Ryan8bit, DW Formulas

Cite as: Ryan8bit, DW Formulas
Original: https://gamefaqs.gamespot.com/nes/563408-dragon-warrior/faqs/61640
sha256: 0c0d73f2c13f4502fff5539d97b7abba618dbeead3cce1882fd7df37c24e7244
Version: v1.0
Archived: https://web.archive.org/web/20250717012136/https://gamefaqs.gamespot.com/nes/563408-dragon-warrior/faqs/61640
Accessed: 2026-10-20
Licence: all rights reserved by the author (GameFAQs guide)
Credit: Ryan8bit, who learned NES assembly to read the game's formulas; section III quotes the code behind each one.
Notes: GameFAQs refuses automated reads, so the text was read in a verbatim repost (https://pastebin.com/pKkihMcv, 27 April 2017). GameFAQs' Dragon Warrior guide list, archived by the Wayback Machine on 2018-12-07, lists it as "Formula Guide", 01/10/11, Ryan8bit, 1.0, 98K. Used as a cross-check on dw1 claims; nothing is copied beyond the short quotes.

Cited on

Claims (12)

`UpdateRandNum` steps a 16-bit state as $s \leftarrow 771 s + 129 (\mod 65536)$ , and battle code reads its high byte, `RandNumUB`.	`III.A, Common algorithms`	Code
`GetJoypadStatus` steps the generator each time it reads the controller.	`IV, Frequently Asked Questions`	Code
Computed from the generator's update, its 65,536 states form two cycles of 32,768, and over each cycle the high byte takes every value exactly 128 times.	`III.A, Common algorithms`	Code
`PlyrCalcHitDmg` takes $X = A - ⌊ D / 2 ⌋$ , the hero's attack power less half the monster's defense byte; if $X \geq 2$ , damage is $⌊ (X + ⌊ r (X + 1) / 256 ⌋) / 4 ⌋$ for a random byte $r$ , so from $⌊ X / 4 ⌋$ to $⌊ X / 2 ⌋$ .	`II.B, Hero attack formulas`	Code
Before the normal formula, a 1-in-32 roll gives the hero an "excellent move", except against either form of the Dragonlord; it deals $A - ⌊ r ⌊ A / 2 ⌋ / 256 ⌋$ for a random byte $r$ , from $⌈ A / 2 ⌉ + 1$ to $A$ (more than half to all of the attack power), and ignores defense.	`II.B, Hero attack formulas`	Code
After the damage is set, an awake monster dodges when a roll of 0–63 falls below $d$ , the low nibble of its resistance byte, a chance of $d / 64$ ; a sleeping monster never dodges, and spells skip the check.	`III.C, Combat`	Code
`EnCalcHitDmg` takes $X = A - ⌊ D / 2 ⌋$ , the monster's attack less half the hero's defense power; if $X \geq ⌊ A / 2 ⌋ + 1$ , it uses the hero's normal formula, and otherwise the monster deals $⌊ (⌊ r (⌊ A / 2 ⌋ + 1) / 256 ⌋ + 2) / 3 ⌋$ , from 0 to about $A / 6$ .	`III.C, Combat`	Code
`TryRun` lets the hero escape when Agility × a random byte is at least the monster's defense byte × a roll whose range grows with the monster: 0–63 from Slime to Druinlord, 0–94 from Drollmagi to Werewolf, 0–127 from Green Dragon to Blue Dragon, and 0–255 from Stoneman on. Running from a sleeping monster always works.	`II.B, Running`	Code
On the overworld's zone 0, the slime-only region around Tantegel Castle, a second byte lets only half of those fights through, and a quarter on hills.	`II.A, Encounters`	Code
The dodge nibble $d$ of the 40 monsters (each dodges $d / 64$ of the hero's attacks, dodge) is 1 or 2 for 27 of them; the Demon Knight's is 15, the Werewolf's 7, the Poltergeist's and Drakeema's 6, six monsters' 4, and the Golem's and both Dragonlord forms' 0.	`II.B, Combat, monster list (#28 Demon Knight)`	Code
The high nibble $h$ of the same byte blocks Hurt and Hurtmore $h / 16$ of the time (hero-spells); it is 0 for 26 of the 40 monsters and 15 for seven, the Metal Slime, Golem, Demon Knight, Wizard, Red Dragon, and both Dragonlord forms.	`II.B, Combat, monster list`	Code
Each fight picks one of its zone's five monster slots with equal chance; zone 0, around Tantegel Castle, holds three Slime slots and two Red Slime slots, and zone 1 adds a Drakee, all with dodge 1.	`II.A, Encounters`	Code