Jet Set Willy Home -> Jet Set Willy 128 -> Henry's Hoard
Lynx/Arena/Mosaic friendly version
This file is mainly based on HENRYSHO.SNA, the earlier (1985) version. Differences in the later (1986) version are pointed out where they occur. If you want to write a game based on Henry's Hoard, you will need to use the 1986 version as the 1985 one has a buggy victory sequence.
Henry's Hoard is based on a modified Jet Set Willy engine; gameplay is almost identical to JSW, while the title screen, game over screen and lives display have been extensively modified. This document is intended to help people writing JSW editors or who want to base JSW games on Henry's Hoard.
It's a nuisance for me in one respect; my programs look for the "AIR" or "WRITETYPER" strings to detect a valid JSW snapshot, and Henry's Hoard has neither.
| Address | Versions | Comments | ||||||||
|---|---|---|---|---|---|---|---|---|---|---|
| 6000h | 1985 | Title screen, only shown before the game runs (since afterwards, the game buffers will have overwritten it). | ||||||||
| 7B00h | 1986 | The string "1 for joystick 0 for keyboard". | ||||||||
| 7B20h-7B4Ah | 1986 | Code to ask whether or not a joystick is present, and set the joystick flag accordingly. | ||||||||
| 8404h | Both | Game start code is at 8886h, not 869Fh. | ||||||||
| 840Ch | Both | The game code is stored on the tape in obfuscated form, and is unobfuscated by the code here. Therefore if you want do do any editing or disassembly, make sure you get a .SNA of the game after this has run. | ||||||||
| 8420h | Both | Normal JSW code resumes, but not for long... | ||||||||
| 8450h | Both | In JSW, this normally contains "AIR" and then the scrolling
message. In HH, this looks up a character in the font at 85E0h. |
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| 845Ah | Both | The code to play the new "treasure picked up" sound. | ||||||||
| 8475h | Both | This routine waits for a keypress while the second title screen is displayed. | ||||||||
| 848Eh | Both | Apparently unused | ||||||||
| 848Fh | Both | The frame count for the animated lives counter. | ||||||||
| 8490h | Both | The count of items collected - three ASCII bytes. | ||||||||
| 8493h | Both | Apparently unused | ||||||||
| 8494h | Both | Routine to clear the attributes to bright yellow on black. This overflows by one byte - see the printer buffer in HENRYSHO.SNA. | ||||||||
| 84A2h | Both | 14 spare bytes | ||||||||
| 84B0h | Both | An orphaned code fragment, or so it seems. | ||||||||
| 84B5h | Both | 75 spare bytes | ||||||||
| 8500h | Both | Change the sprite depending on the room number - more elaborate
than the Nightmare Room or storing the sprite number in the room
definition. Overrides are:
|
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| 8525h | Both | Save a screen shot | ||||||||
| 853Ch | Both | Tape header for saved screens | ||||||||
| 854Dh | Both | 126 spare bytes. Not only has the title screen scrolling message been overwritten, but also the "Items collected 000 Time 00:00 m" message, the "Game Over" message, the "7:00a" message and the "Enter code at grid location" messages. | ||||||||
| 85CBh | Both | Back to JSW. | ||||||||
| 85CEh | 1986 | Kempston joystick flag. In the early version this is always zero and the joystick support cannot be accessed; while in JSW proper the joystick is auto-detected. | ||||||||
| 85E0h | Both | Where you would normally expect to see the WRITETYPER check, title screen tune, game tune and copy protection code, there's a font, covering SPACE to Z. | ||||||||
| 87CAh | Both | Original JSW entry point. There's some orphaned code here to disable the standard infinite lives POKE. The original JSW title screen code has been completely overwritten. | ||||||||
| 87D7h | Both | The current character being scrolled into the title screen message. | ||||||||
| 87DFh | Both | Scroll the title screen message left by one pixel. | ||||||||
| 87F5h | Both | Bring the next row of pixels into the right-hand end of the scrolling message. | ||||||||
| 8812h | Both | Set the next character to be scrolled into the title screen message. | ||||||||
| 8825h | Both | Title screen loop - draw a scrolling message, lie back and think of England. If SPACE is pressed, jumps into the game. Returns at the end of the message. | ||||||||
| 8870h | 1985 | HH has three title screens, the first two only appearing the first time. The code here calls 9866h to draw the first, and waits for a keypress; then copies the second one from 6000h. | ||||||||
| 8870h | 1986 | This version of HH has two title screens. The code calls 9866h to draw the first, and then 7B20h to get the joystick choice. The code to draw what was the second title screen is NOPped out. | ||||||||
| 8886h | Both | The game is entered here from 8400h. It calls 8870h to do the
