Different tools, different priorities.

REPRODUCIBLE EVIDENCE

Six samples, eight toolchains plus an ASM baseline.

* Pure ASM is a diagnostic lower-level baseline, not a ninth high-level toolchain. State Update is behavior-validated but not yet a strict display-equivalent size ranking.

Measured revisions: Amy Studio 02596a3f (2026-10-20); CVBasic 0.9.2 e99aede0 (2026-07-24); z88dk nightly 26587-33d4c333ea-20261020 with zsdcc 4.6; ugBASIC e35e6df (2026-10-10); devkitSMS 533ae572 (2026-09-29) with SDCC 4.5; PVColLib 1.6.0 f9335847 (2026-05-31); NewColeco's historical GETPUT 1.1 snapshot with SDCC 2.9.0 #5416 (March 2009); and PkK libcv 0.28/libcvu 0.21 (2021-10-01) rebuilt with SDCC 4.5. The refreshed z88dk suite saves 15 bytes overall. devkitSMS adds 12 bytes overall to include its corrected ColecoVision VDP acknowledgement, IRQ/NMI vector protection, and bounded RAM clearing.

BIOS-ASSISTED PURE Z80 ASSEMBLY

A measured lower-level baseline for all six samples.

Matching hand-written ASM implementations pass every GearColeco oracle using Amy Studio’s permitted assets, codecs, BIOS services, and behavior. Their six ROMs occupy 5,126 bytes versus Amy Studio’s 7,391, exposing concrete optimization targets. Amy remains safe by default while explicit, bounded NMI/VRAM batches avoid redundant protection in expert code.

The controller ROM fell from 297 to 264 bytes by replacing CONT_SCAN, cartridge decoding, and a keypad table with two BIOS DECODER calls. It passes neutral, keypad, held-direction, FIRE, and release tests. POLLER remains useful for two-sample debounce, but its 12-byte result and 83-91 executed instructions cannot beat one 29-instruction DECODER segment here.

The ASM result is a diagnostic baseline, not evidence that assembly is universally preferable. The State Update ASM fixture validates the complete headless workload but does not reproduce Amy Studio's additional status display.

SPECIALIZED GRAPHICS EXPERIMENTS

Useful evidence, outside the main ranking.

The ZIP also contains an eight-tool PutPixel Motion fixture derived from sverx’s SGlib_CV example; seven pass motion, two-controller, and Name Table checks. All nine principal controller ROMs pass, including Pure ASM and ugBASIC. A source-only pixel, line, and circle study based on Oscar Toledo’s CVBasic example remains unranked work in progress.

AMY SOURCE + GEARCOLECO

All six benchmark cases.

Hello World

text screen
backdrop sky blue
print centered at 11, "HELLO, WORLD!"
screen on

Warrior bitmap

picture WarriorPicture:
  pattern from "@project/warrior.pattern.zx0" codec zx0
  color from "@project/warrior.color.zx0" codec zx0
end picture

show picture WarriorPicture

Exomizer proof: the evidence archive contains this equivalent Amy source, both .exo assets, and the exact 3,319-byte ROM for direct testing.

picture WarriorExomizer:
  pattern from "@project/warrior.pattern.exo" codec exomizer
  color from "@project/warrior.color.exo" codec exomizer
end picture

show picture WarriorExomizer

Controller monitor

InputLoop:
  wait
  if keypad(1) <> 255 then
    backdrop magenta
  elseif joypad(1).fire then
    backdrop light red
  elseif joypad(1).up then
    backdrop light green
  else
    backdrop dark blue
  end if
  goto InputLoop

Animated three-color metasprite

A metasprite is one visual actor assembled from multiple hardware sprites. This example overlaps three 16x16 sprites for white, yellow, and black layers.

u8 PlayerX = 120
u8 PlayerY = 88
u8 AnimationFrame = 0

sprites simple
set sprite count 3

MainLoop:
  wait
  if joypad(1).left then PlayerX -= 1
  if joypad(1).right then PlayerX += 1
  AnimationFrame = 1 - AnimationFrame
  set sprite 0 to PlayerY,PlayerX,0,15
  set sprite 1 to PlayerY,PlayerX,4,11
  set sprite 2 to PlayerY,PlayerX,8,1
  update sprites
  goto MainLoop

Gameplay state update

This deterministic six-actor workload measures state dispatch, record-array updates, timers, movement, collisions, score, and checksum rather than rendering speed.

state machine WorldBehavior:
  Running calls UpdateActors
  Bonus calls UpdateBonus
end state machine

ActorState Actors[6]
u16 Score = 0
u16 Checksum = 0

for Tick = 0 to 47
  dispatch WorldMode using WorldBehavior
  ' UpdateActors handles records, timers, movement and collisions.
next

Graphics II tile animation

One shared pattern animates every star while six stationary 3x2 ships alternate tile frames through Name Table updates.

AnimationLoop:
  wait
  Tick += 1
  if Tick & 3 = 0 then
    StarFrame = (StarFrame + 1) % 3
    copy StarPatterns[StarFrame * 8] count 8 to vram.pattern + StarTile * 8
  end if
  if Tick & 7 = 0 then
    ShipFrame = 1 - ShipFrame
    for Ship = 0 to 5
      put ShipTiles[ShipFrame * 6] frame size 3,2 at ShipX[Ship],ShipY[Ship]
    next
  end if
goto AnimationLoop

GRAPHICS II COMPRESSION CORPUS

42 pictures, 16 codecs, 672 exact checks.

Every 12,288-byte Pattern + Color picture round-tripped exactly. Podiums rank first-use ROM bytes: payload plus one linked decoder. Gallery cards show the three smallest payloads and Pletter's rank when it is outside the top three.

Most, median, and least compressible

Selection is mechanical. Exomizer uses a 226-byte ROM decoder plus 156 bytes of CPU RAM. Amy Studio reserves that workspace at a 256-byte boundary; its generated address varies and must not overlap other RAM. The detailed PDF contains all 42 converted images and per-picture evidence.

AMY'S LEGACY

The compact philosophy predates Amy Studio.

NewColeco links Amy's historical CRTCV, CVLIB, GETPUT 1.1, and DAN2 code without ABI changes. Its Hello, bitmap, and controller ROMs remain small and run correctly today. The exact Warrior test confirms its direct-to-VRAM DAN2 path. Amy Studio continues that BIOS-aware, original-hardware approach with a modern language, integrated tools, and debugging.

January 2018 devkit archive · AtariAge 2018 update · AtariAge history

PVCOLLIB EVIDENCE

A broad ColecoVision C library, not only a ROM-size entry.

PKK'S DEVKIT EVIDENCE

Small linked C code, with a specialized bitmap codec.

Philipp Klaus Krause's devkit uses libcv/libcvu, completes all six runtime fixtures, and has the third-smallest total in this suite at 10,835 occupied bytes. Its Warrior RLE+Huffman path is exact, but needs a 2,934-byte payload, 514-byte shared tree/configuration, about 411 decoder bytes, and 19 bytes of runtime RAM. In the separate 42-picture study, which also includes RAW and libcv's native method, it usually ranks 14th or 15th among 17 methods. That result informs shared-codebook research; it is not a general verdict on PkK's devkit.

Installation tutorial · libcv reference · ColecoVision.eu

Stock and expanded hardware

The measured ranking targets an original ColecoVision with its TMS9918A, SN76489, 1 KB RAM, BIOS, and compact cartridge. Expanded hardware remains a valid strength, but is reported separately.

Philosophy

Language and game systems

Production workflow