forked from opencode.energia.arti.ee/vt1200
arti
d8d54bb990
The XIE path now runs end to end: XieCreateImage -> XieCreatePhoto ->
XiePutTile -> XieExport(photomap -> depth-1 pixmap) -> XCopyArea(pixmap ->
window), and the client's tile appears on screen at the client's own window
position, pixel-exact.
TWO FAULTS BEHIND THE LONG DEAD END
1. Device model (harness/mame/vt1200.cpp, opt-in VT1200_ACCEL=1). The
accelerator's output port 0x5600200 returns the pixel stream the firmware
pushed into the FIFO -- the firmware then stores it into the drawable itself
(file 0x125528: MOVE *B6,*B1 ; ADDK 0x10,B1). The FIFO read pointer was
never reset between transfers, so consecutive exports read stale words and
the same fill produced 759 then 516 set pixels. Reset m_fifo_in/out on the
data-register write; the export is now deterministic.
2. Measurement, not the device.
- dwt/screenshot.py without --real reads 1024x1024 at a 128-byte row stride,
but the VR319 default programs 1280x1024 at a 2048-bit (256-byte) pitch.
That is the "shifted" picture; --real is the correct read.
- The earlier "0 differing bytes over 128 KiB" VRAM comparison stepped peek
by 1024 *bit* addresses, so it scanned rows 0..63 only -- never the window
at rows 200..263. Over the real raster the white/black diff is 576 bytes
spanning exactly those rows.
- New instrument: decclient does a server-side XGetImage readback of the
pixmap and window and counts set pixels. That separated "the server never
drew it" from "the framebuffer view is wrong".
EVIDENCE (reproduced twice, the second time from a fresh machine)
no export vs 0xFF : 4096 / 4096 pixels differ
no export vs 0x00 : 0 / 4096 (the window background is black)
0xFF vs 0x00 : 4096 / 4096
0xAA vs 0x0F : 2048 / 4096 (the two stripe phases)
Tile byte 0xAA reproduces as 1-pixel vertical stripes, 0x0F as 4-pixel, with
no shear -- so the placement is right and the pixels are the client's.
Contents: xie/ holds DEC XIE 2.3 headers, 84 man pages and complete
client+server source; a libXie.a and decclient built from DEC's own code; the
XIE probes; and evidence/ with every measurement, including explicit
retractions of the earlier wrong readings (VRAM_IDENTICAL_FOR_BOTH_FILLS and
friends). xie/evidence/XIE_IMAGE_DISPLAYED.md is the report; frames are in
xie/evidence/png/.
The accelerator model stays opt-in: it answers the status poll and relays the
pixel stream, but performs no compositing, so it is a stand-in and the verified
default configuration is unchanged (a no-env run still parks in the level-0
diagnostics menu at PC=3FDCE400).
38 lines
1.8 KiB
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38 lines
1.8 KiB
Plaintext
EXPORT PAINTS NOTHING -- the "XIE output pattern" was the window's default
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background. Measured on one MAME instance, one X connection, 64x64 window.
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1) Baseline: window created + mapped + GC created, NO export at all:
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BASELINE no-export nz=512 first=88888888888888882222222222222222
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2) Full sequence create -> arm1 -> PUT_TILE -> arm2(v16=0) -> EXPORT,
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then read back the same window:
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AFTER export nz=512 first=88888888888888882222222222222222
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identical to baseline: True
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So every earlier "export OK ... 8888...2222..." result measured the window
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background (a stipple), not XIE output. The white-vs-black comparisons were
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therefore vacuous: export has never drawn anything.
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3) Why: the export chain is present but has no source image.
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Breakpoints in the export driver (file 0x1B152 = bit 0x3F2D8A90):
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EXPORTENTRY
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EXPORTFLAG f=01 ; global @0xA6220 non-zero, render taken
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EX_BAND a5=003DC4B0 elem@d8=003FDA10 ; photoflo->band->element IS present
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EX_ELEM a5=003FDA10 f28=00000000 ; element+0x28 == 0
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The driver copies element+0x28 into the render params
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(0x1B238 MOVE *A5(0x28),*A11(0x610)), i.e. it is the imported source
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image. It is zero because the import never ran: PUT_TILE (minor 19) is
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rejected at the class lookup with BadMatch (S19LOOK a8=00000008), so the
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handoff that fills/uses element+0x28 (0x6B640) is never called.
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4) The per-element render loop (file 0x1BC38..0x1BF30) is never reached:
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its breakpoints (ELTYPE / PIPE_T1..T4 / PIPE_LOOPEND / BADFUNC) do not
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fire during the export.
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Conclusion: export produces no pixels because the source image pointer at
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element+0x28 is NULL. The single remaining blocker is unchanged and is
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upstream of export: PUT_TILE's lookup requires a class-3 resource with
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resource byte 40 == 0, which no reachable request produces.
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