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Sylpheed/docs
sylph-decoder 934fbfbbbf re: the interpolator is not found, and four routes are excluded
Question 1's behavioural half is answered elsewhere and measured. This is
the other half -- which function -- and it is not found. Recorded as a
bounded negative so the next attempt does not repeat four searches.

Excluded, all by exhaustive scans of the image:

  integer lerp shape (divw with mullw and subf within 10 instructions):
    28 sites image-wide, NONE in the UI region 0x82200000-0x823FFFFF
  mulli by 40, the keyframe record stride: 31 sites, NONE in the UI region
  addi rX,rX,40 in the UI region: 43 sites; the screen/bundle ones at
    0x823CCA6C and 0x823CCA94 disassemble to a 40-byte container COPY loop
    (CTR=10, ten-word copy), a vector reallocation, not an evaluator
  fmadd-family in the UI region: 811 sites over 142 pages -- too diffuse to
    select on, so float is neither excluded nor narrowed

The first two together say the evaluator does not compute its fraction with
integer multiply-and-divide and does not index records by multiplication.
With the measured steps landing on exact integers, the likeliest remaining
shape is a float lerp with a per-segment reciprocal, converted to a byte --
stated as a hypothesis, not a finding.

Names the route I would take next and did not have budget for: trace DOWN
from the quad emitter. sub_823C2AC0 has exactly 6 callers, four of them
sibling emitters, and sub_822380B0 reads its colour from this+0x04..0x10.
Whoever writes those fields is one step from the interpolator.

Reach stated: the two opcode negatives are exhaustive over the whole image
rather than sampled, but they do not exclude the interpolator living
outside the UI region, which is an assumption inherited from
ui-quad-class-foothold.md and not independently checked.

Not blocking the port: it needs whether to lerp and how, which is answered.

Co-Authored-By: Claude Opus 5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01Jc4pciRArGHfxGGhEbwp5t
2026-09-02 15:42:25 +00:00
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