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August 24, 2022 ยท View on GitHub

tet

the tetrvm bytecode format

tetrvm bytecode instructions are 10 bytes long. the maximum value this can have is 7.

the first two bytes are reserved for opcodes, the rest is for input.

if an opcode does not take input but one is given, it is ignored.

opcodes

all programs compiling to tet have to end with stop (0o06).

push

pushes to the top of the stack

- -- a

pop

pops the top of the stack, removing it

a -- -

peek

gets the top value on the stack, not useful except internally

a -- a

dup

duplicates the top of the stack

a -- a a

swap

swaps the top two values on the stack

a b -- b a

jump

jumps to the specified label. eg: jump 0o01 jumps to label 1.

does not modify the stack

stop

stops the current execution

put

writes the top of the stack to the console

a -- -

puts

writes the top of the stack's value in ascii to the console

a -- -

mul

multiplies the top two values on the stack

a b -- (b * a)

div

divides the top two values on the stack

a b -- (b / a)

neg

makes the top of the stack negative

note: does not act like a NOT

a -- (-a)

add

adds the top two values on the stack

a b -- (b + a)

sub

subtracts the top two values on the stack

a b -- (b - a)

jit

jumps if the top of the stack is true (value 1).

a -- -

eq

checks if the top two values on the stack are equal

this pushes either 0 or 1 to the stack

a b -- (b == a)

eqi

eq with input, checks if the top value equals the input value

a -- (i == a)

lab

introduces a label. the value/name should be a number.

does not modify the stack.

get

duplicates the top - nth element of the stack to the top

warning: this instruction is unsafe. you can very easily crash tetrvm with it

a b c d e -- e a b c d e

set

set top - nth element of the stack to value on top

warning: this instruction is unsafe. you can very easily crash tetrvm with it

a b c d e -- b c d a

read

reads a character from stdin and pushes its ascii value to the stack

- -- a

jgz

jumps if the top value on the stack is greater than 0.

a -- -

tesm

tesm is a simple assembly dialect. it is so simple in fact, that everything is an instruction, and each instruction is a keyword.

all instructions are listed above.

an example program that prints the result of 1 + 1 to the console, would be

push 1
push 1
add
put
stop

to use labels, use the lab instruction, and jump to the label's value:

labels start from 0, and increment by 1 for each new label. the identifiers are written to the bytecode, but not used. they are purely for readability.

lab 0
push 1
push 1
add
put
jump 0
stop

tesm has comments. you can begin comments by typing a semicolon (;)

push 1 ; pushes 1 to the stack
put    ; pops and prints the top of the stack
stop   ; stops execution