opbasm 1.2

Opbasm is a free cross-platform assembler for the Picoblaze-3 (PB3) and Picoblaze-6 (PB6) microcontrollers provided by Xilinx. It will run readily on any platform with a functional Python intepreter. Opbasm provides a better perfoming solution to assembling Picoblaze code without resorting to DOS or Windows emulation to run the native KCPSM assemblers.

Special features of Opbasm:

• Optional m4 preprocessor macros are available when the m4 program is installed. An extensive set of builtin macros provide more advanced features than the base language. For example, converting temperature scales becomes as easy as this:

reg16(rx, s4,s5)                ; Create a virtual 16-bit register pair

c_to_f:
  load reglower(rx), s0         ; Load 8-bit Celsius temperature
  signex(rx)                    ; Sign extend to 16-bits
  expr2s(rx := rx * 9 / 5 + 32) ; Perform 16x8-bit signed arithmetic to get Fahrenheit
  return

• Static code analysis to identify dead code and optionally remove it. This permits the development of code libraries that can be included without wasting memory on unused functions.

• Code block annotations with user defined PRAGMA meta-comments.

Support for the full Picoblaze-6 syntax is provided as well as enabling most of the new PB6 syntax enhancements in Picoblaze-3 code. The original templating system for ROM components is supported as well as a more flexible generic ROM component that can read .mem and .hex files directly during synthesis and simulation. A utility script is included that permits updating the ROM contents of a bitstream file without requiring resynthesis as was formerly supplied by the DOS-based KCPSM3 tools.

Files generated on non-Windows platforms will not have DOS line endings and Picoblaze-3 files are not restricted to 8.3 file names. Opbasm also runs significantly faster than the native implementation: