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https://github.com/imjasonh/nescript
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An end-to-end FIPS 180-4 SHA-256 hasher running entirely on the NES.
The player types up to 16 ASCII characters on a 5x8 on-screen
keyboard, presses Enter, and the program computes and displays the
64-character hex digest.
Layout (`examples/sha256/*.ne`):
constants.ne layout + K[64] / H_INIT[8] tables
(declared as `var` with init_array because the
v0.1 compiler treats `const u8[N] = [...]` as
a no-op — noted in the file)
assets.ne 44-tile Tileset (A..Z, 0..9, punctuation,
special keys, cursor) shared between BG and
sprite layers
background.ne static nametable (title, labels, keyboard
grid) painted at reset
state.ne globals
sha_core.ne 32-bit byte primitives (copy, xor, and, add,
not, rotr, shr) in inline asm + sigma/Sigma
mixers + schedule/round steps + fold
render.ne OAM helpers for cursor, input buffer, and
64-nibble digest
keyboard.ne key dispatch table
entering_state.ne cursor navigation + typing + auto-demo
computing_state.ne phased driver (48 schedule steps + 64 rounds
+ fold across ~30 frames at 4 iterations each)
showing_state.ne renders the 256-bit digest as 8 rows of 8
sprite glyphs
Implementation notes:
- All 32-bit words live as 4 little-endian bytes in `wk[64]`,
`w[256]`, `h_state[32]` so every primitive walks four bytes with
`LDA {arr},X`/`STA {arr},X` chains and, for adds, a carry chain.
- Every primitive reads its parameters straight out of the
transport slots `$04`/`$05` rather than `{dst}`/`{src}`
substitutions: the inline-asm resolver looks parameters up in
the analyzer's allocation table but the codegen spills them to a
different per-function RAM slot, so `{dst}` would resolve to a
ZP slot nothing ever writes to. Bypassing the substitution
entirely sidesteps the issue without a compiler change.
- Rotate-right by any amount is a byte-rotate loop plus a bit-
rotate loop so the 10 SHA amounts (2, 6, 7, 11, 13, 17, 18, 19,
22, 25) all compile to a handful of chained `ROR`s.
- The headless jsnes golden auto-types "NES" after 1 s of idle and
captures its SHA-256 digest
AE9145DB5CABC41FE34B54E34AF8881F462362EA20FD8F861B26532FFBB84E0D
— byte-identical to `shasum` / `hashlib.sha256(b"NES")`.
Build: `cargo run --release -- build examples/sha256.ne`
https://claude.ai/code/session_01FRmSBruVWCufm3LsUVMs8v
102 lines
3.7 KiB
Text
102 lines
3.7 KiB
Text
// sha256/background.ne — the static nametable.
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//
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// Painted once at reset-time (the first `background` declaration
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// in the program is loaded before rendering is enabled). Contains
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// the title banner, section labels, and the 5 × 8 keyboard grid.
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// The Entering and Showing state handlers draw the dynamic input
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// buffer, the cursor, and the 64-digit hash on top of this
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// background via sprites.
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//
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// Legend characters are chosen to read cleanly when glanced over
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// as ASCII art:
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// upper-case A-Z and 0-9 → their matching glyph tile
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// space ' ' → blank tile (tile 44)
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// ':' ',' '-' '.' → punctuation glyph tiles
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// '_' → space-key glyph on the keyboard
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// 'p' → period-key glyph on the keyboard
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// '<' '>' → backspace / enter key glyphs
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//
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// `palette_map:` leaves every metatile on bg sub-palette 0; the
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// keyboard keys render as lt_gray (palette index 2), which reads
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// cleanly against the dk_blue universal background.
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background Screen {
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legend {
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" ": 44 // blank (universal colour)
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"A": 1
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"B": 2
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"C": 3
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"D": 4
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"E": 5
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"F": 6
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"G": 7
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"H": 8
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"I": 9
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"J": 10
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"K": 11
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"L": 12
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"M": 13
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"N": 14
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"O": 15
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"P": 16
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"Q": 17
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"R": 18
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"S": 19
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"T": 20
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"U": 21
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"V": 22
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"W": 23
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"X": 24
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"Y": 25
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"Z": 26
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"0": 27
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"1": 28
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"2": 29
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"3": 30
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"4": 31
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"5": 32
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"6": 33
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"7": 34
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"8": 35
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"9": 36
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"_": 37 // space-key glyph (underscore bar)
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"p": 38 // period-key glyph
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":": 39
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"-": 40
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"<": 41 // backspace
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">": 42 // enter
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}
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map: [
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" ", // row 0
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" SHA-256 HASHER ", // row 1 — title
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" ", // row 2
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" INPUT: ", // row 3 — input label
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" ", // row 4 — input row A
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" ", // row 5 — input row B
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" ", // row 6
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" TYPE A MESSAGE PRESS > ", // row 7 — prompt
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" ", // row 8
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" ", // row 9
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" ", // row 10
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" ", // row 11
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" A B C D E F G H ", // row 12 — kb row 0
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" I J K L M N O P ", // row 13 — kb row 1
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" Q R S T U V W X ", // row 14 — kb row 2
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" Y Z 0 1 2 3 4 5 ", // row 15 — kb row 3
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" 6 7 8 9 _ p < > ", // row 16 — kb row 4
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" ", // row 17
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" ", // row 18
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" ", // row 19
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" SHA-256: ", // row 20 — hash label
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" ", // row 21 — hash rows
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" ", // row 22
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" ", // row 23
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" ", // row 24
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" ", // row 25
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" ", // row 26
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" ", // row 27
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" ", // row 28
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" " // row 29
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]
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}
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