$ go test -v -run=TestVMNegateA .
=== RUN TestVMNegateA
--- FAIL: TestVMNegateA (0.00s)
vm_bpf_test.go:120: output byte count does not match:
- go: 0
- os: 5
vm_bpf_test.go:124: Go BPF and OS BPF packet outputs do not match
exit status 1
FAIL golang.org/x/net/bpf 0.002s
Same logic seems to apply when subtraction brings the register results below zero. Will keep working on this and try to submit a CL to enable this functionality in the near future.