Punch list §25 item 4.3.6c complete. Digits, upper/lowercase, ASCII
punctuation, Latin-1 Supplement, and General Punctuation, each a
stroke-drawing word in the 4.3.6 em-square convention.
Corrected mid-build: the first pass used G-LINE only, missing that
CIRCLE/ARC/ELLIPSE already existed (4.3.3b). Reworked all round shapes
to use them via new em-square-aware wrappers (G-CIRCLE/G-ARC/G-ELLIPSE/
EM-R, fabric.4th 5000-5002), bounded to quarter/half/three-quarter/
full sweeps to avoid unbounded per-glyph angle tuning. font.4th also
redefines DISPATCH-GLYPH/DRAW-GLYPH themselves, not just the six
DISPATCH-* bucket words, since fabric.4th's originals were compiled
early against the 4.3.6b placeholders (CASE early-binding, §27.6.5).
Three-arch acceptance boot clean, Stadium conservation unchanged.
Co-Authored-By: Claude Sonnet 5 <noreply@anthropic.com>
Punch list §25 item 4.3.6b complete.
capsules/fabric.4th blocks 4921-4924: DISPATCH-GLYPH routing via
WITHIN to six bucket words (DISPATCH-DIGIT/-UPPER/-LOWER/
-ASCII-PUNCT/-LATIN1/-GENPUNCT), TOFU fallback, DRAW-GLYPH. Buckets
carry one placeholder stroke word each (G-TEST-*), not the real
113-glyph set -- that's item 4.3.6c's scope, deliberately deferred.
Also: merged two lines in block 4920 (DECODE-UTF8) to fit mkcapsule's
real 64-char x 16-line block limit once a trailing blank separator
line is counted against it -- mechanical reformat, re-verified via a
DECODE-UTF8 regression check (65/176/8212, unchanged).
Verified live on amd64: one representative codepoint per bucket plus
one out-of-range codepoint, all seven DRAW-GLYPH results matched
expected exactly (400/600/450/250/550/700/500-TOFU). Three-arch
acceptance boot clean, Stadium conservation unaffected.
Co-Authored-By: Claude Sonnet 5 <noreply@anthropic.com>
Punch list §25 item 4.3.6a complete.
capsules/fabric.4th blocks 4918-4920: UTF8-SEQ-LEN/UTF8-CONT? verbatim
from §27.6.2, DECODE-UTF8 dispatching to four UTF8-ASSEMBLE-N helpers
(1/2/3/4-byte). Factored into helpers after the single-word draft hit
mkcapsule's real 64-char x 16-line block limit. Verified live on
amd64: a 6-byte test buffer (ASCII + deg-sign + em-dash) decoded to
65/176/8212 across three sequential calls, exact match against
hand-computed codepoints, buffer fully consumed. Three-arch acceptance
boot clean, Stadium conservation unaffected.
Co-Authored-By: Claude Sonnet 5 <noreply@anthropic.com>
Punch list §25 item 4.3.6 complete.
capsules/fabric.4th blocks 4916-4917: EM-UNITS, GOX/GOY/GSIZE/GCOLOR,
EM-X/EM-Y/G-LINE per §27.6.1, scaling/translating em-square strokes
into CART-PLOT screen coordinates via */. Verified live on amd64 via
a temporary probe (built, run once, reverted): two G-LINE test shapes
at GSIZE 100 and GSIZE 50, one leg each exercising a negative em-y
value chosen to hit */'s truncate-toward-zero behaviour, not a
multiple of EM-UNITS. Screendump pixel-bbox extraction matched
hand-calculated raster coordinates exactly on both shapes. Three-arch
acceptance boot clean, Stadium conservation unaffected
(resident_sum=43691 reservoir=21845 sum=65536 on all three).
Co-Authored-By: Claude Sonnet 5 <noreply@anthropic.com>
Adds VERT/EDGE/CUBE to capsules/fabric.4th (blocks 4913-4915). VERT
( n -- x y z ) reads bits 0/1/2 of a corner index as the X/Y/Z sign
(+-CS from center), so all 8 cube corners come from one word. EDGE
resolves both corners via VERT and calls LINE; CUBE is 12 EDGE calls
(4 bottom, 4 top, 4 vertical).
First item in the 4.3.3.x sequence with no new bug found -- a small signal
that Q.TO-INT, the VARIABLE alignment fix, and the LINE-STUCK? cap were
the real gaps rather than something still lurking in LINE/PROJECT/CART-Y.
