The listing and every number on this site come from the binary and are reproducible with make. Nothing here was measured by eye. The emulator is for checking that what the listing says is what the cartridge does.
openmsx -machine Philips_VG_8020 -cart hypersports2.romAn MSX1 machine is enough: the cartridge maps into page 1 and drives everything from the frame interrupt.
| address | what it holds |
|---|---|
| 0xE000 | the state; 0xE001 the sub-state |
| 0xE005 | the latch that keeps the interrupt from re-entering |
| 0xE036 | non-zero while any of the three channels is playing |
| 0xE080 | the event: 0 skeet, 1 archery, 2 weight lifting, 3 records |
| 0xE1A1 | the step inside the event |
| 0xE1A3 | in the weight lifting, the lift given as good |
| 0xE063 | the points, three bytes of BCD |
To confirm a timing, put a breakpoint at a routine's entry and another at its ret, and take the difference of machine_info time — times 3579545 for Z80 cycles.
tools/omsx_capturas.tcl boots the cartridge, presses keys through the key matrix and takes screenshots. Its log writes the time, the PC and the state next to each shot, so a capture can be tied to the listing:
t= 21.91 foto tiro_03.png PC=0x58F3 estado=2
t= 44.92 foto tiro_05.png PC=0x445A estado=2The first PC falls inside MIRA_LOS_IMPACTOS (0x58E3), the skeet's; the second inside the VDP write helper, with the archery on screen. That is what settles the order of 0xE080: skeet first, archery second — and the ANGLE 0.00 and WIND readouts confirm which event is which without having to reason about it.
-script, the emulator starts with the renderer uninitialized, and screenshot returns a black PNG with a return code of zero. It has to be turned on by hand with set renderer SDLGL-PP.set throttle off the machine runs flat out and the renderer skips frames: ask for the capture with the throttle on and with after realtime, which is wall clock.type space types the word "space". The trigger is row 8 of the key matrix: keymatrixdown 8 0x01 for the bar, 0x10, 0x20, 0x40 and 0x80 for the four arrows./tmp.