Random TODO list

github issue list

To fix:

• arm64 arch_ops.h - arch_cycle_count is bogus
• x86 arch_ops.h - switch to builtin atomics
• riscv - exception decode can be a negation test (top bit set)
• arm arch_ops.h left over pre-armv6 stuff
• see about expanding cycle count to a ulong
• lib console make read only blocks