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Registers

Registers

Registers Component Provides a 32-bit MIPS register file implementation with:

  • 32 general-purpose registers ($0-$31)

  • Program Counter (PC) special register

  • Register naming conventions following MIPS architecture

Source code in sim/registers.py 
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class Registers:
    '''
    Registers Component
    Provides a 32-bit MIPS register file implementation with:\n
    - 32 general-purpose registers ($0-$31)\n
    - Program Counter (PC) special register\n
    - Register naming conventions following MIPS architecture\n
    '''
    def __init__(self):
        # 32 general-purpose registers (including $zero)
        self.registers = [0] * 32
        # Special registers
        self.pc = 0  # Program Counter

    def reset(self):
        '''Reset Register File State\n
        Initializes all general-purpose registers to 0\n
        Resets program counter (PC) to 0\n
        Returns:\n
            None
        '''
        self.registers = [0] * 32
        self.pc = 0

    def read_register(self, register_number):
        '''Read Value from Register\n
        Parameters:\n
            register_number (int): Register number (0-31)\n
        Returns:\n
            int: 32-bit value stored in specified register\n
        Raises:\n
            ValueError: If register_number is outside valid range (0-31)
        '''
        if 0 <= register_number < 32:
            return self.registers[register_number]
        else:
            raise ValueError(f"Invalid register number: {register_number}")

    def write_register(self, register_number, value):
        '''Write Value to Register\n
        Parameters:\n
            register_number (int): Register number (0-31)\n
            value (int): 32-bit value to write\n
        Notes:\n
            - Writing to $zero (register 0) is silently ignored\n
            - Values are masked to 32 bits (& 0xFFFFFFFF)\n
        Raises:\n
            ValueError: If register_number is outside valid range (0-31)
        '''
        if 0 <= register_number < 32:
            if register_number != 0:  # Prevent writing to $zero
                self.registers[register_number] = value & 0xFFFFFFFF
        else:
            raise ValueError(f"Invalid register number: {register_number}")

    def get_register_name(self, register_number):
        '''Get MIPS Register Name\n
        Converts register number to standard MIPS register name\n
        Parameters:\n
            register_number (int): Register number (0-31)\n
        Returns:\n
            str: Register name (e.g., "$zero", "$t0", "$sp")\n
            "Invalid": If register_number is outside valid range\n
        Register naming follows MIPS conventions:\n
            $0: $zero (constant 0)\n
            $1: $at (assembler temporary)\n
            $2-$3: $v0-$v1 (values)\n
            $4-$7: $a0-$a3 (arguments)\n
            $8-$15: $t0-$t7 (temporaries)\n
            $16-$23: $s0-$s7 (saved)\n
            $24-$25: $t8-$t9 (temporaries)\n
            $26-$27: $k0-$k1 (kernel)\n
            $28: $gp (global pointer)\n
            $29: $sp (stack pointer)\n
            $30: $fp (frame pointer)\n
            $31: $ra (return address)
        '''
        register_names = [
            "$zero", "$at", "$v0", "$v1", "$a0", "$a1", "$a2", "$a3",
            "$t0", "$t1", "$t2", "$t3", "$t4", "$t5", "$t6", "$t7",
            "$s0", "$s1", "$s2", "$s3", "$s4", "$s5", "$s6", "$s7",
            "$t8", "$t9", "$k0", "$k1", "$gp", "$sp", "$fp", "$ra"
        ]
        return register_names[register_number] if 0 <= register_number < 32 else "Invalid"

get_register_name(register_number)

Get MIPS Register Name

Converts register number to standard MIPS register name

Parameters:

register_number (int): Register number (0-31)

Returns:

str: Register name (e.g., "$zero", "$t0", "$sp")

"Invalid": If register_number is outside valid range

Register naming follows MIPS conventions:

$0: $zero (constant 0)

$1: $at (assembler temporary)

$2-$3: $v0-$v1 (values)

$4-$7: $a0-$a3 (arguments)

