Chombit - Assembly language

Chombit is an open source assembly language created in 2025 by Pete Gonzalez.

#1523on PLDB

1Years Old

The assembly language for Chombit, the 32-bit CPU of the Hybrix virtual computer. Its 25 instructions each have a documented machine code and cycle cost, and its "framed registers" map a function's stack frame directly onto CPU registers. Devices are controlled exclusively via memory-mapped I/O. The Hybrix kernel and garbage collector are written in hand-coded Chombit assembly.

Tags: assembly language
Chombit is written in TypeScript
1 PLDB concepts link to Chombit: Hybrix

Example from the web:

# -----------------------------------------------------------------------------
# fibonacci(n: int): int    (assembles to 46 bytes)
@main.fibonacci:
    push fp
    move fp, sp
    add sp, 12

    # i:-16 return value
    # i:-12 arg_n
    # i:-8  return ip
    # i:-4  fp
    # i:0   a
    # i:4   b
    # i:8   next

    compare i:-12, 0
    if less
    fail 20 # 20 = function was called with an invalid argument

    move i:0, 0               # a = fibonacci(0)
    move i:4, 1               # b = fibonacci(1)

@main.fibonacci.l_0:
    compare i:-12, 0
    if zero
    jump @main.fibonacci.l_1

    move i:8, i:0
    add i:8, i:4              # next = a + b
    move i:0, i:4             # a = b
    move i:4, i:8             # b = next

    add i:-12, -1
    jump @main.fibonacci.l_0

@main.fibonacci.l_1:
    move i:-16, i:0

    add sp, -12
    pop fp
    pop ip
    fill 4

Fun fact:

Framed registers map a function's stack frame onto CPU registers: negative indexes are parameters and positive indexes are locals, so in i:-12 and i:0 the sign tells you which is which.

Language features

Feature	Supported	Example
Hexadecimals	✓	store [i:4], byte $ac
Bitwise Operators	✓	xor b:kernel.sweep_alloc.dead_mark, $10
Pointers	✓	load b:12, [i:0]
Expressions	✓	add sp, (-12 -16)
Constants	✓	const kernel.constant.io_region = $d0_0000
Conditionals	✓	compare i:-12, 0 if zero jump @main.fibonacci.l_1
Gotos	✓	jump @main.fibonacci.l_0
Labels	✓	@main.fibonacci.l_0:
Processor Registers	✓	move i:8, i:0