From 87467a7d3a241132306647362440ce96a32aab62 Mon Sep 17 00:00:00 2001 From: Anachronaut Date: Sun, 6 Sep 2026 09:02:50 -0400 Subject: [PATCH] Lander starts a flight where a flight starts run does not reload, and that is right: run's job is to run the program that is loaded, which is why it is a separate word from load and why typing a program's name does both. What follows is that the numbers the assembler wrote into a Data Segment are LOAD-time values, true once, and a program that wants them true at every start has to say so itself. Lander did not. Flying is 0x01 in the data and is only ever cleared, so a second run began with the loop already over: the program started and handed the machine straight back. Reproduced by running it, quitting, and running again - the leftover game keys land at the shell prompt, which is what a program that never read them looks like. AND THE TEST FOUND A SECOND ONE, quieter and worse. The terrain seed is a written number, so a fresh load always walks out the same moon - but nextRandom moves it, and a second run generated a DIFFERENT moon. Nobody decided that. A test comparing the whole screen found it without anybody having had to think of it in advance, which is the argument for comparing the picture rather than the variables somebody remembered to check. Only what a flight needs to begin is put back. Anything not on the list keeps what the last run left it, which is deliberate - state surviving a run is sometimes exactly what is wanted, and the way to have that is for the list to be a decision rather than a sweep. The things that are simply nought are a table of NAMES that the assembler turns into addresses, so adding a variable that must start empty means adding it there and nowhere else. video.sh now runs Lander, quits, runs it again, and requires the same picture a hundred frames in - the same moon, the same lander in the same place, the same gauges. break.sh confirms it by taking the seed line back out: 37,995 bytes of the picture differ. Co-Authored-By: Claude Opus 5 Claude-Session: https://claude.ai/code/session_01E2JrLzFvuFX9fgi1LDRjrW --- Programs/CosmOS/Apps/Lander.asm | 95 +++++++++++++++++++++++++++++ Programs/CosmOS/README.md | 2 +- Tests/expected/cosmosCrossDisk.out | 2 +- Tests/expected/cosmosDrives.out | 2 +- Tests/expected/cosmosFault.out | 2 +- Tests/expected/cosmosFlip.out | 2 +- Tests/expected/cosmosGrid.out | 2 +- Tests/expected/cosmosMonitor.out | 2 +- Tests/expected/cosmosMonitorRun.out | 2 +- Tests/expected/cosmosRun.out | 2 +- Tests/expected/cosmosSlowDisk.out | 2 +- Tests/expected/cosmosSprite.out | 2 +- Tests/video.sh | 38 ++++++++++++ 13 files changed, 144 insertions(+), 11 deletions(-) diff --git a/Programs/CosmOS/Apps/Lander.asm b/Programs/CosmOS/Apps/Lander.asm index 46e0783..0d27eb5 100644 --- a/Programs/CosmOS/Apps/Lander.asm +++ b/Programs/CosmOS/Apps/Lander.asm @@ -48,6 +48,20 @@ start: ; floor the system gives every program does not. SWI osTakeScreen + ; ---- A flight starts where a flight starts, and not where the last one stopped ---- + ; + ; RUN DOES NOT RELOAD, and that is right: run's job is to run the program that is loaded, + ; which is why it is a separate word from load and why typing a program's name does both. + ; What follows from it is that the numbers the assembler wrote into the Data Segment are + ; LOAD-time values, true once, and a program that wants them true at every start has to say + ; so itself. This one did not, so a second run began with Flying already nought - the loop + ; ended before it started and the program handed the machine straight back. + ; + ; Only what a flight needs to begin. Anything not named here keeps what the last run left + ; it, which is deliberate: state surviving a run is sometimes exactly what is wanted, and + ; the way to have that is for this list to be a decision rather than a sweep. + CALL initialise + CALL loadState ; Before the view, because a state may say which view to be in. CALL setView ; The block every gauge below reads its screen numbers out of. SETD.0 Wide @@ -3195,6 +3209,76 @@ showHeightSized: ; BINARY, because that is what a file is on this machine. A tool to build one from readable ; text is a small job for another day; until then the tests write the bytes, which is plain ; enough while the fields are named. +; ---- What a new flight is ---- +; +; Called before loadState, so a saved state still wins: this puts the world back to its +; beginning and that puts a remembered one over the top of it. +initialise: + ; Everything that is nought when a flight begins, from a table of WHERE rather than a line + ; each. A label written in the Data Segment comes out as its address, so the list below is + ; names and the assembler turns them into pointers - and 0xFFFF ends it, the same way it + ; ends the music player's order lists, because no useful address can begin up there. + SETD.0 ZeroAtStart +zeroNext: + LDA.0 + INIB 0xFF + XOR + BRQ zeroDone + LDD.1.0 ; DP1 is the place this entry names. + INCD.0 + INCD.0 + RSTA + STA.1 + BRI zeroNext +zeroDone: + + ; The sideways speed is two bytes and the table above deals in one, so it says so here. + RSTA + SETD.1 SpeedAcross + STA.1 + INCD.1 + STA.1 + + ; And the numbers that are not nought: where the lander is, where the station is, a full + ; tank, the gravity tick, and the flag that says the loop should run at all. + INIA 0xA0 + SETD.1 AcrossLow + STA.1 + INIA 0x14 + SETD.1 AcrossHigh + STA.1 + INIA 0x02 + SETD.1 DownHigh + STA.1 + INIA 0xA0 + SETD.1 StationLow + STA.1 + INIA 0x34 + SETD.1 StationHigh + STA.1 + INIA 0xFA + SETD.1 StationDownHigh + STA.1 + INIA 0xFF + SETD.1 Fuel + STA.1 + INIA 0d1 + SETD.1 FallTick + STA.1 + SETD.1 Flying + STA.1 ; A is still one, and this is the one that matters most. + + ; ---- And the moon, which is the same moon every time ---- + ; + ; The seed is a written number rather than anything taken from the world, so a fresh load + ; always walks out the same terrain. nextRandom moves it, though, so a second run started + ; from wherever the first one left it and generated a different moon - which was not a + ; decision anybody made. Put back here, the moon is the moon. + INIA 0x5D + SETD.1 Seed + STA.1 + RET + loadState: SETD.0 StateName SETD.1 StateBuffer @@ -4041,6 +4125,17 @@ KeyHeld: Flying: 0x01 +; ---- Everything a new flight puts back to nought ---- +; +; Names, which the assembler writes out as addresses. Adding a variable that has to start +; empty means adding it here and nowhere else. +ZeroAtStart: + DownLow SpeedDown SpeedDownHigh StationDownLow + Held HasPad KeyHeld + PendNote PendIn ThrustWas ThrustNow Rumbling + AlarmSaid Wide AtBase Carrying Landed BurstLeft Docked Adrift + 0xFF 0xFF + Terrain: #Reserve 0d128 diff --git a/Programs/CosmOS/README.md b/Programs/CosmOS/README.md index 6019130..520751e 100644 --- a/Programs/CosmOS/README.md +++ b/Programs/CosmOS/README.md @@ -731,7 +731,7 @@ from every assembly file in it. Several are old programs written for the bare ma | Grid | The first program to use the screen as a screen. Redefines a tile above the font, fills all 128 map rows, and scrolls it diagonally a pixel at a time. | | Sprite | Moves a ball across the shell's own text, writing not one byte of the map to do it. It leaves the sprite in the table on the way out, because clearing them is the system's job - see below. | | Pad | Says what the controllers are doing, printing a line whenever one changes. It tells apart the three things that look identical from inside a game that is not responding: a pad nobody noticed, a pad mapped to nothing, and a mapping that is wrong. | -| Lander | Lunar Porter, rung one: a lander over a moon that wraps. Flown with a controller if there is one - a held thruster burns every tick it is held for - and with the arrow keys if there is not, where one press is one burn and that is the most the console can say. A bar at the bottom is the sideways drift, drawn as a sprite stretched to the speed - a moon has no air, so a drift never stops by itself and stopping one means cancelling it exactly, which is hard to do blind. It lands or crashes on arrival, and what decides is the speed at the moment it touches: gentler than three quarters of a pixel a frame downwards and half of one sideways, or it is a lander on its side. A fuel gauge sits in the window layer, where the moon turning underneath cannot scroll it away, and every thruster costs a unit of fuel every tick it fires. It turns from green to red at a quarter of a tank, and a warning sounds ONCE on the way down through it - once, because a lander is at its most careful in the last seconds before it touches and something repeating in its ear through that is a distraction rather than a warning. Filling up at a base allows it again. The sound is the moment it happened and the colour is how things stand, and both come off the same number so they cannot disagree. An empty tank is not an ending: it is a lander still flying that can no longer do anything about where. Four landing pads are carved into the moon after it is generated, levelled to whatever height their first column happened to have, and marked in cyan by an attribute rather than a tile of their own. The lander starts above one, because that is where a porter's day begins. Each pad is a base, told apart by the colour it is drawn in, and landing at one either loads cargo for the base across the moon or delivers what is aboard and pays eighty units of fuel. A landing is not an ending: the lander rests where it is until the throttle opens again, and A or Start says "read it" as readily as a key does. What a base says goes in the window rather than out of the console: the console draws into the map, so a message printed while flying is one the lander then flies over, and printing scrolls the whole world up a row. Opening the throttle wipes the line. Two bars read the speeds and are green while a landing would survive and red while it would not, so "can I put down" is a glance rather than