initial sequence; disables the standard infinite lives POKE; and
then we get the code that used to be at 87CAh. The initial room
number is now at 88B6h, and |
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| 888Fh | 1986 | The game reset code has been slightly rearranged. After the user chose keyboard / joystick, the game waits for a keypress (perhaps while the second title screen was supposed to be displayed). If this key is "C", there is a call to 8C01h. | ||||||||
| 88DEh | Both | Still initialising the game, clear the screen, set the border to 0, and call three subroutines. The first (9999h) resets some "room visited" flags, the second (989Dh) draws the final title screen, and the third (970Eh) draws the scrolling messages in k succession. | ||||||||
| 88FBh | Both | 12 spare bytes | ||||||||
| 8907h | Both | Copy in attributes for the bottom third of the screen, from 0F330h. | ||||||||
| 8912h | Both | JSW code resumes. | ||||||||
| 896Ch | Both | The code to draw the room name draws on a different screen line. | ||||||||
| 8971h | Both | Different code to draw the bottom third of the screen. | ||||||||
| 8984h | Both | Back to JSW code. | ||||||||
| 898Fh | Both | Animate the extra lives in a different place. | ||||||||
| 8999h | Both | Use the lives counter at 848Fh. | ||||||||
| 89A2h | Both | Use a different sprite to illustrate lives. | ||||||||
| 89A3h | Both | Back to JSW code. | ||||||||
| 8A3Ah | Both | The call to print the game clock has been NOPped out. | ||||||||
| 8A3Fh | Both | The code to increment the game clock has been removed. | ||||||||
| 8AABh | Both | Back to JSW code. | ||||||||
| 8ABBh | Both | The entire JSW "automatic pause" mechanism has been removed, and the death check which is at 8B17h in true JSW is now here. The remainder of this code is related to playing the in-game tune. | ||||||||
| 8AE4h | 1985 | 187 spare bytes | ||||||||
| 8AE4h | 1986 | The player death code (this is at 8C01h in the 1985 version and in JSW) | ||||||||
| 8B9Fh | Both | Back to JSW code, at the (now disused) WRITETYPER check. | ||||||||
| 8C1Ah | 1985 | These two changes are probably related to the change in the "lose a life" special effect. | ||||||||
| 8C30h | ||||||||||
| 8C01h | 1986 | Code to check for the string "AROL" (ie: the cheat word is
"CAROL"). If it is present, POKE the game engine for infinite lives
and fall-any-height ability. Note: Once the user has pressed the initial "C", they cannot continue until they type "AROL". Other letters are ignored! |
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| 8C34h | 1986 | Display a title-screen scrolling message - see 972Fh below. | ||||||||
| 8C39h | Both | The Game Over sequence is now in a different place. The following code replaces the original JSW game over sequence. | ||||||||
| 8C4Ah | Both | If 'G' is pressed, toggle the in-game tune (using self-modifying code). | ||||||||
| 8C65h | Both | 7 free bytes. | ||||||||
| 8C6Ch | Both | Check for the enable/disable in-game tune command; if it's enabled, play a note. | ||||||||
| 8C73h | Both | 7 free bytes. | ||||||||
| 8C86h | Both | A set of routines to play the GAME OVER tune, using the same jumptable technique as at 979Fh - 983Dh. | ||||||||
| 8D16h | Both | Redundant code to play the GAME OVER tune - not used. | ||||||||
| 8D33h | Both | Back to JSW code. | ||||||||
| 8E17h | Both | For playing some sound: border is always black, sound is shorter. | ||||||||
| 8E1Ah | Both | Back to JSW code. | ||||||||
| 8E86h | Both | Same as 8E17h. | ||||||||
| 8E8Ah | Both | Back to JSW code. | ||||||||
| 9252h | Both | Same as 8E17h. | ||||||||
| 9256h | Both | Back to JSW code. | ||||||||
| 9345h | Both | Don't know what this does. | ||||||||
| 93EEh | Both | The |
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| 93F7h | Both | Back to JSW code. | ||||||||
| 9409h | Both | Call to new treasure beep, old treasure beep NOPped out. | ||||||||
| 941Eh | Both | Back to JSW code. | ||||||||
| 9433h | Both | Treasures don't colour-cycle. | ||||||||
| 9538h | Both | The special-case code that draws Maria and the Bathroom toilet
has been replaced with the following:
|
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| 9566h | 1985 | The first byte of the victory code is overwritten by a RET
instruction. This causes the initial scrolling message to display
repeatedly until the computer is reset. What the code would have done is copied the image at F734h into the screen, then copied in attributes from the start of the ROM(!), waited for a keypress and saved the screen out to tape. |
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| 9566h | 1986 | Victory code. Copies the image at F734h into the top third of the screen, and sets the attributes to 6 (yellow on black). Waits for a keypress, saves the screen to tape, and then stops until the computer is reset. | ||||||||
