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).
42 lines
1.7 KiB
Plaintext
42 lines
1.7 KiB
Plaintext
byte8 WRITE WATCH, NOW WITH A PROVABLE POSITIVE CONTROL.
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Previous attempts at this watch had no control that could be shown to fire, so the
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"0 writes" result was not trustworthy (and one VRAM control also read 0, which
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told us nothing).
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This run installs, alongside the byte8 watch, a control watchpoint on the STACK
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region just below SP -- any function call pushes there, so it must fire if
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watchpoints work at all:
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installed: byte8 watch at 003FDA50 ; stack control at 000052A0 (sp=000053A0)
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arm1 -> SILENT(ok) stack control hits: 1218
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PUT_TILE -> ERROR 8
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arm2 -> ERROR 8
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TOTALS: stack-control hits: 1820 byte8 hits: 0
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So:
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* write watchpoints DO work in this MAME build (1820 positive hits);
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* NOTHING writes object->byte8 during create -> arm1 -> PUT_TILE -> arm2
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(0 hits against that control).
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This CONFIRMS, on validated instrumentation, the earlier claim that only create
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sets byte8 (via word9 >> 8), and therefore confirms the mutual exclusion:
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arm (slot 20) requires byte8 == 1
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import gate (0x6BAF4) requires byte8 == 3
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only create can set byte8
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Together with the previous turn's validated gate trace (T_ENTRY -> T_DISP -> T_C2
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-> T_J1 -> T_B32 -> T_MERGE -> T_GATE -> a8=8), the model is now:
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byte8 = 1 : arm succeeds; PUT_TILE reaches 0x6BAF4 and fails there (BadMatch)
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byte8 = 3 : arm fails; PUT_TILE never reaches the gate
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and no client request can move byte8 between those values. Within the request
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surface I can construct, the two requests are mutually exclusive.
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Status: no client-chosen XIE image; src_base 0; window still the stipple;
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xshow (core X) is the only verified viewer.
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