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).
37 lines
1.8 KiB
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37 lines
1.8 KiB
Plaintext
ANSWER: NOTHING INITIALISES THE BAND ELEMENT'S BYTE 4.
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Test: photomap created with the correct xieCreatePhotoReq (levels 2,2,2,
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#components 1, bitonal), then SetTransport(mode=3, org=1) and PutTile(64x64,
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plane_mask=1, final=1). A write watchpoint was armed on element+0x20 (byte 4)
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as soon as the element existed, with the stack control watch proving the
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mechanism was live (952 control hits).
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obj=003FD7D0 band=003DBAF0 elem=003FD590 elem.b4=55
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after PutTile: elem.b4=55 <-- UNCHANGED
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watch hits: 1, at pc=3F4019D0 (file 0x4033A), val=0000B055
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-- that instruction is `MOVE A8,*A9(0x28)`, i.e. it stores byte 5, the
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adjacent field, not byte 4.
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So across create -> SetTransport -> PutTile the element's compression byte stays
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at the heap fill value 0x55. The import path never initialises it, and the
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export path later copies it verbatim into renderptr->compression_scheme
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(0x1B256: MOVB *A5(0x20),*A11(0x630)), where DDX_RENDER rejects it with
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"unsupported compression scheme".
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That is the complete, measured causal chain from a correct client request to the
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BadValue the client receives.
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STATE
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import verified: element+0x28 = 0xFF white / 0x00 black, QueryResource
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comp_COUNT=1, 64x64, constrained
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export: BadValue in every configuration, from both the hand-rolled client and
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DEC's own 2.3 client built from source
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with a labelled poke setting element byte 4 = 0 (XieK_PCM), the renderer
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passes both DDX gates (CHK_610 val=00911050, PAST_610_OK) and then fails on a
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further, undocumented path
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window: unchanged in every run; white vs black captures differ only by
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Terminal Manager figures and cursor
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xshow (core X) remains the only viewer that has shown an image
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STATUS. NO client-chosen XIE image has been displayed.
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