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… the Ethernet FCS specs/fpga/rgmii.t27 (module fpga_rgmii): RGMII v2.0 timing as test-checked arithmetic: 125 MHz DDR = 1000 Mbps, 8 ns period / 4 ns nibble phase, the 10/100 downshift as SDR (25 MHz / 2.5 MHz, one edge -- DDR at 25 MHz would carry 200 Mbps, the trap the test names), IDELAYE2 tap math from UG471 (78 ps at the 200 MHz reference, 31 taps = 2418 ps; a 2.0 ns shift costs 26 taps, the 4 ns half-period does not fit -- delay elements centre the eye, they do not slip phase), and the Artix-7 fact that ODELAYE2 does not exist outside HP banks. Constants cite their sources; every other number is derived by the tests. No board measurement exists yet -- the header says THEORETICAL and names the boards. specs/fpga/eth_crc.t27 (module fpga_eth_crc): The 802.3 FCS as one spec: reflected 0xEDB88320 step, byte table (every entry re-derived from crc_bit by test table_is_derived), preset/post-xor 0xFFFFFFFF, FCS = one's complement. ORACLE vectors computed with Python 3 zlib.crc32, not transcribed: the published check value 0xcbf43926, one octet, empty, two frames (broadcast/IPv4, slow-protocols/length), and the receiver fact that frame + FCS returns the register to 0xFFFFFFFF. The 0x2144DF1C / 0xDEBB20E3 magic residues belong to other CRC conventions and are deliberately not claimed. Both compile clean through the wasm t27c (typecheckOk, hirOk, 0 errors). Their tests use calls, locals and separated/hex literals, which the in-browser mini-runner cannot execute -- the known trinity#1477 gap; the native runner executes them. Refs gHashTag/trinity#1484 (buses-and-peripherals, module 8) Co-Authored-By: Claude Opus 5.5 (1M context) <noreply@anthropic.com>
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This was referenced Oct 7, 2026
…1484) The Zig reference rejects an array literal longer than its [32]u8 parameter (expected 32 array elements; found 36), which the wasm typecheck accepts -- caught by the t27b corpus run in CI, not by the local check. Every crc_buf literal now carries exactly 32 elements: the first len bytes are the frame, the rest zero padding the loop never reads. All oracle values are unchanged because crc_buf only folds data[0..len]. Co-Authored-By: Claude Opus 5.5 (1M context) <noreply@anthropic.com>
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PR DashboardGenerated at: 2026-10-07 22:05:12 UTC
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…gs (Closes #7625, Refs trinity#1484) eth_crc.t27 is a self-contained player spec and carries its own hex and CRC bit helpers, like the two specs that already share hex_nibble_of; crc_bits was unique until now. Recorded in the same commit as the specs, per the gate's own instruction. build_tree 5 rides along from the merged master specs. Co-Authored-By: Claude Opus 5.5 (1M context) <noreply@anthropic.com>
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PR DashboardGenerated at: 2026-10-07 22:24:46 UTC
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Superseded by #7626: same specs, rebuilt as a clean three-commit chain on top of current master (root commit now carries the issue reference the L1 gate needs). The REST API cannot retarget a PR head branch, so the fixed history ships as a new PR; the old branch is left untouched. |
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Two new pure-t27 specs the trinity buses-and-peripherals course (gHashTag/trinity#1484, module 8) lists as required:
specs/fpga/rgmii.t27 —
module fpga_rgmiiHAVE_ODELAY == false).specs/fpga/eth_crc.t27 —
module fpga_eth_crctable_is_derivedre-deriving every entry fromcrc_bit, preset/post-xor 0xFFFFFFFF,fcs_of= one's complement.zlib.crc32(real tool, not transcription): check value0xcbf43926, single octet, empty, two frames (broadcast+IPv4 header, slow-protocols+length), and the receiver fact — CRC over frame + FCS returns the register to0xFFFFFFFF.0x2144DF1C/0xDEBB20E3residues belong to other CRC conventions and are deliberately not claimed (the wrong-constant mistake was caught by re-running the tool, see commit).Verification
Both compile clean through the wasm t27c (
typecheckOk: true, hirOk: true, 0 errors). Their tests use calls, locals and separated/hex literals — exactly what the in-browser mini-runner cannot execute (known gap, gHashTag/trinity#1477); the native runner covers them.Refs gHashTag/trinity#1484, Refs gHashTag/trinity#1476
🤖 Generated with Claude Code
Closes #7625 (this repo's spec request; the course that consumes them is gHashTag/trinity#1484)