0852666e73a1ded35a89a5d1f5eebeb703bb013d
5
Commits
| Author | SHA1 | Message | Date | |
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  AnachronautandClaude Opus 5
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ff4b025058 |
Make the cursor blink while the machine is waiting, and show how the palette works
THE CURSOR DID NOT BLINK, and the reason is worth stating: it blinks on the machine's clock, and the machine's clock had stopped. A console waiting on a key stops the CPU, so no cycles passed, so the phase never moved - and the one moment somebody is looking at a cursor is the moment they are being asked to type. Waiting is now charged as IDLE CYCLES, which is what they were built for: a machine stopped on a device is not using memory, the same distinction WAIT makes, arrived at from the other direction. And the devices are told as it happens rather than when the instruction finally finishes, because a display controller does not stop blinking because the processor is waiting on a keyboard, any more than a disk stops turning. A keyboard file can now say NOTHING happened. A zero is a byte no keyboard sends, so it is free to mean "a moment went by with nobody typing" - which is the commonest thing behind a window and the only thing a file otherwise could not express. That unlocked the whole waiting path: three checks that the cursor is lit, then dark half a second later, then lit again, which is what blinking is. And Programs/Examples/colours.asm, because the palette had nowhere a newcomer could read it. It prints the sixteen pairs, prints each one again turned inside out, and then CHANGES ONE by writing three bytes into the palette - so the difference between using the colours a machine wakes up with and choosing your own is visible in one program. Its header explains what a cell is, what the attribute nibble does, why palette entries are four bytes rather than three, and why video memory has to be reached through the controller. The manual now says where the palette lives and points at it. SplitLint found a redundant RSTA in the example, which was worth acting on rather than suppressing: the zero was already in A from the mode write two lines up, and saying so in a comment teaches that SETD does not touch A, which is a thing worth knowing. Co-Authored-By: Claude Opus 5 <noreply@anthropic.com> Claude-Session: https://claude.ai/code/session_01E2JrLzFvuFX9fgi1LDRjrW |
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AnachronautandClaude Opus 5
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978aec4809 |
Let the console edit a line, and let a file be a keyboard
BACKSPACE REACHED THE SHELL. A terminal in line mode does not hand a program every keystroke: it collects a line, rubs out a backspace, and delivers the finished thing at Return. CosmOS has always relied on that, and behind a window there is no terminal to do it, so the raw 0x08 went into the command buffer. Correcting a typo produced a line that looked perfectly right on the screen and matched no command at all - "I do not know: help". So the console does it, because behind a window the console IS the terminal. In key mode it does not, and must not: a program in key mode asked for every keystroke as it happens. CosmOS now asks for eighty columns at boot. Its own help text is seventy-four characters wide, and dir, the monitor and the assembler's messages all assume room. The machine still wakes up in the smaller mode, which is right for a machine - it is the system that knows what shape of screen its own output needs, and a game that wants forty columns says so. AND A FILE CAN BE A KEYBOARD, which is the part that matters beyond today. The console behind a window is not the console behind a terminal, and until now the difference was unreachable: it broke twice in two days and a person typing found it both times. --keyboard installs the same hook a window does, so the same path runs, and the manifest has a column for it. cosmosTyped types "halp", backs over it, arrives at "help", and requires the help to come out. Verified by removing the rub-out, which loses the whole help text. It does not test the window. Voyager's key queue and everything about presenting frames are still out of reach. It tests the console, which is where the logic is. Along the way: VOY_OBJS was missing from the dependency include, so voyager.o never rebuilt when a header changed. EmulatorOptions grew a field, Voyager kept an object that disagreed about the size of the struct, and smashed its stack on every run. A clean build hides it and 'make sanitize' cleans first, so that would never have found it either. Tests/voyager.sh did, by failing all 115 tests that start the machine - which is the differential test earning its keep on a bug that has nothing to do with what it was built to check. Co-Authored-By: Claude Opus 5 <noreply@anthropic.com> Claude-Session: https://claude.ai/code/session_01E2JrLzFvuFX9fgi1LDRjrW |
