"A simple assembler for a simple processor."

Writing the @ symbol lets you 'name' the next address in program memory. A label can be used in place of any 5-bit address.

@abc // stores the address of the next command
add
sub
jmp @abc // goes back to the 'add' statement

Writing the * symbol lets you 'name' an address in data memory. A pointer can be used in place of any 4-bit address.

*idx = 0101
st *idx // stores A to 0101

You can enter any number as a binary, decimal, or hexidecimal. All of the following lines do the same thing (set the pointer *idx to 0100). The assembler deduces the number of bits that the number should take up.

*idx = 0b100 // 0b in front means binary
*idx = 0b0100 // any number of leading zeros
*idx = 100 // (no modifier means binary)
*idx = 0d4 // 0d for decimal
*idx = 0x4 // 0x for hexidecimal

If your implementation has extra non-standard commands, good for you! You can still use the assembler if you encode your special commands as literals. When the assmbler comes to a literal number , it translates that number into binary literally. For example:

This

add
sub
0b11110001
0xAD
51
add
sub

Compiles to

00 01 F1 AD 00 01

since 11110001 base 2 is F1 base 16.

Java-style comments are ignored (both line-comments and block-comments).

add // This is a comment
sub /*
this is a comment
so is this
*/
ld 100 // /*
(notably) this is a comment
*/

• add (0000)
• sub (0001)
• ld (0010) takes one 4-bit address
• xchg (0011)
• st (0100) takes one 4-bit address
• jmp (101) takes one 5-bit address
• djmp ("delayed jump") is an alias for jmp
• jmpn (110) takes one 5-bit address
• djmpn ("delayed jump if negative") is an alias for jmpn
• loada (0111)
• sta (1000)
• incr (1001)
• nop (1000)

This

add       sub
ld
1000
st1000

is equivalent to this

add
sub
ld 1000
st 1000

Error messages look really nice with line number and the error line with the offending token underlined. Hopefully you won't have to see them. :)

Execute the program normally (with no arguments) to enter GUI mode as usual.

To use CMD mode, add the argument cmd to the program. It reads source from stdin, outputs the assembled binary to stdout, and outputs errors to stderr. Run this from the prompt to compile test.asm to tset.out: java -jar LALU_Assembler_v*.jar cmd < test.asm > test.out.