# Asserts the autobaud loader's measured unit is the first RAM object: the
# host tool reads the bit period from ram_start (--info's measured clock), so
# the unit's address is wire contract. Run as
#   cmake -DOBJDUMP=... -DELF=... -DRAM_START=<data address> -P check_unit.cmake

execute_process(COMMAND ${OBJDUMP} -t ${ELF} OUTPUT_VARIABLE _syms RESULT_VARIABLE _res)
if(NOT _res EQUAL 0)
	message(FATAL_ERROR "${OBJDUMP} -t ${ELF} failed")
endif()

# The symbol line: "00800100 l     O .noinit  00000002 <mangled>unit_E".
string(REGEX MATCH "\n0*([0-9a-f]+)[^\n]+[ \t][^ \t\n]*unit_[^ \t\n]*\n" _line "${_syms}")
if(NOT _line)
	message(FATAL_ERROR "no unit_ symbol in ${ELF} — is this the autobaud loader?")
endif()

# AVR data-space symbols carry the 0x800000 VMA offset.
math(EXPR _want "0x800000 + ${RAM_START}" OUTPUT_FORMAT HEXADECIMAL)
math(EXPR _have "0x${CMAKE_MATCH_1}" OUTPUT_FORMAT HEXADECIMAL)
if(NOT _have STREQUAL _want)
	message(FATAL_ERROR "unit_ sits at ${_have}, ram_start is ${_want} — the host peeks ram_start")
endif()
message(STATUS "unit_ at ${_have} == ram_start")