Te sad thing is this 'SUCESS' code might actually work...
if it was a global variable and set in an interrupt routine.....buried in a totally unrelated section of code.
The horrors I have seen and been party to in 40 years.....
One of the greatest uses for this sort of programming was in the commodore 1541 disk drive
the BVI flag, if i remember correctly could be branched on which was an overflow condition
so
:loop NOP
Bvi loop
Then a situation the 6502 processor had an extra pin to allow this flag to be set externally......normally never used, but they used it as the BYTE clock for the read /write head, since it was way faster than setting & reading a port.........
IE 2 clock cycles as opposed to 8