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).
40 lines
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40 lines
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SECOND CORRECTION ON byte8. The previous turn claimed "the arm request sets
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object->byte8 = v12". THAT IS WRONG. Controlled before/after on the SAME
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object shows byte8 unchanged by arm.
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Method: one connection per case; create op=2 (id 0x0047000x, w9=0x100);
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take the object pointer from the REGIDSTORE line of THAT create; peek it
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immediately after create and again immediately after arm; then put.
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v12=2:
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after create cls=2 w=64 h=64 b8=01 b9=01 w4=00010102
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after arm cls=2 w=64 h=64 b8=01 b9=01 w4=00010102
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put=ERR8 class1_path=0 e8_main(0x6BAF8)=1 selector_dispatch=0 gate(0x6BAF4)=0
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v12=3:
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after create cls=2 w=64 h=64 b8=01 b9=01 w4=00010102
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after arm cls=2 w=64 h=64 b8=01 b9=01 w4=00010102
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put=ERR8 class1_path=0 e8_main(0x6BAF8)=1 selector_dispatch=0 gate(0x6BAF4)=0
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So:
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* arm with v12=3 does NOT change class, w, h, byte8, byte9 or the word at
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byte4. "b8after == v12" in the previous sweep was an artefact -- in that
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sweep the object was read after the arm had run, and the pointer taken from
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`stores()[-1]` was not reliably the object created by that iteration.
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* The earlier sweep's other observation does still hold and is the useful one:
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arm returns OK for v16 in {0,1} and ERR8 for v16 in {2,3}.
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NEW FACT -- the 0x8 site has more than one entry point:
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* e8_main (0x6BAF8) fires, gate (0x6BAF4, the CMP) does NOT fire, and
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selector_dispatch does not fire either.
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* 0x6BAF8 is the FALL-THROUGH of the JREQ at 0x6BAF6, so reaching it normally
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requires executing 0x6BAF4 first. Reaching it without 0x6BAF4 means there
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is a SECOND entry into 0x6BAF8 from elsewhere in the function.
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* That also explains the earlier confusion where "the gate is not reached" and
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yet the same ERR8 was returned.
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NEXT (bounded): do a reference search in Ghidra for branches/jumps targeting
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0x6BAF8, list them, and instrument each. The one that fires in the
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create(w9=0x100)->arm(v12=3)->put sequence is the true producer of our ERR8,
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and its preceding comparison is the thing to satisfy.
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