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AnachronautandClaude Opus 5
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773b0f8add |
Put CosmOS on the screen without changing a line of it
The console is now a display controller as well as a port: it owns a font, keeps a cursor, handles newline, carriage return, backspace and wrapping, and scrolls. That is an ordinary kind of chip - it is what a video terminal's character generator did - and it is the reason this rung needed no changes to CosmOS at all. CosmOS already writes bytes to port 0x00. It writes to BOTH the screen and standard output, which is deliberate. A machine with a screen and a serial line is an ordinary machine, the emulator's standard output is that serial line, and one console drives both. It is also what keeps all 165 recorded results passing under Voyager, and what makes --screen work on the plain SplitBit: there is one console and it drives everything it has. Scrolling moves the video device's origin and no memory. The row arriving at the bottom is cleared because the map is a ring and it holds what was there 128 rows ago; the rows going off the top are not, and that is a hundred rows of scrollback nothing had to keep. The test reads the register back rather than looking at the screen, because a console blitting rows instead would look identical and cost twelve percent of a frame for every line printed. The font is vendored from Hatchet-GPU with a note saying where it came from, since that repository is not part of this one. 135 glyphs in ASCII order, which is the thing that makes it worth keeping - PETSCII's whole inconvenience was that its order was not ASCII's, so a machine using it needed a translation table in front of every string. Here the machine subtracts 32. It is stored one bit a pixel and expanded into tile memory at reset: 1,088 bytes against 16 kilobytes. Voyager gets a keyboard. A window has no standard input, and a machine blocking on it inside a frame would stop drawing and stop answering, so a front end with a window installs a hook that the console calls while it has nothing: it keeps the window alive and hands back a key. The hook has to tell "nobody has typed yet", which happens sixty times a second, apart from "the window has gone", which is the end of input - one value for both would have made the first keystroke look like a closed machine. In line mode the console echoes what it is given, because there is no terminal behind a window to do it and that was always the terminal's job. Tests/video.sh grew from 14 checks to 26, half of them about the console rather than the device: those programs ask the video device for nothing and write bytes to port 0x00 like every SplitBit program always has. Verified by breaking two things - removing the scroll failed exactly the two checks about scrolling, and removing the cursor advance failed exactly the three that depend on it. Two video checks had quietly depended on palette entry 0 being black, which stopped being true the moment a machine woke up able to show text. They now set what they are about to look at, and a new check pins the waking state itself. Co-Authored-By: Claude Opus 5 <noreply@anthropic.com> Claude-Session: https://claude.ai/code/session_01E2JrLzFvuFX9fgi1LDRjrW |
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AnachronautandClaude Opus 5
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83623a3df3 |
Give the Voyager a screen
A tile engine on ports 0x30 to 0x3F, bringing one bank of video memory registered the way the disk's buffer is. The CPU writes cell indices and the device turns them into pixels, which is the whole reason a screen is affordable at a megahertz: a frame is 16,667 cycles, a full 320 by 200 picture is 64,000 bytes, and a 40 by 25 map is 2,000. A program that changes two cells writes four bytes. The cost of a screen becomes the number of cells that changed rather than the number of pixels on it. Which makes colour depth free, so the tiles are eight bits: an 8 by 8 cell is 64 pixels and each picks independently out of 256 colours, with no per-cell limit of the kind that made a Spectrum two and C64 multicolour four. The low nibble of a cell's attribute is ADDED to every index in its tile, sixteen at a time, so a tile drawn in 0 to 15 appears in any of sixteen schemes without a second copy in tile memory - and a tile wanting all 256 leaves the nibble at zero and gets them. Neither use costs the other anything. Two decisions are arithmetic rather than taste, and both come from the machine having no multiply. A map row is a page whether the mode fills it or not, so a cell address