riscvlib 0.6.0

Resources for working with RISC-V in Python

riscvlib

Resources for working with RISC-V assembly in Python. Supporting instruction creation, pseudo instruction translation and register lookup for extenions:

• M Multiply and Divide
• F Single precision foating point (see limitations)
• B (Zba, Zbb, Zbc, Zbs) bit manipulation
• Zifencei ebreak and ecall
• Zicsr Control register instructions

Installation

The package can be installed using pip:

 $ pip install riscvlib  

Examples

Instruction, Static creation from a string

>> from riscvlib.instruction import Instruction  

>> i = Instruction.from_line("add x1, x2, x3")  
>> print(i) 
add x1, x2, x3  
>> i.to_bytes() 
b'\xb3\x001\x00'  
>> i  
RInstruction 'add' ['x1', 'x2', 'x3']

Specific Instruction Type

>> from riscvlib.instruction import RInstruction, IInstruction

>> r_instr = RInstruction("add", "x1", "x2", "a2")
>> print(r_instr)
add x1, x2, a2

>> i_instr = IInstruction("andi", "a0", "a1", -13)
>> print(i_instr)
andi a0, a1, -13
>> i_instr.to_bytes()  # note: bytes are 'little endian' ordered
b'\x13\xf55\xff'

Pseudo Instruction Translation

>> from riscvlib.instruction import translate_pseudo_instruction

>> out_list = translate_pseudo_instruction("mv", "a0", "x30")
>> print(out_list)
['addi a0, x30, 0']

>> out_list = translate_pseudo_instruction("la", "a0", "400")
>> print(out_list)
['lui a0, %hi(400)', 'addi a0, a0, %lo(400)']

Instruction Data

>> from riscvlib.risvdata import INSTRUCTION_MAP

>> INSTRUCTION_MAP['mul']
('MUL', '0110011', '000', '0000001', 'R', 'm', '32/64')
# (name, opcode, func3, func7, itype, extension, rv32/rv64)

Limitations

• Currently supports RV32IMFB (RISC-V 32 bit I,M,F and B(Zba,Zbb,Zbc,Zbs) extensions)
• F extension does not support "R4" type instructions i.e fmadd.s
• F extension Rounding Modes hardcoded to 'Nearest'(000)

Future

• Additional F extension support
• A, C and D extensions