CSASM contains several predefined variables, called "registers", for usage when creating local/global variables is undesirable.

General-Purpose Registers

The $a, $1, $2, $3, $4 and $5 registers are of type obj, meaning they can be used to store any type of value.
Furthermore, CSASM is smart enough to know what type a value in an obj variable is when used for an instruction, so converting the value beforehand isn't required.

The $a register, named the "accumulator", has special treatment.
A handful of instructions manipulate it directly instead of the stack, namely the conv.a, is.a, lda and sta instructions.

Flag Registers

Registers prefixed with $f. are the flag registers.
These registers use the bool type, a type not directly accessible by CSASM.

Currently, the flag registers include the following registers:

• Carry ($f.c)
  • This register is modified by the rol and ror instructions
  • The clf.c and stf.c instructions clear and set this register, in that order
• Conversion ($f.n)
  • This register is set by the conv instruction when a conversion from a str value to a numerical type was successful
  • The clf.n and stf.n instructions clear and set this register, in that order
• Comparison ($f.o)
  • This register is set by the comp, comp.gt, comp.gte, comp.lt, comp.lte, is, is.a and isarr instructions
  • The clf.o and stf.o instructions clear and set this register, in that order

Console Registers

Registers prefixed with $con. are the console registers.
These registers modify aspects of the console.

Register	Type	Usage
$con.bcol	i32	Gets or sets the background colour for the text written to the console
$con.bh	i32	Gets or sets the buffer height of the console: the amount of rows of characters the console can contain
$con.bw	i32	Gets or sets the buffer width of the console: the amount of columns of characters the console can contain
$con.caps	bool	Gets whether the CAPS LOCK key is active
$con.cx	i32	Gets or sets the column the cursor is located at
$con.cy	i32	Gets or sets the row the cursor is located at
$con.fcol	i32	Gets or sets the foreground colour for the text written to the console
$con.ttl	str	Gets or sets the title of the console window
$con.wh	i32	Gets or sets the window height of the console: how many rows of characters are displayed at once
$con.ww	i32	Gets or sets the window width of the console: how many columns of characters are displayed at once

File I/O Registers

These registers are explained in detail in the File I/O page on the wiki.

Miscellaneous Registers

These registers do not fit in any of the above categories.

• $args: An ~arr:str representing the arguments passed to the program, excluding the defined debugging flags (-verbose and -reportstack)
• $as.e: The empty arithmetic set (∅). This register is of type ~set.