a sum. A third runs up the left edge and is how much sky is under the lander, half a pixel of bar to a pixel of it; it reads nought the moment the lander is down, and it exists because the orbit takes the lander off the top of the screen and a panel that only works while the ground is in sight is no use above it. And gravity here is the pull MINUS the swing outwards, which is what makes an orbit rather than a one way trip: under four pixels a frame sideways the pull wins and the lander falls, over it the swing wins and the lander climbs, and at it they cancel and it circles. Falling buys sideways speed and climbing spends it - at a rate set by the product of the two, so the trade stops by itself as the sideways speed runs out - and that is the cycle: a fall carries the lander past orbital speed and becomes a climb, the climb pays it back and becomes a fall, periapse and apoapse, round and round. Orbital speed is marked on the drift bar, sixty four pixels either side of the middle, because a number nothing points at is folklore. Gravity never falls off and the moon wraps, so a circular orbit is the same length at any height and one orbital speed serves everywhere. There is a ceiling 192 pixels above the world's origin, which is the top of the wide view - it was sixty four while sixty four was all the sky a forty column screen had over the origin, which was a fact about the view rather than about the world. It pins rather than ends: leaving upward is recoverable, so the lander is held there and told so, and one sideways is spent every tick it tries to climb - without that the pin wiped the climb, the trade saw neither fall nor climb, and the speed pushing it up never changed. What kills you out here is running dry a long way from the ground. B, or z on the keyboard, swaps the screen between forty columns and eighty, which is the same map, the same cells and the same engine at half the size: nearly two thirds of the moon at once for the orbit, and twice as big for the landing. The twenty extra rows that buys go to the SKY and not to the moon - the wide view starts twenty four rows above the world's origin rather than at it, so the ground sits near the bottom and the whole flyable band is on the screen. Drawn down from the origin instead it was 71 per cent rock, which is a zoom that shows you more of the thing you cannot fly through. A lander at the ceiling is off the top of a forty column screen, which is where the orbit lives and why the altitude bar had to exist; zoomed out it is in the picture. And there is a station up there, twelve rows above the world's origin - about two thirds of the way from the ground to the ceiling, clear of work near the surface - going round at orbital speed - which needs no physics of its own, because a body at 64 sixteenths is exactly what a circular orbit IS under these rules, at any height, since gravity never falls off and the moon wraps. It is off the top of a forty column screen too, so it is somewhere to go that the zoom is needed to see. Docking it is landing on something that is moving: close enough, and slow enough RELATIVE TO THE STATION, or it is a wreck. Its speed is orbital speed, which is the number the marks on the drift bar point at, so the instrument for it was on the screen before there was anything to dock with. A dock pays eighty units of fuel and holds the lander a tile under the station until a thruster lets go, sliding it into line at half a pixel a frame rather than snapping - a dock is allowed eight pixels out either way, so putting the lander exactly in place the instant it took hold moved it a whole tile in one frame, right at the moment the player was being told they had been careful. It settles squarely under the port, which it did not used to: the lander is drawn from half a screen LESS HALF A TILE, because that is what centres it, and the station was drawn from half a screen exactly, so a perfectly flown dock still looked four pixels out. Getting there is a two burn manoeuvre and not a straight line: climbing SPENDS sideways speed, so a lander cannot rise while matched - it arrives slower than orbital every time, and has to raise the far side of its orbit and then circularise at the top. Which is also why it reads /lander.state if the disk has one: sixteen bytes of position, velocity, station, fuel and screen, laid straight over the numbers it would otherwise start with, so a rendezvous can be examined without flying one first. A disk without the file is the game as it always was. The buffer is a whole block wide because osFileRead lands a file in blocks of 256, and sixteen bytes of room for it wrote over everything that followed. A landing kicks up dust, sideways and up off the lander's feet, because that is where kicked dust goes and there is ground in the way of the rest of it. Letting go of the station vents gas instead, evenly in every direction, since nothing is in the way of a docking port - and that one does NOT stop the world the way the others