant: riscvmodel.variant.Variant)¶

Randomize this instruction

This function randomizes the instance of an instruction according to the given variant.

Parameters:	variant – RISC-V ISA variant
Returns:	nothing

riscvmodel.insn.get_insns(*, cls=None)¶

Get all Instructions. This is based on all known subclasses of cls. If non is given, all Instructions are returned. Only such instructions are returned that can be generated, i.e., that have a mnemonic, opcode, etc. So other classes in the hierarchy are not matched.

Parameters:	cls (Instruction) – Base class to get list
Returns:	List of instruction classes

riscvmodel.insn.get_mnenomics()¶

Get all known mnemonics

Returns:	List of all known mnemonics
Return type:	List[str]

riscvmodel.insn.isa(mnemonic: str, *, opcode: int, funct3: int = None, funct7: int = None, funct12: int = None, variant=Variant(intregs=32, xlen=32, extensions=Extensions(M=False, A=False, F=False, D=False, Q=False, C=False)), extension=None)¶

Decorator for the instructions. The decorator contains the static information for the instructions, in particular the encoding parameters and the assembler mnemonic.

Parameters:	mnemonic – Assembler mnemonic opcode – Opcode of this instruction funct3 – 3 bit function code on bits 14 to 12 (R-, I-, S- and B-type) funct7 – 7 bit function code on bits 31 to 25 (R-type) funct12 – 12 bit function code on bits 31 to 20
Returns:	Wrapper class that overwrites the actual definition and contains static data

riscvmodel.insn.isaC(mnemonic: str, opcode: int, *, funct3=None, funct4=None, funct6=None, variant=Variant(intregs=32, xlen=32, extensions=Extensions(M=False, A=False, F=False, D=False, Q=False, C=False)), extension=Extensions(M=False, A=False, F=False, D=False, Q=False, C=True))¶

Decorator for the instructions. The decorator contains the static information for the instructions, in particular the encoding parameters and the assembler mnemonic.

Parameters:	mnemonic – Assembler mnemonic
Returns:	Wrapper class that overwrites the actual definition and contains static data

riscvmodel.insn.reverse_lookup(mnemonic: str)¶

Find instruction that matches the mnemonic.

Parameters:	mnemonic – Mnemonic to match
Returns:	`Instruction` that matches or None

Developer Handbook¶

Instructions¶

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