Standard Library - Binary Operations

Bitwise operations for Romasm assembly

Overview

The Romasm binary operations library (stdlib/binary.romasm) provides bitwise operations: AND, OR, XOR, and NOT. These operations work on the binary representation of integers.

Note: These are different from the Basic Romasm binary operations (which work on Roman symbol states). These operate on standard integer bit patterns.

Available Functions

bitwise_and

Performs bitwise AND operation: result = value1 & value2

Each bit in the result is 1 only if both corresponding bits in the inputs are 1.

Input Output
R0 = value1
R1 = value2		 R0 = value1 & value2
Example: 
; Calculate 5 & 3 = 1
; 5 = 101₂, 3 = 011₂
; AND = 001₂ = 1
LOAD R0, 5
LOAD R1, 3
CALL bitwise_and
PRINT R0         ; Outputs: 1

bitwise_or

Performs bitwise OR operation: result = value1 | value2

Each bit in the result is 1 if either corresponding bit in the inputs is 1.

Input Output
R0 = value1
R1 = value2		 R0 = value1 | value2
Example: 
; Calculate 5 | 3 = 7
; 5 = 101₂, 3 = 011₂
; OR = 111₂ = 7
LOAD R0, 5
LOAD R1, 3
CALL bitwise_or
PRINT R0         ; Outputs: 7

bitwise_xor

Performs bitwise XOR (exclusive OR) operation: result = value1 ^ value2

Each bit in the result is 1 if the corresponding bits in the inputs are different.

Input Output
R0 = value1
R1 = value2		 R0 = value1 ^ value2
Example: 
; Calculate 5 ^ 3 = 6
; 5 = 101₂, 3 = 011₂
; XOR = 110₂ = 6
LOAD R0, 5
LOAD R1, 3
CALL bitwise_xor
PRINT R0         ; Outputs: 6

bitwise_not

Performs bitwise NOT operation (complement): result = ~value

Flips all bits: 0 becomes 1, 1 becomes 0.

Input Output
R0 = value R0 = ~value
Example: 
; Calculate ~5
; 5 = 101₂ (in 16-bit: 0000000000000101)
; NOT = 1111111111111010 = 65530 (16-bit)
LOAD R0, 5
CALL bitwise_not
PRINT R0         ; Outputs: 65530 (for 16-bit)

Implementation Details

These functions implement bitwise operations by:

  1. Processing bits one at a time (from least significant to most significant)
  2. Using MOD 2 to extract the lowest bit
  3. Using SHR (shift right) to move to the next bit
  4. Using SHL (shift left) to build the result

Note: The current implementation processes up to 32 bits, but can be extended for larger values.

Use Cases

  • Flags: Pack multiple boolean flags into a single integer
  • Masks: Extract specific bits from values
  • Cryptography: XOR operations for simple encryption
  • Low-level Programming: Direct bit manipulation

Related Documentation