do, because it goes off on the frame a thruster is pressed and freezing then would be felt as the controls sticking. There is none on docking: a dock is a catch and not a touchdown, and there is nothing under it to kick. A lander also has to get two tiles clear of the station before it can take hold of it again, because a docked one sits exactly one tile under it - so letting go upwards docked it straight back on, took the fuel again, and sat waiting to be told the message had been read. A thruster bangs when it lights and rumbles while it burns, and EVERY thruster that catches bangs - a pilot already burning upwards who then adds a sideways one has lit an engine, so what is watched is which of them are lit rather than whether any is. The rumble is struck once and runs until every one is out, since restriking it when a second joins would start its attack over, which is a stutter rather than an engine, and the rumble is a HELD note: its gate goes down when one lights and does not come up until every one is out - or until anything stops to wait, because a held note outlives the loop that was holding it and landing on the thruster used to leave it roaring under the verdict. Arriving somewhere latches two notes quickly, middle C then the C above for taking hold of the station and the same pair reversed for letting go, two octaves lower for the ground. The second note is pending rather than played, since at an undocking the pilot is mid-burn and stopping the world for an eighth of a second would be felt as the controls sticking. Four channels for five sounds: the bang and the latch share one, because a lander arriving either arrives or does not and a crash ends the run outright. No instrument is set up once at startup: each sound loads its patch immediately before its note, because the bang and the latch share a channel and a channel used by two sounds has to be told which of them it is about to be. That rule arrived as a workaround for something worse - an LFO used to belong to the DEVICE and not to a channel, so whichever patch was loaded last owned both of them for every voice at once, which is what made the warning's trill vanish after the first landing of a run when the landing's patch carried an LFO switched off. An intermittent fault of the worst kind, right until something unrelated plays and right again next time the machine starts. Loading at the note fixed each sound as it STARTED and could not fix two of them overlapping, so the device was changed instead and an LFO now belongs to the channel it was written to. A crash also makes a noise, which was the first sound this game had, and it is a TRIGGERED voice - struck once and then playing its own length, so nothing has to come back and end it. That the program says so rather than the patch is deliberate: the patch decides what the bang sounds like and the program decides that it is a bang. It is noise through a low pass that the modulation envelope shuts as the level falls, so the bright part is only at the front and it is a boom rather than a hiss. The instrument is built at startup the way the tiles are, because a patch is twenty odd writes and a note is two - which is what the selector and value registers are for. It plays on channel THREE: effects count down from the top so that music, if it ever arrives, can take nought and count up and the two never have to negotiate. A crash takes the lander apart: it goes, and six pieces of it leave in a rough hexagon at its own colour for about a second before the verdict is said. It used to be a line of text and a lander still sitting there in one piece, so a watcher had to read the words to know what had happened. The world is not running while that plays - it is a loop of its own, so nothing else has to know how to be half destroyed. A plume hangs off whichever side the engine is pushing from - under the lander to lift, over it to retro, and on the far side from the way it is being pushed sideways, since that is where the gas leaves. Every other reading here is a number drawn as a bar and all of them say what is happening TO the lander, so without this a watcher has to read gauges to work out that a thruster is even lit. It is drawn while the BUTTON IS HELD rather than while the engine fires: the engine fires one frame in ten, because that is the tick gravity is applied on, and a flame that honest is a fault lamp rather than a rocket. An empty tank draws none, and neither does the retro thruster on the ground, because in both cases the button really is doing nothing. Down is a retro thruster at half the strength of up - one sixteenth a tick against two, which is exactly gravity's own step, so it can stop a climb and hurry a descent and can never turn a landing approach into a crash faster than letting go would. Arresting a rise otherwise meant a sideways burn and a wait for the orbit to come round, which is how a rendezvous really is flown and a lot to ask of somebody who has not flown one. It does nothing at all to a lander