6 trits, 243 trytes

This is an esolang created by islptng. Unlike most of "x bits, y bytes", this esolang is serious.

Note: 1 tryte is 6 trits.

Syntax

This language uses the balanced ternary. The syntax is like a high-level language, because it has "if", "while", "break", etc. However, it has only a limited memory of 1,458 trits(and memory are wrapped at 729 i.e. 728+1=0), while program is stored in the memory.
Note that every instruction's length is a multiply of 6 trits.

Trits	Character notation	Meaning
0<address>	get	Read memory
t<address><value>	set	Write value to memory
1t<codes>1100	do ... end	Code block
11t1<cond>10<codeblock>	while ... then	While loop
11tt<cond>10<codeblock>	if ... then	If block
110t00	halt	halt
110t01	continue	continue
110t0t	break	break
111tt0	inp	Get a number from user.
111tt1<val>	outp	Output the value as signed number.
111t10	getch	Get a character form user.
111t1t<val>	putch	Output the value as a character.
Commands below has 1 argument.
110t10	neg	Tritwise NOT (1->t->1, 0->0)
110t11	rotu	Tritwise Rotate Up (t->0->1->t)
110t1t	rotd	Tritwise Rotate Down (t->1->0->t)
110tt1	rise	Tritwise Rise (t->0->1->1)
110ttt	fall	Tritwise Fall (1->0->t->t)
110tt0	sign	Take its sign. Returns 000000, 111111 or tttttt
Commands below begins with 111.	They have 2 arguments.
00t	mod	Modulo.
001	mul	Multiplication
000	add	Addition
0tt	and	Tritwise AND.
0t1	or	Tritwise OR.
0t0	teql	Tritwise Equal. 1 if two trits were equal, t otherwise.
01t	shl	Tritwise shift left.
011	shr	Tritwise shift right.
010	rol	Tritwise rotate left.
t00	eql	Equality. 111111 if two arguments are the same, tttttt otherwise.
t11	div	Division.
ttt	abs	Absolute value.
t0t	lsi	Less than. (Signed)
t01	lsu	Less than. (Unsigned)

Examples

Hello World

Character:

while lsu get_p get_enddat then do putch do do p:data end end set_p add get_p get_const1 end halt
data: 72 101 108 108 111 44 32 87 111 114 108 100 33 enddat:const1:1

Ternary dump:

11t111 1t0100 01t000
100110 1t111t 1t1t1t
00011t 110011 00t001
t01110 000001 t00010
011100 110t00
; below is decimal
72 101 108 108 111 44 32 87 111 114 108 100 33 10 1