EXA Quick Reference

A quick reference for the language used to control EXAs

Introduction

Here's a quick-reference guide to the language used in EXAPUNKS to control EXAs.

Basic Commands

Command	Syntax	Usage
COPY	R/N R	Copy the specified value to the specified register
ADDI	R/N R/N R	Adds the first two values and stores the result in the specified register
SUBI	R/N R/N R	Subtracts the second value from the first and store the result in the specified register
MULI	R/N R/N R	Multiplies the first two values and stores the result in the specified register
DIVI	R/N R/N R	Return how many times the second value fits completely into the first value, and stores it in the specified register
MODI	R/N R/N R	Returns the modulus of a division operation and stores it in the specified register
SWIZ	R/N R/N R	Modifies the given number according to a mask (Please see the section labelled "Swizzle")
MARK	L	Create a label with the specified name. Does not add to the line count - similar to NOTE
JUMP	L	Jumps to the specified label
TJMP	L	Jumps to the specified label if the T register is greater than 0
FJMP	L	Jumps to the specified label if the T register is 0
TEST	R/N =/</> R/N | EOF | MRD	Tests the specified condition, writing the result to T. Please see the "Testing" section
REPL	L	Creates a new EXA running from the specified label
HALT		Kills the current EXA, dropping any held file
KILL		Kills a random EXA in this host (Prefers EXAs owned by the player)
LINK	R/N	Traverses the specified link
HOST	R	Writes the current host name to the specified register
MODE		Toggles the M register's access mode between Local and Global
VOID	M/F	Removes the current value from the currently held file / M register
MAKE		Create a new file, held by this EXA
GRAB	R/N	Grab the specified file
FILE	R	Write the current file name to the specified register
SEEK	R/N	Move X values in the held file, where X can be between -9999 and 9999
DROP		Drops the currently held file
WIPE		Deletes the currently held file
NOTE		Note instructions do not count towards the line-count
NOOP		Do nothing for 1 cycle

Testing

The TEST command has many uses.

All uses of TEST overwrite the T register with 1 (true) or 0 (false).

This can be used to trigger jumps to labels, with TJMP and FJMP.

You can use TEST EOF to check if the file-pointer is at the end of the current file.

You can use TEST MRD to check if there is anything available to read on the M register.

Swizzle

SWIZ allows you to modify a number.

You pass the original number (or location/register) as the first argument, a mask to apply (or the location/register containing it) to the second argument, and the register to store the result in as the third.

The mask should be a number of up to four digits consisting of digits 0-4.

Unusual Commands

Command	Syntax	Usage
RAND	R/N R/N R	Only available in some challenges
DATA	N N N ?	Only available in REDSHIFT, this specifies a file for an EXA to begin holding
WAIT		Only available in REDSHIFT, this waits for the next frame render

[gardenapple]

TJMP will also jump if T contains a word, since words are "not equal to 0".

[wi1d3]

TJMP will jump when T is ANYTHING OTHER THAN 0
Not just when it's greater than 0.
For example T = -1 will cause a jump.

[595Blue]

For peaslee:
Digits that aren't 1, 2, 3 or 4, when used as a mask in a SWIZ command, will insert a zero. Great for those [rare] times when you need to null out a specific digit or insert some padding.

[ElNico56]

@REP 4
LINK @{803,2}
@END

Would be a better way to do what Gargish said

[L4z3r]

I believe MARK does count towards size / line count.

[Zane49er]

Semicolons work as notes.
;HELLO
is the same as
NOTE HELLO

[Gargish🐸]

Adding to weev's macro comment: Macro counter substitution

@REP 4
LINK 80@{3,2}
@END

expands to

LINK 803
LINK 805
LINK 807
LINK 809

that is, first number in braces is the initial value, the second is the step count, and since it is just a text replacement you can string it together with other text.

[skellington]

Using

@REP N
thing to repeat
@END

is a hidden convenience for repeating something a fixed number of times - I don't think you can use a register in place of N.

@REP 5
copy m x
@END

expands at runtime to

copy m x
copy m x
copy m x
copy m x
copy m x

You can also alt-click on a line to run the program to that point, like a breakpoint. Not sure if there are any other hidden gems like this.

[peaslee]

You can use a one-digit mask with SWIZ.

SWIZ 1234 2 X (copies 3 into X)

[Statement]

MARK adds to size, but not to cycles. Rather strange, since one would presume it's a precompiled address, however EXAPUNKS doesn't support absolute or relative branching so it's its own goofy thing.