on the ground, which is not politeness: touchdown has already had its say and will not speak again, so without that guard a landed lander holding it goes straight through the moon. | +| Lander | Lunar Porter, rung one: a lander over a moon that wraps. Flown with a controller if there is one - a held thruster burns every tick it is held for - and with the arrow keys if there is not, where one press is one burn and that is the most the console can say. A bar at the bottom is the sideways drift, drawn as a sprite stretched to the speed - a moon has no air, so a drift never stops by itself and stopping one means cancelling it exactly, which is hard to do blind. A flight begins where a flight begins: run does not reload, so the numbers the assembler wrote are load-time values and an init routine puts back the ones a new flight needs - including the terrain seed, which is a written number, so the moon is the same moon every time rather than whatever the last run's random walk left behind. What is not on that list keeps what the last run left it, which is a decision rather than an oversight. It lands or crashes on arrival, and what decides is the speed at the moment it touches: gentler than three quarters of a pixel a frame downwards and half of one sideways, or it is a lander on its side. A fuel gauge sits in the window layer, where the moon turning underneath cannot scroll it away, and every thruster costs a unit of fuel every tick it fires. It turns from green to red at a quarter of a tank, and a warning sounds ONCE on the way down through it - once, because a lander is at its most careful in the last seconds before it touches and something repeating in its ear through that is a distraction rather than a warning. Filling up at a base allows it again. The sound is the moment it happened and the colour is how things stand, and both come off the same number so they cannot disagree. An empty tank is not an ending: it is a lander still flying that can no longer do anything about where. Four landing pads are carved into the moon after it is generated, levelled to whatever height their first column happened to have, and marked in cyan by an attribute rather than a tile of their own. The lander starts above one, because that is where a porter's day begins. Each pad is a base, told apart by the colour it is drawn in, and landing at one either loads cargo for the base across the moon or delivers what is aboard and pays eighty units of fuel. A landing is not an ending: the lander rests where it is until the throttle opens again, and A or Start says "read it" as readily as a key does. What a base says goes in the window rather than out of the console: the console draws into the map, so a message printed while flying is one the lander then flies over, and printing scrolls the whole world up a row. Opening the throttle wipes the line. Two bars read the speeds and are green while a landing would survive and red while it would not, so "can I put down" is a glance rather than a sum. A third runs up the left edge and is how much sky is under the lander, half a pixel of bar to a pixel of it; it reads nought the moment the lander is down, and it exists because the orbit takes the lander off the top of the screen and a panel that only works while the ground is in sight is no use above it. And gravity here is the pull MINUS the swing outwards, which is what makes an orbit rather than a one way trip: under four pixels a frame sideways the pull wins and the lander falls, over it the swing wins and the lander climbs, and at it they cancel and it circles. Falling buys sideways speed and climbing spends it - at a rate set by the product of the two, so the trade stops by itself as the sideways speed runs out - and that is the cycle: a fall carries the lander past orbital speed and becomes a climb, the climb pays it back and becomes a fall, periapse and apoapse, round and round. Orbital speed is marked on the drift bar, sixty four pixels either side of the middle, because a number nothing points at is folklore. Gravity never falls off and the moon wraps, so a circular orbit is the same length at any height and one orbital speed serves everywhere. There is a ceiling 192 pixels above the world's origin, which is the top of the wide view - it was sixty four while sixty four was all the sky a forty column screen had over the origin, which was a fact about the view rather than about the world. It pins rather than ends: leaving upward is recoverable, so the lander is held there and told so, and one sideways is spent every tick it tries to climb - without that the pin wiped the climb, the trade saw neither fall nor climb, and the speed pushing it up never changed. What kills you out here is running dry a long way from the ground. B, or z on the keyboard, swaps the screen between forty columns and eighty, which is the same map, the same cells and the same engine at half the size: nearly two thirds of the moon at once for the orbit, and twice as big for the