is the row number as the high byte and the doubled column as the low byte with no arithmetic at all; otherwise every cursor move on a 40 column screen would cost a row-times-40 in software. And a palette entry is four bytes rather than three, so entry n is at n times four, a shift. THE MAP IS A RING and the Scroll register says which of its 128 rows is on top. Scrolling moves a register and no memory: blitting a 40 by 25 screen up one line is 1,920 bytes inside one bank, which is twelve percent of a frame even with the controller widened, and a program printing one page would spend six frames shuffling memory. It is now one port write - and the rows that scrolled off are still there, which is where a terminal gets scrollback it never had. The device is part of the machine rather than part of the window. It renders into a buffer that is a pure function of video memory, so the same program draws the same picture with nobody watching; Voyager puts that buffer on the glass and decides nothing. Both binaries take --screen, which saves a PPM when the machine stops, and that is what makes a screen checkable on a host with no display at all. Tests/video.sh checks fourteen named behaviours rather than comparing a recorded image, because a recorded image would say "something changed" and leave which of the palette, the tile, the attribute, the map or the scroll register broke to be found by hand. Verified by breaking three things in turn: the additive nibble failed exactly one check, the scroll origin exactly two, and moving every cell one pixel sideways exactly the four about placement. Tests/docs.sh could not count past nine, which is how a suite of ten scripts reported itself as wrong for the wrong reason. Co-Authored-By: Claude Opus 5 <noreply@anthropic.com> Claude-Session: https://claude.ai/code/session_01E2JrLzFvuFX9fgi1LDRjrW |
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AnachronautandClaude Opus 5
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e3ef25e3b3 |
Split the machine from its front end, and add Voyager
The Segan Voyager is the same SplitBit with a screen and a speaker instead of a terminal, and this is the rung that makes there be two of them at all. Everything that is actually the machine - the CPU, the controller, the devices, the run loop, the reporting - moves to machine.c, and each front end brings one file of its own. emulator.c is now sixty lines of argument handling and a three line loop. The machine runs in SLICES rather than to completion, because that is the cut a window needs: run a slice, present a frame, run another. A terminal runs slices until the machine stops. Both loops are three lines, which is why the cut is there rather than anywhere else. At this stage Voyager's window is empty. There is no video device yet and inventing a temporary way to draw would mean building something to throw away. PLAIN MAKE STILL WORKS WITH NO GRAPHICS LIBRARY. Raylib is probed by compiling and linking against it rather than by looking for a file, because a header with no library behind it passes a file check and then fails at link time. Where it is missing, make says so once and builds everything else - the machine, the assembler, the disk tool, the linter and the whole suite. A project about a small understandable CPU should not need OpenGL to run its tests. That nearly broke here: make strict globs Source/Emulator/*.c, so it would have tried to compile voyager.c and failed on precisely the machines the split exists to support, and this machine has Raylib so nothing would have caught it. Tests/voyager.sh runs the WHOLE MANIFEST through Voyager and holds it to the recorded results SplitBit is held to. Not that the two look alike: that one satisfies every recording the other does, byte for byte, exit status included. It reuses run.sh, which now takes the machine from SPLITBIT_EMULATOR, rather than keeping a second copy of the runner that would drift. Voyager not being built is not a failure - it says so and passes. Verified both ways. Made Voyager print one extra line, and 114 of 165 failed: exactly the tests that run the emulator, with the 51 assemble-only and xfail cases correctly untouched. Removed the binary, and the script skipped. Built with HAVE_RAYLIB=no, and everything else still built and checked clean. --headless is taken out of the arguments in voyager.c rather than in the shared parser, which should not learn about a window only one binary has. It exists so the suite can run this binary at all: a front end that could only be exercised by a person looking at it would be a front end nothing checks. loadFile takes a const char * now, which it always should have. Co-Authored-By: Claude Opus 5 <noreply@anthropic.com> Claude-Session: https://claude.ai/code/session_01E2JrLzFvuFX9fgi1LDRjrW |