Dr. Mario (NES) (Nostaljipi/dr-mario-disassembly)

With completeCleanup = 0 and ver_revA = 1, the disassembly builds the No-Intro Dr. Mario (Japan, USA) (Rev 1) ROM byte for byte, apart from its 16-byte header. dr-mario/rom-is-disassembly

Value: 59b43881456c0720e9a35e391b11c4b2c55a8f91

So the lines cited below, on their original-build paths, are code in this ROM.

Cited by: Dr. Mario (NES)

fallingPill_checkYMove counts frames at the pill's row and drops it when the count passes an entry of speedCounterTable, so a row takes the entry plus one frame. The speed setting picks the starting entry, index 15, 25, or 31 for Low, Med, and Hi, which is 40, 20, or 14 frames per row; entries 0 to 14 are never reached. dr-mario/frames-per-row

About: Dr. Mario (NES) Drop speed

{
 "low": 40,
 "med": 20,
 "hi": 14
}

Cited by: Dr. Mario (NES), Drop speed

Every 10th pill moves the speed one step further along speedCounterTable, up to 49 steps, and each level past 20 starts a step further. After 49 steps a row takes 4 frames at Low, 2 at Med, and 1 at Hi, the table's last entry. dr-mario/speed-ups

About: Dr. Mario (NES) Drop speed

{
 "everyPills": 10,
 "maxSteps": 49,
 "lastLow": 4,
 "lastMed": 2,
 "lastHi": 1
}

Cited by: Dr. Mario (NES), Drop speed

Holding Down, and no other direction, drops the pill a row on every other frame, and the drop resets the gravity count. dr-mario/soft-drop

About: Dr. Mario (NES) Drop speed

Value: 2 frames/row

Cited by: Dr. Mario (NES)

When a drop is blocked, the pill moves back up and is placed in the bottle at once, so a pill resting on the stack locks at its next gravity step. dr-mario/no-lock-delay

About: Dr. Mario (NES) Lock delay

Cited by: Dr. Mario (NES), Lock delay

A press of Left or Right moves the pill at once and zeroes currentP_horVelocity; held, the count rises each frame and at 16 the pill moves and the count restarts at 10, so it moves again 16 frames after the press and then every 6. The European build uses 13 and 5. dr-mario/das

About: Dr. Mario (NES) Delayed auto shift

{
 "delay": 16,
 "repeat": 6,
 "palDelay": 13,
 "palRepeat": 5
}

Cited by: Delayed auto shift, Dr. Mario (NES)

A blocked shift sets the count to 15, so a pill held against a wall or the stack moves on the first frame the way is clear. dr-mario/das-wall-charge

About: Dr. Mario (NES) Delayed auto shift

Value: 15

Cited by: Delayed auto shift, Dr. Mario (NES)

At the start of each level generatePillsReserve deals 128 pills, shared by both players. Each pill is one of 9 color pairs, found by adding a random 0 to 15 to the previous pill's index and subtracting 9 until it fits; the game reads the reserve in a loop, so the same 128 pills come round again. dr-mario/pill-reserve

About: Dr. Mario (NES) Piece randomizer

{
 "reserve": 128,
 "pairs": 9
}

Cited by: Demo playback, Dr. Mario (NES), Piece randomizer

Because the 16 random values wrap at 9, steps of 0 to 6 from the previous pill's index each come from two values and steps of 7 and 8 from one, so the same pill follows itself with chance 2/16, where a uniform pick would give 1/9. dr-mario/pill-step-bias

About: Dr. Mario (NES) Piece randomizer

Value: 0.125

The arithmetic assumes the low four bits of rng0 are uniform; the generator itself hasn't been analysed.

Cited by: Dr. Mario (NES), Piece randomizer

A level holds (level + 1) × 4 viruses; for player 1 levels past 20 count as 20, while player 2's count is uncapped. The count of viruses still to add runs down, and its low two bits pick the color (0 yellow, 1 red, 2 blue, 3 a color from a 16-entry table), so each run of four from a multiple of 4 goes yellow, random, blue, red. Each virus goes at a random height no higher than the level allows and a random column, moving on to the next free cell, and takes another color if one of its own lies two cells away in a straight line. dr-mario/virus-placement

About: Dr. Mario (NES) Piece randomizer

{
 "perLevel": 4,
 "max": 84
}

Cited by: Dr. Mario (NES)

After a pill lands the game scans the bottle row by row for 4 or more cells of one color in a row, then column by column for 4 or more in a column, and clears every run it finds. dr-mario/match-four

About: Dr. Mario (NES) Clearing

Value: 4

Cited by: Clearing, Dr. Mario (NES)

When a clear happens, updateField sends the placed pill's steps back to checkDrop, which lets unsupported halves fall, and the match checks run again, so one pill can set off a chain of clears. dr-mario/cascade

About: Dr. Mario (NES) Chain

Cited by: Chain, Clearing, Dr. Mario (NES)

In a one-player game each virus cleared scores 100, 200, or 300 points at Low, Med, or Hi, times 1, 2, 4, 8, 16, then 32 for the 6th to 11th virus cleared by the same pill. The multiplier isn't capped (the clamp is one of the disassembler's bugfix options, not in the original build), so from the 12th virus on it indexes bytes past the end of the 11-entry table. dr-mario/virus-score

About: Dr. Mario (NES) Chain

[
 1,
 2,
 4,
 8,
 16,
 32
]

The multiplier isn't capped at the table's end, which the disassembler blames for glitches after very long combos.

Cited by: Chain, Dr. Mario (NES)

In a two-player game, 2 or more matches from one pill send that many half-pills, at most 4, in the colors of the matches, to the other player's bottle, where they land at its top row in a frame-dependent column. dr-mario/attack

About: Dr. Mario (NES) Garbage

{
 "min": 2,
 "max": 4
}

Cited by: Dr. Mario (NES), Garbage

In a one-player game each new pill waits for Mario's throw: action_sendPill steps the pill along a table of 21 positions, once a frame at Med and Hi and on every other frame at Low, and puts it in the bottle when the table ends. In a two-player game the pill goes straight to the bottle. dr-mario/throw

About: Dr. Mario (NES) Entry delay

{
 "positions": 21,
 "framesPerStepLow": 2,
 "framesPerStepMedHi": 1
}

The full lock-to-spawn time also counts the frames the landing checks take; it hasn't been measured.

Cited by: Dr. Mario (NES), Entry delay