landing. The twenty extra rows that buys go to the SKY and not to the moon - the wide view starts twenty four rows above the world's origin rather than at it, so the ground sits near the bottom and the whole flyable band is on the screen. Drawn down from the origin instead it was 71 per cent rock, which is a zoom that shows you more of the thing you cannot fly through. A lander at the ceiling is off the top of a forty column screen, which is where the orbit lives and why the altitude bar had to exist; zoomed out it is in the picture. And there is a station up there, twelve rows above the world's origin - about two thirds of the way from the ground to the ceiling, clear of work near the surface - going round at orbital speed - which needs no physics of its own, because a body at 64 sixteenths is exactly what a circular orbit IS under these rules, at any height, since gravity never falls off and the moon wraps. It is off the top of a forty column screen too, so it is somewhere to go that the zoom is needed to see. Docking it is landing on something that is moving: close enough, and slow enough RELATIVE TO THE STATION, or it is a wreck. Its speed is orbital speed, which is the number the marks on the drift bar point at, so the instrument for it was on the screen before there was anything to dock with. A dock pays eighty units of fuel and holds the lander a tile under the station until a thruster lets go, sliding it into line at half a pixel a frame rather than snapping - a dock is allowed eight pixels out either way, so putting the lander exactly in place the instant it took hold moved it a whole tile in one frame, right at the moment the player was being told they had been careful. It settles squarely under the port, which it did not used to: the lander is drawn from half a screen LESS HALF A TILE, because that is what centres it, and the station was drawn from half a screen exactly, so a perfectly flown dock still looked four pixels out. Getting there is a two burn manoeuvre and not a straight line: climbing SPENDS sideways speed, so a lander cannot rise while matched - it arrives slower than orbital every time, and has to raise the far side of its orbit and then circularise at the top. Which is also why it reads /lander.state if the disk has one: sixteen bytes of position, velocity, station, fuel and screen, laid straight over the numbers it would otherwise start with, so a rendezvous can be examined without flying one first. A disk without the file is the game as it always was. The buffer is a whole block wide because osFileRead lands a file in blocks of 256, and sixteen bytes of room for it wrote over everything that followed. A landing kicks up dust, sideways and up off the lander's feet, because that is where kicked dust goes and there is ground in the way of the rest of it. Letting go of the station vents gas instead, evenly in every direction, since nothing is in the way of a docking port - and that one does NOT stop the world the way the others do, because it goes off on the frame a thruster is pressed and freezing then would be felt as the controls sticking. There is none on docking: a dock is a catch and not a touchdown, and there is nothing under it to kick. A lander also has to get two tiles clear of the station before it can take hold of it again, because a docked one sits exactly one tile under it - so letting go upwards docked it straight back on, took the fuel again, and sat waiting to be told the message had been read. A thruster bangs when it lights and rumbles while it burns, and EVERY thruster that catches bangs - a pilot already burning upwards who then adds a sideways one has lit an engine, so what is watched is which of them are lit rather than whether any is. The rumble is struck once and runs until every one is out, since restriking it when a second joins would start its attack over, which is a stutter rather than an engine, and the rumble is a HELD note: its gate goes down when one lights and does not come up until every one is out - or until anything stops to wait, because a held note outlives the loop that was holding it and landing on the thruster used to leave it roaring under the verdict. Arriving somewhere latches two notes quickly, middle C then the C above for taking hold of the station and the same pair reversed for letting go, two octaves lower for the ground. The second note is pending rather than played, since at an undocking the pilot is mid-burn and stopping the world for an eighth of a second would be felt as the controls sticking. Four channels for five sounds: the bang and the latch share one, because a lander arriving either arrives or does not and a crash ends the run outright. No instrument is set up once at startup: each sound loads its patch immediately before its note, because the bang and the latch share a channel and a channel used by two sounds has to be told which of them it is about to be. That rule arrived as a workaround for something worse - an LFO used to belong to