The game

Hole in One Professional is HAL's second pass at their 1984 golf game. Where that one had a course, this has two; where that one loaded courses from tape, this one carries an editor inside; and where that one let you play alone or against a friend, this one sits you across from thirty-five real professionals.

Four lines, and all four come out of the binary:

line	variable	values
PLAYER	0xC003	1 or 2
LEVEL	0xC007	AVERAGE · EXPERT · PROFESSIONAL
GAME	0xC005	STROKE PLAY · MATCH PLAY · TOURNAMENT · CONSTRUCTION
COURSE	0xC004	QUEEN SIDE · KING SIDE · USER

USER only appears if a user course is loaded: 0x40EF and 0x40FD check (0xCED3) and, if it is zero, treat the line as if it had two values instead of three.

And the level is not cosmetic. It decides the speed of the power and curve bars (0x560A: one on AVERAGE, two on PROFESSIONAL), the width of the accuracy window (0x53B1 uses one window per club on AVERAGE and one per two clubs from EXPERT up), the scatter when playing out of rough (0x584C: 0x26 against 0x40) and the strength of the wind (0x7073 clears bit 6 on AVERAGE).

The two courses

course	par	length	par 3s	par 4s	par 5s
QUEEN SIDE	72	6,166 m	4	10	4
KING SIDE	72	6,290 m	4	10	4

Same par and same spread, and yet thirty-six different holes. KING SIDE is longer and, looking at them, a good deal harder: more water, narrower fairways and much more black — which is tile 0x00, and the game treats it as out of bounds.

The thirty-six scripts take 11,193 bytes in total, 311 on average per hole.

The shot

Three steps, and all three are the same machine with different limits:

the aim, which the joystick turns a degree at a time (0x54AF);
the power, a bar that runs up and down between 0 and 0x1C and that the trigger stops (0x55E6);
the curve, another bar between 0 and 0x38 (0x5676).

The power that comes off the bar is not the one used: the real one is (0xC641) × 8 + 0x1F, so there is a minimum you cannot take off. And what decides whether the ball flies straight is the window at 0x5495: two bytes per club, a low limit and a high one. If the curve bar stops below the first, the difference is stored as hook; above the second, as slice. Then, during the flight, 0x58F0 bends the angle a degree every so many frames.

There is no curve bar with the putter: 0x539F only plays it if the club is below 13.

The fifteen clubs

1W 2W 3W 4W | 3I 4I 5I 6I | 7I 8I 9I | PW SW PT PT

Three bytes per club at 0x4B16: the first groups the swing — 0x00 the woods, 0x04 and 0x08 the irons, 0x0C the wedges and putter — and the other two are the label's two letters. The last entry repeats PT, and it is not an oversight: on the fairway you can select club 13, and on the green the game forces 14 (0x5589).

And that same table, byte for byte, is inside the CONST file on the 1985 Hole In One Extension Course tape.

The modes

STROKE PLAY: count strokes and that is that.
MATCH PLAY: count holes won. 0x43BD tracks the lead (0xC074) and who has it (0xC073), and when the lead exceeds the holes remaining the match ends with its "3 AND 2" written out by hand at 0x4451.
TOURNAMENT: thirty-six entrants, thirty-five of them real professionals, with a live leaderboard.
CONSTRUCTION: the editor. It has its own page.

The keys

key	what it does
F1	shows the eighteen-hole scorecard
F2	the tournament leaderboard (the arrows page through it)
F10 then F6	back to the menu
STOP	cancels the shot being set up