Question & Answer: In the lc3 the 16 bit data element xACCA is located at address x4000 (hex 4000). Address x300B holds the value x4000. What instructio…..

In the lc3 the 16 bit data element xACCA is located at address x4000 (hex 4000). Address x300B holds the value x4000.   What instruction located at address x3004 will load the value xACCA into Register 2. Write the complete instruction in 16 binary ________________

Expert Answer



LC3 Tools Reference

Assemblers, simulators, C compiler, IDEs, course sites, reference material.
(Also see user guides in this directory.)

LC3 Simulators and Assemblers and C Compiler.

P&P textbook’s web site, student materials.

  • MS Windows version:

      a. LC3Edit.exe: LC3 assembler and text editor.
         You don't have to use the editor, just open your already 
         edited text file in LC3Edit to assemble it. Also accepts ascii
         text files representing machine instructions in binary or hex notation,
         see menu "Translate", "Convert base 2" and "Convert base 16".
         Assembling (ie., "Translate"ing) foo.asm produces:
         1. foo.bin (foo.obj represented in ascii, one 16-bit binary number per line)
         2. foo.hex (foo.obj represented in ascii, one 16-bit hex number per line)
         3. foo.obj (the actual bits of an LC3 machine-language load-object suitable 
                     for a loader; first line contains load address).
         4. foo.sym (assembly language labels and their values, the symbol table)
         5. foo.lst (detailed listing of assembly output along with corresponding 
                     assembly source code)
          Translation of binary and hex inputs yeilds a .obj load module.
      b. Simulate.exe: LC3 simulator to execute foo.obj.
         Provides a graphical display of memory contents, register values, 
         translation of memory contents to assembly language, and controls like 
         single-stepping exectuion and setting execution break points. Pre-loads 
         an OS (mostly code for some traps and exceptions).
  • Unix version (by Steven Lumetta):
    See ../src/

        Contains sources and makefiles to build,
        a. lc3as: commandline LC3 assembler producing (see details below),
          1. foo.obj, as above.
          2. foo.sym, as above.
        b. lc3sim: commandline LC3 simulator, 
           reads .obj files, simulates LC3 execution.
        c. lc3convert: commandline translator (see details below). 
           Takes .bin input and produces .obj output. The .bin input can be 
           binary (-b2) or hex (-b16).
        d. lc3os.asm: an lc3 operating system.
  • LC3 C compiler, lcc
        Ccompiler that runs on Unix flavors. Produces LC3 assembly code.
           See P&P textbook's web site:

Other Sources for LC3 tools

  • Course site w/ language manuals (UCR, CS-61, Jason Villarreal):

    • lc3_pseudoops.html: lc3Edit.exe assembler directives.
    • lc3_summary.html: LC3 Instruction Set Summary.
    • lc3_linking.html: A short note on linking in LC-3.
  • Course site documentation (CIS, U Penn, Diana Palsetia).
    Contains an lc3 assembler/simulator written in Java. Uses a version of the lc3 which includes a MCR (machine control reg), MPR (memory protection reg), TMR/TMI (timer), and memory-mapped video RAM. The simulator’s version of the lc3 ISA also includes an instruction that sets user/supervisor mode, jumpt. Site also has source code for an OS for the lc3. The OS code can be easily edited to convert it to standard lc3 ISA.
  • Ashley Wise’s LC-3 and LC-3b Tools (Simulator, Assembler, IDE)
    Pre-compiled IDE for Windows/Linux/Solaris.


  • End-of-lines, unix/dos/apple
    • MS Windows, DOS: x0D x0A
      (aka: CR LF, r f, ^13 ^10, ^M ^J, 0x0D 0x0A)
    • Apple Macintosh OS 9 and earlier: x0D (CR)
    • Unix (e.g., Linux), also Apple OS X and higher: x0A (LF)

LC3 assembler tools, unix version (Lumetta)

Build these tools using gcc (see README in distribution).

--- lc3as:        LC3 assembler, produces .obj files.
--- lc3convert:   ascii to .obj converter.


Assembles LC3 assembly source code to an .obj file.

Command            ---- Description 
-------------      ---------------------------
lc3as file.asm     ---- Creates file.obj and file.sym, the symbol table. 

Error Message                      ---- Explanation
------------------------           ---------------------------
file contains only comments        ---- no assembly instructions in file.
no .ORIG or .END directive found   ---- .ORIG/.END must be first/last line.
multiple .ORIG directives found    ---- one .ORIG is allowed per file. 
instruction appears before .ORIG   ---- instructions must start after .ORIG.
no .END directive found            ---- all programs must end with .END. 
label appears before .ORIG         ---- nothing should appear before .ORIG.
label has already appeared         ---- label can only be defined once.
unknown label x                    ---- label x is referenced, but not defined. 
illegal operands for x             ---- instruction has bad operand specification. 
unterminated string                ---- .STRINGZ has no close-quotes.
contains unrecognizable characters ---- found chars that assembler cannot parse. 
WARNING: All text after .END is ignored.
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