the DEVICE and not to a channel, so whichever patch was loaded last owned both of them for every voice at once, which is what made the warning's trill vanish after the first landing of a run when the landing's patch carried an LFO switched off. An intermittent fault of the worst kind, right until something unrelated plays and right again next time the machine starts. Loading at the note fixed each sound as it STARTED and could not fix two of them overlapping, so the device was changed instead and an LFO now belongs to the channel it was written to. A crash also makes a noise, which was the first sound this game had, and it is a TRIGGERED voice - struck once and then playing its own length, so nothing has to come back and end it. That the program says so rather than the patch is deliberate: the patch decides what the bang sounds like and the program decides that it is a bang. It is noise through a low pass that the modulation envelope shuts as the level falls, so the bright part is only at the front and it is a boom rather than a hiss. The instrument is built at startup the way the tiles are, because a patch is twenty odd writes and a note is two - which is what the selector and value registers are for. It plays on channel THREE: effects count down from the top so that music, if it ever arrives, can take nought and count up and the two never have to negotiate. A crash takes the lander apart: it goes, and six pieces of it leave in a rough hexagon at its own colour for about a second before the verdict is said. It used to be a line of text and a lander still sitting there in one piece, so a watcher had to read the words to know what had happened. The world is not running while that plays - it is a loop of its own, so nothing else has to know how to be half destroyed. A plume hangs off whichever side the engine is pushing from - under the lander to lift, over it to retro, and on the far side from the way it is being pushed sideways, since that is where the gas leaves. Every other reading here is a number drawn as a bar and all of them say what is happening TO the lander, so without this a watcher has to read gauges to work out that a thruster is even lit. It is drawn while the BUTTON IS HELD rather than while the engine fires: the engine fires one frame in ten, because that is the tick gravity is applied on, and a flame that honest is a fault lamp rather than a rocket. An empty tank draws none, and neither does the retro thruster on the ground, because in both cases the button really is doing nothing. Down is a retro thruster at half the strength of up - one sixteenth a tick against two, which is exactly gravity's own step, so it can stop a climb and hurry a descent and can never turn a landing approach into a crash faster than letting go would. Arresting a rise otherwise meant a sideways burn and a wait for the orbit to come round, which is how a rendezvous really is flown and a lot to ask of somebody who has not flown one. It does nothing at all to a lander on the ground, which is not politeness: touchdown has already had its say and will not speak again, so without that guard a landed lander holding it goes straight through the moon. | | Depth | Four pillars at four distances and a ball walking past them, behind the near ones and in front of the far ones. The ball is sprite nought and every pillar is numbered after it, so table order puts it in front of all four - what actually decides is the depth buffer, asked a column at a time. | | Flip | Draws a whole screen into the bank that is not being shown, waits, and then shows it in one byte out of one port. It writes nothing else at all - not a tile, not a colour - so it does not ask for the screen to be saved, and the line it printed is still there when it comes back. It deliberately does not put the displayed screen back either, because that is the system's to restore: a program that faulted while flipped could not have. | | Edit | A line editor. | diff --git a/Tests/expected/cosmosCrossDisk.out b/Tests/expected/cosmosCrossDisk.out index ca58fb1..a472407 100644 --- a/Tests/expected/cosmosCrossDisk.out +++ b/Tests/expected/cosmosCrossDisk.out @@ -25,7 +25,7 @@ Mode.sbx 48 Flip.sbx 173 Sprite.sbx 442 Depth.sbx 672 -Lander.sbx 9201 +Lander.sbx 9361 Pad.sbx 264 Crash.sbx 632 vars.script 50 diff --git a/Tests/expected/cosmosDrives.out b/Tests/expected/cosmosDrives.out index bb360ba..e7abd2d 100644 --- a/Tests/expected/cosmosDrives.out +++ b/Tests/expected/cosmosDrives.out @@ -15,7 +15,7 @@ Mode.sbx 48 Flip.sbx 173 Sprite.sbx 442 Depth.sbx 672 -Lander.sbx 9201 +Lander.sbx 9361 Pad.sbx 264 Crash.sbx 632 vars.script 50 diff --git a/Tests/expected/cosmosFault.out b/Tests/expected/cosmosFault.out index faee994..144ec74 100644 --- a/Tests/expected/cosmosFault.out +++ b/Tests/expected/cosmosFault.out @@ -32,7 +32,7 @@ Mode.sbx 48 Flip.sbx 173 Sprite.sbx 442 Depth.sbx 672 -Lander.sbx 9201 +Lander.sbx 9361 Pad.sbx 264 Crash.sbx 632 vars.script 50 diff --git a/Tests/expected/cosmosFlip.out