gmcAww, no love for the Sinclair ZX-81?
#Sinclair #SinclairZX81 #ZX81 #RetroComputing
video.chasmcity.net/w/6BaPY1TS…
RE: video.chasmcity.net/videos/wat…
Third Foundation#zx81 printing its _unique_ 8-bit character set, which makes no attempt to imitate ASCII and has no lowercase characters, and no accents or accented characters. (Take that! ya dirty europeans.)
the source code
first page of output
second page of output
the result code 5/20 indicates that printing has filled up the screen while executing line 20.
the "cont" command continues execution and we get the final page of output.
all numeric variables are floating point encoded into 5 bytes, which is slightly better precision than 32-bit floats. I wonder why they made that choice, given the memory cost. (the zx80 didn't have floating point, it used 16-bit integers, and so it did math much faster.)
** is the raise to a power operator, but it doesn't handle negative numbers properly, and it's very slow. ABS(X)**2 is WAY SLOWER than X*X. Without ABS, the expression (-21)**2 returns -441 or fails with error "A".
https://www.timexsinclair.com/product/zx-forth/index.html
"Full implementation of FORTH for the ZX81/TS1000. Runs up to 10 times faster than Basic.
"ZX-FORTH complies with the FORTH-79 standard, with the exceptions [for zx81's unique char set] FORTH is unique in its ability to allow the programmer to build program solving modules then assign them user—defined names.
"User can exit to BASIC and return to ZX-FORTH through a USR call. ZX-FORTH retains all variables, constants, operators and the dictionary.
"Though written for cassette storage, ZX-FORTH can be patched to support disks with routines less than 40 bytes long. Cassette load/save is faster than Sinclair BASIC.
"ZX-FORTH comes with a 64 page manual that include a bibliography of FORTH references. It has 6K of workspace when used with a 16K RAM pack. The size of the workspace can be increased with more memory."
(16 KB should be enough RAM for anybody)
" the command GO TO 9000 costs two more memory bytes than GO TO 60. This is a small saving but costs nothing more than the effort to develop a programming habit…"
when I had a real zx81, I purchased a Forth implementation for it, but I did not do much with Forth. (todo: see if that Forth implementation is on the internet.)
since GOSUB doesn't take parameters, and zx81 basic doesn't allow user-defined functions, I'm thinking about abusing VAL to parse strings containing variable names but first I'm going to read another book about programming zx81.
I just realized zx81 basic did not have the keyword "else".
Now with 16k#ZX81 Game development for Orphion Seven (or Zevious or ZXevious): Got the First Level finalised and 4 to 6 to go depending on space. Added some gun overheating, and a few bug fixes. The game seems to play really well after the bug fixes (I can't stop playing at least).
retroscandinavianSR-2605: Sinclair ZX-81 part 1
