/ac-assembler

the assembler for A-instruction and C-instruction

Primary LanguageJavaMIT LicenseMIT

ac-assembler

This is an assembler for A-instruction and C-instruction.

This assembler is for course nand2tetirs programming assignment.

Usage

  • java -jar assemble.jar file.asm
  • The input file path should end with .asm
  • The target file will end with .hack

Manual - Specifications

  • A register A: the register holding an address
  • D register D: the register holding data
  • M register M: the virtual register holding the data in memory located by A register
  • symbol: the string representing variable or label; it should not be a string of which all characters are digits

Manual - Instructions and Grammars

  • Comment

    • single line comment //<comments>

  • Label

    • grammar: (<label>)
      • <label> is a symbol
    • semantics
      • add a lable for conviniently jump

  • A instruction

    • grammar: @<value>
      • <value> is a symbol
    • semantics
      • load <value> to address register A
      • <value> can be a deciaml integer in [0,16641)
      • <value> can be a label or variable

  • C instruction

    • grammar: <destination>=<computation>[;<jump>] or [<destination>=]<computation>;<jump>
    • semantics:
      • load the result of <computation> to <destination>; if the result meets condition <jump>, the address of next instruction will be the one stored in A

Supported Computations and Jump Conditions

Computations

A computations M computations
0
1
-1
D
A M
!D
!A !M
-D
-A -M
D+1
A+1 M+1
D-1
A-1 M-1
D+A D+M
D-A D-M
A-D M-D
D&A D&M
D|A D|M

Jump Conditions

<jump> description
JMP jump without any condition
JEQ jump when the result is 0
JNE jump when the result is not 0
JGT jump when the result is greater than 0
JLT jump when the result is less than 0
JGE jump when the result is greater than or equal to 0
JLE jump when the result is less than or equal to 0