b/Tests/expected/cosmosFlip.out index 0636b2e..10601ec 100644 --- a/Tests/expected/cosmosFlip.out +++ b/Tests/expected/cosmosFlip.out @@ -22,7 +22,7 @@ Mode.sbx 48 Flip.sbx 173 Sprite.sbx 442 Depth.sbx 672 -Lander.sbx 9201 +Lander.sbx 9361 Pad.sbx 264 Crash.sbx 632 vars.script 50 diff --git a/Tests/expected/cosmosGrid.out b/Tests/expected/cosmosGrid.out index a5ced45..63655be 100644 --- a/Tests/expected/cosmosGrid.out +++ b/Tests/expected/cosmosGrid.out @@ -22,7 +22,7 @@ Mode.sbx 48 Flip.sbx 173 Sprite.sbx 442 Depth.sbx 672 -Lander.sbx 9201 +Lander.sbx 9361 Pad.sbx 264 Crash.sbx 632 vars.script 50 diff --git a/Tests/expected/cosmosMonitor.out b/Tests/expected/cosmosMonitor.out index 5a7856e..d813222 100644 --- a/Tests/expected/cosmosMonitor.out +++ b/Tests/expected/cosmosMonitor.out @@ -108,7 +108,7 @@ Mode.sbx 48 Flip.sbx 173 Sprite.sbx 442 Depth.sbx 672 -Lander.sbx 9201 +Lander.sbx 9361 Pad.sbx 264 Crash.sbx 632 vars.script 50 diff --git a/Tests/expected/cosmosMonitorRun.out b/Tests/expected/cosmosMonitorRun.out index 7d71961..7ba52d5 100644 --- a/Tests/expected/cosmosMonitorRun.out +++ b/Tests/expected/cosmosMonitorRun.out @@ -27,7 +27,7 @@ Mode.sbx 48 Flip.sbx 173 Sprite.sbx 442 Depth.sbx 672 -Lander.sbx 9201 +Lander.sbx 9361 Pad.sbx 264 Crash.sbx 632 vars.script 50 diff --git a/Tests/expected/cosmosRun.out b/Tests/expected/cosmosRun.out index 8dc4138..019ad4f 100644 --- a/Tests/expected/cosmosRun.out +++ b/Tests/expected/cosmosRun.out @@ -15,7 +15,7 @@ Mode.sbx 48 Flip.sbx 173 Sprite.sbx 442 Depth.sbx 672 -Lander.sbx 9201 +Lander.sbx 9361 Pad.sbx 264 Crash.sbx 632 vars.script 50 diff --git a/Tests/expected/cosmosSlowDisk.out b/Tests/expected/cosmosSlowDisk.out index cc42e68..c257bae 100644 --- a/Tests/expected/cosmosSlowDisk.out +++ b/Tests/expected/cosmosSlowDisk.out @@ -13,7 +13,7 @@ Mode.sbx 48 Flip.sbx 173 Sprite.sbx 442 Depth.sbx 672 -Lander.sbx 9201 +Lander.sbx 9361 Pad.sbx 264 Crash.sbx 632 vars.script 50 diff --git a/Tests/expected/cosmosSprite.out b/Tests/expected/cosmosSprite.out index 041a1a9..91490c4 100644 --- a/Tests/expected/cosmosSprite.out +++ b/Tests/expected/cosmosSprite.out @@ -22,7 +22,7 @@ Mode.sbx 48 Flip.sbx 173 Sprite.sbx 442 Depth.sbx 672 -Lander.sbx 9201 +Lander.sbx 9361 Pad.sbx 264 Crash.sbx 632 vars.script 50 diff --git a/Tests/video.sh b/Tests/video.sh index a943dd8..1fddc2d 100755 --- a/Tests/video.sh +++ b/Tests/video.sh @@ -3249,6 +3249,44 @@ PY2 )" [ "$LETTERS" = "16" ] && result ok "and does not rub out what it moves over" "all sixteen letters are still there" || result no "and does not rub out what it moves over" "$LETTERS of sixteen cells still have ink" +# ---- Running a program twice is the same as running it once ---- +# +# RUN DOES NOT RELOAD, and that is right: run's job is to run the program that is loaded, +# which is why it is a separate word from load and why typing a program's name does both. It +# follows that the numbers the assembler wrote into a Data Segment are LOAD-time values, true +# once - and a program that wants them true at every start has to say so itself. +# +# Lander did not. A second run began with Flying already nought, so the loop ended before it +# started and the program handed the machine straight back. Worse and quieter: the terrain +# seed is a written number, so a fresh load always walks out the same moon - but nextRandom +# moves it, and a second run generated a different moon, which was nobody's decision. +# +# THE CHECK IS THE WHOLE SCREEN, because that is the only thing that knows about all of it at +# once. A hundred frames in, run once and run twice have to be the same picture: the same +# moon, the same lander in the same place, the same gauges. Any state that survives a run and +# should not shows up here without anybody having to have thought of it in advance. +python3 -c " +open('$BUILD/once.keys','wb').write(b'Lander\n' + b'\x00'*100) +open('$BUILD/twice.keys','wb').write(b'Lander\n' + b'\x00'*100 + b'q' + b'\x00'*20 + b'run\n' + b'\x00'*100) +open('$BUILD/still.pad','wb').write(b'\x00' * 20000)" +for WHEN in once twice; do + timeout 60 "$EMU" --fast --cycles 24000000 --keyboard "$BUILD/$WHEN.keys" \ + --pad "$BUILD/still.pad" --screen "$BUILD/run$WHEN.ppm" \ + --disk "$ROOT/Tests/build/disks/cosmos.img" --ram-disk 2048 \ + "$BUILD/cosmos.bin" > "$BUILD/run$WHEN.out" 2>&1 || true +done +if [ ! -f "$BUILD/runonce.ppm" ] || [ ! -f "$BUILD/runtwice.ppm" ]; then + result no "a program run twice starts where it started" "no picture came out" +elif cmp -s "$BUILD/runonce.ppm" "$BUILD/runtwice.ppm"; then + result ok "a program run twice starts where it started" "the same screen a hundred frames in" +else + DIFFERS="$(python3 -c " +a = open('$BUILD/runonce.ppm','rb').read() +b = open('$BUILD/runtwice.ppm','rb').read() +print(sum(1 for x, y in zip(a, b) if x != y))")" + result no "a program run twice starts where it started" "$DIFFERS bytes of the picture differ" +fi + echo if [ "$FAIL" -eq 0 ]; then echo "All $PASS video checks passed."