Intel's optimization manual has suggestions for fast versions at 15.12.3 (recommended by @James https://stackoverflow.com/a/2637823/10981777) Don't look especially long to implement for 22-bit approximation.
Thanks. So much more of that code makes sense now. IFD, SGNU, FORN, FORM. FORM especially. So many codes now have the word FORM as a special word.
What a nightmare to read though if you don't know what it's supposed to be written like. Is it a: "FORM=" or a "FOR M=" ? Is it: "S GNU:G", "SG NU:G", "SGN U:G"? SQRD totally looks like some special kind of square root implementation.
Yeah, early BASICs tended to let you skip the spaces, and in fact it sometimes did have a measurable effect on parsing/execution speed. And of course on file size too… Additionally, at least C64 Basic had two-character shorthands for all keywords.