ball

name	ball
description	Create a new Buckyball Ball operator named $ARGUMENTS, covering the full flow from implementation to verification.

Important: all build/simulation operations must go through MCP tools (validate, bbdev_workload_build, bbdev_verilator_run, etc.). Do not use bbdev CLI or nix develop directly.

Phase 1 - Requirement Collection

1. Inspect registration state and decide ballId + funct7:
   • arch/src/main/scala/framework/balldomain/configs/default.json
   • examples/chips/toy/arch/src/main/scala/balldomain/DISA.scala
2. Check for partial existing implementation (incremental mode):
   • existing directory in examples/balls/
   • existing ISA macro in bb-tests/workloads/lib/bbhw/isa/
   • existing CTest in bb-tests/workloads/src/CTest/toy/
3. Confirm with user:
   • operator semantics
   • inBW / outBW
   • whether op2 is needed
   • meaning of iter

Phase 2 - Implement the Ball

1. Read references:
   • simple example: .../prototype/relu/ReluBall.scala, Relu.scala
   • complex example: .../prototype/systolicarray/
   • Blink protocol: .../blink/blink.scala, bank.scala, status.scala
   • SRAM IO: .../memdomain/backend/banks/SramIO.scala
2. Create files under examples/balls/<name>/arch/src/main/scala/ using templates from references/.

Key constraints

• SRAM read latency is 1 cycle (resp.valid in the cycle after req.fire)
• Latch command fields when cmdReq.fire
• Base FSM pattern: idle -> read -> compute -> write -> complete -> idle
• status.idle and status.running must map correctly to FSM states

Phase 3 - Register the Ball

Update files in order:

1. .../configs/default.json - append ballIdMappings entry and update ballNum
2. .../bbus/busRegister.scala - add import + match case
3. .../DISA.scala - add val XXX = BitPat("bxxxxxxx")
4. .../DomainDecoder.scala - add decode row (BID = ballId.U)

Phase 4 - Add ISA C Macro

Create <funct7_decimal>_<name>.c under bb-tests/workloads/lib/bbhw/isa/, then include it in isa.h.

Phase 5 - Add CTest

1. Create <name>_test.c under bb-tests/workloads/src/CTest/toy/
2. Register in bb-tests/workloads/src/CTest/toy/CMakeLists.txt using add_cross_platform_test_target

Phase 6 - Validate, Build, and Simulate

1. Run validate and ensure all 6 invariants pass
2. Run bbdev_workload_build
3. Run bbdev_verilator_run for this Ball's CTest binary
4. Interpret results:
   • PASSED -> done
   • FAILED -> switch to /debug