Frank O'Hara

Articles (9)

TitleAuthor(s)PublicationDate
Numbers Held Inexactly in the ZX81 (Part 2)
Second part of the series on ZX81 floating-point representation, focusing on positive integral powers of 10. Explains that powers of...
Frank O'HaraSyntaxApril 1982
Numbers Held Inexactly on the ZX81
The largest is really this 39-digit number: 170141183420855150474555134919112130560.
SyntaxMay 1982
Numbers Held Inexactly on the ZX81
First in a series of articles on numerical errors in the 8K ROM.
SyntaxMarch 1982
Numbers Held Inexactly on the ZX81 (Part 1)
First part of a series examining floating-point representation errors in the ZX81 8K ROM. Focuses on integer powers of 2...
Frank O'HaraSyntaxMarch 1982
Numbers Held Inexactly on the ZX81 (Part 5)
Fifth and final part of the series, covering FOR-NEXT loop counter behavior with non-integral step values. Explains why floating-point imprecision...
Frank O'HaraSyntaxJuly 1982
Numbers Held Inexactly on the ZX81, Part 4
The ZX81 doesn’t hold simple decimals like .5 & .25 exactly.
SyntaxJune 1982
Program Improvements
Improvements to Big Characters, Line Renumbering and Powers of Negative Numbers.
SyntaxAugust 1982
Program Improvements
Improvements to READ-DATA-RESTORE, Flower Plot, Income Tax program.
Martin Irons (K2MI)
Frank O'Hara
Bill Bruton
SyntaxJune 1982
Spaces in REM Statements
If you put your machine code in large REM statements, you need not laboriously type in spaces or digits.
SyntaxAugust 1982

Books (2)

TitleAuthor(s)Date
The Complete Spectrum ROM Disassembly
American readers found this book invaluable in understanding the Timex/Sinclair 2068 ROM.
Ian Logan, Frank O'Hara1983
The Complete Timex TS1000/Sinclair ZX81 ROM Disassembly
Includes Part A: 0000H-0F54H & Part B: 0F55H – 1DFFH.
Ian Logan; Frank O'Hara1982
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