$8-$15: $t0-$t7 (temporaries)

$16-$23: $s0-$s7 (saved)

$24-$25: $t8-$t9 (temporaries)

$26-$27: $k0-$k1 (kernel)

$28: $gp (global pointer)

$29: $sp (stack pointer)

$30: $fp (frame pointer)

$31: $ra (return address)
Source code in sim/registers.py 
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def get_register_name(self, register_number):
    '''Get MIPS Register Name\n
    Converts register number to standard MIPS register name\n
    Parameters:\n
        register_number (int): Register number (0-31)\n
    Returns:\n
        str: Register name (e.g., "$zero", "$t0", "$sp")\n
        "Invalid": If register_number is outside valid range\n
    Register naming follows MIPS conventions:\n
        $0: $zero (constant 0)\n
        $1: $at (assembler temporary)\n
        $2-$3: $v0-$v1 (values)\n
        $4-$7: $a0-$a3 (arguments)\n
        $8-$15: $t0-$t7 (temporaries)\n
        $16-$23: $s0-$s7 (saved)\n
        $24-$25: $t8-$t9 (temporaries)\n
        $26-$27: $k0-$k1 (kernel)\n
        $28: $gp (global pointer)\n
        $29: $sp (stack pointer)\n
        $30: $fp (frame pointer)\n
        $31: $ra (return address)
    '''
    register_names = [
        "$zero", "$at", "$v0", "$v1", "$a0", "$a1", "$a2", "$a3",
        "$t0", "$t1", "$t2", "$t3", "$t4", "$t5", "$t6", "$t7",
        "$s0", "$s1", "$s2", "$s3", "$s4", "$s5", "$s6", "$s7",
        "$t8", "$t9", "$k0", "$k1", "$gp", "$sp", "$fp", "$ra"
    ]
    return register_names[register_number] if 0 <= register_number < 32 else "Invalid"

read_register(register_number)

Read Value from Register

Parameters:

register_number (int): Register number (0-31)

Returns:

int: 32-bit value stored in specified register

Raises:

ValueError: If register_number is outside valid range (0-31)
Source code in sim/registers.py 
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def read_register(self, register_number):
    '''Read Value from Register\n
    Parameters:\n
        register_number (int): Register number (0-31)\n
    Returns:\n
        int: 32-bit value stored in specified register\n
    Raises:\n
        ValueError: If register_number is outside valid range (0-31)
    '''
    if 0 <= register_number < 32:
        return self.registers[register_number]
    else:
        raise ValueError(f"Invalid register number: {register_number}")

reset()

Reset Register File State

Initializes all general-purpose registers to 0

Resets program counter (PC) to 0

Returns:

None
Source code in sim/registers.py 
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def reset(self):
    '''Reset Register File State\n
    Initializes all general-purpose registers to 0\n
    Resets program counter (PC) to 0\n
    Returns:\n
        None
    '''
    self.registers = [0] * 32
    self.pc = 0

write_register(register_number, value)

Write Value to Register

Parameters:

register_number (int): Register number (0-31)

value (int): 32-bit value to write

Notes:

- Writing to $zero (register 0) is silently ignored

- Values are masked to 32 bits (& 0xFFFFFFFF)

Raises:

ValueError: If register_number is outside valid range (0-31)
Source code in sim/registers.py 
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def write_register(self, register_number, value):
    '''Write Value to Register\n
    Parameters:\n
        register_number (int): Register number (0-31)\n
        value (int): 32-bit value to write\n
    Notes:\n
        - Writing to $zero (register 0) is silently ignored\n
        - Values are masked to 32 bits (& 0xFFFFFFFF)\n
    Raises:\n
        ValueError: If register_number is outside valid range (0-31)
    '''
    if 0 <= register_number < 32:
        if register_number != 0:  # Prevent writing to $zero
            self.registers[register_number] = value & 0xFFFFFFFF
    else:
        raise ValueError(f"Invalid register number: {register_number}")