| 958Bh | Both | Normal JSW code resumes (though it is unused until 95C8h). | ||||||||
| 962Dh | Both | Change in the attribute used for something - ropes? | ||||||||
| 9653h | Both | When generating the player sprite, call the check routines at 8500h (new sprites) and 99A7h (restore player lives). | ||||||||
| 9680h | Both | The JSW "print string" code has been adapted to use the custom font. JSW code replaced from here on includes: The original in-game tune playing code, the routine to reset the computer on incorrect code entry, and the title screen attributes. | ||||||||
| 96A2h | Both | Draw the pillar to the left of the lives display. | ||||||||
| 96D8h | Both | Draw the pillar to the right of the lives display. | ||||||||
| 970Eh | Both | Display three scrolling messages (one at 9F00h, one at AC80h, one at 9731h) in succession. More of this code is at AE44h. For some reason this routine uses the two-byte version of the LD (nn),HL opcodes. | ||||||||
| 972F | 1986 | In the 1985 version, the code at 971Bh drew a message at AC80h. It now draws one at FF34h. It then jumps to 8C34h to draw the message at AC80h. | ||||||||
| 9731h | Both | Scrolling message as mentioned above. | ||||||||
| 979Fh | Both | A table of BEEP routines, each 8 bytes long. The in-game tune at F200h consists of indexes into this table. | ||||||||
| 980Fh | Both | Get the next note of the in-game tune, and play it. | ||||||||
| 9852h | Both | Draw the bottom third of the screen. | ||||||||
| 9866h | Both | Clear the screen and draw the first title screen. | ||||||||
| 989Dh | Both | Clear the screen and draw the third title screen. Rather than returning, jumps to AE51h which changes the attributes to yellow and magenta. AE51h in turn jumps to AEA7h which draws some more messages at the top. | ||||||||
| 98BCh | Both | Draw the Game Over screen. | ||||||||
| 9908h | Both | Print "CHOW". Not used. | ||||||||
| 991Eh | Both | Clear the screen to black. | ||||||||
| 992Ch | Both | Does nothing more than call 8494h - clear attributes. | ||||||||
| 9937h | Both | Set the top two-thirds of the screen to bright green on black, and the bottom third to cyan. As 8494h, overflows its buffer. | ||||||||
| 9999h | Both | Resets "room visited" flags used by next routine. | ||||||||
| 99A7h | Both | The first time the player visits rooms 41, 35, 27 or 18, their lives are restored. | ||||||||
| 99F2h | Both | Title screen scrolling message; first byte is its length, and the rest is the text; add 32 to get the correct ASCII value. | ||||||||
| 9AB6h | Both | Spare up to 9B00h. | ||||||||
| 9B00h | Both | Three sprite pages:
|
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| 9E00h | Both | Don't know. | ||||||||
| 9F00h | Both | First scrolling message for routine at 970Eh | ||||||||
| A000h | Both | Guardian table | ||||||||
| A3FFh | Both | Object table | ||||||||
| A600h | Both | Sprite pages:
|
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| AC80h | Both | Second scrolling message for routine at 970Eh. | ||||||||
| AD00h | Both | Sprite page (first frame blank in 1985 version) for Chuckie Egg protagonist | ||||||||
| AE00h | Both | Sprite for bell (2 frames only) | ||||||||
| AE44h | Both | Wedged into a sprite page, code there wasn't room for elsewhere. The routine at AE44h (along with that at 970Eh) displays three scrolling messages while waiting for a keypress. | ||||||||
| AE51h | Both | Part of drawing the third and final title screen. | ||||||||
| AE70h | Both | Third title screen, messages | ||||||||
| AEA7h | Both | Third title screen, code to print the messages at AE70h. | ||||||||
| AF00h | Both | Remaining sprites | ||||||||
| C000h | Both | Rooms 0-49. | ||||||||
| F200h | Both | In-game tune. Note numbers are indexes into a table of calls to the BEEP routine in the ROM; that table being at 979Fh. Each call is 8 bytes long, so these numbers will usually be a multiple of 8. The tune ends with 0FFh. | ||||||||
| F2F5h | Both | Tune for GAME OVER screen. | ||||||||
| F330h | Both | Bottom third of screen: Attributes to use in the game. | ||||||||
| F430h | Both | Seems to be unused. | ||||||||
| F500h | Both | Room 53. | ||||||||
| F600h | Both | Seems to be unused. | ||||||||
| F606h | Both | Text messages used by the game. | ||||||||
| F722h | Both | The gnomic message "EALLY LIKE DARK S" - unused. | ||||||||
| F734h | Both | Victory screen (top third, in Spectrum format); displayed only in the later version. | ||||||||
| FF34h | 1986 | Another scrolling message for the title screen (1986 version); unused in the 1985 version. | ||||||||
| FFFEh | Both | Border colour is saved here during beeps. | ||||||||
| FFFFh | Both | Index into the in-game tune. |