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Usage Guide

Supported Instructions

ASMsim supports the following MIPS32 instructions:

R-Format Instructions

  • add $rd, $rs, $rt - Add registers
  • sub $rd, $rs, $rt - Subtract registers
  • and $rd, $rs, $rt - Bitwise AND
  • or $rd, $rs, $rt - Bitwise OR
  • slt $rd, $rs, $rt - Set less than
  • sll $rd, $rt, shamt - Shift left logical
  • srl $rd, $rt, shamt - Shift right logical
  • jr $rs - Jump register

I-Format Instructions

  • addi $rt, $rs, imm - Add immediate
  • lw $rt, offset($rs) - Load word
  • sw $rt, offset($rs) - Store word
  • beq $rs, $rt, label - Branch if equal
  • bne $rs, $rt, label - Branch if not equal

J-Format Instructions

  • j label - Jump
  • jal label - Jump and link

Program Features

Code Editor

  • Syntax highlighting
  • Real-time error checking
  • Line numbers
  • File loading support

Code Execution

  1. Step Mode: Execute one instruction at a time
  2. Shows current instruction
  3. Updates registers and memory

  4. Displays PC counter

  5. Run Mode: Execute entire program

  6. Runs to completion
  7. Shows final state
  8. Displays execution status

Memory View

  • Instruction memory display
  • Data memory display
  • Word-aligned addressing
  • Binary/Hex display options

Register View

  • All 32 MIPS registers
  • Real-time value updates
  • Register naming conventions

Code Examples

Basic Arithmetic

# Add two numbers
addi $s0, $zero, 5    # s0 = 5
addi $s1, $zero, 3    # s1 = 3
add $s2, $s0, $s1     # s2 = 8

Memory Operation

# Store and load a number
addi $t0, $zero, 100  # t0 = 100
sw $t0, 0($sp)        # Store 100 at stack pointer
lw $t1, 0($sp)        # Load value into t1

Branching

# Branch example
addi $t0, $zero, 5
addi $t1, $zero, 5
beq $t0, $t1, equal    # Branch if t0 = t1
j exit
equal: 
  addi $t2, $zero, 1
exit: