Assembler

The Assembler will let you create EV3 Bytecode programs (.rbf) outside of the LEGO-provided environment.

The Opcodes are described in the "EV3 Firmware Developer Kit" on The Mindstorms Download Page

There are some minor changes compared to the documentation:

• The 'STRINGS' opcode is spelled 'STRING' in EV3Utils

• The 'GET_BUMBED' subcode for UI_READ was obviously a typo in the LEGO doc and the EV3Utils uses the correct spelling of 'GET_BUMPED'

• For 'INIT_BYTES' and the INIT functions in 'ARRAY', the count of objects is generated by the assember and is not needed.

The EV3Utils assembler has different syntax and features than the one which comes with the LMS2012 source code. Key differences include:

Feature	LMS2012	EV3Utils
Multi-line comments	/* a comment */	Not supported
Single-line comments	// my comment	; my coment
Line continuation	'=' at the end of the line	Not (yet) supported
Define	define NAME value	%define NAME value
Include Files	Not supported	%include "filename.inc"
Line Directives	Not supported	%line 33 myfile.lms
Subcall parameters	Listed as local variables	subcall fact(IN_32 n, OUT_32 result) {
Arrays and String Sizes	DataS string 32	DataS[32] string
Subcodes	UI_WRITE(LED, LED_RED)	UI_WRITE.LED(LED_RED)
Strings	Single-quote delimited	double-quote delimited
Character constants	Not supported	Single-quote delimited
Preprocessor Arithmetic	???	basic math supported
Output Listing	Not Supported	The 3rd filename of the assembler is the listing file name
Error Checking	Hardly any	Lots...too much, sometimes
Relative Jump Size	+/- 32K	+/- 2G
Implementation Language	Some LOGO Dialect	JAVA
Usability	Hard to use outside of LMS2012 Environment	Single runnable JAR

Bytecode definitions are based on the 1.07 source code, but can be regenerated in the source by running a perl script to regenerate the java source.