This Ferranti Mark I computer is notable because, despite being one of the earliest electronic computers, its instruction set included 4 instructions that are now included in most modern ISAs, but which have been missing for many decades from the instruction sets of most later computers, with the exception of the supercomputers made by CDC and Cray.
Those 4 instructions, with their mnemonics in the Intel/AMD x86 CPUs are:
LZCNT (leading zero bits count), which was named "The position of the most significant digit" in this manual.
POPCNT (population count), which was named "Sideways adder" in Mark I (it is listed in a table at the end of this manual).
RDRAND (read random number), which was named "The random numbers generator" in this manual.
RDTSC (read time stamp counter), "The clock" in this manual.
It is said that some or even all of these less usual instructions had been suggested by Alan Turing himself to the designers of Ferranti Mark I.
Another notable instruction of Ferranti Mark I was used to produce an audible beep, like the internal loudspeaker of the older IBM PC compatibles, "The hooter" in this manual.
Those 4 instructions, with their mnemonics in the Intel/AMD x86 CPUs are:
LZCNT (leading zero bits count), which was named "The position of the most significant digit" in this manual.
POPCNT (population count), which was named "Sideways adder" in Mark I (it is listed in a table at the end of this manual).
RDRAND (read random number), which was named "The random numbers generator" in this manual.
RDTSC (read time stamp counter), "The clock" in this manual.
It is said that some or even all of these less usual instructions had been suggested by Alan Turing himself to the designers of Ferranti Mark I.
Another notable instruction of Ferranti Mark I was used to produce an audible beep, like the internal loudspeaker of the older IBM PC compatibles, "The hooter" in this manual.