Pep and Nom

the ℙ𝕖𝕡 flag register

The 'flag' register: an internal ℙ𝕖𝕡 machine register.

Possibly, I should not even both to document the flag register because you never explicitly access it when you are writing a ℕ𝕠𝕞 script. The flag register is used by the machine when executing pep assembly language instructions.

The flag register affects the operation of the conditional jump instructions “jumpfalse” and “jumptrue” and it is affected by the test instructions such as “testis",” testtape", “testeof” etc. But these instructions are only used in ℙ𝕖𝕡 assembler not in a nom script. The flag is analogous to a “flags ” register in a cpu, but it only contains one boolean (true/false) value.

 testis, testbegins, testends, testtape, testeof 

 jumptrue, jumpfalse

The script writer does not read or write the machine flag register directly. It is set automatically by the testing instructions

notes

If you are curious about the pep assembly language (which is the format which is directly executed by the pep interpreter) then you can look at the file sav.pp in any directory where you have run a nom script. The pep interpreter compiles any script to a sav.pp assembly file before it loads the script assembly and executes it, so you can see how any script is converted to assembly by looking at this file.