SpASM 6502 Assembler Updated

The SpASM 6502 Spreadsheet Assembler has been updated. SpASM version 1.2.0 includes a new Linker as part of the Assembler and also includes Error Checking.

According the the A2SE posting by Francois Vander Linden , SpASM’s author, “

You can now use the worksheets as code modules. All the assemblies are then automatically linked, ready to be copied/pasted into your favorite emulator.Sample code that displays Mario on screen, callable from Applesoft is included.”

SpASM 1.20 will work in either Microsoft Excel or in Libre Office 7.1 or newer. SpASM is a full featured assembler and includes the following features:

  • all the 6502 instructions plus a couple of pseudo-instructions
  • all addressing modes
  • global and local labels
  • EQUs to declare constants
  • use of +/- offsets with constants/labels
  • use of “#” to reference values
  • decimal notation by default (0-65535)
  • use of “$” for hexadecimal notation (2 bytes max)
  • use of “%” for binary notation (16 bits max)
  • use of “>” and “<” to point to MSB and LSB (2 bytes only)
  • display cycle count
  • ORG within code to define different starting addresses for modules
  • HEX pseudo-instruction to define HEX data
  • ASC/STR pseudo-instructions to define text constants (with ASC, hi-bit is unset, while with STR, it is)
  • syntax highlighting
  • linking of object modules (sheets) in the same workbook
  • global labels across the workbook
  • negative values are supported for decimal notation
  • error checking (highlighted in brown)

The SpASM 6502 Spreadsheet Assembler is available for free from:

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