Verified live on amd64: a centered, half-size-100 cube renders correctly
-- front/back face squares, back face offset diagonally up-right by
exactly the 45-degree cavalier projection's depth term, all 12 edges
connecting at the right corners.
All three architectures boot clean to ok> with the DoE completing;
dict_hash identical across all three and unchanged from 4.3.3a/4.3.3b.
FABRIC.md item 4.3.4 marked done. This is the checkpoint -- 4.3.x
groundwork stops here for review per this item's own acceptance criterion.
Adds LINE (Bresenham in raster space, endpoints projected once each --
valid because the cavalier projection is linear), CIRCLE/ELLIPSE
(36-segment polygon approximation), and ARC (18 segments over a caller
radian range) to capsules/fabric.4th (blocks 4903-4912). TO-RASTER
factored out of CART-PLOT (same behavior) so LINE can reuse the
projection+flip for both endpoints.
Found mid-implementation: colon definitions cannot span block boundaries
in this capsule loader -- verified with a throwaway test capsule, the
continuation lands in a [CAPSULE][DEFER] path that never resolves. LINE's
body is split across LINE-SETUP/LINE-DONE?/LINE-STUCK?/LINE-STEP, each
self-contained within its block, rather than one long definition.
A fourth real bug, serious this time: CIRCLE's first live test rendered
only one quadrant, then hung the VM for several minutes on a follow-up
call. Root cause: q48_to_u64() (include/q48_16.h and
include/starkernel/q48_16.h, backing Q.TO-INT) did an unsigned logical
shift, corrupting any negative Q48.16 value into a huge garbage integer
instead of sign-extending -- inevitable once Q.SIN/Q.COS leave the first
quadrant. That garbage became a bogus LINE target with no bound on
LINE-STEP's Bresenham loop. Fixed q48_to_u64 to shift through a signed
int64_t intermediate (bit-identical for the non-negative case). Also added
LINE-STUCK? (LSTEPS vs FB-WIDTH+FB-HEIGHT, the true worst case for an
on-screen line) as a defense-in-depth cap against any future bad target.
Verified live on amd64 after both fixes: -65536 Q.TO-INT . now prints -1;
LINE/CIRCLE/ARC/ELLIPSE all complete without hanging or erroring, and a
combined screendump shows all four rendering correctly and distinctly.
All three architectures boot clean to ok> with the DoE completing;
dict_hash identical across all three and unchanged from 4.3.3a (expected
-- fabric.4th isn't loaded at boot, and the Q.TO-INT fix doesn't change
dictionary structure).
FABRIC.md item 4.3.3b marked done with full acceptance evidence.
Adds Module 28 (framebuffer_words.c/.h): PLOT ( x y color -- ), FB-WIDTH,
FB-HEIGHT -- raw hardware-boundary C primitives, kernel-only, no-op on
hosted builds, same pattern as every other module.
Adds capsules/fabric.4th (blocks 4900-4902, mkcapsule --lint clean):
COS45/Z->DELTA/PROJECT/CART-Y/CART-PLOT -- the 45-degree cavalier
orthographic projection and Y-flip, in FORTH per the compose-in-FORTH-first
rule (this is policy, not hardware access).
Found and fixed a second real bug while live-testing CART-PLOT over the
serial socket: defining_word_variable() (defining_words.c) captured
vm->here as a VARIABLE's address with no alignment call first, while
vm_load_cell/vm_store_cell require 8-byte-aligned addresses. This capsule's
VARIABLE ZD landed misaligned (945) purely by chance of what preceded it;
other capsules' variables happened to land aligned by luck, not guarantee.
Real deviation from FORTH-83/ANS, which specifies VARIABLE reserves an
aligned cell. Fixed with vm_align(vm) before capturing addr -- ALIGN
already existed as a word but VARIABLE wasn't calling it.
Verified end-to-end on amd64 via manual serial injection + QEMU screendump:
plotted 4 marker points (origin, +100 X, +100 Y, +50 Z) and confirmed all
landed at hand-calculated raster coordinates, including the diagonal
up-right shift for the Z-axis point -- the projection math is correct, not
just non-crashing. fb/fabric-test-cart-plot.png. 4.3.1's corner diagnostic
still renders correctly in the same shot, confirming no regression.
All three architectures (amd64/aarch64/riscv64) boot clean to ok> with the
DoE completing; dict_hash identical across all three
(0xc7f9adf885e306d2), confirming parity is unaffected.
FABRIC.md item 4.3.3 marked done with full acceptance evidence.
