Hyper Olympic 1 is the MSX conversion of Konami's athletics arcade machine, known in the West as Track & Field. You play it by hammering keys: two to run and one to jump or throw.
0xE016 runs from 1 to 4 and picks the event; 0xE015 counts up to twelve. So the four events, three times each. Photographed one by one in the emulator (medidas/pruebas.txt):
| event | record it shows | |
|---|---|---|
| 1 | 100 METER DASH | 09 SEC 95 |
| 2 | LONG JUMP | 08 M 90 |
| 3 | HAMMER THROW | 83 M 98 |
| 4 | 400 METER DASH | 43 SEC 86 |
The 400 metres does not exist in the arcade. Event 4 reuses event 1's screen list and scoreboard; the only thing that changes is the label on the board, and that label (0x6332) is the 100 metres one with its first glyph changed from "1" to "4". A new event for the price of one character.
Every round has a mark to beat, and they live in marcas_de_clasificacion (0x5008): two BCD bytes per round, which 0x4625 reads with 2*(round-1). They come out as
14.00 06.00 80.00 55.00
12.00 07.00 85.00 50.00
11.00 08.00 95.00 40.00The four events repeat three times and each lap tightens the screw: in the 100 metres you have to get under 14, then under 12, then under 11; in the long jump, past 6, 7 and 8 metres.
Fail to qualify and that is that. 0xE021 carries one bit per player saying whether they are still in, and 0xE022 who goes through to the next round.
In the throwing and jumping events there is not one run and done: there are four attempts. 0xE023/0xE024 count the ones used up per player and 0xE025/0xE026 the one under way. Each result goes in 0xE02A/0xE02B: 1 foul, 2 valid, 3 record.
When an attempt does not count, the scoreboard writes the foul label (rotulo_de_fallo, 0x5133), and two different places ask for it: 0x433A and 0x44D0.
The routine that counts the time (0x5695) adds 1.665 hundredths per frame, that is, one sixtieth of a second. It was worked out for a 60 Hz machine.
Measured with tools/omsx_reloj.tcl on both:
| machine | Hz | game clock per real second |
|---|---|---|
| Philips VG-8020 (PAL) | 50 | 0.8325 s |
| C-BIOS MSX1 JP (NTSC) | 60 | 0.9990 s |
On a European MSX, a "12.00" is really 14.4 seconds. And it is not that the game runs slow: it is that the clock counts short. The qualifying marks and the world records are meant for the Japanese machine.
Careful reading that backwards: it is a period, not a speed. The detail and the raw tables are in In the emulator.
0xE010 says whether two are playing and 0xE011 whose turn it is. When both run at once, 0x51AD looks at bit 0 of the frame counter: on even frames it moves player 1's athlete and on odd ones player 2's. Half the work per frame, and at 50 or 60 Hz nobody notices.
When nobody touches anything a demo starts. It does not carry a recorded game: the interrupt plays it, and the pilot is about as dumb as you can write. With 0xE002 at 1, the routine at 0x4030 drops into 0xE00B a value from ld a,r —the memory refresh register— masked to two bits, once every four frames. That is all of it: random keypresses.
There is one detail that misleads, and it is measured, not assumed. Bit 7 of 0xE029 looks like the demo switch, because 0x5849 sets it and 0x4030 reads it; but in the emulator (medidas/demo.txt) it is set the same in the demo and in a real game: 0xE029 holds 0x82 in both. The one in charge is 0xE002, which is 1 in the demo and 0 in a game, and is the first thing the interrupt looks at.
0xE004 says whether you play with joystick or keyboard, and 0xE005 carries what was read this frame: bit 0 up, bit 1 down, bit 4 space, bit 5 F5. With a joystick, the two buttons. For each player both the previous and the current controls are kept (0xE008-0xE00F), which is how you detect an edge rather than a held key — indispensable in a game built on mashing one.