Editing Turbo Pascal (section)

==== Version 2 ====
Version 2, released a few months later on 17 April 1984, was an incremental improvement to the original Turbo Pascal, to the point that the reference manual was at first identical to version 1's, down to having 1983 as the copyright date on some of the compiler's sample output, but had a separate "Addendum to Reference Manual: Version 2.0 and 8087 Supplement" manual with separate page numbering.<ref name=turbop>{{cite book |url=http://bitsavers.org/pdf/borland/turbo_pascal/Turbo_Pascal_Version_2.0_Reference_1984.pdf |title=Turbo Pascal version 2.0}}</ref> Additions included an [[Overlay (programming)|overlay system]], where separate overlay procedures would be automatically swapped from disk into a reserved space in memory. This memory was part of the 64kB RAM used by the program's code, and was automatically the size of the largest overlay procedure.<ref name=turbop/> Overlay procedures could include overlay sections themselves, but unless a RAM disk was used, the resulting disk swapping could be slow. 2.0 also added the Dispose procedure to manage the [[Heap (programming)|heap]], allowing individual dynamic variables to be freed, as an alternative to the more primitive 'Mark/Release' system and increased compatibility with WordStar commands plus use of the numeric keypad on the IBM PC and compatibles.<ref name=turbop/> Such PCs also had new text window and [[Color Graphics Adapter|CGA]] graphics mode commands as well as being able to use the PC's speaker for tones. Finally, DOS and CP/M-86 machines with an [[8087]] maths coprocessor (or later compatible) had an alternative TURBO-87 compiler available to purchase.<ref name=turbop/> It supported the 8087's ''long real'' data types with a range of 1.67E-307 to 1.67E+308 to 14 significant figure precision but with a much greater processing speed. The manual notes that although source code for the Turbo Pascal's software real data types offering a range of 1E-63 to 1E+63 to 11 significant figures, these were incompatible at a binary level: as well as having a much larger range, the software reals took six bytes in memory and the 8087 ones were eight.

Version 2 for CP/M-80 only runs on Z80-based [[CP/M]] machines.<ref name="rodman198409">{{Cite magazine |last=Rodman |first=Richard |date=1984 |title=Turbo Pascal v2.0 |url=https://archive.org/details/Computer_Language_Issue_01_1984-09_CL_Publications_US/page/n79/mode/1up?view=theater |access-date=2025-04-06 |magazine=Computer Language |pages=78–79 |volume=1 |issue=1}}</ref>